Variable Interest Entities

Consolidated variable interest entities-TPDI and ADDCL, joint venture companies in which we hold interests, were formed to own and operate certain ultra-deepwater drillships. We have determined that each of these joint venture companies meets the criteria of a variable interest entity for accounting purposes because their equity at risk is insufficient to permit them to carry on their activities without additional subordinated financial support from us. We have also determined, in each case, that we are the primary beneficiary for accounting purposes since (a) we have the power to direct the construction, marketing and operating activities, which are the activities that most significantly impact each entity's economic performance, and (b) we have the obligation to absorb a majority of the losses or the right to receive a majority of the benefits that could be potentially significant to the variable interest entity. As a result, we consolidate TPDI and ADDCL in our consolidated financial statements, we eliminate intercompany transactions, and we present the interests that are not owned by us as noncontrolling interest on our consolidated balance sheets. The carrying amounts associated with these joint venture companies, after eliminating the effect of intercompany transactions, were as follows (in millions):

	December 31, 2010						December 31, 2009
	Assets		Liabilities		Net carrying amount		Assets		Liabilities		Net carrying amount
Variable interest entity
TPDI	$	1,598	$	763	$	835	$	1,500	$	763	$	737
ADDCL		864		345		519		582		482		100
Total	$	2,462	$	1,108	$	1,354	$	2,082	$	1,245	$	837

At December 31, 2010 and 2009, the aggregate carrying amount of assets of our consolidated variable interest entities that were pledged as security for the outstanding debt of our consolidated variable interest entities was $2,191 million and $1,975 million, respectively. See Note 11-Debt.

Pacific Drilling Limited ("Pacific Drilling"), a Liberian company, owns the 50 percent interest in TPDI that is not owned by us, and we present its interest in TPDI as noncontrolling interest on our consolidated balance sheets. Beginning on October 18, 2010, Pacific Drilling had the unilateral right to exchange its interest in TPDI for our shares or cash, at its election, at an amount based on an appraisal of the fair value of the drillships, subject to certain adjustments. Accordingly, when this option became exercisable, we reclassified the carrying amount of Pacific Drilling's interest from permanent equity to temporary equity, located between liabilities and equity on our consolidated balance sheets, since the event that gives rise to a potential redemption of the noncontrolling interest is not within our control. See Note 15-Redeemable Noncontrolling Interest.

Unconsolidated variable interest entities-In January 2010, we completed the sale of two Midwater Floaters, GSF Arctic II and GSF Arctic IV, to subsidiaries of Awilco Drilling Limited ("ADL"), a U.K. company (see Note 9-Drilling Fleet). We have determined that ADL meets the criteria of a variable interest entity for accounting purposes because its equity at risk is insufficient to permit it to carry on its activities without additional subordinated financial support. We have also determined that we are not the primary beneficiary for accounting purposes since, although we hold a significant financial interest in the variable interest entity and have the obligation to absorb losses or receive benefits that could be potentially significant to the variable interest entity, we do not have the power to direct the marketing and operating activities, which are the activities that most significantly impact the entity's economic performance.

In connection with the sale, we received net cash proceeds of $38 million and non-cash proceeds in the form of two notes receivable in the aggregate amount of $165 million. The notes receivable, which are secured by the drilling units, have stated interest rates of 9 percent and are payable in scheduled quarterly installments of principal and interest through maturity in January 2015 (see Note 19-Fair Values of Financial Instruments). We have also committed to provide ADL with a working capital loan, which is also secured by the drilling units, with a maximum borrowing amount of $35 million. Additionally, we operated GSF Arctic IV under a short-term bareboat charter with ADL, until November 2010. We evaluate the credit quality and financial condition of ADL quarterly. At December 31, 2010, the notes receivable and working capital loan receivable had no amounts past due and had aggregate carrying amounts of $109 million and $6 million, respectively.

Disclosure of variable interest entities (VIE), including, but not limited to the nature, purpose, size, and activities of the VIE, the carrying amount and classification of consolidated assets that are collateral for the VIE's obligations, lack of recourse if creditors (or beneficial interest holders) of a consolidated VIE have no recourse to the general credit of the primary beneficiary. An enterprise that holds a significant variable interest in a VIE but is not the primary beneficiary may disclose the nature of its involvement with the VIE and when that involvement began, the nature, purpose, size, and activities of the VIE and the enterprise's maximum exposure to loss as a result of its involvement with the VIE.

+ References+ Details

Impairments	12 Months Ended
Impairments	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Impairments	Long-lived assets-During the year ended December 31, 2010, we determined that the Standard Jackup asset group in our contract drilling services reporting unit was impaired due to projected declines in dayrates and utilization. We measured the fair value of this asset group by applying a combination of income and market approaches, using projected discounted cash flows and estimates of the exchange price that would be received for the assets in the principal or most advantageous market for the assets in an orderly transaction between market participants as of the measurement date. Our valuation utilized the projection of the future performance of the asset group based on unobservable inputs that require significant judgment for which there is little or no market data, including assumptions regarding long-term projections for future revenues and costs, dayrates, rig utilization and idle time. As a result, we determined that the carrying amount of the Standard Jackup asset group exceeded its fair value, and we recognized a loss on impairment of long-lived assets in the amount of $1.0 billion ($3.15 per diluted share), which had no tax effect, during the year ended December 31, 2010. Goodwill and other indefinite-lived intangible assets-As a result of interim impairment testing in the year ended December 31, 2010, we determined that the goodwill associated with our oil and gas properties reporting unit was impaired. Accordingly, we recognized a loss on impairment of the full carrying amount of the goodwill associated with the reporting unit in the amount of $2 million ($0.01 per diluted share), which had no tax effect. As a result of our annual impairment testing in the year ended December 31, 2008, we determined that the goodwill associated with our drilling management services reporting unit was impaired. Accordingly, we recognized a loss on impairment of the full carrying amount of goodwill associated with this reporting unit in the amount of $176 million ($0.55 per diluted share), which had no tax effect. During the years ended December 31, 2009 and 2008, we determined that the trade name intangible asset associated with our drilling management services reporting unit was impaired due to market conditions resulting from the global economic downturn and continued pressure on commodity prices. We estimated the fair value of the trade name intangible asset using the relief from royalty method, a valuation methodology that applies the income approach. Our valuation required us to project the future performance of the drilling management services reporting unit based on unobservable inputs that require significant judgment for which there is little or no market data, including assumptions for future commodity prices, projected demand for our services, rig availability and dayrates. As a result of our evaluations in each of the years ended December 31, 2009 and 2008, we determined that the carrying amount of the trade name intangible asset exceeded its fair value, and we recognized a loss on impairment of $6 million ($0.02 per diluted share, which had no tax effect) and $31 million ($20 million or $0.06 per diluted share, net of tax), respectively. The carrying amount of the trade name intangible asset, recorded in other assets on our consolidated balance sheets, was $39 million at both December 31, 2010 and December 31, 2009. Definite-lived intangible assets-During the years ended December 31, 2009 and 2008, we determined that the customer relationships intangible asset associated with our drilling management services reporting unit was impaired due to market conditions resulting from the global economic downturn and continued pressure on commodity prices. We estimated the fair value of the customer relationships intangible asset using the multiperiod excess earnings method, a valuation methodology that applies the income approach. Our valuation required us to project the future performance of the drilling management services reporting unit based on unobservable inputs that require significant judgment for which there is little or no market data, including assumptions for future commodity prices, projected demand for our services, rig availability and dayrates. As a result of our evaluations in each of the years ended December 31, 2009 and 2008, we determined that the carrying amount of the customer relationships intangible asset exceeded its fair value and recognized a loss on impairment of $49 million ($0.15 per diluted share, which had no tax effect) and $16 million ($11 million or $0.04 per diluted share, net of tax), respectively. There was no impairment for the year ended December 31, 2010. The carrying amount of the customer relationships intangible asset, recorded in other assets on our consolidated balance sheets was $59 million and $64 million at December 31, 2010 and 2009, respectively. Assets held for sale-During the years ended December 31, 2009 and 2008, we determined that GSF Arctic II and GSF Arctic IV, both classified as assets held for sale, were impaired due to the global economic downturn and pressure on commodity prices, both of which had an adverse effect on our industry. We estimated the fair values of these rigs based on an exchange price that would be received for the assets in the principal or most advantageous market for the assets in an orderly transaction between market participants as of the measurement date and considering our undertakings to the Office of Fair Trading in the U.K. ("OFT") that required the sale of the rigs with certain limitations and in a limited amount of time. We based our estimates on unobservable inputs that require significant judgment, for which there is little or no market data, including non-binding price quotes from unaffiliated parties, considering the then-current market conditions and restrictions imposed by the OFT. For each of the years ended December 31, 2009 and 2008, as a result of our evaluation, we recognized a loss on impairment of $279 million ($0.87 per diluted share) and $97 million ($0.30 per diluted share), respectively, which had no tax effect. The carrying amount of assets held for sale was $186 million at December 31, 2009, and these assets were sold in the year ended December 31, 2010. See Note 9-Drilling Fleet.

Income Taxes

12 Months Ended

Dec. 31, 2010

Income Taxes

Tax Provision-Transocean Ltd., a holding company and Swiss resident, is exempt from cantonal and communal income tax in Switzerland, but is subject to Swiss federal income tax. At the federal level, qualifying net dividend income and net capital gains on the sale of qualifying investments in subsidiaries are exempt from Swiss federal income tax. Consequently, Transocean Ltd. expects dividends from its subsidiaries and capital gains from sales of investments in its subsidiaries to be exempt from Swiss federal income tax.

We conduct operations through our various subsidiaries in a number of countries throughout the world, all of which have taxation regimes with varying nominal rates, deductions, credits and other tax attributes. Our provision for income taxes is based on the tax laws and rates applicable in the jurisdictions in which we operate and earn income. There is little to no expected relationship between the provision for or benefit from income taxes and income or loss before income taxes considering, among other factors, (a) changes in the blend of income that is taxed based on gross revenues versus income before taxes, (b) rig movements between taxing jurisdictions and (c) our rig operating structures.

The components of our provision (benefit) for income taxes were as follows (in millions):

	Years ended December 31,
	2010			2009			2008
Current tax expense	$	456		$	741		$	735
Deferred tax expense (benefit)		(145	)		13			8
Income tax expense	$	311		$	754		$	743

Effective tax rate		23.9	%		19.2	%		15.6	%

We are subject to changes in tax laws, treaties and regulations in and between the countries in which we operate, or in which we are incorporated or resident. A material change in these tax laws, treaties or regulations could result in a higher or lower effective tax rate on our worldwide earnings.

A reconciliation of the differences between our income tax expense computed at the Swiss holding company statutory rate of 7.83 percent and our reported provision for income taxes for the years ended December 31, 2010 and 2009, was as follows (in millions):

	Years ended December 31,
	2010			2009
Income tax expense at the federal statutory rate	$	102		$	307
Taxes on earnings subject to rates greater than the Swiss rate		89			321
Taxes on impairment loss subject to rates less than the Swiss rate		79			-
Changes in unrecognized tax benefits		71			135
Change in valuation allowance		(4	)		46
Benefit from foreign tax credits		(23	)		(49	)
Other, net		(3	)		(6	)
Income tax expense	$	311		$	754

For the year ended December 31, 2008, our parent holding company was a Cayman Islands company and our earnings were not subject to income tax in the Cayman Islands because the country does not levy tax on corporate income. As a result, we have not presented a reconciliation of the differences between the income tax provision computed at the statutory rate and the reported provision for income taxes for this period.

The significant components of our deferred tax assets and liabilities were as follows (in millions):

	December 31,
	2010			2009
Deferred tax assets
Drilling contract intangibles	$	6		$	14
Net operating loss carryforwards		114			135
Tax credit carryforwards		29			29
Accrued payroll expenses not currently deductible		72			74
Deferred income		84			74
Other		61			29
Valuation allowance		(94	)		(98	)
Total deferred tax assets		272			257

Deferred tax liabilities
Depreciation and amortization		(699	)		(834	)
Drilling management services intangibles		(26	)		(27	)
Other		(26	)		(18	)
Total deferred tax liabilities		(751	)		(879	)

Net deferred tax liabilities	$	(479	)	$	(622	)

Our deferred tax assets include U.S. foreign tax credit carryforwards of $29 million, which will expire between 2015 and 2020. Deferred tax assets related to our NOLs were generated in various worldwide tax jurisdictions. The tax effect of our Brazilian NOLs, which do not expire, was $53 million and $59 million at December 31, 2010 and 2009, respectively. On December 31, 2009, our unrecognized U.S. capital loss carryforward expired. We did not recognize a deferred tax asset for the capital loss carryforward, as it was not probable that we would realize the benefit of this tax attribute. Our operations do not normally generate capital gain income, which is the only type of income that may be offset by capital losses. Certain activities related to the TODCO tax sharing agreement also serve to increase or decrease the capital loss carryforward.

For the year ended December 31, 2010, the valuation allowance against our non-current deferred tax assets did not change significantly. For the year ended December 31, 2009, the valuation allowance against our non-current deferred tax assets increased from $52 million to $98 million, resulting primarily from reassessments of valuation allowances, as well as the corresponding NOLs associated with our Brazil operations.

Our deferred tax liabilities include taxes related to the earnings of certain subsidiaries that are not permanently reinvested or that will not be permanently reinvested in the future. Should our expectations change regarding future tax consequences, we may be required to record additional deferred taxes that could have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

We consider the earnings of certain of our subsidiaries to be indefinitely reinvested. As such, we have not provided for taxes on these unremitted earnings. Should we make a distribution from the unremitted earnings of these subsidiaries, we would be subject to taxes payable to various jurisdictions. At December 31, 2010, the amount of indefinitely reinvested earnings was approximately $2.0 billion. If all of these indefinitely reinvested earnings were distributed, we would be subject to estimated taxes of $150 million to $200 million.

Tax returns-We file federal and local tax returns in several jurisdictions throughout the world. With few exceptions, we are no longer subject to examinations of our U.S. and non-U.S. tax matters for years prior to 1999. For the years ended December 31, 2010 and December 31, 2009, the amount of current tax benefit recognized from the settlement of disputes with tax authorities and from the expiration of statutes of limitations was insignificant.

Our tax returns in the other major jurisdictions in which we operate are generally subject to examination for periods ranging from three to six years. We have agreed to extensions beyond the general examination periods in four major jurisdictions for up to 16 years. Tax authorities in certain jurisdictions are examining our tax returns and in some cases have issued assessments. We are defending our tax positions in those jurisdictions. While we cannot predict or provide assurance as to the final outcome of these proceedings, we do not expect the ultimate liability to have a material adverse effect on our consolidated statement of financial position, or results of operations, although it may have a material adverse effect on our consolidated cash flows.

The following is a reconciliation of our unrecognized tax benefits, excluding interest and penalties (in millions):

	Years ended December 31,
		2010			2009			2008
Balance, beginning of period	$	460		$	372		$	299
Additions for current year tax positions		46			64			46
Additions for prior year tax positions		9			62			67
Reductions for prior year tax positions		(11	)		(22	)		(36	)
Settlements		(17	)		(3	)		(3	)
Reductions related to statute of limitation expirations		(2	)		(13	)		(1	)
Balance, end of period	$	485		$	460		$	372

The liabilities related to our unrecognized tax benefits, including related interest and penalties that we recognize as a component of income tax expense, were as follows (in millions):

	December 31,
		2010		2009
Unrecognized tax benefits, excluding interest and penalties	$	485	$	460
Interest and penalties		235		200
Unrecognized tax benefits, including interest and penalties	$	720	$	660

For the years ended December 31, 2010, 2009 and 2008, we recognized interest and penalties related to our unrecognized tax benefits, recorded as a component of income tax expense, in the amount of $35 million, $51 million and $24 million, respectively. If recognized, $693 million of our unrecognized tax benefits, including interest and penalties, as of December 31, 2010, would favorably impact our effective tax rate.

It is reasonably possible that our existing liabilities for unrecognized tax benefits may increase or decrease in the year ending December 31, 2011 primarily due to the progression of open audits or the expiration of statutes of limitation. However, we cannot reasonably estimate a range of potential changes in our existing liabilities for unrecognized tax benefits due to various uncertainties, such as the unresolved nature of various audits.

Tax positions-With respect to our 2004 and 2005 U.S. federal income tax returns, the U.S. tax authorities have withdrawn all of their previously proposed tax adjustments, except a claim regarding transfer pricing for certain charters of drilling rigs between our subsidiaries, resulting in a total proposed adjustment of approximately $79 million, excluding interest. We believe an unfavorable outcome on this assessment with respect to 2004 and 2005 activities would not result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. Although we believe the transfer pricing for these charters is materially correct, we have been unable to reach a resolution with the tax authorities. In August 2010, we filed a petition with the U.S. Tax Court to resolve this issue.

In May 2010, we received an assessment from the U.S. tax authorities related to our 2006 and 2007 U.S. federal income tax returns. In July 2010, we filed a protest letter with the U.S. tax authorities covering this assessment. The significant issues raised in the assessment relate to transfer pricing for certain charters of drilling rigs between our subsidiaries and the creation of intangible assets resulting from the performance of engineering services between our subsidiaries. These two items would result in net adjustments of approximately $278 million of additional taxes, excluding interest. An unfavorable outcome on these adjustments could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. We believe our returns are materially correct as filed, and we intend to continue to vigorously defend against all such claims.

In addition, the May 2010 assessment included adjustments related to a series of restructuring transactions that occurred between 2001 and 2004. These restructuring transactions impacted our basis in our former subsidiary TODCO, which we disposed of in 2004 and 2005. The authorities are disputing the amount of capital losses that resulted from the disposition of TODCO. We utilized a portion of the capital losses to offset capital gains on our 2006, 2007, 2008 and 2009 tax returns. The majority of the capital losses were unutilized and expired on December 31, 2009. The adjustments would also impact the amount of certain net operating losses and other carryovers into 2006 and later years. The authorities are also contesting the characterization of certain amounts of income received in 2006 and 2007 as capital gain and thus the availability of the capital gain for offset by the capital loss. These claims with respect to our U.S. federal income tax returns for 2006 through 2009 could result in net tax adjustments of approximately $295 million. An unfavorable outcome on these potential adjustments could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. We believe that our tax returns are materially correct as filed, and we intend to vigorously defend against any potential claims.

The May 2010 assessment also included certain claims with respect to withholding taxes and certain other items resulting in net tax adjustments of approximately $166 million, exclusive of interest. In addition, the tax authorities assessed penalties associated with the various tax adjustments in the aggregate amount of approximately $92 million, exclusive of interest. We believe that our tax returns are materially correct as filed, and we intend to vigorously defend against any potential claims.

Norwegian civil tax and criminal authorities are investigating various transactions undertaken by our subsidiaries in 2001 and 2002 as well as the actions of certain of our former external advisors on these transactions. The authorities issued tax assessments of (a) approximately $268 million plus interest, related to certain restructuring transactions, (b) approximately $117 million plus interest, related to the migration of a subsidiary that was previously subject to tax in Norway, (c) approximately $71 million plus interest, related to a 2001 dividend payment and (d) approximately $7 million plus interest, related to certain foreign exchange deductions and dividend withholding tax. We have filed or expect to file appeals to these tax assessments. We may be required to provide some form of financial security, in an amount up to $1.0 billion, including interest and penalties, for these assessed amounts as this dispute is appealed and addressed by the Norwegian courts. The authorities have indicated that they plan to seek penalties of 60 percent on all matters. For these matters, we believe our returns are materially correct as filed, and we have and will continue to respond to all information requests from the Norwegian authorities. We intend to vigorously contest any assertions by the Norwegian authorities in connection with the various transactions being investigated. An unfavorable outcome on these Norwegian civil tax matters could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. While we cannot predict or provide assurance as to the final outcome of these proceedings, we do not expect the ultimate resolution of these matters to have a material adverse effect on our consolidated statement of financial position or results of operations, although it may have a material adverse effect on our consolidated cash flows.

The Norwegian authorities issued notification of criminal charges against Transocean Ltd. and certain of its subsidiaries related to disclosures included in one of our Norwegian tax returns. This notification, however, does not itself constitute an indictment under Norwegian law nor does it initiate legal proceedings but represents a formal expression of suspicion and continued investigation. All income taxes, interest charges and penalties related to this Norwegian tax return have previously been settled. We believe that these charges are without merit and plan to vigorously defend Transocean Ltd. and its subsidiaries to the fullest extent.

Certain of our Brazilian income tax returns for the years 2000 through 2004 are currently under examination. The Brazilian tax authorities have issued tax assessments totaling $115 million, plus a 75 percent penalty of $86 million and $138 million of interest through December 31, 2010. An unfavorable outcome on these proposed assessments could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. We believe our returns are materially correct as filed, and we are vigorously contesting these assessments. On January 25, 2008, we filed a protest letter with the Brazilian tax authorities, and we are currently engaged in the appeals process.

Earnings Per Share

12 Months Ended

Dec. 31, 2010

Earnings Per Share

The reconciliation of the numerator and denominator used for the computation of basic and diluted earnings per share is as follows (in millions, except per share data):

	Years ended December 31,
	2010						2009						2008
	Basic			Diluted			Basic			Diluted			Basic			Diluted
Numerator for earnings per share
Net income attributable to controlling interest	$	961		$	961		$	3,181		$	3,181		$	4,031		$	4,031
Undistributed earnings allocable to participating securities		(5	)		(5	)		(18	)		(18	)		(10	)		(10	)
Net income available to shareholders	$	956		$	956		$	3,163		$	3,163		$	4,021		$	4,021

Denominator for earnings per share
Weighted-average shares outstanding		320			320			320			320			318			318
Effect of dilutive securities:
Stock options and other share-based awards		-			-			-			1			-			2
Stock warrants		-			-			-			-			-			1
Weighted-average shares for per share calculation		320			320			320			321			318			321

Earnings per share	$	2.99		$	2.99		$	9.87		$	9.84		$	12.63		$	12.53

For the years ended December 31, 2010, 2009 and 2008 we have excluded 2.2 million, 1.7 million and 0.4 million share-based awards, respectively, from the calculation since the effect would have been anti-dilutive.

The 1.625% Series A Convertible Senior Notes, 1.50% Series B Convertible Senior Notes and 1.50% Series C Convertible Senior Notes did not have an effect on the calculation for the periods presented. See Note 11-Debt.

Other Comprehensive Income

12 Months Ended

Dec. 31, 2010

Other Comprehensive Income

The allocation of other comprehensive income (loss) attributable to controlling interest and to noncontrolling interest was as follows (in millions):

		Years ended December 31,
		2010									2009								2008
		Controlling interest			Non-controlling interest (a)			Total			Controlling interest			Non-controlling interest (a)		Total			Controlling interest			Non-controlling interest (a)		Total
Unrecognized components of net periodic benefit costs	$	(8	)	$	-		$	(8	)	$	37		$	-	$	37		$	(388	)	$	-	$	(388	)
Recognized components of net periodic benefit costs		16			-			16			24			-		24			5			-		5
Unrecognized gain (loss) on derivative instruments		(10	)		(19	)		(29	)		(4	)		2		(2	)		(1	)		-		(1	)
Recognized (gain) loss on derivative instruments		14			(2)			12			3			3		6			-			-		-
Other, net		-			-			-			1			-		1			(3	)		-		(3	)

Other comprehensive income (loss) before income taxes		12			(21	)		(9	)		61			5		66			(387	)		-		(387	)
Income taxes related to other comprehensive income		(9	)		-			(9	)		24			-		24			9			-		9
Other comprehensive income (loss), net of tax	$	3		$	(21	)	$	(18	)	$	85		$	5	$	90		$	(378	)	$	-	$	(378	)

______________________________

(a)	Includes amounts attributable to noncontrolling interest and redeemable noncontrolling interest.

The components of accumulated other comprehensive income (loss), net of tax, were as follows (in millions):

	December 31, 2010									December 31, 2009
		Controlling interest			Non-controlling interest			Redeemable non-controlling interest			Controlling interest			Non-controlling interest		Redeemable non-controlling interest
Unrecognized components of net periodic benefit costs (a)	$	(335	)	$	-		$	-		$	(334	)	$	-	$	-
Unrecognized gain (loss) on derivative investments		5			(3	)		(13	)		1			5		-
Unrealized loss on marketable securities		(2	)		-			-			(2	)		-		-
Accumulated other comprehensive income (loss)	$	(332	)	$	(3	)	$	(13	)	$	(335	)	$	5	$	-

______________________________

(a)	Amounts are net of income tax effect of $36 million and $45 million for December 31, 2010 and 2009, respectively.

This label may include the following: 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. Components of comprehensive income include: (1) foreign currency translation adjustments; (2) gains and losses on foreign currency transactions that are designated as, and are effective as, economic hedges of a net investment in a foreign entity; (3) gains and losses on intercompany foreign currency transactions that are of a long-term-investment nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; (4) change in the market value of a futures contract that qualifies as a hedge of an asset reported at fair value; (5) unrealized holding gains and losses on available-for-sale securities and that resulting from transfers of debt securities from the held-to-maturity category to the available-for-sale category; (6) a net loss recognized as an additional pension liability not yet recognized as net periodic pension cost; and (7) the net gain or loss and net prior service cost or credit for pension plans and other postretirement benefit plans.

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Drilling Fleet

12 Months Ended

Dec. 31, 2010

Drilling Fleet

Expansion-Construction work in progress, recorded in property and equipment, was $1.5 billion and $3.7 billion at December 31, 2010 and 2009, respectively. The following table presents actual capital expenditures and other capital additions, including capitalized interest, for our remaining major construction projects for the three years ended December 31, 2010 (in millions):

	Years ended December 31,
	2010		2009		2008		2007 - 2006		Total
Deepwater Champion (a)	$	206	$	263	$	155	$	109	$	733
Discoverer India (b)		203		291		250		-		744
Discoverer Luanda (b) (c)		174		220		208		107		709
Transocean Honor (d)		97		-		-		-		97
Dhirubhai Deepwater KG2 (b) (e)		36		371		91		179		677
Development Driller III (b) (a)		24		117		133		350		624
Discoverer Inspiration (b)		12		224		205		238		679
High-Specification Jackup TBN1 (f)		9		-		-		-		9
High-Specification Jackup TBN2 (f)		9		-		-		-		9
Discoverer Americas (b)		6		148		167		311		632
Discoverer Clear Leader (b)		6		115		107		409		637
Petrobras 10000 (b) (g)		6		735		-		-		741
Dhirubhai Deepwater KG1 (b) (e)		-		295		105		279		679
Sedco 700-series upgrades (b)		-		71		124		396		591
Capitalized interest		89		182		147		93		511
Mobilization costs		89		155		-		-		244
Total	$	966	$	3,187	$	1,692	$	2,471	$	8,316

______________________________

(a)	These costs include our initial investment in Deepwater Champion of $109 million and our initial investment in Development Driller III of $350 million, representing the estimated fair value of the rig at the time of our merger with GlobalSantaFe in November 2007.

(b)	The accumulated construction costs of these rigs are no longer included in construction work in progress, as their construction projects had been completed as of December 31, 2010.

(c)	The costs for Discoverer Luanda represent 100 percent of expenditures incurred since inception. ADDCL is responsible for all of these costs. We hold a 65 percent interest in ADDCL, and Angco Cayman Limited holds the remaining 35 percent interest.

(d)

In November 2010, we made an initial installment payment of $97 million to purchase a PPL Pacific Class 400 design jackup, to be named Transocean Honor, for $195 million. The High-Specification Jackup is under construction at PPL Shipyard Pte Ltd. in Singapore and is expected for delivery in the fourth quarter of 2011.

(e)

The costs for Dhirubhai Deepwater KG1 and Dhirubhai Deepwater KG2 represent 100 percent of TPDI's expenditures, including those incurred prior to our investment in the joint venture. TPDI is responsible for all of these costs. We hold a 50 percent interest in TPDI, and Pacific Drilling holds the remaining 50 percent interest.

(f)

In December 2010, we made initial installment payments of $9 million each, to purchase two Keppel FELS Super B class design jackups for $186 million each. The two High-Specification Jackups are under construction at Keppel FELS yard in Singapore and are expected for delivery in the fourth quarter of 2012.

(g)

In June 2008, we reached an agreement with a joint venture formed by subsidiaries of Petrobras and Mitsui to acquire Petrobras 10000 under a capital lease contract. In connection with the agreement, we agreed to provide assistance and advisory services for the construction of the rig and operating management services once the rig commenced operations. On August 4, 2009, we accepted delivery of Petrobras 10000 and recorded non-cash additions of $716 million to property and equipment, net, along with a corresponding increase to long-term debt. Total capital additions include $716 million in capital costs incurred by Petrobras and Mitsui for the construction of the drillship and $19 million of other capital expenditures. The capital lease agreement has a 20-year term, after which we will have the right and obligation to acquire the drillship for one dollar. See Note 11-Debt and Note 14-Commitments and Contingencies.

In March 2010, we acquired GSF Explorer, an asset formerly held under capital lease, in exchange for a cash payment in the amount of $15 million, terminating the capital lease obligation. See Note 11-Debt.

Dispositions-During the year ended December 31, 2010, we completed the sale of two Midwater Floaters, GSF Arctic II and GSF Arctic IV. In connection with the sale, we received net cash proceeds of $38 million and non-cash proceeds in the form of two notes receivable in the aggregate amount of $165 million (see Note 4-Variable Interest Entities and Note 19-Fair Values of Financial Instruments). We operated GSF Arctic IV under a short-term bareboat charter with the new owner of the vessel, until November 2010. As a result of the sale, we recognized a loss on disposal of assets in the amount of $15 million ($0.04 per diluted share), which had no tax effect for the year ended December 31, 2010. For the year ended December 31, 2010, we recognized a gain on disposal of other unrelated assets in the amount of $5 million. In December 2010, we entered into an agreement to sell our Standard Jackup Transocean Mercury and related equipment. As of December 31, 2010, Transocean Mercury had a net carrying amount of less than $1 million, recorded in assets held for sale on our consolidated balance sheet. See Note 25-Subsequent Events.

During the year ended December 31, 2009, we received net proceeds of $10 million in connection with our sale of Sedco 135-D and disposals of other unrelated property and equipment, and these disposals had no net effect on income taxes or net income. In addition, we received net proceeds of $4 million in exchange for our 45 percent ownership interest in Caspian Drilling Company Limited, which operates Dada Gorgud and Istigal under long-term bareboat charters with the owner of the rigs and $38 million in exchange for our interest in Arab Drilling & Workover Company. During the year ended December 31, 2009, we recognized a loss on disposal of assets of $9 million, which had no tax effect.

During the year ended December 31, 2008, we completed the sale of three Standard Jackups, GSF High Island VIII, GSF Adriatic III and GSF High Island I. We received cash proceeds of $320 million associated with the sales, which had no effect on earnings.

Deepwater Horizon-On April 22, 2010, the Ultra-Deepwater Floater Deepwater Horizon sank after a blowout of the Macondo well caused a fire and explosion on the rig. The rig's insured value was $560 million, which was not subject to a deductible, and our insurance underwriters declared the vessel a total loss. During the year ended December 31, 2010, we received $560 million in cash proceeds from insurance recoveries related to the loss of the drilling unit and, for the year ended December 31, 2010, we recognized a gain on the loss of the rig in the amount of $267 million ($0.83 per diluted share), which had no tax effect. See Note 14-Commitments and Contingencies.

Goodwill and Other Intangibles Assets

12 Months Ended

Dec. 31, 2010

Goodwill And Intangible Assets

Goodwill and other indefinite-lived intangible assets-The gross carrying amounts of goodwill and accumulated impairment were as follows (in millions):

	Year ended December 31, 2010								Year ended December 31, 2009
	Gross carrying amount		Accumulated impairment			Net carrying amount			Gross carrying amount		Accumulated impairment			Net carrying amount
Contract drilling services
Balance, beginning of period	$	10,626	$	(2,494	)	$	8,132		$	10,620	$	(2,494	)	$	8,126
Purchase price adjustment		-		-			-			6		-			6
Balance, end of period		10,626		(2,494	)		8,132			10,626		(2,494	)		8,132

Drilling management services
Balance, beginning of period		176		(176	)		-			176		(176	)		-
Balance, end of period		176		(176	)		-			176		(176	)		-

Oil and gas properties
Balance, beginning of period		2		-			2			2		-			2
Impairment		-		(2	)		(2	)		-		-			-
Balance, end of period		2		(2	)		-			2		-			2

Total goodwill
Balance, beginning of period		10,804		(2,670	)		8,134			10,798		(2,670	)		8,128
Impairment		-		(2	)		(2	)		-		-			-
Purchase price adjustment		-		-			-			6		-			6
Balance, end of period	$	10,804	$	(2,672	)	$	8,132		$	10,804	$	(2,670	)	$	8,134

The gross carrying amounts of the ADTI trade name, which we consider to be an indefinite-lived intangible asset, and accumulated impairment were as follows (in millions):

	Year ended December 31, 2010							Year ended December 31, 2009
	Gross carrying amount		Accumulated impairment			Net carrying amount		Gross carrying amount		Accumulated impairment			Net carrying amount
Trade name
Balance, beginning of period	$	76	$	(37	)	$	39	$	76	$	(31	)	$	45
Impairment		-		-			-		-		(6	)		(6	)
Balance, end of period	$	76	$	(37	)	$	39	$	76	$	(37	)	$	39

Definite-lived intangible assets-The gross carrying amounts of our drilling contract intangibles and drilling management customer relationships, both of which we consider to be definite-lived intangible assets and intangible liabilities, and accumulated amortization and impairment were as follows (in millions):

	Year ended December 31, 2010								Year ended December 31, 2009
	Gross carrying amount		Accumulated amortization and impairment			Net carrying amount			Gross carrying amount		Accumulated amortization and impairment			Net carrying amount
Drilling contract intangible assets
Balance, beginning of period	$	191	$	(167	)	$	24		$	191	$	(123	)	$	68
Amortization		-		(18	)		(18	)		-		(44	)		(44	)
Balance, end of period		191		(185	)		6			191		(167	)		24

Customer relationships
Balance, beginning of period		148		(84	)		64			148		(27	)		121
Amortization		-		(5	)		(5	)		-		(8	)		(8	)
Impairment		-		-			-			-		(49	)		(49	)
Balance, end of period		148		(89	)		59			148		(84	)		64

Total definite-lived intangible assets
Balance, beginning of period		339		(252	)		87			339		(150	)		189
Amortization		-		(23	)		(23	)		-		(53	)		(53	)
Impairment		-		-			-			-		(49	)		(49	)
Balance, end of period	$	339		(275	)		64		$	339	$	(252	)	$	87

Drilling contract intangible liabilities
Balance, beginning of period	$	1,494	$	(1,226	)	$	268		$	1,494	$	(901	)	$	593
Amortization		-		(116	)		(116	)		-		(325	)		(325	)
Balance, end of period	$	1,494		(1,342	)		152		$	1,494	$	(1,226	)	$	268

We amortize the drilling contract intangibles over the term of the respective drilling contracts using the straight-line method of amortization, recognized in contract intangible revenues on our consolidated statements of operations. We amortize the customer relationships intangible asset over its 15-year life using the straight-line method of amortization, recognized in operating and maintenance expense on our consolidated statements of operations. The estimated net future amortization related to intangible assets and liabilities as of December 31, 2010, was as follows (in millions):

	Drilling contract intangibles			Customer relationships
Years ending December 31,
2011	$	(45	)	$	5
2012		(42	)		5
2013		(25	)		5
2014		(15	)		5
2015		(14	)		5
Thereafter		(6	)		34
Total intangible assets (liabilities), net	$	(147	)	$	59

Discloses the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain or loss on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss. This element may be used as a single block of text to include the entire intangible asset disclosure including data and tables.

+ References+ Details

Debt

12 Months Ended

Dec. 31, 2010

Debt

Debt, net of unamortized discounts, premiums and fair value adjustments, was comprised of the following (in millions):

	December 31, 2010						December 31, 2009
	Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total		Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total
ODL Loan Facility	$	10	$	-	$	10	$	10	$	-	$	10
Commercial paper program (a)		88		-		88		281		-		281
6.625% Notes due April 2011 (a)		167		-		167		170		-		170
5% Notes due February 2013		255		-		255		247		-		247
5.25% Senior Notes due March 2013 (a)		511		-		511		496		-		496
TPDI Credit Facilities due March 2015		-		560		560		-		581		581
4.95% Senior Notes due November 2015 (a)		1,099		-		1,099		-		-		-
ADDCL Credit Facilities due November 2017		-		242		242		-		454		454
6.00% Senior Notes due March 2018 (a)		997		-		997		997		-		997
7.375% Senior Notes due April 2018 (a)		247		-		247		247		-		247
TPDI Notes due October 2019		-		148		148		-		148		148
6.50% Senior Notes due November 2020 (a)		899		-		899		-		-		-
Capital lease obligation due July 2026		-		-		-		15		-		15
8% Debentures due April 2027 (a)		57		-		57		57		-		57
7.45% Notes due April 2027 (a)		96		-		96		96		-		96
7% Notes due June 2028		313		-		313		313		-		313
Capital lease contract due August 2029		694		-		694		711		-		711
7.5% Notes due April 2031 (a)		598		-		598		598		-		598
1.625% Series A Convertible Senior Notes due December 2037 (a)		11		-		11		1,261		-		1,261
1.50% Series B Convertible Senior Notes due December 2037 (a)		1,625		-		1,625		2,057		-		2,057
1.50% Series C Convertible Senior Notes due December 2037 (a)		1,605		-		1,605		1,979		-		1,979
6.80% Senior Notes due March 2038 (a)		999		-		999		999		-		999
Total debt		10,271		950		11,221		10,534		1,183		11,717
Less debt due within one year
ODL Loan Facility		10		-		10		10		-		10
Commercial paper program (a)		88		-		88		281		-		281
6.625% Notes due April 2011 (a)		167		-		167		-		-		-
TPDI Credit Facilities due March 2015		-		70		70		-		52		52
ADDCL Credit Facilities due November 2017		-		25		25		-		248		248
Capital lease contract due August 2029		16		-		16		16		-		16
1.625% Series A Convertible Senior Notes due December 2037 (a)		11		-		11		1,261		-		1,261
1.50% Series B Convertible Senior Notes due December 2037 (a)		1,625		-		1,625		-		-		-
Total debt due within one year		1,917		95		2,012		1,568		300		1,868
Total long-term debt	$	8,354	$	855	$	9,209	$	8,966	$	883	$	9,849

______________________________

(a)

Transocean Inc., a 100 percent owned subsidiary of Transocean Ltd., is the issuer of the notes and debentures, which have been guaranteed by Transocean Ltd. Transocean Ltd. has also guaranteed borrowings under the commercial paper program and the Five-Year Revolving Credit Facility. Transocean Ltd. has no independent assets or operations, its guarantee of debt securities of Transocean Inc. is full and unconditional and its only other subsidiary, not owned indirectly through Transocean Inc., is minor. Transocean Inc.'s only operating assets are its investments in its operating subsidiaries. Transocean Inc.'s independent assets and operations, other than those related to investments in its subsidiaries and balances primarily pertaining to its cash and cash equivalents and debt are less than two percent of the total consolidated assets and operations of Transocean Ltd., and thus, substantially all of the assets and operations exist within these non-guarantor operating companies. Furthermore, Transocean Ltd. and Transocean Inc. are not subject to any significant restrictions on their ability to obtain funds from their consolidated subsidiaries or entities accounted for under the equity method by dividends, loans or return of capital distributions.

Scheduled maturities-In preparing the scheduled maturities of our debt, we assume the noteholders will exercise their options to require us to repurchase the 1.50% Series B Convertible Senior Notes and 1.50% Series C Convertible Senior Notes in December 2011 and 2012, respectively. At December 31, 2010, the scheduled maturities of our debt were as follows (in millions):

	Transocean Ltd. and subsidiaries			Consolidated variable interest entities		Consolidated total
Years ending December 31,
2011	$	1,970		$	95	$	2,065
2012		1,741			97		1,838
2013		770			98		868
2014		22			100		122
2015		1,123			340		1,463
Thereafter		4,797			220		5,017
Total debt, excluding unamortized discounts, premiums and fair value adjustments		10,423			950		11,373
Total unamortized discounts, premiums and fair value adjustments		(152	)		-		(152	)
Total debt	$	10,271		$	950	$	11,221

ODL Loan Facility-We have a $10 million loan facility with Overseas Drilling Limited ("ODL") under a loan agreement dated December 2009, as amended (the "ODL Loan Facility"). ODL may demand repayment of the borrowings under the loan facility at any time upon written notice, five business days in advance. Any amounts due to us from ODL may be offset against the borrowings at the time of repayment. As of December 31, 2010 and 2009, $10 million was outstanding under the ODL Loan Facility.

Commercial paper program-We maintain a commercial paper program (the "Program"), which is supported by the Five-Year Revolving Credit Facility, under which we may issue privately placed, unsecured commercial paper notes for general corporate purposes up to a maximum aggregate outstanding amount of $1.5 billion. Proceeds from commercial paper issuance under the Program may be used for general corporate purposes. At December 31, 2010, $88 million in commercial paper was outstanding at a weighted-average interest rate of 1.0 percent, including commissions.

6.625% Notes and 7.5% Notes-In April 2001, Transocean Inc. issued $700 million aggregate principal amount of 6.625% Notes due April 2011 and $600 million aggregate principal amount of 7.5% Notes due April 2031. The indenture pursuant to which the notes were issued contains restrictions on creating liens, engaging in sale/leaseback transactions and engaging in merger, consolidation or reorganization transactions. At December 31, 2010, $166 million and $600 million principal amount of the 6.625% Notes and 7.5% Notes, respectively, were outstanding.

Five-Year Revolving Credit Facility-We have a $2.0 billion, five-year revolving credit facility under the Five-Year Revolving Credit Facility Agreement dated November 27, 2007, as amended ("Five-Year Revolving Credit Facility"). We may borrow under the Five-Year Revolving Credit Facility at either (1) the adjusted London Interbank Offered Rate ("LIBOR") plus a margin (the "Five-Year Revolving Credit Facility Margin") based on our Debt Rating (based on our current Debt Rating, a margin of 1.325 percent) or (2) the Base Rate plus the Five-Year Revolving Credit Facility Margin, less one percent per annum. Throughout the term of the Five-Year Revolving Credit Facility, we pay a facility fee on the daily amount of the underlying commitment, whether used or unused, which ranges from 0.10 percent to 0.30 percent, based on our Debt Rating, and was 0.175 percent at December 31, 2010. The Five-Year Revolving Credit Facility expires on November 27, 2012 and may be prepaid in whole or in part without premium or penalty. The Five-Year Revolving Credit Facility includes limitations on creating liens, incurring subsidiary debt, transactions with affiliates, sale/leaseback transactions, mergers and the sale of substantially all assets. The Five-Year Revolving Credit Facility also includes a covenant imposing a maximum debt to tangible capitalization ratio of 0.6 to 1.0. Borrowings under the Five-Year Revolving Credit Facility are subject to acceleration upon the occurrence of an event of default. At December 31, 2010, we had $1.9 billion available borrowing capacity, we had $81 million in letters of credit issued and outstanding and we had no borrowings outstanding under the Five-Year Revolving Credit Facility.

5% Notes and 7% Notes-Two of our wholly-owned subsidiaries are the obligors on the 5% Notes due 2013 (the "5% Notes") and the 7% Notes due 2028 (the "7% Notes"), and we have not guaranteed either obligation. The respective obligor may redeem the 5% Notes and the 7% Notes in whole or in part at a price equal to 100 percent of the principal amount plus accrued and unpaid interest, if any, and a make-whole premium. The indentures related to the 5% Notes and the 7% Notes contain limitations on creating liens and sale/leaseback transactions. At December 31, 2010, $250 million and $300 million aggregate principal amount of the 5% Notes and the 7% Notes, respectively, remained outstanding. See Note 12-Derivatives and Hedging.

5.25%, 6.00% and 6.80% Senior Notes-In December 2007, Transocean Inc. issued $500 million aggregate principal amount of 5.25% Senior Notes due March 2013 (the "5.25% Senior Notes"), $1.0 billion aggregate principal amount of 6.00% Senior Notes due March 2018 (the "6.00% Senior Notes") and $1.0 billion aggregate principal amount of 6.80% Senior Notes due March 2038 (the "6.80% Senior Notes"). Transocean Inc. may redeem some or all of the notes at any time, at a redemption price equal to 100 percent of the principal amount plus accrued and unpaid interest, if any, and a make-whole premium. The indenture pursuant to which the notes were issued contains restrictions on creating liens, engaging in sale/leaseback transactions and engaging in merger, consolidation or reorganization transactions. At December 31, 2010, $500 million, $1 billion and $1 billion principal amount of the 5.25% Senior Notes, the 6.00% Senior Notes and the 6.80% Senior Notes, respectively, were outstanding. See Note 12-Derivatives and Hedging.

TPDI Credit Facilities-TPDI has a bank credit agreement for a $1.265 billion secured credit facility (the "TPDI Credit Facilities"), comprised of a $1.0 billion senior term loan, a $190 million junior term loan and a $75 million revolving credit facility, which was established to finance the construction of and is secured by Dhirubhai Deepwater KG1 and Dhirubhai Deepwater KG2. One of our subsidiaries participates in the senior and junior term loans with an aggregate commitment of $595 million. The senior term loan, the junior term loan and the revolving credit facility bear interest at LIBOR plus the applicable margins of 1.45 percent, 2.25 percent and 1.45 percent, respectively. The senior term loan requires quarterly payments with a final payment in March 2015. The junior term loan and the revolving credit facility are due in full in March 2015. The TPDI Credit Facilities may be prepaid in whole or in part without premium or penalty. The TPDI Credit Facilities have covenants that require TPDI to maintain a minimum cash balance and available liquidity, a minimum debt service ratio and a maximum leverage ratio. At December 31, 2010, $1.1 billion was outstanding under the TPDI Credit Facilities, of which $543 million was due to one of our subsidiaries and was eliminated in consolidation. The weighted-average interest rate on December 31, 2010 was 1.9 percent.

In April 2010, TPDI obtained a letter of credit in the amount of $60 million to satisfy its liquidity requirements under the TPDI Credit Facilities. The letter of credit was issued under an uncommitted credit facility that has been established by one of our subsidiaries.

4.95% Senior Notes and 6.50% Senior Notes-In September 2010, we issued $1.1 billion aggregate principal amount of 4.95% Senior Notes due November 2015 (the "4.95% Senior Notes") and $900 million aggregate principal amount of 6.50% Senior Notes due November 2020 (the "6.50% Senior Notes," and together with the 4.95% Senior Notes, the "Senior Notes"). We are required to pay interest on the Senior Notes on May 15 and November 15 of each year, beginning November 15, 2010. We may redeem some or all of the Senior Notes at any time at a redemption price equal to 100 percent of the principal amount plus accrued and unpaid interest, if any, and a make whole premium. The indenture pursuant to which the Senior Notes were issued contains restrictions on creating liens, engaging in sale/leaseback transactions and engaging in merger, consolidation or reorganization transactions. At December 31, 2010, $1.1 billion and $900 million aggregate principal amount of the 4.95% Senior Notes and 6.50% Senior Notes, respectively, were outstanding.

ADDCL Credit Facilities-ADDCL has a senior secured bank credit agreement for a credit facility (the "ADDCL Primary Loan Facility") comprised of Tranche A, Tranche B and Tranche C for $215 million, $270 million and $399 million, respectively, which was established to finance the construction of and is secured by Discoverer Luanda. Unaffiliated financial institutions provide the commitment for and borrowings under Tranche A, and one of our subsidiaries provides the commitment for Tranche C. In March 2010, ADDCL terminated Tranche B, having repaid borrowings of $235 million under Tranche B using borrowings under Tranche C. Tranche A bears interest at LIBOR plus the applicable margin of 0.725 percent. Tranche A requires semi-annual payments beginning six months after the rig's first well commencement date and matures in December 2017. The ADDCL Primary Loan Facility contains covenants that require ADDCL to maintain certain cash balances to service the debt and also limits ADDCL's ability to incur additional indebtedness, to acquire assets, or to make distributions or other payments. At December 31, 2010, $215 million was outstanding under Tranche A at a weighted-average interest rate of 1.2 percent. At December 31, 2010, $399 million was outstanding under Tranche C, which was eliminated in consolidation.

Additionally, ADDCL has a secondary bank credit agreement for a $90 million credit facility (the "ADDCL Secondary Loan Facility"), for which one of our subsidiaries provides 65 percent of the total commitment. The facility bears interest at LIBOR plus the applicable margin, ranging from 3.125 percent to 5.125 percent, depending on certain milestones. The ADDCL Secondary Loan Facility is payable in full in December 2015, and it may be prepaid in whole or in part without premium or penalty. Borrowings under the ADDCL Secondary Loan Facility are subject to acceleration by the unaffiliated financial institution upon the occurrence of certain events of default, including the occurrence of a credit rating assignment of less than Baa3 or BBB- by Moody's Investors Service or Standard & Poor's Ratings Services, respectively, for Transocean Inc.'s long-term, unsecured, unguaranteed and unsubordinated indebtedness. At December 31, 2010, $77 million was outstanding under the ADDCL Secondary Loan Facility, of which $50 million was provided by one of our subsidiaries and has been eliminated in consolidation. The weighted-average interest rate on December 31, 2010 was 3.4 percent.

7.375% Senior Notes-In March 2002, we completed an exchange offer and consent solicitation for TODCO's 7.375% Senior Notes (the "Exchange Offer"). As a result of the Exchange Offer, we issued $247 million principal amount of our 7.375% Senior Notes. The indenture pursuant to which the 7.375% Senior Notes were issued contains restrictions on creating liens, engaging in sale/leaseback transactions and engaging in merger, consolidation or reorganization transactions. At December 31, 2010, $246 million principal amount of the 7.375% Senior Notes were outstanding.

TPDI Notes-TPDI has issued promissory notes (the "TPDI Notes") payable to its two shareholders, Pacific Drilling and one of our subsidiaries, which have maturities through October 2019. At December 31, 2010, the aggregate outstanding principal amount was $296 million, of which $148 million was due to one of our subsidiaries and has been eliminated in consolidation. The weighted-average interest rate on December 31, 2010 was 2.6 percent.

7.45% Notes and 8% Debentures-In April 1997, a predecessor of Transocean Inc. issued $100 million aggregate principal amount of 7.45% Notes due April 2027 (the "7.45% Notes") and $200 million aggregate principal amount of 8% Debentures due April 2027 (the "8% Debentures"). The 7.45% Notes and the 8% Debentures are redeemable at any time at Transocean Inc.'s option subject to a make-whole premium. The indenture pursuant to which the 7.45% Notes and the 8% Debentures were issued contains restrictions on creating liens, engaging in sale/leaseback transactions and engaging in merger, consolidation or reorganization transactions. At December 31, 2010, $100 million and $57 million principal amount of the 7.45% Notes and the 8% Debentures, respectively, were outstanding.

GSF Explorer capital lease obligation-During the year ended December 31, 2010, we acquired GSF Explorer, an asset formerly held under a capital lease, in exchange for a cash payment of $15 million, thereby terminating the capital lease obligation. In connection with the termination of the capital lease obligation, we recognized a gain on debt retirement of $2 million, which had no per diluted share or tax effect. See Note 9-Drilling Fleet.

1.625% Series A, 1.50% Series B and 1.50% Series C Convertible Senior Notes-In December 2007, we issued $2.2 billion aggregate principal amount of 1.625% Series A Convertible Senior Notes due December 2037 (the "Series A Convertible Senior Notes"), $2.2 billion aggregate principal amount of 1.50% Series B Convertible Senior Notes due December 2037 (the "Series B Convertible Senior Notes") and $2.2 billion aggregate principal amount of 1.50% Series C Convertible Senior Notes due December 2037 (the "Series C Convertible Senior Notes," and together with the Series A Convertible Senior Notes and Series B Convertible Senior Notes, the "Convertible Senior Notes"). The Convertible Senior Notes may be converted under the circumstances specified below at a rate of 5.9310 shares per $1,000 note, equivalent to a conversion price of $168.61 per share, subject to adjustments upon the occurrence of certain events. Upon conversion, we will deliver, in lieu of shares, cash up to the aggregate principal amount of notes to be converted and shares in respect of the remainder, if any, of our conversion obligation. In addition, if certain fundamental changes occur on or before December 20, 2011, with respect to Series B Convertible Senior Notes, or December 20, 2012, with respect to Series C Convertible Senior Notes, we will, in some cases, increase the conversion rate for a holder electing to convert notes in connection with such fundamental change.

Holders may convert their notes only under the following circumstances: (1) during any calendar quarter if the last reported sale price of our shares for at least 20 trading days in a period of 30 consecutive trading days ending on the last trading day of the preceding calendar quarter is more than 130 percent of the conversion price, (2) during the five business days after the average trading price per $1,000 principal amount of the notes is equal to or less than 98 percent of the average conversion value of such notes during the preceding five trading-day period as described herein, (3) during specified periods if specified distributions to holders of our shares are made or specified corporate transactions occur, (4) prior to the close of business on the business day preceding the redemption date if the notes are called for redemption or (5) on or after September 15, 2037 and prior to the close of business on the business day prior to the stated maturity of the notes. As of December 31, 2010, no shares were issuable upon conversion of any series of the Convertible Senior Notes since none of the circumstances giving rise to potential conversion were present.

We may redeem some or all of the notes at any time after December 20, 2011, in the case of the Series B Convertible Senior Notes, and December 20, 2012, in the case of the Series C Convertible Senior Notes, in each case at a redemption price equal to 100 percent of the principal amount plus accrued and unpaid interest, if any. Holders of the Series B Convertible Senior Notes have the right to require us to repurchase their notes on December 15, 2011. In addition, holders of any series of notes will have the right to require us to repurchase their notes on December 14, 2012, December 15, 2017, December 15, 2022, December 15, 2027 and December 15, 2032, and upon the occurrence of a fundamental change, at a repurchase price in cash equal to 100 percent of the principal amount of the notes to be repurchased plus accrued and unpaid interest, if any.

The carrying amounts of the liability components of the Convertible Senior Notes were as follows (in millions):

	December 31, 2010							December 31, 2009
	Principal amount		Unamortized discount			Carrying amount		Principal amount		Unamortized discount			Carrying amount
Carrying amount of liability component
Series A Convertible Senior Notes due 2037	$	11	$	-		$	11	$	1,299	$	(38	)	$	1,261
Series B Convertible Senior Notes due 2037		1,680		(55	)		1,625		2,200		(143	)		2,057
Series C Convertible Senior Notes due 2037		1,722		(117	)		1,605		2,200		(221	)		1,979

The carrying amounts of the equity components of the Convertible Senior Notes were as follows (in millions):

	December 31,
	2010		2009
Carrying amount of equity component
Series A Convertible Senior Notes due 2037	$	1	$	114
Series B Convertible Senior Notes due 2037		210		275
Series C Convertible Senior Notes due 2037		276		352

Including the amortization of the unamortized discount, the effective interest rates were 5.08 percent for the Series B Convertible Senior Notes and 5.28 percent for the Series C Convertible Senior Notes. At December 31, 2010, the remaining period over which the discount will be amortized is less than one year for the Series B Convertible Senior Notes and 1.9 years for the Series C Convertible Senior Notes. Interest expense, excluding amortization of debt issue costs, was as follows (in millions):

	Years ended December 31,
		2010	2009		2008
Interest expense
Series A Convertible Senior Notes due 2037	$	58	$	85	$	97
Series B Convertible Senior Notes due 2037		98		100		97
Series C Convertible Senior Notes due 2037		98		100		97

Holders of the Series A Convertible Senior Notes had the option to require Transocean Inc., our wholly owned subsidiary and the issuer of the Series A Convertible Senior Notes, to repurchase all or any part of such holder's notes on December 15, 2010. As a result, we were required to repurchase an aggregate principal amount of $1,288 million of our Series A Convertible Senior Notes for an aggregate cash payment of $1,288 million. On December 31, 2010, Transocean Inc. called the remaining $11 million of Series A Convertible Senior Notes for redemption on January 31, 2011. See Note 25-Subsequent Events.

During the year ended December 31, 2010, we repurchased an aggregate principal amount of $520 million of the Series B Convertible Senior Notes for an aggregate cash payment of $505 million and an aggregate principal amount of $478 million of the Series C Convertible Senior Notes for an aggregate cash payment of $453 million. In connection with the repurchases, we recognized a loss on retirement of $35 million ($0.11 per diluted share), with no tax effect, associated with the debt components of the repurchased notes, and we recorded additional paid-in capital of $14 million associated with the equity components of the repurchased notes.

During the year ended December 31, 2009, we repurchased an aggregate principal amount of $901 million of the Series A Convertible Senior Notes for an aggregate cash payment of $865 million. We recognized a loss of $28 million associated with the debt component of the instrument and recorded additional paid-in capital of $22 million associated with the equity component of the instrument.

Derivatives and Hedging	12 Months Ended
Derivatives and Hedging	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Derivatives and Hedging	Cash flow hedges-TPDI has entered into interest rate swaps, which have been designated and have qualified as a cash flow hedge, to reduce the variability of cash interest payments associated with the variable-rate borrowings under the TPDI Credit Facilities. The aggregate notional amount corresponds with the aggregate outstanding amount of the borrowings under the TPDI Credit Facilities. As of December 31, 2010, the aggregate notional amount was $1.1 billion, of which $543 million was attributable to the intercompany borrowings provided by one of our subsidiaries and the related balances have been eliminated in consolidation. At December 31, 2010, the weighted-average variable interest rate associated with the interest rate swaps was 0.3 percent, and the weighted-average fixed interest rate was 2.3 percent. At December 31, 2010, the interest rate swaps represented a liability measured at a fair value of $11 million, recorded in other long-term liabilities, with a corresponding increase to accumulated other comprehensive loss. At December 31, 2009, the interest rate swaps represented an asset measured at a fair value of $6 million, recorded in other assets, and a liability measured at a fair value of less than $1 million, recorded in other long-term liabilities, with a corresponding net decrease to accumulated other comprehensive loss. The amount associated with the ineffective portion of the cash flow hedges was less than $1 million, recorded in interest expense for the years ended December 31, 2010 and 2009. In February 2009, Transocean Inc. entered into interest rate swaps with an aggregate notional value of $1 billion, which were designated and qualified as a cash flow hedge, to reduce the variability of our cash interest payments on the borrowings under a term loan. Under the interest rate swaps, Transocean Inc. received interest at one-month LIBOR and paid interest at a fixed rate of 0.768 percent over the six-month period ended August 6, 2009. Upon their stated maturity, Transocean Inc. settled these interest rate swaps with no gain or loss recognized. No ineffectiveness was recorded in interest expense. Fair value hedges-Two of our wholly owned subsidiaries have entered into interest rate swaps, which are designated and have qualified as fair value hedges, to reduce our exposure to changes in the fair values of the 5.25% Senior Notes and the 5.00% Notes. The interest rate swaps have aggregate notional amounts of $500 million and $250 million, respectively, equal to the face values of the hedged instruments and have stated maturities that coincide with those of the hedged instruments. We have determined that the hedging relationships qualify for, and we have applied, the shortcut method of accounting, under which the interest rate swaps are considered to have no ineffectiveness and no ongoing assessment of effectiveness is required. At December 31, 2010, the weighted-average variable interest rate on the interest rate swaps was 3.5 percent, and the fixed interest rates matched those of the underlying debt instruments. At December 31, 2010, the interest rate swaps represented an asset measured at fair value of $17 million, recorded in other assets, with a corresponding increase to the carrying amounts of the underlying debt instruments. At December 31, 2009, the interest rate swaps represented a liability measured at a fair value of $4 million, recorded in other long-term liabilities, with a corresponding decrease to the carrying amount of the underlying debt instrument.

Postemployment Benefit Plans

12 Months Ended

Dec. 31, 2010

Postemployment Benefit Plans

Defined benefit pension plans and other postretirement employee benefit plans

Overview-We maintain a single qualified defined benefit pension plan in the U.S. (the "U.S. Plan") and a single funded supplemental benefit plan (the "Supplemental Plan"). The U.S. Plan covers substantially all U.S. employees, and the Supplemental Plan, along with two other unfunded supplemental benefit plans (the "Other Supplemental Plans"), provide certain eligible employees with benefits in excess of those allowed under the U.S. Plan. Additionally, we maintain two funded and two unfunded defined benefit plans (collectively, the "Frozen Plans") that we assumed in connection with our mergers with GlobalSantaFe and R&B Falcon, all of which were frozen prior to the respective mergers and for which benefits no longer accrue but the pension obligations have not been fully distributed. We refer to the U.S. Plan, the Supplemental Plan, the Other Supplemental Plans and the Frozen Plans, collectively, as the "U.S. Plans."

We maintain a defined benefit plan in the U.K. (the "U.K. Plan") covering certain current and former employees in the U.K. We also provide several funded defined benefit plans, primarily group pension schemes with life insurance companies, and two unfunded plans, covering our eligible Norway employees and former employees (the "Norway Plans"). We also maintain unfunded defined benefit plans (the "Other Plans") that provide retirement and severance benefits for certain of our Indonesian, Nigerian and Egyptian employees. We refer to the U.K. Plan, the Norway Plans and the Other Plans, collectively, as the "Non-U.S. Plans."

We refer to the U.S. Plans and the Non-U.S. Plans, collectively, as the "Transocean Plans". Additionally, we have several unfunded contributory and noncontributory other postretirement employee benefits plans (the "OPEB Plans") covering substantially all of our U.S. employees.

Assumptions-The following were the weighted-average assumptions used to determine benefit obligations:

	December 31, 2010									December 31, 2009
	U.S. Plans			Non-U.S. Plans			OPEB Plans			U.S. Plans			Non-U.S. Plans			OPEB Plans
Discount rate		5.48	%		5.81	%		4.92	%		5.84	%		5.59	%		5.52	%
Compensation trend rate		4.24	%		4.65	%		n/a			4.21	%		4.73	%		n/a

The following were the weighted-average assumptions used to determine net periodic benefit costs:

	Year ended December 31, 2010									Year ended December 31, 2009									Year ended December 31, 2008
	U.S. Plans			Non-U.S. Plans			OPEB Plans			U.S. Plans			Non-U.S. Plans			OPEB Plans			U.S. Plans			Non-U.S. Plans			OPEB Plans
Discount rate		5.86	%		5.67	%		5.51	%		5.41	%		6.06	%		5.34	%		6.14	%		5.97	%		5.96	%
Expected rate of return		8.49	%		6.65	%		n/a			8.50	%		6.59	%		n/a			8.50	%		7.16	%		n/a
Compensation trend rate		4.21	%		4.77	%		n/a			4.21	%		4.55	%		n/a			4.57	%		4.64	%		n/a
Health care cost trend rate
-initial		n/a			n/a			8.00	%		n/a			n/a			8.99	%		n/a			n/a			8.55	%
-ultimate		n/a			n/a			5.00	%		n/a			n/a			5.00	%		n/a			n/a			5.00	%
-ultimate year		n/a			n/a			2016			n/a			n/a			2016			n/a			n/a			2014

______________________________

"n/a" means not applicable.

Funded status-The changes in projected benefit obligation, plan assets and funded status and the amounts recognized on our consolidated balance sheets were as follows (in millions):

	Year ended December 31, 2010												Year ended December 31, 2009
	U.S. Plans			Non-U.S. Plans			OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans			Total
Change in projected benefit obligation
Projected benefit obligation, beginning of period	$	932		$	403		$	54		$	1,389		$	900		$	250		$	64		$	1,214
Plan amendments		-			-			-			-			-			-			5			5
Actuarial (gains) losses, net		89			(46	)		2			45			(31	)		86			(16	)		39
Service cost		42			20			1			63			44			18			1			63
Interest cost		54			20			3			77			50			17			3			70
Foreign currency exchange rate		-			(13	)		-			(13	)		-			40			-			40
Benefits paid		(51	)		(14	)		(5	)		(70	)		(32	)		(11	)		(4	)		(47	)
Participant contributions		-			2			1			3			-			2			1			3
Special termination benefits		3			-			-			3			-			-			-			-
Settlements and curtailments		(1	)		2			-			1			1			1			-			2
Projected benefit obligation, end of period	$	1,068		$	374		$	56		$	1,498		$	932		$	403		$	54		$	1,389

Change in plan assets
Fair value of plan assets, beginning of period	$	594		$	281		$	-		$	875		$	455		$	208		$	-		$	663
Actual return on plan assets		85			29			-			114			121			31			-			152
Foreign currency exchange rate changes		-			(11	)		-			(11	)		-			31			-			31
Employer contributions		69			45			4			118			50			20			3			73
Participant contributions		-			2			1			3			-			2			1			3
Benefits paid		(51	)		(14	)		(5	)		(70	)		(32	)		(11	)		(4	)		(47	)
Fair value of plan assets, end of period	$	697		$	332		$	-		$	1,029		$	594		$	281		$	-		$	875

Funded status, end of period	$	(371	)	$	(42	)	$	(56	)	$	(469	)	$	(338	)	$	(122	)	$	(54	)	$	(514	)

Balance sheet classification, end of period:
Pension asset, non-current	$	-		$	(8	)	$	-		$	(8	)	$	-		$	-		$	-		$	-
Accrued pension liability, current		3			2			4			9			5			2			3			10
Accrued pension liability, non-current		368			48			52			468			333			120			51			504
Accumulated other comprehensive income (loss) (a)		(308	)		(61	)		(2	)		(371	)		(264	)		(117	)		2			(379	)

______________________________

(a)	Amounts are before income tax effect.

The aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets were as follows (in millions):

	December 31, 2010								December 31, 2009
	U.S. Plans		Non-U.S. Plans		OPEB Plans		Total		U.S. Plans		Non-U.S. Plans		OPEB Plans		Total
Projected benefit obligation	$	1,068	$	290	$	56	$	1,414	$	932	$	403	$	54	$	1,389
Fair value of plan assets		697		248		-		945		594		281		-		875

The accumulated benefit obligation for all defined benefit pension plans was $1.3 billion and $1.1 billion at December 31, 2010 and 2009, respectively. The aggregate accumulated benefit obligation and fair value of plan assets for plans with an accumulated benefit obligation in excess of plan assets were as follows (in millions):

	December 31, 2010								December 31, 2009
	U.S. Plans		Non-U.S. Plans		OPEB Plans		Total		U.S. Plans		Non-U.S. Plans		OPEB Plans		Total
Accumulated benefit obligation	$	921	$	269	$	56	$	1,246	$	789	$	344	$	54	$	1,187
Fair value of plan assets		697		248		-		945		594		281		-		875

Plan assets-We periodically review our investment policies, plan assets and asset allocation strategies to evaluate performance relative to specified objectives. In determining our asset allocation strategies for the U.S. Plans, we review the results of regression models to assess the most appropriate target allocation for each plan, given the plan's status, demographics and duration. For the U.K. Plans, the plan trustees establish the asset allocation strategies consistent with the regulations of the U.K. pension regulators and in consultation with financial advisors and company representatives. Investment managers for the U.S. Plans and the U.K. Plan are given established ranges within which the investments may deviate from the target allocations. For the Norway Plans, we establish minimum returns under the terms of investment contracts with insurance companies.

As of December 31, 2010 and 2009, the weighted-average target and actual allocations of the investments for our funded Transocean Plans were as follows:

							Actual allocation at December 31,
	Target allocation						2010						2009
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Equity securities		65	%		52	%		65	%		53	%		72	%		57	%
Fixed income securities		35	%		15	%		34	%		10	%		27	%		11	%
Other investments		-	%		33	%		1	%		37	%		1	%		32	%
Total		100	%		100	%		100	%		100	%		100	%		100	%

As of December 31, 2010, the investments for our funded Transocean Plans were categorized as follows (in millions):

	December 31, 2010
	Quoted prices in active markets for identical assets						Significant other observable inputs						Total
	U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans
Equity securities:
U.S.	$	359	$	-	$	359	$	-	$	28	$	28	$	359	$	28	$	387
Non-U.S.		91		-		91		2		148		150		93		148		241
Total equity securities		450		-		450		2		176		178		452		176		628

Fixed income securities:
U.S. government		59		-		59		-		-		-		59		-		59
U.S. corporate		175		-		175		-		-		-		175		-		175
Non-U.S. government		-		-		-		-		34		34		-		34		34
Non-U.S.		7		-		7		-		-		-		7		-		7
Total fixed income securities		241		-		241		-		34		34		241		34		275

Other investments:
Cash		4		31		35		-		-		-		4		31		35
Property		-		-		-		-		7		7		-		7		7
Investment contracts		-		-		-		-		84		84		-		84		84
Total other investments		4		31		35		-		91		91		4		122		126

Total investments	$	695	$	31	$	726	$	2	$	301	$	303	$	697	$	332	$	1,029

As of December 31, 2009, the investments for our funded Transocean Plans were categorized as follows (in millions):

	December 31, 2009
	Quoted prices in active markets for identical assets						Significant other observable inputs						Total
	U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans
Equity securities:
U.S.	$	341	$	-	$	341	$	-	$	25	$	25	$	341	$	25	$	366
Non-U.S.		88		-		88		2		136		138		90		136		226
Total equity securities		429		-		429		2		161		163		431		161		592

Fixed income securities:
U.S. government		109		-		109		-		-		-		109		-		109
U.S. corporate		38		-		38		-		-		-		38		-		38
Non-U.S. government		-		-		-		-		30		30		-		30		30
Non-U.S.		12		-		12		-		-		-		12		-		12
Total fixed income securities		159		-		159		-		30		30		159		30		189

Other investments:
Cash		4		2		6		-		-		-		4		2		6
Property		-		-		-		-		11		11		-		11		11
Investment contracts		-		-		-		-		77		77		-		77		77
Total other investments		4		2		6		-		88		88		4		90		94

Total investments	$	592	$	2	$	594	$	2	$	279	$	281	$	594	$	281	$	875

The U.S. Plans invest in passively managed funds that reference market indices. The Non-U.S. Plans invest in actively managed funds that are measured for performance against relevant index benchmarks or that are subject to contractual terms under selected insurance programs. Each plan's investment managers have discretion to select the securities held within each asset category. Given this discretion, the managers may occasionally invest in our debt or equity securities, and may hold either long or short positions in such securities. As the plan investment managers are required to maintain well diversified portfolios, the actual investment in our securities would be immaterial relative to asset categories and the overall plan assets.

Net periodic benefit costs-Net periodic benefit costs, before tax, included the following components (in millions):

	Year ended December 31, 2010									Year ended December 31, 2009									Year ended December 31, 2008
	U.S. Plans			Non-U.S. Plans			Transocean Plans			U.S. Plans			Non-U.S. Plans			Transocean Plans			U.S. Plans			Non-U.S. Plans			Transocean Plans
Service cost	$	42		$	20		$	62		$	44		$	18		$	62		$	30		$	16		$	46
Interest cost		54			20			74			50			17			67			47			17			64
Expected return on plan assets		(58	)		(17	)		(75	)		(55	)		(16	)		(71	)		(53	)		(21	)		(74	)
Settlements and curtailments		5			3			8			4			2			6			(1	)		-			(1	)
Special termination benefits		3			-			3			-			-			-			3			-			3
Actuarial losses, net		13			4			17			18			2			20			4			-			4
Prior service cost (credit), net		(1	)		-			(1	)		(1	)		1			-			-			1			1
Transition obligation, net		-			1			1			-			-			-			-			1			1
Net periodic benefit costs	$	58		$	31		$	89		$	60		$	24		$	84		$	30		$	14		$	44

For the OPEB Plans, the combined components of net periodic benefit costs, including service cost, interest cost, amortization of prior service cost and recognized net actuarial losses were $2 million, $3 million and $3 million for the years ended December 31, 2010, 2009 and 2008, respectively.

The following table presents the amounts in accumulated other comprehensive income, before tax, that have not been recognized as components of net periodic benefit costs (in millions):

	December 31, 2010											December 31, 2009
	U.S. Plans			Non-U.S. Plans		OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans			Total
Actuarial loss, net	$	319		$	52	$	7		$	378		$	277		$	117		$	5		$	399
Prior service cost (credit), net		(11	)		8		(5	)		(8	)		(13	)		(2	)		(7	)		(22	)
Transition obligation, net		-			1		-			1			-			2			-			2
Total	$	308		$	61	$	2		$	371		$	264		$	117		$	(2	)	$	379

The following table presents the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit costs during the year ending December 31, 2011 (in millions):

	Year ending December 31, 2011
	U.S. Plans			Non-U.S. Plans		OPEB Plans			Total
Actuarial loss, net	$	22		$	2	$	-		$	24
Prior service cost (credit), net		(1	)		1		(2	)		(2	)
Transition obligation, net		-			-		-			-
Total amount expected to be recognized	$	21		$	3	$	(2	)	$	22

Funding contributions-During the years ended December 31, 2010, 2009 and 2008, we contributed $115 million, $73 million and $78 million, respectively, to the Transocean Plans and the OPEB Plans using our cash flows from operations. For the year ending December 31, 2011, we expect to contribute $93 million to the Transocean Plans, and we expect to fund benefit payments of approximately $4 million for the OPEB Plans as costs are incurred.

Benefit payments-The following were the projected benefits payments (in millions):

		U.S. Plans	Non-U.S. Plans		OPEB Plans		Total
Years ending December 31,
2011	$	37	$	7	$	4	$	48
2012		40		7		4		51
2013		42		8		4		54
2014		45		8		4		57
2015		47		9		4		60
2016-2020		285		57		22		364

Defined contribution plans

We sponsor three defined contribution plans, including (1) one qualified defined contribution savings plan covering certain employees working in the U.S. (the "U.S. Savings Plan"), (2) one defined contribution savings plan covering certain employees working outside the U.S. and U.K. (the "Non-U.S. Savings Plan"), and (3) one defined contribution pension plan that covers certain employees working outside the U.S. (the "Non-U.S. Pension Plan").

For the U.S. Savings Plan and the Non-U.S. Savings Plan, we make a matching contribution of up to 6.0 percent of each covered employee's base salary, based on the employee's contribution to the plan. For the Non-U.S. Pension Plan, we contribute between 4.5 percent and 6.5 percent of each covered employee's base salary, based on the employee's years of eligible service. We recorded approximately $69 million, $67 million and $51 million of expense related to our defined contribution plans for the years ended December 31, 2010, 2009 and 2008, respectively.

Severance plan

Following our merger with GlobalSantaFe in 2007, we established a plan to consolidate operations and administrative functions and identified 377 employees that were involuntarily terminated pursuant to this plan. We recognized $5 million, $17 million and $5 million of severance expense, recorded in operating and maintenance expense and in general and administrative expense, for the years ended December 31, 2010, 2009 and 2008, respectively. No additional expense will be recognized under the severance plan, which expired in January 2010. The liability associated with the severance plan, recorded in other current liabilities, was $1 million and $17 million at December 31, 2010 and 2009, respectively. Since the severance plan's inception in 2007, we have paid an aggregate amount of $74 million in termination benefits under the plan, including $21 million, $18 million and $33 million paid during the years ended December 31, 2010, 2009 and 2008, respectively.

Description containing the entire pension and other postretirement benefits disclosure as a single block of text.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 158

-Paragraph 7, 21, 22

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5, 6, 7, 8

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 8

-Subparagraph m

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 106

-Paragraph 518

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph b

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph a

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph h

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph q

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS106-2

-Paragraph 20, 21, 22

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-2

-Paragraph 8

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 30

-Paragraph 26

Reference 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Implementation Guide (Q and A)

-Number FAS88

-Paragraph 63

+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2010

Commitments And Contingencies

Lease obligations

We have operating lease commitments expiring at various dates, principally for real estate, office space and office equipment. In August 2009, we accepted delivery of Petrobras 10000, an asset held under a capital lease through August 2029. Additionally, in March 2010, we acquired GSF Explorer, an asset formerly held under a capital lease, in exchange for a cash payment terminating the capital lease obligation in the amount of $15 million (see Note 11-Debt). Rental expenses for all leases, including leases with terms of less than one year, was approximately $98 million, $99 million and $89 million for the years ended December 31, 2010, 2009 and 2008, respectively. As of December 31, 2010, future minimum rental payments related to noncancellable operating leases and the capital leases were as follows (in millions):

	Capital leases			Operating leases
Years ending December 31,
2011	$	66		$	36
2012		72			31
2013		72			23
2014		73			16
2015		73			12
Thereafter		990			32
Total future minimum rental payment	$	1,346		$	150
Less amount representing imputed interest		(652	)
Present value of future minimum rental payments under capital leases		694
Less current portion included in debt due within one year		(16	)
Long-term capital lease obligation	$	678

The following were the aggregate carrying amount of our assets held under capital lease, as of December 31, 2010 and 2009, respectively (in millions):

	December 31,
		2010		2009
Property and equipment, cost	$	740		$	982
Accumulated depreciation		(20	)		(27	)
Property and equipment, net	$	720		$	955

Depreciation expense associated with our assets held under capital lease was $23 million, $14 million and $12 million for the years ended December 31, 2010, 2009 and 2008, respectively. The amount for the year ended December 31, 2010 includes only three months of depreciation expense for GSF Explorer through the date of our acquisition of the rig in March 2010.

Purchase obligations

At December 31, 2010, our purchase obligations, primarily related to our newbuilds, were as follows (in millions):

	Purchase obligations
Years ending December 31,
2011	$	381
2012		149
2013		-
2014		-
2015		-
Thereafter		-
Total	$	530

Macondo well incident

Overview-On April 22, 2010, the Ultra-Deepwater Floater Deepwater Horizon sank after a blowout of the Macondo well caused a fire and explosion on the rig. Eleven persons were declared dead and others were injured as a result of the incident. At the time of the explosion, Deepwater Horizon was located approximately 41 miles off the coast of Louisiana in Mississippi Canyon Block 252 and was contracted to BP America Production Co.

As we continue to investigate the cause or causes of the incident, we are evaluating its consequences. Although we cannot predict the final outcome or estimate the reasonably possible range of loss with certainty, we have recognized a liability for estimated loss contingencies that we believe are probable and for which a reasonable estimate can be made. We have also recognized a receivable for the portion of this liability that we believe is recoverable from insurance. As of December 31, 2010, the amount of the estimated liability was $135 million, recorded in other current liabilities, and the corresponding estimated recoverable amount was $94 million, recorded in accounts receivable, net, on our consolidated balance sheet. New information or future developments could require us to adjust our disclosures and our estimated liabilities and insurance recoveries. See "-Contractual indemnity."

Litigation-As of December 31, 2010, 304 actions or claims were pending against Transocean entities, along with other unaffiliated defendants, in state and federal courts. Additionally, government agencies have initiated investigations into the Macondo well incident. We have categorized below the nature of the legal actions or claims. We are evaluating all claims and intend to vigorously defend any claims and pursue any and all defenses available. In addition, we believe we are entitled to contractual defense and indemnity for all wrongful death and personal injury claims made by non-employees and third-party subcontractors' employees as well as all liabilities for pollution or contamination, other than for pollution or contamination originating on or above the surface of the water. See "-Contractual indemnity."

Wrongful death and personal injury-As of December 31, 2010, we and one or more of our subsidiaries have been named, along with other unaffiliated defendants, in 30 complaints that were pending in state and federal courts in Louisiana and Texas involving multiple plaintiffs that allege wrongful death and other personal injuries arising out of the Macondo well incident. Per the order of the Multi-District Litigation Panel (the "MDL"), these claims have been centralized for discovery purposes in the U.S. District Court, Eastern District of Louisiana. The complaints generally allege negligence and seek awards of unspecified economic damages and punitive damages. BP plc (together with its affiliates, "BP"), MI-SWACO, Weatherford Ltd. and Cameron International Corporation and certain of its affiliates have, based on contractual arrangements, also made indemnity demands upon us with respect to personal injury and wrongful death claims asserted by our employees or representatives of our employees against these entities. See "-Contractual indemnity."

Economic loss-As of December 31, 2010, we and one or more of our subsidiaries were named, along with other unaffiliated defendants, in 70 individual complaints as well as 185 putative class-action complaints that were pending in the federal and state courts in Louisiana, Texas, Mississippi, Alabama, Georgia, Kentucky, South Carolina, Tennessee, Florida and possibly other courts. The complaints generally allege, among other things, potential economic losses as a result of environmental pollution arising out of the Macondo well incident and are based primarily on the Oil Pollution Act of 1990 ("OPA") and state OPA analogues. See "-Environmental matters." One complaint also alleges a violation of the Racketeer Influenced and Corrupt Organizations Act, but we were not named in this particular master complaint. The plaintiffs are generally seeking awards of unspecified economic, compensatory and punitive damages, as well as injunctive relief. See "-Contractual indemnity." Per the order of the MDL, the economic loss claims filed in federal courts have been or will be centralized for discovery purposes in the U.S. District Court, Eastern District of Louisiana. Absent agreement of the parties, however, the cases will be tried in the courts from which they were transferred.

Federal securities claims-Three federal securities law class actions are currently pending in the U.S. District Court, Southern District of New York, naming us and certain of our officers and directors as defendants. Two of these actions generally allege violations of Section 10(b) of the Securities Exchange Act of 1934 (the "Exchange Act"), Rule 10b-5 promulgated under the Exchange Act and Section 20(a) of the Exchange Act in connection with the Macondo well incident. The plaintiffs are generally seeking awards of unspecified economic damages, including damages resulting from the decline in our stock price after the Macondo well incident. The third action was filed by a former GlobalSantaFe shareholder, alleging that the proxy statement related to our shareholder meeting in connection with our merger with GlobalSantaFe violated Section 14(a) of the Exchange Act, Rule 14a-9 promulgated thereunder and Section 20(a) of the Exchange Act. The plaintiff claims that GlobalSantaFe shareholders received inadequate consideration for their shares as a result of the alleged violations and seeks rescission and compensatory damages.

Shareholder derivative claims-In June 2010, two shareholder derivative suits were filed by our shareholders naming us as a nominal defendant and certain of our officers and directors as defendants in the District Courts of the State of Texas. The first case generally alleges breach of fiduciary duty, unjust enrichment, abuse of control, gross mismanagement and waste of corporate assets in connection with the Macondo well incident and the other generally alleges breach of fiduciary duty, unjust enrichment and waste of corporate assets in connection with the Macondo well incident. The plaintiffs are generally seeking, on behalf of Transocean, restitution and disgorgement of all profits, benefits and other compensation from the defendants.

Environmental matters-Environmental claims under two different schemes, statutory and common law, and in two different regimes, federal and state, have been asserted against us. See "-Litigation-Economic loss." Liability under many statutes is imposed without fault, but such statutes often allow the amount of damages to be limited. In contrast, common law liability requires proof of fault and causation, but generally has no readily defined limitation on damages, other than the type of damages that may be redressed. We have described below certain significant applicable environmental statutes and matters relating to the Macondo well incident. As described below, we believe that we have limited statutory environmental liability and we are entitled to contractual defense and indemnity for all liabilities for pollution or contamination, other than for pollution or contamination originating on or above the surface of the water. See "-Contractual indemnity."

Oil Pollution Act-OPA imposes strict liability on responsible parties of vessels or facilities from which oil is discharged into or upon navigable waters or adjoining shore lines. OPA defines the responsible parties with respect to the source of discharge. We believe that the owner or operator of a mobile offshore drilling unit ("MODU"), such as Deepwater Horizon, is only a responsible party with respect to discharges from the vessel that occur on or above the surface of the water. As the responsible party for Deepwater Horizon, we believe we are responsible only for the discharges of oil emanating from the rig. Therefore, we believe we are not responsible for the discharged hydrocarbons from the Macondo well.

Responsible parties for discharges are liable for: (1) removal and cleanup costs, (2) damages that result from the discharge, including natural resources damages, generally up to a statutorily defined limit, (3) reimbursement for government efforts and (4) certain other specified damages. For responsible parties of MODUs, the limitation on liability is determined based on the gross tonnage of the vessel. The statutory limits are not applicable, however, if the discharge is the result of gross negligence, willful misconduct, or violation of federal construction or permitting regulations by the responsible party or a party in a contractual relationship with the responsible party.

Additionally, the National Pollution Funds Center ("NPFC"), a division of the U.S. Coast Guard, is charged with administering the Oil Spill Liability Trust Fund ("OSLTF"). The NPFC collects fines and civil penalties under OPA from responsible parties, as defined in the statute. The payments are directed to the OSLTF. To date, the NPFC has issued nine invoices to BP, Anadarko Petroleum Corporation (together with its affiliates, "Anadarko") and MOEX Offshore LLC (together with its affiliates, "MOEX"), as the operator and leasehold owners of the well and, thus, the statutorily defined responsible parties for discharges from the well and wellhead. To date, BP has paid all nine of these invoices. Invoices have also been sent to us, and we have acknowledged responsible party status only with respect to discharges from the vessel on or above the surface of the water, if any.

In addition, on December 15, 2010, the Department of Justice (the "DOJ") filed a civil lawsuit against us and other unaffiliated defendants. The complaint alleges violations under OPA and the Clean Water Act, and the DOJ reserved its rights to amend the complaint to add new claims and defendants. The complaint asserts that all defendants named are jointly and severally liable for all removal costs and damages resulting from the Macondo well incident. In addition to the civil complaint, the DOJ served us with Civil Investigative Demands ("CIDs") on December 8, 2010. These demands are part of an on-going investigation by the DOJ to determine if we made false claims in connection with the operator's acquisition of the leasehold interest in the Mississippi Canyon Block 252, Gulf of Mexico and drilling operations on Deepwater Horizon.

We have also received claims directly from individuals, pursuant to OPA, requesting compensation for loss of income as a result of the Macondo well incident. BP has accepted responsible party status with the U.S. Coast Guard for the release of hydrocarbons from the Macondo well and has stated its intent to pay all legitimate claims, and we have not paid any of these claims.

Other federal statutes-Several of the claimants have made assertions under other statutes, including the Clean Water Act, the Endangered Species Act, the Migratory Bird Treaty Act, the Clean Air Act, the Comprehensive Environmental Response Compensation and Liability Act and the Emergency Planning and Community Right-to-Know Act.

State environmental laws-As of December 31, 2010, claims had been asserted by private claimants under state environmental statutes in Florida, Louisiana, Mississippi and Texas. As described below, claims asserted by various state and local governments are pending in Alabama, Florida, Louisiana and Texas.

In June 2010, the Louisiana Department of Environmental Quality (the "LDEQ") issued a consolidated compliance order and notice of potential penalty to us and certain of our subsidiaries asking us to eliminate and remediate discharges of oil and other pollutants into waters and property located in the State of Louisiana, and to submit a plan and report in response to the order. We requested that the LDEQ rescind the enforcement actions against us and our subsidiaries because the remediation actions that are the subject of such orders are actions that do not involve us or our subsidiaries, as we are not involved in the remediation or clean-up activities. Alternatively, if the LDEQ would not rescind the enforcement actions altogether, we requested the LDEQ to dismiss the enforcement actions against us and certain of our subsidiaries as these entities are not proper parties to the enforcement actions and were improperly served. In October 2010, the LDEQ rescinded its enforcement actions against us and our subsidiaries but reserved its rights to seek civil penalties for future violations of the Louisiana Environmental Quality Act.

In September 2010, the State of Louisiana filed a declaratory judgment seeking to designate us as a responsible party under OPA and the Louisiana Oil Spill Prevention and Response Act ("LOSPRA") for the discharges emanating from the Macondo well. Specifically the declaratory judgment claims (1) that we are a responsible party under OPA for all hydrocarbons discharged from the Macondo well, including underwater discharges of oil from the well head; (2) that we, as a responsible party, are jointly, severally, and strictly liable for the spill from the Macondo well in accordance with OPA; (3) that we are a responsible party under the Louisiana Oil Spill Prevention and Response Act for all hydrocarbons discharged from the Macondo well, including underwater discharges of oil from the well head; (4) that we, as a responsible party, are jointly, severally, and strictly liable for the spill from the Macondo well in accordance with the LOSPRA; and (5) seeks an award Plaintiff's costs incurred in pursuing this action as allowed by law.

Additionally, suits have been filed by the State of Alabama and the cities of Greenville, Evergreen, Georgiana and McKenzie, Alabama in the U.S. District Court, Middle District of Alabama; the Mexican States of Veracruz, Quintana Roo and Tamaulipas in the U.S. District Court, Western District of Texas; and the City of Panama City Beach, Florida in the U.S. District Court, Northern District of Florida. Generally, these governmental entities allege economic losses under OPA and other statutory environmental state claims and also assert various common law state claims. The claims of the State of Alabama, the cities in Alabama, and the Mexican States have been centralized in the MDL and will proceed in accordance with the MDL scheduling order, and the City of Panama City Beach's claim was voluntarily dismissed.

By letter dated May 5, 2010, the Attorneys General of the five Gulf Coast states of Alabama, Florida, Louisiana, Mississippi and Texas informed us that they intend to seek recovery of pollution clean-up costs and related damages arising from the Macondo well incident. In addition, by letter dated June 21, 2010, the Attorneys General of the 11 Atlantic Coast states of Connecticut, Delaware, Georgia, Maine, Maryland, Massachusetts, New Hampshire, New York, North Carolina, Rhode Island and South Carolina informed us that their states have not sustained any damage from the Macondo well incident but they would like assurances that we will be responsible financially if damages are sustained. We responded to each letter from the Attorneys General and indicated that we intend to fulfill our obligations as a responsible party for any discharge of oil from Deepwater Horizon on or above the surface of the water, and we assume that the operator will similarly fulfill its obligations under OPA for discharges from the undersea well. Other than the lawsuit filed by the State of Alabama discussed above, no further requests have been made or actions taken with regard to the initial communication.

Wreck removal-By letter dated December 6, 2010, the Coast Guard requested us to formulate and submit a comprehensive oil removal plan to remove any diesel fuel contained in the sponsons and fuel tanks that can be recovered from Deepwater Horizon. We have conducted a survey of the rig wreckage and are reviewing the results. We have insurance coverage for wreck removal for up to 25 percent of Deepwater Horizon's insured value, or $140 million, with any excess wreck removal liability generally covered to the extent of our remaining excess liability limits.

Contractual indemnity-Under our drilling contract for Deepwater Horizon, the operator has agreed, among other things, to assume full responsibility for and defend, release and indemnify us from any loss, expense, claim, fine, penalty or liability for pollution or contamination, including control and removal thereof, arising out of or connected with operations under the contract other than for pollution or contamination originating on or above the surface of the water from hydrocarbons or other specified substances within the control and possession of the contractor, as to which we agreed to assume responsibility and protect, release and indemnify the operator. Although we do not believe it is applicable to the Macondo well incident, we also agreed to indemnify and defend the operator up to a limit of $15 million for claims for loss or damage to third parties arising from pollution caused by the rig while it is off the drilling location, while the rig is underway or during drive off or drift off of the rig from the drilling location. The operator has also agreed, among other things, (1) to defend, release and indemnify us against loss or damage to the reservoir, and loss of property rights to oil, gas and minerals below the surface of the earth and (2) to defend, release and indemnify us and bear the cost of bringing the well under control in the event of a blowout or other loss of control. We agreed to defend, release and indemnify the operator for personal injury and death of our employees, invitees and the employees of our subcontractors while the operator agreed to defend, release and indemnify us for personal injury and death of its employees, invitees and the employees of its other subcontractors, other than us. We have also agreed to defend, release and indemnify the operator for damages to the rig and equipment, including salvage or removal costs.

Although we believe we are entitled to contractual defense and indemnity, given the potential amounts involved in connection with the Macondo well incident, the operator may seek to avoid its indemnification obligations. In particular, the operator, in response to our request for indemnification, has generally reserved all of its rights and stated that it could not at this time conclude that it is obligated to indemnify us. In doing so, the operator has asserted that the facts are not sufficiently developed to determine who is responsible and has cited a variety of possible legal theories based upon the contract and facts still to be developed. We believe this reservation of rights is without justification and that the operator is required to honor its indemnification obligations contained in our contract and described above.

Other legal proceedings

Asbestos litigation-In 2004, several of our subsidiaries were named, along with numerous other unaffiliated defendants, in 21 complaints filed on behalf of 769 plaintiffs in the Circuit Courts of the State of Mississippi and which claimed injuries arising out of exposure to asbestos allegedly contained in drilling mud during these plaintiffs' employment in drilling activities between 1965 and 1986. A Special Master, appointed to administer these cases pre-trial, subsequently required that each individual plaintiff file a separate lawsuit, and the original 21 multi-plaintiff complaints were then dismissed by the Circuit Courts. The amended complaints resulted in one of our subsidiaries being named as a direct defendant in seven cases. We have or may have an indirect interest in an additional 12 cases. The complaints generally allege that the defendants used or manufactured asbestos-containing products in connection with drilling operations and have included allegations of negligence, products liability, strict liability and claims allowed under the Jones Act and general maritime law. The plaintiffs generally seek awards of unspecified compensatory and punitive damages. In each of these cases, the complaints have named other unaffiliated defendant companies, including companies that allegedly manufactured the drilling-related products that contained asbestos. The preliminary information available on these claims is not sufficient to determine if there is an identifiable period for alleged exposure to asbestos, whether any asbestos exposure in fact occurred, the vessels potentially involved in the claims, or the basis on which the plaintiffs would support claims that their injuries were related to exposure to asbestos. However, the initial evidence available would suggest that we would have significant defenses to liability and damages. In 2009, two cases that were part of the original 2004 multi-plaintiff suits went to trial in Mississippi against unaffiliated defendant companies which allegedly manufactured drilling-related products containing asbestos. We were not a defendant in either of these cases. One of the cases resulted in a substantial jury verdict in favor of the plaintiff, and this verdict was subsequently vacated by the trial judge on the basis that the plaintiff failed to meet its burden of proof. While the court's decision is consistent with our general evaluation of the strength of these cases, it has not been reviewed on appeal. The second case resulted in a verdict completely in favor of the defendants. There were two additional trials in 2010, one resulting in a substantial verdict for the plaintiff and one resulting in a complete verdict for the defendants. We were not a defendant in either case and both of the matters are currently on appeal. We intend to defend these lawsuits vigorously, although there can be no assurance as to the ultimate outcome. We historically have maintained broad liability insurance, although we are not certain whether insurance will cover the liabilities, if any, arising out of these claims. Based on our evaluation of the exposure to date, we do not expect the liability, if any, resulting from these claims to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

One of our subsidiaries was involved in lawsuits arising out of the subsidiary's involvement in the design, construction and refurbishment of major industrial complexes. The operating assets of the subsidiary were sold and its operations discontinued in 1989, and the subsidiary has no remaining assets other than the insurance policies involved in its litigation, with its insurers and, either directly or indirectly as the beneficiary of a qualified settlement fund, funding from settlements with insurers, assigned rights from insurers and "coverage-in-place" settlement agreements with insurers, and funds received from the communication of certain insurance policies. The subsidiary has been named as a defendant, along with numerous other companies, in lawsuits alleging bodily injury or personal injury as a result of exposure to asbestos. As of December 31, 2010, the subsidiary was a defendant in approximately 1,037 lawsuits. Some of these lawsuits include multiple plaintiffs and we estimate that there are approximately 2,440 plaintiffs in these lawsuits. For many of these lawsuits, we have not been provided with sufficient information from the plaintiffs to determine whether all or some of the plaintiffs have claims against the subsidiary, the basis of any such claims, or the nature of their alleged injuries. The first of the asbestos-related lawsuits was filed against this subsidiary in 1990. Through December 31, 2010, the amounts expended to resolve claims, including both defense fees and expenses and settlement costs, have not been material, all known deductibles have been satisfied or are inapplicable, and the subsidiary's defense fees and expenses and costs of settlement have been met by insurance made available to the subsidiary. The subsidiary continues to be named as a defendant in additional lawsuits, and we cannot predict the number of additional cases in which it may be named a defendant nor can we predict the potential costs to resolve such additional cases or to resolve the pending cases. However, the subsidiary has in excess of $1 billion in insurance limits potentially available to the subsidiary. Although not all of the policies may be fully available due to the insolvency of certain insurers, we believe that the subsidiary will have sufficient funding from settlements and claims payments from insurers, assigned rights from insurers and "coverage-in-place" settlement agreements with insurers to respond to these claims. While we cannot predict or provide assurance as to the final outcome of these matters, we do not believe that the current value of the claims where we have been identified will have a material impact on our consolidated statement of financial position, results of operations or cash flows.

Rio de Janeiro tax assessment-In the third quarter of 2006, we received tax assessments of approximately $188 million from the state tax authorities of Rio de Janeiro in Brazil against one of our Brazilian subsidiaries for taxes on equipment imported into the state in connection with our operations. The assessments resulted from a preliminary finding by these authorities that our subsidiary's record keeping practices were deficient. We currently believe that the substantial majority of these assessments are without merit. We filed an initial response with the Rio de Janeiro tax authorities on September 9, 2006 refuting these additional tax assessments. In September 2007, we received confirmation from the state tax authorities that they believe the additional tax assessments are valid, and as a result, we filed an appeal on September 27, 2007 to the state Taxpayer's Council contesting these assessments. While we cannot predict or provide assurance as to the final outcome of these proceedings, we do not expect it to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

Brazilian import license assessment-In the fourth quarter of 2010, one of our Brazilian subsidiaries received an assessment from the Brazilian federal tax authorities in Rio de Janeiro of approximately $235 million based upon the alleged failure to timely apply for import licenses for certain equipment and for allegedly providing improper information on import license applications. We responded to the assessment on December 22, 2010, and we currently believe that a substantial majority of the assessment is without merit. While we cannot predict or provide assurance as to the final outcome of these proceedings, we do not expect it to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

Patent litigation-In 2007, several of our subsidiaries were sued by Heerema Engineering Services ("Heerema") in the United States District Court for the Southern District of Texas for patent infringement, claiming that we infringe their U.S. patent entitled Method and Device for Drilling Oil and Gas. Heerema claims that our Enterprise class, advanced Enterprise class, Express class and Development Driller class of drilling rigs operating in the U.S. Gulf of Mexico infringe on this patent. Heerema seeks unspecified damages and injunctive relief. The court has held a hearing on construction of Heerema's patent but has not yet issued a decision. We deny liability for patent infringement, believe that Heerema's patent is invalid and intend to vigorously defend against the claim. We do not expect the liability, if any, resulting from this claim to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

Other matters-We are involved in various tax matters and various regulatory matters. We are also involved in lawsuits relating to damage claims arising out of hurricanes Katrina and Rita, all of which are insured and which are not material to us. In addition, as of December 31, 2010, we were involved in a number of other lawsuits, including a dispute for municipal tax payments in Brazil and a dispute involving customs procedures in India, neither of which is material to us, and all of which have arisen in the ordinary course of our business. We do not expect the liability, if any, resulting from these other matters to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. We cannot predict with certainty the outcome or effect of any of the litigation matters specifically described above or of any such other pending or threatened litigation. There can be no assurance that our beliefs or expectations as to the outcome or effect of any lawsuit or other litigation matter will prove correct and the eventual outcome of these matters could materially differ from management's current estimates.

Other environmental matters

Hazardous waste disposal sites-We have certain potential liabilities under the Comprehensive Environmental Response, Compensation and Liability Act ("CERCLA") and similar state acts regulating cleanup of various hazardous waste disposal sites, including those described below. CERCLA is intended to expedite the remediation of hazardous substances without regard to fault. Potentially responsible parties ("PRPs") for each site include present and former owners and operators of, transporters to and generators of the substances at the site. Liability is strict and can be joint and several.

We have been named as a PRP in connection with a site located in Santa Fe Springs, California, known as the Waste Disposal, Inc. site. We and other PRPs have agreed with the U.S. Environmental Protection Agency ("EPA") and the DOJ to settle our potential liabilities for this site by agreeing to perform the remaining remediation required by the EPA. The form of the agreement is a consent decree, which has been entered by the court. The parties to the settlement have entered into a participation agreement, which makes us liable for approximately eight percent of the remediation and related costs. The remediation is complete, and we believe our share of the future operation and maintenance costs of the site is not material. There are additional potential liabilities related to the site, but these cannot be quantified, and we have no reason at this time to believe that they will be material.

One of our subsidiaries has been ordered by the California Regional Water Quality Control Board ("CRWQCB") to develop a testing plan for a site known as Campus 1000 Fremont in Alhambra, California. This site was formerly owned and operated by certain of our subsidiaries. It is presently owned by an unrelated party, which has received an order to test the property. We have also been advised that one or more of our subsidiaries is likely to be named by the EPA as a PRP for the San Gabriel Valley, Area 3, Superfund site, which includes this property. Testing has been completed at the property but no contaminants of concern were detected. In discussions with CRWQCB staff, we were advised of their intent to issue us a "no further action" letter but it has not yet been received. Based on the test results, we would contest any potential liability. We have no knowledge at this time of the potential cost of any remediation, who else will be named as PRPs, and whether in fact any of our subsidiaries is a responsible party. The subsidiaries in question do not own any operating assets and have limited ability to respond to any liabilities.

Resolutions of other claims by the EPA, the involved state agency or PRPs are at various stages of investigation. These investigations involve determinations of:

�	the actual responsibility attributed to us and the other PRPs at the site;

�	appropriate investigatory or remedial actions; and

�	allocation of the costs of such activities among the PRPs and other site users.

Our ultimate financial responsibility in connection with those sites may depend on many factors, including:

�	the volume and nature of material, if any, contributed to the site for which we are responsible;

�	the numbers of other PRPs and their financial viability; and

�	the remediation methods and technology to be used.

It is difficult to quantify with certainty the potential cost of these environmental matters, particularly in respect of remediation obligations. Nevertheless, based upon the information currently available, we believe that our ultimate liability arising from all environmental matters, including the liability for all other related pending legal proceedings, asserted legal claims and known potential legal claims which are likely to be asserted, is adequately accrued and should not have a material effect on our financial position, or ongoing results of operations. Estimated costs of future expenditures for environmental remediation obligations are not discounted to their present value.

Contamination litigation

On July 11, 2005, one of our subsidiaries was served with a lawsuit filed on behalf of three landowners in Louisiana in the 12th Judicial District Court for the Parish of Avoyelles, State of Louisiana. The lawsuit named 19 other defendants, all of which were alleged to have contaminated the plaintiffs' property with naturally occurring radioactive material, produced water, drilling fluids, chlorides, hydrocarbons, heavy metals and other contaminants as a result of oil and gas exploration activities. Experts retained by the plaintiffs issued a report suggesting significant contamination in the area operated by the subsidiary and another codefendant, and claimed that over $300 million would be required to properly remediate the contamination. The experts retained by the defendants conducted their own investigation and concluded that the remediation costs would amount to no more than $2.5 million.

The plaintiffs and the codefendant threatened to add GlobalSantaFe as a defendant in the lawsuit under the "single business enterprise" doctrine contained in Louisiana law. The single business enterprise doctrine is similar to corporate veil piercing doctrines. On August 16, 2006, our subsidiary and its immediate parent company, each of which is an entity that no longer conducts operations or holds assets, filed voluntary petitions for relief under Chapter 11 of the U.S. Bankruptcy Code in the U.S. Bankruptcy Court for the District of Delaware. Later that day, the plaintiffs dismissed our subsidiary from the lawsuit. Subsequently, the codefendant filed various motions in the lawsuit and in the Delaware bankruptcies attempting to assert alter ego and single business enterprise claims against GlobalSantaFe and two other subsidiaries in the lawsuit. The efforts to assert alter ego and single business enterprise theory claims against GlobalSantaFe were rejected by the Court in Avoyelles Parish, and the lawsuit against the other defendant went to trial on February 19, 2007. This lawsuit was resolved at trial with a settlement by the codefendant that included a $20 million payment and certain cleanup activities to be conducted by the codefendant. The codefendant further claimed to receive a right to continue to pursue the original plaintiff's claims.

The codefendant sought to dismiss the bankruptcies. In addition, the codefendant filed proofs of claim against both our subsidiary and its parent with regard to its claims arising out of the settlement of the lawsuit. On February 15, 2008, the Bankruptcy Court denied the codefendant's request to dismiss the bankruptcy case but modified the automatic stay to allow the codefendant to proceed on its claims against the debtors, our subsidiary and its parent, and their insurance companies. The codefendant subsequently filed suit against the debtors and certain of its insurers in the Court of Avoyelles Parish to determine their liability for the settlement. The denial of the motion to dismiss the bankruptcies was appealed. On appeal the bankruptcy cases were ordered to be dismissed, and the bankruptcies were dismissed on June 14, 2010.

On March 10, 2010, GlobalSantaFe and the two subsidiaries filed a declaratory judgment action in State District Court in Houston, Texas against the codefendant and the debtors seeking a declaration that GlobalSantaFe and the two subsidiaries had no liability under legal theories advanced by the codefendant. This action is currently stayed.

On March 11, 2010, the codefendant filed a motion for leave to amend the pending litigation in Avoyelles Parish to add GlobalSantaFe, Transocean Worldwide Inc., its successor and our wholly owned subsidiary, and one of the subsidiaries as well as various additional insurers. Leave to amend was granted and the amended petition was filed. An extension to respond for all purposes was agreed until April 28, 2010 for the debtors, GlobalSantaFe, Transocean Worldwide Inc. and the subsidiary. On April 28, 2010, GlobalSantaFe and its two subsidiaries filed various exceptions seeking dismissal of the Avoyelles Parish lawsuit, which have been denied. Subsequent to denial supervisory writs were filed with the Third Circuit Court of Appeals for the State of Louisiana.

On December 15, 2010, as permitted under the existing Case Management Order, GlobalSantaFe and various subsidiaries served third-party demands joining various insurers in the Avoyelles Parish lawsuit seeking insurance coverage for the claims brought against GlobalSantaFe and various subsidiaries.

We believe that these legal theories should not be applied against GlobalSantaFe or Transocean Worldwide Inc. Our subsidiary, its parent and GlobalSantaFe intend to continue to vigorously defend against any action taken in an attempt to impose liability against them under the theories discussed above or otherwise and believe they have good and valid defenses thereto. We do not believe that these claims will have a material impact on our consolidated statement of financial position, results of operations or cash flows.

Retained risk

Our hull and machinery and excess liability insurance program consists of commercial market and captive insurance policies primarily with 12-month and 11-month policy periods beginning on May 1, 2010 and June 1, 2010, respectively.

Under the hull and machinery program, we generally maintain a $125 million per occurrence deductible, limited to a maximum of $250 million per policy period. Subject to the same shared deductible, we also have coverage for costs incurred to mitigate damage to a rig up to an amount equal to 25 percent of a rig's insured value. Also subject to the same shared deductible, we have coverage for wreck removal for an amount up to 25 percent of a rig's insured value, with any excess generally covered to the extent of our excess liability coverage described below. However, the shared deductible is $0 in the event of a total loss or a constructive total loss of a drilling unit.

We carry $950 million of commercial market excess liability coverage, exclusive of deductibles and self-insured retention, noted below, which generally covers offshore risks such as personal injury, third-party property claims, and third-party non-crew claims, including wreck removal and pollution. Our excess liability coverage has separate (1) $10 million per occurrence deductibles on crew personal injury liability and on collision liability claims and (2) a separate $5 million per occurrence deductible on other third-party non-crew claims. These types of excess liability coverages are subject to an additional aggregate self-insured retention of $50 million that is applied to any occurrence in excess of the per occurrence deductible until the $50 million is exhausted. We generally retain the risk for any liability losses in excess of $1.0 billion.

We also carry $100 million of additional insurance that generally covers expenses that would otherwise be assumed by the well owner, such as costs to control the well, redrill expenses and pollution from the well. This additional insurance provides coverage for such expenses in circumstances in which we have legal or contractual liability arising from our gross negligence or willful misconduct. As of December 31, 2010, the insured value of our drilling rig fleet was approximately $38.5 billion in the aggregate, excluding rigs under construction.

We have elected to self-insure operators extra expense coverage for ADTI and CMI. This coverage provides protection against expenses related to well control, pollution and redrill liability associated with blowouts. ADTI's customers assume, and indemnify ADTI for, liability associated with blowouts in excess of a contractually agreed amount, generally $50 million.

We generally do not have commercial market insurance coverage for physical damage losses, including liability for wreck removal expenses, to our fleet caused by named windstorms in the U.S. Gulf of Mexico and war perils worldwide. Except with respect to Dhirubhai Deepwater KG1 and Dhirubhai Deepwater KG2, we generally do not carry insurance for loss of revenue unless contractually required.

Letters of credit and surety bonds

We had letters of credit outstanding totaling $595 million and $567 million at December 31, 2010 and December 31, 2009, respectively. These letters of credit guarantee various import duties, contract bidding and performance activities under various committed and uncommitted credit lines provided by several banks.

In April 2010, TPDI obtained a letter of credit in the amount of $60 million to satisfy its liquidity requirements under the TPDI Credit Facilities, which is included in the total as of December 31, 2010. The letter of credit was issued under an uncommitted credit facility that has been established by one of our subsidiaries. See Note 11-Debt.

As is customary in the contract drilling business, we also have various surety bonds in place that secure customs obligations relating to the importation of our rigs and certain performance and other obligations. Surety bonds outstanding totaled $27 million and $31 million at December 31, 2010 and December 31, 2009, respectively.

Redeemable Noncontrolling Interest

12 Months Ended

Dec. 31, 2010

Redeemable Noncontrolling Interest

In October 2010, Pacific Drilling's interest in TPDI became redeemable, and we reclassified to temporary equity the carrying amount associated with its interest (see Note 4-Variable Interest Entities). Changes in redeemable noncontrolling interest were as follows:

	Years ended December 31,
		2010		2009		2008
Redeemable noncontrolling interest
Balance, beginning of period	$	-		$	-	$	-
Reclassification from noncontrolling interest		26			-		-
Net income attributable to noncontrolling interest (a)		13			-		-
Other comprehensive income attributable to noncontrolling interest (a)		(14	)		-		-
Balance, end of period	$	25		$	-	$	-

______________________________

(a)	Amounts represent activity following reclassification to temporary equity in October 2010.

Equity	12 Months Ended
Equity	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Equity	Shares held by subsidiary-In connection with the Redomestication Transaction in December 2008, we issued 16 million of our shares to one of our subsidiaries for future use to satisfy our obligations to deliver shares in connection with awards granted under our incentive plans or other rights to acquire our shares. At December 31, 2010 and December 31, 2009, our subsidiary held 13,291,353 shares and 14,011,416 shares, respectively. Share repurchase program-In May 2009, at our annual general meeting, our shareholders approved and authorized our board of directors, at its discretion, to repurchase an amount of our shares for cancellation with an aggregate purchase price of up to CHF 3.5 billion, which is equivalent to approximately $3.8 billion, using an exchange rate of USD 1.00 to CHF 0.93 as of the close of trading on December 31, 2010. On February 12, 2010, our board of directors authorized our management to implement the share repurchase program. During the year ended December 31, 2010, following the authorization by our board of directors, we repurchased 2,863,267 of our shares under our share repurchase program for an aggregate purchase price of CHF 257 million, equivalent to $240 million. At December 31, 2010, we held 2,863,267 treasury shares purchased under our share repurchase program, recorded at cost. Distribution-In May 2010, at our annual general meeting, our shareholders approved a cash distribution in the form of a par value reduction in the aggregate amount of CHF 3.44 per issued share, equal to approximately $3.70, using an exchange rate of USD 1.00 to CHF 0.93 as of the close of trading on December 31, 2010. According to the May 2010 shareholder resolution and pursuant to applicable Swiss law, we were required to submit an application to the Commercial Register of the Canton of Zug in relation to each quarterly installment to register the relevant partial par value reduction, together with, among other things, a compliance deed issued by an independent notary public. On August 13, 2010, the Commercial Register of the Canton of Zug rejected our application to register the first of the four partial par value reductions. We appealed the Commercial Register's decision, and on December 9, 2010, the Administrative Court of the Canton of Zug rejected our appeal. The Administrative Court held that the statutory requirements for the registration of the par value reduction in the commercial register could not be met given the existence of lawsuits filed in the United States related to the Macondo well incident that were served in Switzerland and the reference to such lawsuits in the compliance deed. The Administrative Court's opinion also held that under these circumstances it was not possible to submit an amended compliance deed. Based on these considerations, we do not believe that a financial obligation existed for the distribution. See Note 25-Subsequent Events.

Disclosures related to accounts comprising shareholders' equity, including other comprehensive income. Includes: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables; effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

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Share based compensation

12 Months Ended

Dec. 31, 2010

Share based compensation

Overview-We have (i) a long-term incentive plan (the "Long-Term Incentive Plan") for executives, key employees and outside directors under which awards can be granted in the form of stock options, restricted shares, deferred units, SARs and cash performance awards and (ii) other incentive plans under which awards are currently outstanding. Awards that may be granted under the Long-Term Incentive Plan include traditional time-vesting awards ("time-based awards") and awards that are earned based on the achievement of certain performance criteria ("performance-based awards") or market factors ("market-based awards"). Our executive compensation committee of our board of directors determines the terms and conditions of the awards granted under the Long-Term Incentive Plan. As of December 31, 2010, we had 36 million shares authorized and 16 million shares available to be granted under the Long-Term Incentive Plan.

Time-based awards typically vest either in three equal annual installments beginning on the first anniversary date of the grant or in an aggregate installment at the end of the stated vesting period. Performance-based and market-based awards are typically awarded subject to either a two-year or a three-year measurement period during which the number of options, shares or deferred units remains uncertain. At the end of the measurement period, the awarded number of options, shares or deferred units is determined (the "determination date") subject to the stated vesting period. The two-year awards generally vest in three equal installments beginning on the determination date and on January 1 of each of the two subsequent years. The three-year awards generally vest in one aggregate installment following the determination date. Once vested, options and SARs generally have a 10-year term during which they are exercisable.

In connection with the Redomestication Transaction, we adopted and assumed the Long-Term Incentive Plan and other employee benefit plans and arrangements of Transocean Inc., and those plans and arrangements were amended as necessary to give effect to the Redomestication Transaction, including to provide (1) that our shares will be issued, held, available or used to measure benefits as appropriate under the plans and arrangements, in lieu of Transocean Inc. ordinary shares, including upon exercise of any options or SARs issued under those plans and arrangements; and (2) for the appropriate substitution of us for Transocean Inc. in those plans and arrangements. Additionally, we issued 16 million of our shares to Transocean Inc., 13 million of which remained available as of December 31, 2010, for future use to satisfy our obligations to deliver shares in connection with awards granted under incentive plans, warrants or other rights to acquire our shares (see Note 16-Shareholders' Equity).

As of December 31, 2010, total unrecognized compensation costs related to all unvested share-based awards totaled $99 million, which is expected to be recognized over a weighted-average period of 1.8 years. During the years ended December 31, 2010 and 2009, we recognized additional share-based compensation expense of $12 million and $8 million, respectively, in connection with modifications of share-based awards. During the year ended December 31, 2008, we did not recognize a significant amount of additional share-based compensation expense in connection with modifications of share-based awards.

Option valuation assumptions-We estimated the fair value of each option award under the Long-Term Incentive Plan on the grant date using the Black-Scholes-Merton option-pricing model with the following weighted-average assumptions:

	Years ended December 31,
	2010		2009		2008
Dividend yield		4%		-		-
Expected price volatility		39%		49%		36%
Risk-free interest rate		2.30%		1.80%		3.00%
Expected life of options		4.7 years		4.8 years		4.4 years
Weighted-average fair value of options granted	$	30.03	$	26.07	$	49.32

We estimated the fair value of each option grant under the Employee Stock Purchase Plan ("ESPP") using the Black-Scholes-Merton option-pricing model with the following weighted-average assumptions:

	Years ended December 31,
	2010 (a)		2009 (a)		2008
Dividend yield		-		-		-
Expected price volatility		-		-		31%
Risk-free interest rate		-		-		3.15%
Expected life of options		-		-		1.0 year
Weighted-average fair value of options granted	$	-	$	-	$	41.39

______________________________

(a)	As of January 1, 2009, we discontinued offering the ESPP.

Time-Based Awards

Stock options-The following table summarizes vested and unvested time-based vesting stock option ("time-based options") activity under our incentive plans during the year ended December 31, 2010:

	Number of shares under option		Weighted-average exercise price per share		Weighted-average remaining contractual term (years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2010	1,828,655		$	60.69	4.96	$	40
Granted	253,288			82.55
Exercised	(289,445	)		42.26
Forfeited	(138,815	)		71.37
Outstanding at December 31, 2010	1,653,683		$	66.37	5.29	$	5

Vested and exercisable at December 31, 2010	1,183,283		$	61.28	3.99	$	10

The weighted-average grant-date fair value of time-based options granted during the year ended December 31, 2010 was $30.03 per share. The total pretax intrinsic value of time-based options exercised during the year ended December 31, 2010 was $11 million. There were 470,400 unvested time-based options outstanding as of December 31, 2010.

There were time-based options to purchase 597,898 and 276,281 shares granted during the years ended December 31, 2009 and 2008, respectively, with weighted-average grant-date fair values of $26.07 and $49.32 per share, respectively. There were 980,105 and 1,066,173 time-based options exercised during the years ended December 31, 2009 and 2008, respectively. The total pretax intrinsic value of time-based options exercised was $43 million and $101 million during the years ended December 31, 2009 and 2008, respectively. There were 656,790 and 273,314 unvested time-based options outstanding as of December 31, 2009 and 2008, respectively.

Restricted shares-The following table summarizes unvested share activity for time-based vesting restricted shares ("time-based shares") granted under our incentive plans during the year ended December 31, 2010:

	Number of shares		Weighted-average grant-date fair value per share
Unvested at January 1, 2010	98,386		$	112.14
Vested	(92,573	)		111.32
Forfeited	(1,874	)		109.97
Unvested at December 31, 2010	3,939		$	132.32

We did not grant any time-based shares during the years ended December 31, 2010 and 2009. There were 259,057 time-based shares granted during the year ended December 31, 2008. The weighted-average grant-date fair value of time-based shares granted was $126.26 per share for the year ended December 31, 2008. There were 320,782 and 129,979 time-based shares that vested during the years ended December 31, 2009 and 2008, respectively. The total grant-date fair value of time-based shares that vested was $10 million, $39 million and $14 million for the years ended December 31, 2010, 2009 and 2008, respectively.

Deferred units-A deferred unit is a unit that is equal to one share but has no voting rights until the underlying shares are issued. The following table summarizes unvested activity for time-based vesting deferred units ("time-based units") granted under our incentive plans during the year ended December 31, 2010:

	Number of units		Weighted-average grant-date fair value per share
Unvested at January 1, 2010	1,455,447		$	76.58
Granted	1,055,367			76.83
Vested	(559,339	)		81.11
Forfeited	(106,691	)		78.65
Unvested at December 31, 2010	1,844,784		$	75.23

The total grant-date fair value of the time-based units vested during the year ended December 31, 2010 was $45 million.

There were 1,287,893 and 498,216 time-based units granted during the years ended December 31, 2009 and 2008, respectively. The weighted-average grant-date fair value of time-based units granted was $60.53 and $143.85 per share for the years ended December 31, 2009 and 2008, respectively. There were 282,543 and 25,740 time-based units that vested during the years ended December 31, 2009 and 2008, respectively. The total grant-date fair value of deferred units that vested was $33 million and $3 million for the years ended December 31, 2009 and 2008, respectively.

SARs-The following table summarizes share-settled SARs activity under our incentive plans during the year ended December 31, 2010:

	Number of awards	Weighted-average exercise price per share		Weighted-average remaining contractual term (years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2010	189,139	$	93.28	6.76	$	-
Outstanding at December 31, 2010	189,139	$	93.28	5.76	$	-

Vested and exercisable at December 31, 2010	189,139	$	93.28	5.76	$	-

At January 1 and December 31, 2010, we have presented the aggregate intrinsic value as zero since the weighted-average exercise price per share exceeded the market price of our shares on those dates. We did not grant share-settled SARs during the years ended December 31, 2010, 2009, and 2008. There were no performance-based options exercised during the year ended December 31, 2010. There were 224 and 315,408 share-settled SARs exercised, with a total pretax intrinsic value of zero, during the years ended December 31, 2009 and 2008, respectively. There were no unvested share-settled SARs outstanding as of December 31, 2010, 2009 and 2008.

Performance-Based Awards

Stock options-We grant performance-based stock options ("performance-based options") that can be earned depending on the achievement of certain performance targets. The number of options earned is quantified upon completion of the performance period at the determination date. The following table summarizes vested and unvested performance-based option activity under our incentive plans during the year ended December 31, 2010:

	Number of shares under option	Weighted-average exercise price per share		Weighted-average remaining contractual term (years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2010	179,262	$	75.30	6.22	$	1
Outstanding at December 31, 2010	179,262	$	75.30	5.22	$	-

Vested and exercisable at December 31, 2010	179,262	$	75.30	5.22	$	-

At December 31, 2010, we have presented the aggregate intrinsic value as zero since the weighted-average exercise price per share exceeded the market price of our shares on that date. We did not grant performance-based options during the years ended December 31, 2010, 2009 and 2008. There were no performance-based options exercised during the years ended December 31, 2010 and 2009. There were 212,840 performance-based options exercised, with a total pretax intrinsic value of $22 million, during the year ended December 31, 2008. There were no unvested performance-based stock options outstanding as of December 31, 2010, 2009 and 2008.

Market-Based Awards

Deferred units-We grant market-based deferred units ("market-based units") that can be earned depending on the achievement of certain market conditions. The number of units earned is quantified upon completion of the specified period at the determination date. The following table summarizes unvested activity for market-based units granted under our incentive plans during the year ended December 31, 2010:

	Number of units		Weighted-average grant-date fair value per share
Unvested at January 1, 2010	330,870		$	93.70
Granted	122,934			82.55
Forfeited	(30,898	)		84.48
Unvested at December 31, 2010	422,906		$	89.14

There were 285,012 and 99,464 market-based units granted with a weighted-average grant-date fair value of $75.98 and $144.32 per share during the years ended December 31, 2009 and 2008, respectively. No market-based units vested in the years ended December 31, 2009 and 2008.

ESPP-Through December 31, 2008, we offered an ESPP under which certain full-time employees could choose to have between two and 20 percent of their annual base earnings withheld to purchase up to $21,150 of our shares each year. The purchase price of the shares was 85 percent of the lower of the beginning-of-year or end-of-year market price of our shares. At December 31, 2008, 577,537 shares were available for issuance under the ESPP. As of January 1, 2009, we discontinued offering the ESPP.

Supplemental Balance Sheet Information

12 Months Ended

Dec. 31, 2010

Supplemental Balance Sheet Information

Other current liabilities were comprised of the following (in millions):

	December 31,
	2010		2009
Other current liabilities
Accrued payroll and employee benefits	$	272	$	263
Deferred revenue		150		147
Accrued taxes, other than income		123		102
Accrued interest		97		83
Unearned income		15		15
Other		204		120
Total other current liabilities	$	861	$	730

Other long-term liabilities were comprised of the following (in millions):

	December 31,
	2010		2009
Other long-term liabilities
Long-term income taxes payable	$	655	$	594
Accrued pension liabilities		416		453
Deferred revenue		393		214
Drilling contract intangibles		152		268
Accrued retiree life insurance and medical benefits		53		51
Other		103		104
Total other long-term liabilities	$	1,772	$	1,684

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2010

Fair Value of Financial Instruments

We estimate the fair value of each class of financial instruments, for which estimating fair value is practicable, by applying the following methods and assumptions:

Cash and cash equivalents-The carrying amount of cash and cash equivalents, which are stated at cost plus accrued interest, approximates fair value because of the short maturities of those instruments.

Accounts receivable-The carrying amount, net of valuation allowance, approximates fair value because of the short maturities of those instruments.

Short-term investments-The carrying amount of our short-term investments approximates fair value and represents our estimate of the amount we expect to recover. Our short-term investments primarily include our investment in The Reserve International Liquidity Fund Ltd. At December 31, 2010, we did not hold any short-term investments. At December 31, 2009, the carrying amount of our short-term investments was $38 million, recorded in other current assets on our consolidated balance sheets (see Note 21-Supplemental Cash Flow Information).

Notes receivable and working capital loan receivable-The carrying amount represents the estimated fair value, measured using unobservable inputs that require significant judgment, for which there is little or no market data, including the credit rating of the borrower. At December 31, 2010, the aggregate carrying amount of our notes receivable and working capital loan receivable was $115 million, including $4 million and $111 million recorded in other current assets and other assets, respectively. We did not hold notes receivable as of December 31, 2009.

Debt-The fair value of our fixed-rate debt is measured using direct or indirect observable inputs, including quoted prices or other market data, for similar assets or liabilities in active markets or identical assets or liabilities in less active markets. Our variable-rate debt is included in the fair values stated below at its carrying amount since the short-term interest rates cause the face value to approximate its fair value. The TPDI Notes and ODL Loan Facility are included in the fair values stated below at their aggregate carrying amount of $158 million at December 31, 2010 and December 31, 2009, since there is no available market price for such related-party debt (see Note 23-Related Party Transactions). The carrying amounts and estimated fair values of our long-term debt, including debt due within one year, were as follows (in millions):

	December 31, 2010				December 31, 2009
	Carrying amount		Fair value		Carrying amount		Fair value
Long-term debt, including current maturities	$	10,271	$	10,562	$	10,534	$	11,218
Long-term debt of consolidated variable interest entities, including current maturities		950		964		1,183		1,178

Derivative instruments-The carrying amount of our derivative instruments represents the estimated fair value, measured using direct or indirect observable inputs, including quoted prices or other market data for similar assets or liabilities in active markets or identical assets or liabilities in less active markets. At December 31, 2010, the carrying amounts of our derivative instruments were $17 million and $13 million, recorded in other assets and other long-term liabilities, respectively, on our consolidated balance sheets. At December 31, 2009, the carrying amounts of our derivative instruments were $5 million and $5 million, recorded in other assets and other long-term liabilities, respectively, on our consolidated balance sheets.

This item represents the complete disclosure regarding the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the Company is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risk is are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

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Financial Instruments and Risk Concentration	12 Months Ended
Financial Instruments and Risk Concentration	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Financial Instruments and Risk Concentration	Interest rate risk-Financial instruments that potentially subject us to concentrations of interest rate risk include our cash equivalents, short-term investments, debt and capital lease obligations. We are exposed to interest rate risk related to our cash equivalents and short-term investments, as the interest income earned on these investments changes with market interest rates. Floating rate debt, where the interest rate can be adjusted every year or less over the life of the instrument, exposes us to short-term changes in market interest rates. Fixed rate debt, where the interest rate is fixed over the life of the instrument and the instrument's maturity is greater than one year, exposes us to changes in market interest rates when we refinance maturing debt with new debt. From time to time, we may use interest rate swap agreements to manage the effect of interest rate changes on future income. These derivatives are used as hedges and are not used for speculative or trading purposes. Interest rate swaps are designated as a hedge of underlying future interest payments. These agreements involve the exchange of amounts based on variable interest rates and amounts based on a fixed interest rate over the life of the agreement without an exchange of the notional amount upon which the payments are based. The interest rate differential to be received or paid on the swaps is recognized over the lives of the swaps as an adjustment to interest expense. Gains and losses on terminations of interest rate swap agreements are deferred and recognized as an adjustment to interest expense over the remaining life of the underlying debt. In the event of the early retirement of a designated debt obligation, any realized or unrealized gain or loss from the swap would be recognized in income. Foreign exchange risk-Our international operations expose us to foreign exchange risk. This risk is primarily associated with compensation costs denominated in currencies other than the U.S. dollar, which is our functional currency, and with purchases from foreign suppliers. We use a variety of techniques to minimize the exposure to foreign exchange risk, including customer contract payment terms and, from time to time, the use of foreign exchange derivative instruments. Our primary foreign exchange risk management strategy involves structuring customer contracts to provide for payment in both U.S. dollars and local currency. The payment portion denominated in local currency is based on anticipated local currency requirements over the contract term. Due to various factors, including customer acceptance, local banking laws, other statutory requirements, local currency convertibility and the impact of inflation on local costs, actual foreign exchange needs may vary from those anticipated in the customer contracts, resulting in partial exposure to foreign exchange risk. Fluctuations in foreign currencies typically have not had a material impact on overall results. In situations where payments of local currency do not equal local currency requirements, we may use foreign exchange derivative instruments, specifically foreign exchange forward contracts, or spot purchases, to mitigate foreign currency risk. A foreign exchange forward contract obligates us to exchange predetermined amounts of specified foreign currencies at specified exchange rates on specified dates or to make an equivalent U.S. dollar payment equal to the value of such exchange. We do not enter into derivative transactions for speculative purposes. Gains and losses on foreign exchange derivative instruments that qualify as accounting hedges are deferred as other comprehensive income and recognized when the underlying foreign exchange exposure is realized. Gains and losses on foreign exchange derivative instruments that do not qualify as hedges for accounting purposes are recognized currently based on the change in market value of the derivative instruments. At December 31, 2010 and 2009, we had no outstanding foreign exchange derivative instruments. Credit risk-Financial instruments that potentially subject us to concentrations of credit risk are primarily cash and cash equivalents, short-term investments and trade receivables. It is our practice to place our cash and cash equivalents in time deposits at commercial banks with high credit ratings or mutual funds, which invest exclusively in high quality money market instruments. We limit the amount of exposure to any one institution and do not believe we are exposed to any significant credit risk. We derive the majority of our revenue from services to international oil companies, government-owned and government-controlled oil companies. Receivables are dispersed in various countries (see Note 22-Segments, Geographical Analysis and Major Customers). We maintain an allowance for doubtful accounts receivable based upon expected collectability and establish reserves for doubtful accounts on a case-by-case basis when we believe the required payment of specific amounts owed to us is unlikely to occur. Although we have encountered isolated credit concerns related to independent oil companies, we are not aware of any significant credit risks related to our customer base and do not generally require collateral or other security to support customer receivables. Labor agreements-We require highly skilled personnel to operate our drilling units. We conduct extensive personnel recruiting, training and safety programs. At December 31, 2010, we had approximately 18,050 employees, including approximately 1,950 persons engaged through contract labor providers. Some of our employees working in Angola, the U.K., Norway and Australia, are represented by, and some of our contracted labor work under, collective bargaining agreements. Many of these represented individuals are working under agreements that are subject to annual salary negotiation. These negotiations could result in higher personnel expenses, other increased costs or increased operational restrictions as the outcome of such negotiations apply to all offshore employees not just the union members. Additionally, the unions in the U.K. sought an interpretation of the application of the Working Time Regulations to the offshore sector. Although the Employment Tribunal endorsed the unions' position that offshore workers are entitled to 28 days of annual leave, at the subsequent appeals to date, both the Employment Appeal Tribunal and the Court of Session have reversed the Employment Tribunal's decision. However, the unions have intimated their intention to lodge a further appeal to the Supreme Court which may not be heard until the fourth quarter of 2011 or 2012. The application of the Working Time Regulations to the offshore sector could result in higher labor costs and could undermine our ability to obtain a sufficient number of skilled workers in the U.K. Legislation has been introduced in the U.S. Congress that could encourage additional unionization efforts in the U.S., as well as increase the chances that such efforts succeed. Additional unionization efforts, if successful, new collective bargaining agreements or work stoppages could materially increase our labor costs and operating restrictions.

Supplemental Cash Flow Information

12 Months Ended

Dec. 31, 2010

Supplemental Cash Flow Information

We include investments in highly liquid debt instruments with an original maturity of three months or less in cash and cash equivalents. In September 2008, The Reserve announced that certain funds, including The Reserve Primary Fund and The Reserve International Liquidity Fund Ltd. (together, the "Reserve Funds"), had lost the ability to maintain a net asset value of $1.00 per share due to losses in connection with the bankruptcy of Lehman Brothers Holdings, Inc. ("Lehman Holdings"). According to its public disclosures, The Reserve stopped processing redemption requests in order to develop an orderly plan of liquidation that would protect all of the funds' shareholders. At the time of The Reserve's announcements, we had an aggregate investment of $408 million in the Reserve Funds. We collected $37 million, $296 million and $58 million from the Reserve Funds in the years ended December 31, 2010, 2009 and 2008, respectively. As of December 31, 2010, we had collected our total expected recoveries from the Reserve Funds, having recognized losses on impairment of $1 million and $16 million, recorded in other, net in the years ended December 31, 2010 and 2008, respectively. There was no loss on impairment for the year ended December 31, 2009.

Net cash provided by (used in) operating activities attributable to the net change in operating assets and liabilities were composed of the following (in millions):

	Years ended December 31,
	2010			2009			2008
Changes in operating assets and liabilities
Decrease (increase) in accounts receivable	$	386		$	504		$	(501	)
Increase in other current assets		(75	)		(50	)		(118	)
Increase in other assets		(40	)		(30	)		(8	)
Increase (decrease) in accounts payable and other current liabilities		227			(60	)		75
Decrease in other long-term liabilities		(52	)		(7	)		(43	)
Change in income taxes receivable / payable, net		(37	)		77			274
	$	409		$	434		$	(321	)

Additional cash flow information were as follows (in millions):

	Years ended December 31,
	2010		2009		2008
Certain cash operating activities
Cash payments for interest	$	641	$	683	$	545
Cash payments for income taxes		493		663		461

Non-cash investing and financing activities
Capital expenditures, accrued at end of period (a)	$	69	$	139	$	268
Asset capitalized under capital leases (b)		-		716		-
Non-cash proceeds received for the sale of assets (c)		134		-		-

______________________________

(a)	These amounts represent additions to property and equipment for which we had accrued a corresponding liability in accounts payable.

(b)	On August 4, 2009, we accepted delivery of Petrobras 10000 and recorded non-cash additions of $716 million to property and equipment, net along with a corresponding increase to long-term debt. See Note 11-Debt and Note 14-Commitments and Contingencies.

(c)

During the year ended December 31, 2010, we completed the sale of two Midwater Floaters, GSF Arctic II and GSF Arctic IV. In connection with the sale, we received net cash proceeds of $38 million and non-cash proceeds in the form of two notes receivable in the aggregate face value amount of $165 million. We recognized the notes receivable at their estimated fair value, in the aggregate amount of $134 million, measured at the time of the sale. See Note 4-Variable Interest Entities and Note 9-Drilling Fleet.

Segments, Geographical Analysis and Major Customers

12 Months Ended

Dec. 31, 2010

Segments, Geographical Analysis and Major Customers

We have established two reportable segments: (1) contract drilling services and (2) other operations. The drilling management services and oil and gas properties businesses do not meet the quantitative thresholds for determining reportable segments and are combined for reporting purposes in the other operations segment.

Our contract drilling services segment fleet operates in a single, global market for the provision of contract drilling services. The location of our rigs and the allocation of resources to build or upgrade rigs are determined by the activities and needs of our customers.

Operating revenues by country were as follows (in millions):

	Years ended December 31,
	2010		2009		2008
Operating revenues
U.S.	$	2,117	$	2,239	$	2,578
Brazil		1,288		1,108		547
U.K.		1,183		1,563		2,012
India		828		1,084		890
Other countries (a)		4,160		5,562		6,647
Total operating revenues	$	9,576	$	11,556	$	12,674

______________________________

(a)	Other countries represents countries in which we operate that individually had operating revenues representing less than 10 percent of total operating revenues earned.

Long-lived assets by country were as follows (in millions):

	December 31,
	2010		2009
Long-lived assets
U.S.	$	5,573	$	6,203
India		2,632		1,358
Brazil		2,472		1,433
South Korea		820		3,128
Other countries (a)		9,961		10,896
Total long-lived assets	$	21,458	$	23,018

______________________________

(a)	Other countries represents countries in which we operate that individually had long-lived assets representing less than 10 percent of total long-lived assets.

A substantial portion of our assets are mobile. Asset locations at the end of the period are not necessarily indicative of the geographic distribution of the revenues generated by such assets during the periods. Although we are organized under the laws of Switzerland, we do not conduct any operations and do not have operating revenues in Switzerland. At December 31, 2010 and 2009, we had $15 million and $19 million, respectively, of long-lived assets in Switzerland.

Our international operations are subject to certain political and other uncertainties, including risks of war and civil disturbances (or other events that disrupt markets), expropriation of equipment, repatriation of income or capital, taxation policies, and the general hazards associated with certain areas in which operations are conducted.

For the years ended December 31, 2010, 2009 and 2008, BP accounted for approximately 10 percent, 12 percent and 11 percent, respectively, of our operating revenues. The loss of this customer or other significant customers could have a material adverse effect on our results of operations.

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Related Party Transactions	Pacific Drilling Limited-We hold a 50 percent interest in TPDI, a consolidated British Virgin Islands joint venture company formed by us and Pacific Drilling, a Liberian company, to own and operate Dhirubhai Deepwater KG1 and Dhirubhai Deepwater KG2. Effective October 18, 2010, Pacific Drilling has the unilateral right to exchange its interest in the joint venture for our shares or cash, at an amount based on an appraisal of the fair value of the drillships, subject to certain adjustments. As of December 31, 2010 and 2009, TPDI had outstanding promissory notes in the aggregate amount of $296 million, of which $148 million was due to Pacific Drilling and was included in long-term debt on our consolidated balance sheet. Angco Cayman Limited-We hold a 65 percent interest in ADDCL, a consolidated Cayman Islands joint venture company formed to own and operate Discoverer Luanda. Angco Cayman Limited, a Cayman Islands company, holds the remaining 35 percent interest in ADDCL. Beginning January 31, 2016, Angco Cayman Limited will have the right to exchange its interest in the joint venture for cash at an amount based on the appraisal of the fair value of the drillship, subject to certain adjustments. Overseas Drilling Limited-We hold a 50 percent interest in ODL, an unconsolidated Cayman Islands joint venture company, which owns the Joides Resolution. Siem Offshore Invest AS owns the other 50 percent interest in ODL. Under a management services agreement with ODL, we provide certain operational and management services. We earned $2 million for these services in each of the years ended December 31, 2010, 2009 and 2008. We have a $10 million loan facility with ODL. ODL may demand repayment of the borrowings at any time upon five business days prior written notice, and any amounts due to us from ODL may be offset against the borrowings at the time of repayment. As of December 31, 2010 and 2009, $10 million was outstanding under this loan agreement.

This element may be used for the entire related party transactions disclosure as a single block of text. Disclosure may include: the nature of the relationship(s), a description of the transactions, the amount of the transactions, the effects of any change in the method of establishing the terms of the transaction from the previous period, stated interest rate, expiration date, terms and manner of settlement per the agreement with the related party, and amounts due to or from related parties. If the entity and one or more other entities are under common ownership or management control and this control affects the operating results or financial position, disclosure includes the nature of the control relationship even if there are no transactions between the entities. Disclosure may also include the aggregate amount of current and deferred tax expense for each statement of earnings presented where the entity is a member of a group that files a consolidated tax return, the amount of any tax related balances due to or from affiliates as of the date of each statement of financial position presented, the principal provisions of the method by which the consolidated amount of current and deferred tax expense is allocated to the members of the group and the nature and effect of any changes in that method. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References+ Details

Quarterly Results

12 Months Ended

Dec. 31, 2010

Quarterly Results (Unaudited)

Shown below are selected unaudited quarterly data. Amounts are rounded for consistency in presentation with no effect to the results of operations previously reported on Form 10-Q or Form 10-K.

	Three months ended
	March 31,		June 30,		September 30,		December 31,
	(In millions, except per share data)
2010
Operating revenues	$	2,602	$	2,505	$	2,309	$	2,160
Operating income (loss) (a)		926		957		645		(662	)
Net income (loss) attributable to controlling interest (a)		677		715		368		(799	)
Earnings (loss) per share
Basic	$	2.10	$	2.23	$	1.15	$	(2.51	)
Diluted	$	2.09	$	2.22	$	1.15	$	(2.51	)
Weighted-average shares outstanding
Basic		321		319		319		319
Diluted		322		320		319		319

2009
Operating revenues	$	3,118	$	2,882	$	2,823	$	2,733
Operating income (b)		1,319		1,121		957		1,003
Net income attributable to controlling interest (b)		942		806		710		723
Earnings per share
Basic	$	2.94	$	2.50	$	2.20	$	2.24
Diluted	$	2.93	$	2.49	$	2.19	$	2.24
Weighted-average shares outstanding
Basic		319		320		321		321
Diluted		320		321		322		322

______________________________

(a)	First quarter included loss on impairment of $2 million. Second quarter included gain on the loss of Deepwater Horizon of $267 million. Fourth quarter included loss on impairment of $1.0 billion. See Note 5-Impairments and Note 9-Drilling Fleet.

(b)	First quarter included loss on impairment of $221 million. Second quarter included loss on impairment of $67 million. Third quarter included loss on impairment of $46 million and settlement charges related to litigation matters of $132 million. See Note 5-Impairments.

This element can be used to disclose the entire quarterly financial data disclosure in the annual financial statements as a single block of text. The disclosure includes a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income (loss) before extraordinary items and cumulative effect of a change in accounting principle and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished. Alternatively, the details of this disclosure can be reported using the elements in this group, or by using other taxonomy elements and applying the appropriate quarterly date and period contexts when creating an instance document. For example, the element for "Interest and Dividend Income, Operating" may be used by financial institutions from the Statement of Income, applying the appropriate quarterly date and period context when creating an instance document.

+ References+ Details

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Subsequent Events (Unaudited)	Debt-On December 31, 2010, Transocean Inc. called the remaining Series A Convertible Senior Notes for redemption. On January 31, 2011, we redeemed the remaining aggregate principal amount of $11 million of our Series A Convertible Senior Notes for an aggregate cash payment of $11 million. As a result, no Series A Convertible Senior Notes remain outstanding as of January 31, 2011. Disposition-Subsequent to December 31, 2010, we completed the sale of the High-Specification Jackup Trident 20 and received net cash proceeds of $262 million. Distribution-On January 24, 2011, we filed an appeal on the decision of the Administrative Court of the Canton of Zug to the Swiss Federal Supreme Court. On February 11, 2011, our board of directors recommended that shareholders at the May 2011 annual general meeting approve a U.S. dollar-denominated dividend of approximately U.S. $1 billion out of qualifying additional paid-in capital and payable in four quarterly installments. The board of directors expects that the four payment dates will be set in June 2011, September 2011, December 2011 and March 2012. The proposed dividend will, among other things, be contingent on shareholders approving at the same meeting a rescission of the 2010 distribution. Due to, among other things, the uncertainty of the timing and outcome of the pending appeal with the Swiss Federal Supreme Court, our board of directors believes it is in the best interest of the Company to discontinue with the disputed 2010 distribution and to file a request to stay the pending appeal with the Swiss Federal Supreme Court against the decision of the Administrative Court until shareholders have voted on the proposed rescission.

Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Accounting estimates	The preparation of financial statements in accordance with accounting principles generally accepted in the United States ("U.S.") requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosures of contingent assets and liabilities. On an ongoing basis, we evaluate our estimates and assumptions, including those related to our allowance for doubtful accounts, materials and supplies obsolescence, property and equipment, investments, notes receivable, goodwill and other intangible assets, income taxes, share-based compensation, defined benefit pension plans and other postretirement benefits and contingencies. We base our estimates and assumptions on historical experience and on various other factors we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying amounts of assets and liabilities that are not readily apparent from other sources. Actual results could differ from such estimates.
Fair value measurements	We estimate fair value at a price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants in the principal market for the asset or liability. Our valuation techniques require inputs that we categorize using a three-level hierarchy, from highest to lowest level of observable inputs, as follows: (1) unadjusted quoted prices for identical assets or liabilities in active markets ("Level 1"), (2) direct or indirect observable inputs, including quoted prices or other market data, for similar assets or liabilities in active markets or identical assets or liabilities in less active markets ("Level 2") and (3) unobservable inputs that require significant judgment for which there is little or no market data ("Level 3"). When multiple input levels are required for a valuation, we categorize the entire fair value measurement according to the lowest level of input that is significant to the measurement even though we may have also utilized significant inputs that are more readily observable.
Principles of consolidation	We consolidate entities in which we have a majority voting interest and entities that meet the criteria for variable interest entities for which we are deemed to be the primary beneficiary for accounting purposes. We eliminate intercompany transactions and accounts in consolidation. We apply the equity method of accounting for investments in entities if we have the ability to exercise significant influence over an entity that (a) does not meet the variable interest entity criteria or (b) meets the variable interest entity criteria, but for which we are not deemed to be the primary beneficiary. We apply the cost method of accounting for investments in other entities if we do not have the ability to exercise significant influence over the unconsolidated affiliate. See Note 4-Variable Interest Entities. Our investments in and advances to unconsolidated affiliates, recorded in other assets on our consolidated balance sheets, had carrying amounts of $19 million and $11 million at December 31, 2010 and 2009, respectively. We recognized equity in earnings of unconsolidated affiliates, recorded in other, net, on our consolidated statements of operations, in the amount of $8 million, $2 million and $2 million for the years ended December 31, 2010, 2009 and 2008, respectively.
Cash and cash equivalents	Cash equivalents are highly liquid debt instruments with original maturities of three months or less that may include time deposits with commercial banks that have high credit ratings, U.S. Treasury and government securities, Eurodollar time deposits, certificates of deposit and commercial paper. We may also invest excess funds in no-load, open-end, management investment trusts ("management trusts"). The management trusts invest exclusively in high-quality money market instruments.
Allowance for doubtful accounts	We establish an allowance for doubtful accounts on a case-by-case basis, considering changes in the financial position of a major customer, when we believe the required payment of specific amounts owed is unlikely to occur. We derive a majority of our revenues from services to international oil companies and government-owned or government-controlled oil companies. We evaluate the credit quality of our customers on an ongoing basis, and we do not generally require collateral or other security to support customer receivables. The allowance for doubtful accounts was $38 million and $65 million at December 31, 2010 and 2009, respectively.
Materials and supplies	Materials and supplies are carried at average cost less an allowance for obsolescence. The allowance for obsolescence was $70 million and $66 million at December 31, 2010 and 2009, respectively.
Property and equipment	Property and equipment, consisting primarily of offshore drilling rigs and related equipment, represented approximately 58 percent of our total assets at December 31, 2010. The carrying amounts of these assets are based on estimates, assumptions and judgments relative to capitalized costs, useful lives and salvage values of our rigs. These estimates, assumptions and judgments reflect both historical experience and expectations regarding future industry conditions and operations. We compute depreciation using the straight-line method after allowing for salvage values. We capitalize expenditures for renewals, replacements and improvements, and we expense maintenance and repair costs as incurred. Upon sale or other disposition of an asset, we recognize a net gain or loss on disposal of the asset, which is measured as the difference between the net carrying amount of the asset and the net proceeds received. Estimated original useful lives of our drilling units range from 18 to 35 years, buildings and improvements from 10 to 30 years and machinery and equipment from four to 12 years. From time to time, we may review the estimated remaining useful lives of our drilling units, and we may extend the useful life when events and circumstances indicate a drilling unit can operate beyond its remaining useful life. During 2010, we adjusted the useful lives for five rigs, extending the estimated useful lives from between 20 and 36 years to between 25 and 39 years. During 2009, we adjusted the useful lives for 10 rigs, extending the estimated useful lives from between 30 and 35 years to between 33 and 50 years. During 2008, we adjusted the useful lives for five rigs, extending the estimated useful lives from between 30 and 35 years to between 34 and 50 years. We deemed the life extensions appropriate for each of these rigs based on the respective contracts under which the rigs were operating and the additional life-extending work, upgrades and inspections we performed on the rigs. For each of the years ended December 31, 2010, 2009 and 2008, the changes in estimated useful lives of these rigs resulted in a reduction in depreciation expense of $23 million ($0.07 per diluted share), $23 million ($0.07 per diluted share) and $6 million ($0.02 per diluted share), respectively, which had no tax effect for any period. During 2008, we also adjusted the useful lives for four rigs that we acquired through a merger transaction (the "Merger") with GlobalSantaFe Corporation ("GlobalSantaFe"), reducing the estimated useful lives from between eight and 16 years to between three and nine years. We determined the appropriate useful lives for each of these rigs based on our review of technical specifications of the rigs and comparisons to the remaining useful lives of comparable rigs in our fleet. In 2008, the change in estimated useful life of these rigs resulted in an increase in depreciation expense of $46 million ($0.14 per diluted share), which had no tax effect. See Note 9-Drilling Fleet.
Assets held for sale	We classify an asset as held for sale when the facts and circumstances meet the criteria for such classification, including the following: (a) we have committed to a plan to sell the asset, (b) the asset is available for immediate sale, (c) we have initiated actions to complete the sale, including locating a buyer, (d) the sale is expected to be completed within one year, (e) the asset is being actively marketed at a price that is reasonable relative to its fair value, and (f) the plan to sell is unlikely to be subject to significant changes or termination. At December 31, 2010, assets held for sale were less than $1 million. At December 31, 2009, we had assets held for sale, included in current assets, in the amount of $186 million. See Note 9-Drilling Fleet and Note 25-Subsequent Events.
Long-lived assets and definite-lived intangible assets	We review the carrying amounts of long-lived assets and definite-lived intangible assets, principally property and equipment and a drilling management services customer relationships intangible asset, for potential impairment when events occur or circumstances change that indicate that the carrying value of such assets may not be recoverable. For assets classified as held and used, we determine recoverability by evaluating the undiscounted estimated future net cash flows, based on projected dayrates and utilization, of the asset group under review. We consider our asset groups to be Ultra-Deepwater Floaters, Deepwater Floaters, Harsh Environment Floaters, Midwater Floaters, High-Specification Jackups, Standard Jackups and Other Rigs. When an impairment of one or more of our asset groups is indicated, we measure the impairment as the amount to which the asset group's carrying amount exceeds its fair value. We measure the fair values of our contract drilling asset groups by applying a combination of income and market approaches, using projected discounted cash flows and estimates of the exchange price that would be received for the assets in the principal or most advantageous market for the assets in an orderly transaction between market participants as of the measurement date. For our drilling management services customer relationships asset, we estimate fair value using the excess earnings method, which applies the income approach. For an asset classified as held for sale, we consider the asset to be impaired to the extent its carrying amount exceeds fair value less cost to sell. In the years ended December 31, 2010, 2009 and 2008, respectively, we concluded that our Standard Jackup asset group, customer relationships intangible asset and our assets held for sale were impaired. See Note 5-Impairments and Note 10-Goodwill and Other Intangible Assets.
Goodwill and other indefinite-lived intangible assets	We conduct impairment testing for our goodwill and other indefinite-lived intangible assets annually as of October 1 and more frequently, on an interim basis, when an event occurs or circumstances change that may indicate a reduction in the fair value of a reporting unit or the indefinite-lived intangible asset is below its carrying value. We test goodwill at the reporting unit level, which is defined as an operating segment or a component of an operating segment that constitutes a business for which financial information is available and is regularly reviewed by management. We have identified three reporting units for this purpose: (1) contract drilling services, (2) drilling management services and (3) oil and gas properties. We test goodwill for impairment by comparing the carrying amount of the reporting unit, including goodwill, to the fair value of the reporting unit. For our contract drilling services reporting unit, we estimate fair value using projected discounted cash flows, publicly traded company multiples and acquisition multiples. To develop the projected cash flows associated with our contract drilling services reporting unit, which are based on estimated future dayrates and utilization, we consider key factors that include assumptions regarding future commodity prices, credit market conditions and the effect these factors may have on our contract drilling operations and the capital expenditure budgets of our customers. We discount the projected cash flows using a long-term weighted-average cost of capital, which is based on our estimate of the investment returns that market participants would require for each of our reporting units. We derive publicly traded company multiples for companies with operations similar to our reporting units using observable information related to shares traded on stock exchanges and, when available, observable information related to recent acquisitions. If the reporting unit's carrying amount exceeds its fair value, we consider goodwill impaired and perform a second step to measure the amount of the impairment loss, if any. As a result of our annual impairment testing in each of the years ended December 31, 2010 and 2009, we concluded that goodwill was not impaired. As a result of our interim impairment testing in the year ended December 31, 2010, we concluded that the goodwill associated with our oil and gas properties reporting unit was impaired. As a result of our annual impairment testing in the year ended December 31, 2008, we concluded that the goodwill associated with our drilling management services reporting unit was impaired. See Note 5-Impairments and Note 10-Goodwill and Other Intangible Assets. For our trade name intangible asset, which we have identified as indefinite-lived, we estimate fair value using the relief from royalty method, which applies the income approach. As a result of our annual impairment testing in the year ended December 31, 2010, we concluded that the trade name intangible asset for our drilling management services reporting unit was not impaired. As a result of interim impairment testing in the year ended December 31, 2009 and as a result of our annual impairment testing in the year ended December 31, 2008, we concluded that the trade name intangible asset for our drilling management services reporting unit was impaired. See Note 5-Impairments and Note 10-Goodwill and Other Intangible Assets.
Contingent liabilities	We establish liabilities for estimated loss contingencies when we believe a loss is probable and the amount of the probable loss can be reasonably estimated. Once established, we adjust the carrying amount of a contingent liability upon the occurrence of a recognizable event when facts and circumstances change, altering our previous assumptions with respect to the likelihood or amount of loss. See Note 14-Commitments and Contingencies.
Operating revenues and expenses	We recognize operating revenues as they are earned, based on contractual daily rates or on a fixed-price basis. In connection with drilling contracts, we may receive revenues for preparation and mobilization of equipment and personnel or for capital improvements to rigs. In connection with new drilling contracts, revenues earned and incremental costs incurred directly related to contract preparation and mobilization are deferred and recognized over the primary contract term of the drilling project using the straight-line method. Our policy to amortize the fees related to contract preparation, mobilization and capital upgrades on a straight-line basis over the estimated firm period of drilling is consistent with the general pace of activity, level of services being provided and dayrates being earned over the life of the contract. For contractual daily rate contracts, we account for loss contracts as the losses are incurred. Costs of relocating drilling units without contracts to more promising market areas are expensed as incurred. Upon completion of drilling contracts, any demobilization fees received are reported in income, as are any related expenses. Capital upgrade revenues received are deferred and recognized over the primary contract term of the drilling project. The actual cost incurred for the capital upgrade is depreciated over the estimated useful life of the asset. We incur periodic survey and drydock costs in connection with obtaining regulatory certification to operate our rigs on an ongoing basis. Costs associated with these certifications are deferred and amortized on a straight-line basis over the period until the next survey.
Contract drilling intangible revenues	In connection with the Merger, we acquired drilling contracts for future contract drilling services of GlobalSantaFe. The terms of these contracts include fixed dayrates that were above or below the market dayrates available for similar contracts as of the date of the Merger. We recognized the fair value adjustments as contract intangible assets and liabilities, recorded in other assets and other long-term liabilities, respectively. We amortize the resulting contract drilling intangible revenues on a straight-line basis over the respective contract period. During the years ended December 31, 2010, 2009 and 2008, we recognized contract intangible revenues of $98 million, $281 million and $690 million, respectively. See Note 10-Goodwill and Other Intangible Assets.
Other revenues	Our other revenues represent those derived from drilling management services, integrated services, oil and gas properties, and customer reimbursable revenues. For fixed-price contracts associated with our drilling management services, we recognize revenues and expenses upon well completion and customer acceptance, and we recognize loss provisions on contracts in progress when losses are anticipated. We refer to integrated services as those services we provide through contractors and our employees under certain contracts that include well and logistics services in addition to our normal drilling services. We consider customer reimbursable revenues to be billings to our customers for reimbursement of certain equipment, materials and supplies, third-party services, employee bonuses and other expenses that we recognize in operating and maintenance expense, the result of which has little or no effect on operating income.
Share-based compensation	For time-based awards, we recognize compensation expense on a straight-line basis through the date the employee is no longer required to provide service to earn the award (the "service period"). For market-based awards that vest at the end of the service period, we recognize compensation expense on a straight-line basis through the end of the service period. For performance-based awards with graded vesting conditions, we recognize compensation expense on a straight-line basis over the service period for each separately vesting portion of the award as if the award was, in substance, multiple awards. Share-based compensation expense is recognized, net of a forfeiture rate, estimated at the time of grant based on historical experience and adjusted, if necessary, in subsequent periods based on actual forfeitures. To measure the fair values of time-based restricted shares and deferred units granted or modified, we use the market price of our shares on the grant date or modification date. To measure the fair values of stock options and stock appreciation rights ("SARs") granted or modified, we use the Black-Scholes-Merton option-pricing model and apply assumptions for the expected life, risk-free interest rate, dividend yield and expected volatility. The expected life is based on historical information of past employee behavior regarding exercises and forfeitures of options. The risk-free interest rate is based upon the published U.S. Treasury yield curve in effect at the time of grant or modification for instruments with a similar life. The dividend yield is based on our history and expectation of dividend payouts. The expected volatility is based on a blended rate with an equal weighting of the (a) historical volatility based on historical data for an amount of time approximately equal to the expected life and (b) implied volatility derived from our at-the-money long-dated call options. To measure the fair values of market-based deferred units granted or modified, we use a Monte Carlo simulation model and, in addition to the assumptions applied for the Black-Scholes-Merton option-pricing model, we apply assumptions using a risk neutral model and an average price at the performance start date. The risk neutral model assumes that all peer group stocks grow at the risk-free rate. The average price at the performance start date is based on the average stock price for the preceding 30 trading days. We recognize share-based compensation expense in the same financial statement line item as cash compensation paid to the respective employees. Tax deduction benefits for awards in excess of recognized compensation costs are reported as a financing cash flow. Share-based compensation expense was $102 million, $81 million and $64 million in the years ended December 31, 2010, 2009 and 2008, respectively. Income tax benefit on share-based compensation expense was $10 million, $8 million, and $8 million in the years ended December 31, 2010, 2009 and 2008, respectively. See Note 17-Share-Based Compensation Plans.
Pension and other postretirement benefits	We use a measurement date of January 1 for determining net periodic benefit costs and December 31 for determining benefit obligations and the fair value of plan assets. We determine our net periodic benefit costs based on a market-related valuation of assets that reduces year-to-year volatility by recognizing investment gains or losses over a five-year period from the year in which they occur. Investment gains or losses for this purpose are measured as the difference between the expected return calculated using the market-related value of assets and the actual return based on the market-related value of assets. The obligations and related costs for our defined benefit pension and other postretirement benefit plans, retiree life insurance and medical benefits, are actuarially determined by applying assumptions, including long-term rate of return on plan assets, discount rates, compensation increases, employee turnover rates and health care cost trend rates. The two most critical assumptions are the long-term rate of return on plan assets and the discount rate. For the long-term rate of return, we develop our assumptions regarding the expected rate of return on plan assets based on historical experience and projected long-term investment returns, which are weighted to consider each plan's target asset allocation. For the discount rate, we base our assumptions on a yield curve approach using Aa-rated corporate bonds and the expected timing of future benefit payments. For the projected compensation trend rate, we consider short-term and long-term compensation expectations for participants, including salary increases and performance bonus payments. For the health care cost trend rate for other postretirement benefits, we establish our assumptions for health care cost trends, applying an initial trend rate that reflects both our recent historical experience and broader national statistics with an ultimate trend rate that assumes that the portion of gross domestic product devoted to health care eventually becomes constant. Pension and other postretirement benefit plan obligations represented an aggregate liability in the amount of their net underfunded status of $469 million and $514 million, at December 31, 2010 and 2009, respectively. Net periodic benefit costs were $91 million, $87 million and $47 million for the years ended December 31, 2010, 2009 and 2008, respectively. See Note 13-Postemployment Benefit Plans.
Capitalized interest	We capitalize interest costs for qualifying construction and upgrade projects. We capitalized interest costs on construction work in progress of $89 million, $182 million and 147 million for the years ended December 31, 2010, 2009 and 2008, respectively.
Derivatives and hedging	From time to time, we may enter into a variety of derivative financial instruments in connection with the management of our exposure to variability in foreign exchange rates and interest rates. We record derivatives on our consolidated balance sheet, measured at fair value. For derivatives that do not qualify for hedge accounting, we recognize the gains and losses associated with changes in the fair value in current period earnings. See Note 12-Derivatives and Hedging and Note 20-Financial Instruments and Risk Concentration. We may enter into cash flow hedges to manage our exposure to variability of the expected future cash flows of recognized assets or liabilities or of unrecognized forecasted transactions. For a derivative that is designated and qualifies as a cash flow hedge, we initially recognize the effective portion of the gains or losses in other comprehensive income and subsequently recognize the gains and losses in earnings in the period in which the hedged forecasted transaction affects earnings. We recognize the gains and losses associated with the ineffective portion of the hedges in interest expense in the period in which they are realized. We may enter into fair value hedges to manage our exposure to changes in fair value of recognized assets or liabilities, such as fixed-rate debt, or of unrecognized firm commitments. For a derivative that is designated and qualifies as a fair value hedge, we simultaneously recognize in current period earnings the gains or losses on the derivative along with the offsetting losses or gains on the hedged item attributable to the hedged risk. The resulting ineffective portion, which is measured as the difference between the change in fair value of the derivative and the hedged item, is recognized in current period earnings.
Foreign currency	The majority of our revenues and expenditures are denominated in U.S. dollars to limit our exposure to foreign currency fluctuations, resulting in the use of the U.S. dollar as the functional currency for all of our operations. Foreign currency exchange gains and losses are primarily included in other income (expense) as incurred. We had a net foreign currency exchange gain of less than $1 million for the year ended December 31, 2010. We had net foreign currency exchange losses of $34 million and $3 million for the years ended December 31, 2009 and 2008, respectively.
Income taxes	We provide for income taxes based upon the tax laws and rates in effect in the countries in which operations are conducted and income is earned. There is little or no expected relationship between the provision for or benefit from income taxes and income or loss before income taxes because the countries in which we operate have taxation regimes that vary not only with respect to nominal rate, but also in terms of the availability of deductions, credits and other benefits. Variations also arise because income earned and taxed in any particular country or countries may fluctuate from year to year. We recognize deferred tax assets and liabilities for the anticipated future tax effects of temporary differences between the financial statement basis and the tax basis of our assets and liabilities using the applicable jurisdictional tax rates in effect at year end. We record a valuation allowance for deferred tax assets when it is more likely than not that some or all of the benefit from the deferred tax asset will not be realized. We provide a valuation allowance to offset deferred tax assets for net operating losses ("NOL") incurred during the year in certain jurisdictions and for other deferred tax assets where, in our opinion, it is more likely than not that the financial statement benefit of these losses will not be realized. We provide a valuation allowance for foreign tax credit carryforwards to reflect the possible expiration of these benefits prior to their utilization. We maintain liabilities for estimated tax exposures in our jurisdictions of operation, and the provisions and benefits resulting from changes to those liabilities are included in our annual tax provision along with related interest and penalties. Tax exposure items include potential challenges to permanent establishment positions, intercompany pricing, disposition transactions, and withholding tax rates and their applicability. These exposures are resolved primarily through the settlement of audits within these tax jurisdictions or by judicial means, but can also be affected by changes in applicable tax law or other factors, which could cause us to revise past estimates. See Note 6-Income Taxes.
Reclassifications	We have made certain reclassifications to prior period amounts to conform with the current year's presentation. These reclassifications did not have a material effect on our consolidated statement of financial position, results of operations or cash flows.
Subsequent events	We evaluate subsequent events through the time of our filing on the date we issue our financial statements. See Note 25-Subsequent Events.

New Accounting Pronouncements (Policies)	12 Months Ended
New Accounting Pronouncements (Policies)	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Consolidation	Effective January 1, 2010, we adopted the accounting standards update that requires enhanced transparency of our involvement with variable interest entities, which (a) amends certain guidance for determining whether an enterprise is a variable interest entity, (b) requires a qualitative rather than a quantitative analysis to determine the primary beneficiary, and (c) requires continuous assessments of whether an enterprise is the primary beneficiary of a variable interest entity. We evaluated these requirements, particularly with regard to our interests in Transocean Pacific Drilling Inc. ("TPDI") and Angola Deepwater Drilling Company Limited ("ADDCL") and our adoption did not have a material effect on our consolidated statement of financial position, results of operations or cash flows. See Note 4-Variable Interest Entities.
Fair value measurements and disclosures	We estimate fair value at a price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants in the principal market for the asset or liability. Our valuation techniques require inputs that we categorize using a three-level hierarchy, from highest to lowest level of observable inputs, as follows: (1) unadjusted quoted prices for identical assets or liabilities in active markets ("Level 1"), (2) direct or indirect observable inputs, including quoted prices or other market data, for similar assets or liabilities in active markets or identical assets or liabilities in less active markets ("Level 2") and (3) unobservable inputs that require significant judgment for which there is little or no market data ("Level 3"). When multiple input levels are required for a valuation, we categorize the entire fair value measurement according to the lowest level of input that is significant to the measurement even though we may have also utilized significant inputs that are more readily observable.
Subsequent events	We evaluate subsequent events through the time of our filing on the date we issue our financial statements. See Note 25-Subsequent Events.

Describes an entity's accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. An entity also may describe its accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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Income Taxes (Tables)

12 Months Ended

Dec. 31, 2010

Components of the provision (benefit) for income taxes

The components of our provision (benefit) for income taxes were as follows (in millions):

	Years ended December 31,
	2010			2009			2008
Current tax expense	$	456		$	741		$	735
Deferred tax expense (benefit)		(145	)		13			8
Income tax expense	$	311		$	754		$	743

Effective tax rate		23.9	%		19.2	%		15.6	%

Reconciliation of the differences between income tax expense computed at the Swiss holding company statutory rate and the reported provision for income taxes

	Years ended December 31,
	2010			2009
Income tax expense at the federal statutory rate	$	102		$	307
Taxes on earnings subject to rates greater than the Swiss rate		89			321
Taxes on impairment loss subject to rates less than the Swiss rate		79			—
Changes in unrecognized tax benefits		71			135
Change in valuation allowance		(4	)		46
Benefit from foreign tax credits		(23	)		(49	)
Other, net		(3	)		(6	)
Income tax expense	$	311		$	754

Significant components of deferred tax assets and liabilities

The significant components of our deferred tax assets and liabilities were as follows (in millions):

	December 31,
	2010			2009
Deferred tax assets
Drilling contract intangibles	$	6		$	14
Net operating loss carryforwards		114			135
Tax credit carryforwards		29			29
Accrued payroll expenses not currently deductible		72			74
Deferred income		84			74
Other		61			29
Valuation allowance		(94	)		(98	)
Total deferred tax assets		272			257

Deferred tax liabilities
Depreciation and amortization		(699	)		(834	)
Drilling management services intangibles		(26	)		(27	)
Other		(26	)		(18	)
Total deferred tax liabilities		(751	)		(879	)

Net deferred tax liabilities	$	(479	)	$	(622	)

Reconciliation of unrecognized tax benefits, excluding interest and penalties, and liabilities related to unrecognized tax benefits, including related interest and penalties, recognized as a component of income tax expense

The following is a reconciliation of our unrecognized tax benefits, excluding interest and penalties (in millions):

	Years ended December 31,
		2010			2009			2008
Balance, beginning of period	$	460		$	372		$	299
Additions for current year tax positions		46			64			46
Additions for prior year tax positions		9			62			67
Reductions for prior year tax positions		(11	)		(22	)		(36	)
Settlements		(17	)		(3	)		(3	)
Reductions related to statute of limitation expirations		(2	)		(13	)		(1	)
Balance, end of period	$	485		$	460		$	372

The liabilities related to our unrecognized tax benefits, including related interest and penalties that we recognize as a component of income tax expense, were as follows (in millions):

	December 31,
		2010		2009
Unrecognized tax benefits, excluding interest and penalties	$	485	$	460
Interest and penalties		235		200
Unrecognized tax benefits, including interest and penalties	$	720	$	660

The disclosure required for tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities (i.e., uncertain tax positions) and other types of income tax contingencies, including: (1) the policy on classification of interest and penalties; (2) a tabular reconciliation of the total amounts of unrecognized tax benefits at the beginning and end of the period; the total amount(s) of: (3) unrecognized tax benefits that, if recognized, would affect the effective tax rate, and (4) interest and penalties recognized in each of the income statement and balance sheet; (5) for positions for which it is reasonably possible that the total amounts unrecognized will significantly change within 12 months of the reporting date the: (i) nature of the uncertainty, (ii) nature of the event that could occur that would cause the change, and (iii) an estimate of the range of the reasonably possible change or a statement that an estimate of the range cannot be made; and (6) a description of tax years that remain subject to examination by major tax jurisdictions.

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Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2010

Earnings Per Share

The reconciliation of the numerator and denominator used for the computation of basic and diluted earnings per share is as follows (in millions, except per share data):

	Years ended December 31,
	2010						2009						2008
	Basic			Diluted			Basic			Diluted			Basic			Diluted
Numerator for earnings per share
Net income attributable to controlling interest	$	961		$	961		$	3,181		$	3,181		$	4,031		$	4,031
Undistributed earnings allocable to participating securities		(5	)		(5	)		(18	)		(18	)		(10	)		(10	)
Net income available to shareholders	$	956		$	956		$	3,163		$	3,163		$	4,021		$	4,021

Denominator for earnings per share
Weighted-average shares outstanding		320			320			320			320			318			318
Effect of dilutive securities:
Stock options and other share-based awards		-			-			-			1			-			2
Stock warrants		-			-			-			-			-			1
Weighted-average shares for per share calculation		320			320			320			321			318			321

Earnings per share	$	2.99		$	2.99		$	9.87		$	9.84		$	12.63		$	12.53

Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2010

Allocation of other comprehensive income (loss) attributable to controlling interest and to non-controlling interest

The allocation of other comprehensive income (loss) attributable to controlling interest and to noncontrolling interest was as follows (in millions):

		Years ended December 31,
		2010									2009								2008
		Controlling interest			Non-controlling interest (a)			Total			Controlling interest			Non-controlling interest (a)		Total			Controlling interest			Non-controlling interest (a)		Total
Unrecognized components of net periodic benefit costs	$	(8	)	$	—		$	(8	)	$	37		$	—	$	37		$	(388	)	$	—	$	(388	)
Recognized components of net periodic benefit costs		16			—			16			24			—		24			5			—		5
Unrecognized gain (loss) on derivative instruments		(10	)		(19	)		(29	)		(4	)		2		(2	)		(1	)		—		(1	)
Recognized (gain) loss on derivative instruments		14			(2)			12			3			3		6			—			—		—
Other, net		—			—			—			1			—		1			(3	)		—		(3	)

Other comprehensive income (loss) before income taxes		12			(21	)		(9	)		61			5		66			(387	)		—		(387	)
Income taxes related to other comprehensive income		(9	)		—			(9	)		24			—		24			9			—		9
Other comprehensive income (loss), net of tax	$	3		$	(21	)	$	(18	)	$	85		$	5	$	90		$	(378	)	$	—	$	(378	)

______________________________

(a)	Includes amounts attributable to noncontrolling interest and redeemable noncontrolling interest.

Components of accumulated other comprehensive income (loss), net of tax

The components of accumulated other comprehensive income (loss), net of tax, were as follows (in millions):

	December 31, 2010									December 31, 2009
		Controlling interest			Non-controlling interest			Redeemable non-controlling interest			Controlling interest			Non-controlling interest		Redeemable non-controlling interest
Unrecognized components of net periodic benefit costs (a)	$	(335	)	$	—		$	—		$	(334	)	$	—	$	—
Unrecognized gain (loss) on derivative investments		5			(3	)		(13	)		1			5		—
Unrealized loss on marketable securities		(2	)		—			—			(2	)		—		—
Accumulated other comprehensive income (loss)	$	(332	)	$	(3	)	$	(13	)	$	(335	)	$	5	$	—

______________________________

(a)	Amounts are net of income tax effect of $36 million and $45 million for December 31, 2010 and 2009, respectively.

Drilling Fleet (Tables)

12 Months Ended

Dec. 31, 2010

Actual capital expenditures and other capital additions, including capitalized interest

The following table presents actual capital expenditures and other capital additions, including capitalized interest, for our remaining major construction projects for the three years ended December 31, 2010 (in millions):

	Years ended December 31,
	2010		2009		2008		2007 - 2006		Total
Deepwater Champion (a)	$	206	$	263	$	155	$	109	$	733
Discoverer India (b)		203		291		250		-		744
Discoverer Luanda (b) (c)		174		220		208		107		709
Transocean Honor (d)		97		-		-		-		97
Dhirubhai Deepwater KG2 (b) (e)		36		371		91		179		677
Development Driller III (b) (a)		24		117		133		350		624
Discoverer Inspiration (b)		12		224		205		238		679
High-Specification Jackup TBN1 (f)		9		-		-		-		9
High-Specification Jackup TBN2 (f)		9		-		-		-		9
Discoverer Americas (b)		6		148		167		311		632
Discoverer Clear Leader (b)		6		115		107		409		637
Petrobras 10000 (b) (g)		6		735		-		-		741
Dhirubhai Deepwater KG1 (b) (e)		-		295		105		279		679
Sedco 700-series upgrades (b)		-		71		124		396		591
Capitalized interest		89		182		147		93		511
Mobilization costs		89		155		-		-		244
Total	$	966	$	3,187	$	1,692	$	2,471	$	8,316

______________________________

(a)	These costs include our initial investment in Deepwater Champion of $109 million and our initial investment in Development Driller III of $350 million, representing the estimated fair value of the rig at the time of our merger with GlobalSantaFe in November 2007.

(b)	The accumulated construction costs of these rigs are no longer included in construction work in progress, as their construction projects had been completed as of December 31, 2010.

(c)	The costs for Discoverer Luanda represent 100 percent of expenditures incurred since inception. ADDCL is responsible for all of these costs. We hold a 65 percent interest in ADDCL, and Angco Cayman Limited holds the remaining 35 percent interest.

(d)

(e)

(f)

(g)

Goodwill and Other Intangibles Assets (Tables)

12 Months Ended

Dec. 31, 2010

Carrying amount of goodwill and changes in the balance

The gross carrying amounts of goodwill and accumulated impairment were as follows (in millions):

	Year ended December 31, 2010								Year ended December 31, 2009
	Gross carrying amount		Accumulated impairment			Net carrying amount			Gross carrying amount		Accumulated impairment			Net carrying amount
Contract drilling services
Balance, beginning of period	$	10,626	$	(2,494	)	$	8,132		$	10,620	$	(2,494	)	$	8,126
Purchase price adjustment		-		-			-			6		-			6
Balance, end of period		10,626		(2,494	)		8,132			10,626		(2,494	)		8,132

Drilling management services
Balance, beginning of period		176		(176	)		-			176		(176	)		-
Balance, end of period		176		(176	)		-			176		(176	)		-

Oil and gas properties
Balance, beginning of period		2		-			2			2		-			2
Impairment		-		(2	)		(2	)		-		-			-
Balance, end of period		2		(2	)		-			2		-			2

Total goodwill
Balance, beginning of period		10,804		(2,670	)		8,134			10,798		(2,670	)		8,128
Impairment		-		(2	)		(2	)		-		-			-
Purchase price adjustment		-		-			-			6		-			6
Balance, end of period	$	10,804	$	(2,672	)	$	8,132		$	10,804	$	(2,670	)	$	8,134

Carrying value of ADTI trade name

The gross carrying amounts of the ADTI trade name, which we consider to be an indefinite-lived intangible asset, and accumulated impairment were as follows (in millions):

	Year ended December 31, 2010							Year ended December 31, 2009
	Gross carrying amount		Accumulated impairment			Net carrying amount		Gross carrying amount		Accumulated impairment			Net carrying amount
Trade name
Balance, beginning of period	$	76	$	(37	)	$	39	$	76	$	(31	)	$	45
Impairment		-		-			-		-		(6	)		(6	)
Balance, end of period	$	76	$	(37	)	$	39	$	76	$	(37	)	$	39

Carrying value of definite-lived intangible assets and intangible liabilities

The gross carrying amounts of our drilling contract intangibles and drilling management customer relationships, both of which we consider to be definite-lived intangible assets and intangible liabilities, and accumulated amortization and impairment were as follows (in millions):

	Year ended December 31, 2010								Year ended December 31, 2009
	Gross carrying amount		Accumulated amortization and impairment			Net carrying amount			Gross carrying amount		Accumulated amortization and impairment			Net carrying amount
Drilling contract intangible assets
Balance, beginning of period	$	191	$	(167	)	$	24		$	191	$	(123	)	$	68
Amortization		-		(18	)		(18	)		-		(44	)		(44	)
Balance, end of period		191		(185	)		6			191		(167	)		24

Customer relationships
Balance, beginning of period		148		(84	)		64			148		(27	)		121
Amortization		-		(5	)		(5	)		-		(8	)		(8	)
Impairment		-		-			-			-		(49	)		(49	)
Balance, end of period		148		(89	)		59			148		(84	)		64

Total definite-lived intangible assets
Balance, beginning of period		339		(252	)		87			339		(150	)		189
Amortization		-		(23	)		(23	)		-		(53	)		(53	)
Impairment		-		-			-			-		(49	)		(49	)
Balance, end of period	$	339		(275	)		64		$	339	$	(252	)	$	87

Drilling contract intangible liabilities
Balance, beginning of period	$	1,494	$	(1,226	)	$	268		$	1,494	$	(901	)	$	593
Amortization		-		(116	)		(116	)		-		(325	)		(325	)
Balance, end of period	$	1,494		(1,342	)		152		$	1,494	$	(1,226	)	$	268

Estimated net future amortization expense (income) related to intangible assets and liabilities

The estimated net future amortization related to intangible assets and liabilities as of December 31, 2010, was as follows (in millions):

	Drilling contract intangibles			Customer relationships
Years ending December 31,
2011	$	(45	)	$	5
2012		(42	)		5
2013		(25	)		5
2014		(15	)		5
2015		(14	)		5
Thereafter		(6	)		34
Total intangible assets (liabilities), net	$	(147	)	$	59

Debt (Tables)

12 Months Ended

Dec. 31, 2010

Debt, net of unamortized discounts, premiums and fair value adjustments

Debt, net of unamortized discounts, premiums and fair value adjustments, was comprised of the following (in millions):

	December 31, 2010						December 31, 2009
	Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total		Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total
ODL Loan Facility	$	10	$	-	$	10	$	10	$	-	$	10
Commercial paper program (a)		88		-		88		281		-		281
6.625% Notes due April 2011 (a)		167		-		167		170		-		170
5% Notes due February 2013		255		-		255		247		-		247
5.25% Senior Notes due March 2013 (a)		511		-		511		496		-		496
TPDI Credit Facilities due March 2015		-		560		560		-		581		581
4.95% Senior Notes due November 2015 (a)		1,099		-		1,099		-		-		-
ADDCL Credit Facilities due November 2017		-		242		242		-		454		454
6.00% Senior Notes due March 2018 (a)		997		-		997		997		-		997
7.375% Senior Notes due April 2018 (a)		247		-		247		247		-		247
TPDI Notes due October 2019		-		148		148		-		148		148
6.50% Senior Notes due November 2020 (a)		899		-		899		-		-		-
Capital lease obligation due July 2026		-		-		-		15		-		15
8% Debentures due April 2027 (a)		57		-		57		57		-		57
7.45% Notes due April 2027 (a)		96		-		96		96		-		96
7% Notes due June 2028		313		-		313		313		-		313
Capital lease contract due August 2029		694		-		694		711		-		711
7.5% Notes due April 2031 (a)		598		-		598		598		-		598
1.625% Series A Convertible Senior Notes due December 2037 (a)		11		-		11		1,261		-		1,261
1.50% Series B Convertible Senior Notes due December 2037 (a)		1,625		-		1,625		2,057		-		2,057
1.50% Series C Convertible Senior Notes due December 2037 (a)		1,605		-		1,605		1,979		-		1,979
6.80% Senior Notes due March 2038 (a)		999		-		999		999		-		999
Total debt		10,271		950		11,221		10,534		1,183		11,717
Less debt due within one year
ODL Loan Facility		10		-		10		10		-		10
Commercial paper program (a)		88		-		88		281		-		281
6.625% Notes due April 2011 (a)		167		-		167		-		-		-
TPDI Credit Facilities due March 2015		-		70		70		-		52		52
ADDCL Credit Facilities due November 2017		-		25		25		-		248		248
Capital lease contract due August 2029		16		-		16		16		-		16
1.625% Series A Convertible Senior Notes due December 2037 (a)		11		-		11		1,261		-		1,261
1.50% Series B Convertible Senior Notes due December 2037 (a)		1,625		-		1,625		-		-		-
Total debt due within one year		1,917		95		2,012		1,568		300		1,868
Total long-term debt	$	8,354	$	855	$	9,209	$	8,966	$	883	$	9,849

______________________________

(a)

Scheduled maturities of debt

At December 31, 2010, the scheduled maturities of our debt were as follows (in millions):

	Transocean Ltd. and subsidiaries			Consolidated variable interest entities		Consolidated total
Years ending December 31,
2011	$	1,970		$	95	$	2,065
2012		1,741			97		1,838
2013		770			98		868
2014		22			100		122
2015		1,123			340		1,463
Thereafter		4,797			220		5,017
Total debt, excluding unamortized discounts, premiums and fair value adjustments		10,423			950		11,373
Total unamortized discounts, premiums and fair value adjustments		(152	)		-		(152	)
Total debt	$	10,271		$	950	$	11,221

Carrying amounts of liability components of convertible senior notes

The carrying amounts of the liability components of the Convertible Senior Notes were as follows (in millions):

	December 31, 2010							December 31, 2009
	Principal amount		Unamortized discount			Carrying amount		Principal amount		Unamortized discount			Carrying amount
Carrying amount of liability component
Series A Convertible Senior Notes due 2037	$	11	$	-		$	11	$	1,299	$	(38	)	$	1,261
Series B Convertible Senior Notes due 2037		1,680		(55	)		1,625		2,200		(143	)		2,057
Series C Convertible Senior Notes due 2037		1,722		(117	)		1,605		2,200		(221	)		1,979

Carrying amounts of equity components of convertible senior notes

The carrying amounts of the equity components of the Convertible Senior Notes were as follows (in millions):

	December 31,
	2010		2009
Carrying amount of equity component
Series A Convertible Senior Notes due 2037	$	1	$	114
Series B Convertible Senior Notes due 2037		210		275
Series C Convertible Senior Notes due 2037		276		352

Interest expense, excluding amortization of debt issue costs

Interest expense, excluding amortization of debt issue costs, was as follows (in millions):

	Years ended December 31,
		2010	2009		2008
Interest expense
Series A Convertible Senior Notes due 2037	$	58	$	85	$	97
Series B Convertible Senior Notes due 2037		98		100		97
Series C Convertible Senior Notes due 2037		98		100		97

Postemployment Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2010

Schedule of defined benefit plans disclosure

Assumptions-The following were the weighted-average assumptions used to determine benefit obligations:

	December 31, 2010									December 31, 2009
	U.S. Plans			Non-U.S. Plans			OPEB Plans			U.S. Plans			Non-U.S. Plans			OPEB Plans
Discount rate		5.48	%		5.81	%		4.92	%		5.84	%		5.59	%		5.52	%
Compensation trend rate		4.24	%		4.65	%		n/a			4.21	%		4.73	%		n/a

Weighted-average assumptions used to determine benefit obligations and net periodic benefit costs

The following were the weighted-average assumptions used to determine net periodic benefit costs:

	Year ended December 31, 2010									Year ended December 31, 2009									Year ended December 31, 2008
	U.S. Plans			Non-U.S. Plans			OPEB Plans			U.S. Plans			Non-U.S. Plans			OPEB Plans			U.S. Plans			Non-U.S. Plans			OPEB Plans
Discount rate		5.86	%		5.67	%		5.51	%		5.41	%		6.06	%		5.34	%		6.14	%		5.97	%		5.96	%
Expected rate of return		8.49	%		6.65	%		n/a			8.50	%		6.59	%		n/a			8.50	%		7.16	%		n/a
Compensation trend rate		4.21	%		4.77	%		n/a			4.21	%		4.55	%		n/a			4.57	%		4.64	%		n/a
Health care cost trend rate
-initial		n/a			n/a			8.00	%		n/a			n/a			8.99	%		n/a			n/a			8.55	%
-ultimate		n/a			n/a			5.00	%		n/a			n/a			5.00	%		n/a			n/a			5.00	%
-ultimate year		n/a			n/a			2016			n/a			n/a			2016			n/a			n/a			2014

______________________________

"n/a" means not applicable.

Changes in projected benefit obligation, plan assets and funded status and the amounts recognized on our consolidated balance sheets

The changes in projected benefit obligation, plan assets and funded status and the amounts recognized on our consolidated balance sheets were as follows (in millions):

	Year ended December 31, 2010												Year ended December 31, 2009
	U.S. Plans			Non-U.S. Plans			OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans			Total
Change in projected benefit obligation
Projected benefit obligation, beginning of period	$	932		$	403		$	54		$	1,389		$	900		$	250		$	64		$	1,214
Plan amendments		-			-			-			-			-			-			5			5
Actuarial (gains) losses, net		89			(46	)		2			45			(31	)		86			(16	)		39
Service cost		42			20			1			63			44			18			1			63
Interest cost		54			20			3			77			50			17			3			70
Foreign currency exchange rate		-			(13	)		-			(13	)		-			40			-			40
Benefits paid		(51	)		(14	)		(5	)		(70	)		(32	)		(11	)		(4	)		(47	)
Participant contributions		-			2			1			3			-			2			1			3
Special termination benefits		3			-			-			3			-			-			-			-
Settlements and curtailments		(1	)		2			-			1			1			1			-			2
Projected benefit obligation, end of period	$	1,068		$	374		$	56		$	1,498		$	932		$	403		$	54		$	1,389

Change in plan assets
Fair value of plan assets, beginning of period	$	594		$	281		$	-		$	875		$	455		$	208		$	-		$	663
Actual return on plan assets		85			29			-			114			121			31			-			152
Foreign currency exchange rate changes		-			(11	)		-			(11	)		-			31			-			31
Employer contributions		69			45			4			118			50			20			3			73
Participant contributions		-			2			1			3			-			2			1			3
Benefits paid		(51	)		(14	)		(5	)		(70	)		(32	)		(11	)		(4	)		(47	)
Fair value of plan assets, end of period	$	697		$	332		$	-		$	1,029		$	594		$	281		$	-		$	875

Funded status, end of period	$	(371	)	$	(42	)	$	(56	)	$	(469	)	$	(338	)	$	(122	)	$	(54	)	$	(514	)

Balance sheet classification, end of period:
Pension asset, non-current	$	-		$	(8	)	$	-		$	(8	)	$	-		$	-		$	-		$	-
Accrued pension liability, current		3			2			4			9			5			2			3			10
Accrued pension liability, non-current		368			48			52			468			333			120			51			504
Accumulated other comprehensive income (loss) (a)		(308	)		(61	)		(2	)		(371	)		(264	)		(117	)		2			(379	)

______________________________

(a)	Amounts are before income tax effect.

Aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets

The aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets were as follows (in millions):

	December 31, 2010								December 31, 2009
	U.S. Plans		Non-U.S. Plans		OPEB Plans		Total		U.S. Plans		Non-U.S. Plans		OPEB Plans		Total
Projected benefit obligation	$	1,068	$	290	$	56	$	1,414	$	932	$	403	$	54	$	1,389
Fair value of plan assets		697		248		-		945		594		281		-		875

Aggregate accumulated benefit obligation and fair value of plan assets for plans with an accumulated benefit obligation in excess of plan assets

	December 31, 2010								December 31, 2009
	U.S. Plans		Non-U.S. Plans		OPEB Plans		Total		U.S. Plans		Non-U.S. Plans		OPEB Plans		Total
Accumulated benefit obligation	$	921	$	269	$	56	$	1,246	$	789	$	344	$	54	$	1,187
Fair value of plan assets		697		248		-		945		594		281		-		875

Actual and targeted weighted-average asset allocations for funded Transocean Plans by asset category

As of December 31, 2010 and 2009, the weighted-average target and actual allocations of the investments for our funded Transocean Plans were as follows:

							Actual allocation at December 31,
	Target allocation						2010						2009
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Equity securities		65	%		52	%		65	%		53	%		72	%		57	%
Fixed income securities		35	%		15	%		34	%		10	%		27	%		11	%
Other investments		-	%		33	%		1	%		37	%		1	%		32	%
Total		100	%		100	%		100	%		100	%		100	%		100	%

Schedule of fair value of financial assets for pension and postretirement benefits

As of December 31, 2010, the investments for our funded Transocean Plans were categorized as follows (in millions):

	December 31, 2010
	Quoted prices in active markets for identical assets						Significant other observable inputs						Total
	U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans
Equity securities:
U.S.	$	359	$	-	$	359	$	-	$	28	$	28	$	359	$	28	$	387
Non-U.S.		91		-		91		2		148		150		93		148		241
Total equity securities		450		-		450		2		176		178		452		176		628

Fixed income securities:
U.S. government		59		-		59		-		-		-		59		-		59
U.S. corporate		175		-		175		-		-		-		175		-		175
Non-U.S. government		-		-		-		-		34		34		-		34		34
Non-U.S.		7		-		7		-		-		-		7		-		7
Total fixed income securities		241		-		241		-		34		34		241		34		275

Other investments:
Cash		4		31		35		-		-		-		4		31		35
Property		-		-		-		-		7		7		-		7		7
Investment contracts		-		-		-		-		84		84		-		84		84
Total other investments		4		31		35		-		91		91		4		122		126

Total investments	$	695	$	31	$	726	$	2	$	301	$	303	$	697	$	332	$	1,029

As of December 31, 2009, the investments for our funded Transocean Plans were categorized as follows (in millions):

	December 31, 2009
	Quoted prices in active markets for identical assets						Significant other observable inputs						Total
	U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans		U.S. Plans		Non-U.S. Plans		Transocean Plans
Equity securities:
U.S.	$	341	$	-	$	341	$	-	$	25	$	25	$	341	$	25	$	366
Non-U.S.		88		-		88		2		136		138		90		136		226
Total equity securities		429		-		429		2		161		163		431		161		592

Fixed income securities:
U.S. government		109		-		109		-		-		-		109		-		109
U.S. corporate		38		-		38		-		-		-		38		-		38
Non-U.S. government		-		-		-		-		30		30		-		30		30
Non-U.S.		12		-		12		-		-		-		12		-		12
Total fixed income securities		159		-		159		-		30		30		159		30		189

Other investments:
Cash		4		2		6		-		-		-		4		2		6
Property		-		-		-		-		11		11		-		11		11
Investment contracts		-		-		-		-		77		77		-		77		77
Total other investments		4		2		6		-		88		88		4		90		94

Total investments	$	592	$	2	$	594	$	2	$	279	$	281	$	594	$	281	$	875

Components of net periodic benefit costs, before tax

Net periodic benefit costs, before tax, included the following components (in millions):

	Year ended December 31, 2010									Year ended December 31, 2009									Year ended December 31, 2008
	U.S. Plans			Non-U.S. Plans			Transocean Plans			U.S. Plans			Non-U.S. Plans			Transocean Plans			U.S. Plans			Non-U.S. Plans			Transocean Plans
Service cost	$	42		$	20		$	62		$	44		$	18		$	62		$	30		$	16		$	46
Interest cost		54			20			74			50			17			67			47			17			64
Expected return on plan assets		(58	)		(17	)		(75	)		(55	)		(16	)		(71	)		(53	)		(21	)		(74	)
Settlements and curtailments		5			3			8			4			2			6			(1	)		-			(1	)
Special termination benefits		3			-			3			-			-			-			3			-			3
Actuarial losses, net		13			4			17			18			2			20			4			-			4
Prior service cost (credit), net		(1	)		-			(1	)		(1	)		1			-			-			1			1
Transition obligation, net		-			1			1			-			-			-			-			1			1
Net periodic benefit costs	$	58		$	31		$	89		$	60		$	24		$	84		$	30		$	14		$	44

Amounts in accumulated other comprehensive income

The following table presents the amounts in accumulated other comprehensive income, before tax, that have not been recognized as components of net periodic benefit costs (in millions):

	December 31, 2010											December 31, 2009
	U.S. Plans			Non-U.S. Plans		OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans			Total
Actuarial loss, net	$	319		$	52	$	7		$	378		$	277		$	117		$	5		$	399
Prior service cost (credit), net		(11	)		8		(5	)		(8	)		(13	)		(2	)		(7	)		(22	)
Transition obligation, net		-			1		-			1			-			2			-			2
Total	$	308		$	61	$	2		$	371		$	264		$	117		$	(2	)	$	379

	Year ending December 31, 2011
	U.S. Plans			Non-U.S. Plans		OPEB Plans			Total
Actuarial loss, net	$	22		$	2	$	-		$	24
Prior service cost (credit), net		(1	)		1		(2	)		(2	)
Transition obligation, net		-			-		-			-
Total amount expected to be recognized	$	21		$	3	$	(2	)	$	22

Projected pension benefits payments

The following were the projected benefits payments (in millions):

		U.S. Plans	Non-U.S. Plans		OPEB Plans		Total
Years ending December 31,
2011	$	37	$	7	$	4	$	48
2012		40		7		4		51
2013		42		8		4		54
2014		45		8		4		57
2015		47		9		4		60
2016-2020		285		57		22		364

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2010

Future minimum rental payments related to noncancellable operating leases and capital leases and aggregate carrying amount of assets under capital lease

As of December 31, 2010, future minimum rental payments related to noncancellable operating leases and the capital leases were as follows (in millions):

	Capital leases			Operating leases
Years ending December 31,
2011	$	66		$	36
2012		72			31
2013		72			23
2014		73			16
2015		73			12
Thereafter		990			32
Total future minimum rental payment	$	1,346		$	150
Less amount representing imputed interest		(652	)
Present value of future minimum rental payments under capital leases		694
Less current portion included in debt due within one year		(16	)
Long-term capital lease obligation	$	678

The following were the aggregate carrying amount of our assets held under capital lease, as of December 31, 2010 and 2009, respectively (in millions):

	December 31,
		2010		2009
Property and equipment, cost	$	740		$	982
Accumulated depreciation		(20	)		(27	)
Property and equipment, net	$	720		$	955

Purchase obligations

At December 31, 2010, our purchase obligations, primarily related to our newbuilds, were as follows (in millions):

	Purchase obligations
Years ending December 31,
2011	$	381
2012		149
2013		-
2014		-
2015		-
Thereafter		-
Total	$	530

Redeemable Noncontrolling Interest (Tables)

12 Months Ended

Dec. 31, 2010

Changes in redeemable noncontrolling interest

	Years ended December 31,
		2010		2009		2008
Redeemable noncontrolling interest
Balance, beginning of period	$	-		$	-	$	-
Reclassification from noncontrolling interest		26			-		-
Net income attributable to noncontrolling interest (a)		13			-		-
Other comprehensive income attributable to noncontrolling interest (a)		(14	)		-		-
Balance, end of period	$	25		$	-	$	-

______________________________

(a)	Amounts represent activity following reclassification to temporary equity in October 2010.

Share based compensation (Tables)

12 Months Ended

Dec. 31, 2010

Option valuation assumptions

We estimated the fair value of each option award under the Long-Term Incentive Plan on the grant date using the Black-Scholes-Merton option-pricing model with the following weighted-average assumptions:

	Years ended December 31,
	2010		2009		2008
Dividend yield		4%		-		-
Expected price volatility		39%		49%		36%
Risk-free interest rate		2.30%		1.80%		3.00%
Expected life of options		4.7 years		4.8 years		4.4 years
Weighted-average fair value of options granted	$	30.03	$	26.07	$	49.32

We estimated the fair value of each option grant under the Employee Stock Purchase Plan ("ESPP") using the Black-Scholes-Merton option-pricing model with the following weighted-average assumptions:

	Years ended December 31,
	2010 (a)		2009 (a)		2008
Dividend yield		-		-		-
Expected price volatility		-		-		31%
Risk-free interest rate		-		-		3.15%
Expected life of options		-		-		1.0 year
Weighted-average fair value of options granted	$	-	$	-	$	41.39

______________________________

(a)	As of January 1, 2009, we discontinued offering the ESPP.

Summary of vested and unvested time-based vesting stock option activity

The following table summarizes vested and unvested time-based vesting stock option ("time-based options") activity under our incentive plans during the year ended December 31, 2010:

	Number of shares under option		Weighted-average exercise price per share		Weighted-average remaining contractual term (years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2010	1,828,655		$	60.69	4.96	$	40
Granted	253,288			82.55
Exercised	(289,445	)		42.26
Forfeited	(138,815	)		71.37
Outstanding at December 31, 2010	1,653,683		$	66.37	5.29	$	5

Vested and exercisable at December 31, 2010	1,183,283		$	61.28	3.99	$	10

Summary of unvested share activity for time-based vesting restricted shares

The following table summarizes unvested share activity for time-based vesting restricted shares ("time-based shares") granted under our incentive plans during the year ended December 31, 2010:

	Number of shares		Weighted-average grant-date fair value per share
Unvested at January 1, 2010	98,386		$	112.14
Vested	(92,573	)		111.32
Forfeited	(1,874	)		109.97
Unvested at December 31, 2010	3,939		$	132.32

Summary of unvested activity for time-based vesting deferred units

The following table summarizes unvested activity for time-based vesting deferred units ("time-based units") granted under our incentive plans during the year ended December 31, 2010:

	Number of units		Weighted-average grant-date fair value per share
Unvested at January 1, 2010	1,455,447		$	76.58
Granted	1,055,367			76.83
Vested	(559,339	)		81.11
Forfeited	(106,691	)		78.65
Unvested at December 31, 2010	1,844,784		$	75.23

Summary of share-settled SARs activity

The following table summarizes share-settled SARs activity under our incentive plans during the year ended December 31, 2010:

	Number of awards	Weighted-average exercise price per share		Weighted-average remaining contractual term (years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2010	189,139	$	93.28	6.76	$	-
Outstanding at December 31, 2010	189,139	$	93.28	5.76	$	-

Vested and exercisable at December 31, 2010	189,139	$	93.28	5.76	$	-

Summary of vested and unvested performance-based option activity

The following table summarizes vested and unvested performance-based option activity under our incentive plans during the year ended December 31, 2010:

	Number of shares under option	Weighted-average exercise price per share		Weighted-average remaining contractual term (years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2010	179,262	$	75.30	6.22	$	1
Outstanding at December 31, 2010	179,262	$	75.30	5.22	$	-

Vested and exercisable at December 31, 2010	179,262	$	75.30	5.22	$	-

Summary of unvested activity for market-based units

The following table summarizes unvested activity for market-based units granted under our incentive plans during the year ended December 31, 2010:

	Number of units		Weighted-average grant-date fair value per share
Unvested at January 1, 2010	330,870		$	93.70
Granted	122,934			82.55
Forfeited	(30,898	)		84.48
Unvested at December 31, 2010	422,906		$	89.14

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2010

Carrying amounts and estimated fair values of long-term debt, including debt due within one year

The carrying amounts and estimated fair values of our long-term debt, including debt due within one year, were as follows (in millions):

	December 31, 2010				December 31, 2009
	Carrying amount		Fair value		Carrying amount		Fair value
Long-term debt, including current maturities	$	10,271	$	10,562	$	10,534	$	11,218
Long-term debt of consolidated variable interest entities, including current maturities		950		964		1,183		1,178

This item represents certain of the disclosures concerning the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

+ References+ Details

Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2010

Supplemental cash flow information

Net cash provided by (used in) operating activities attributable to the net change in operating assets and liabilities were composed of the following (in millions):

	Years ended December 31,
	2010			2009			2008
Changes in operating assets and liabilities
Decrease (increase) in accounts receivable	$	386		$	504		$	(501	)
Increase in other current assets		(75	)		(50	)		(118	)
Increase in other assets		(40	)		(30	)		(8	)
Increase (decrease) in accounts payable and other current liabilities		227			(60	)		75
Decrease in other long-term liabilities		(52	)		(7	)		(43	)
Change in income taxes receivable / payable, net		(37	)		77			274
	$	409		$	434		$	(321	)

Additional cash flow information were as follows (in millions):

	Years ended December 31,
	2010		2009		2008
Certain cash operating activities
Cash payments for interest	$	641	$	683	$	545
Cash payments for income taxes		493		663		461

Non-cash investing and financing activities
Capital expenditures, accrued at end of period (a)	$	69	$	139	$	268
Asset capitalized under capital leases (b)		-		716		-
Non-cash proceeds received for the sale of assets (c)		134		-		-

______________________________

(a)	These amounts represent additions to property and equipment for which we had accrued a corresponding liability in accounts payable.

(b)	On August 4, 2009, we accepted delivery of Petrobras 10000 and recorded non-cash additions of $716 million to property and equipment, net along with a corresponding increase to long-term debt. See Note 11-Debt and Note 14-Commitments and Contingencies.

(c)

Segments, Geographical Analysis and Major Customers (Tables)

12 Months Ended

Dec. 31, 2010

Operating revenues by country

Operating revenues by country were as follows (in millions):

	Years ended December 31,
	2010		2009		2008
Operating revenues
U.S.	$	2,117	$	2,239	$	2,578
Brazil		1,288		1,108		547
U.K.		1,183		1,563		2,012
India		828		1,084		890
Other countries (a)		4,160		5,562		6,647
Total operating revenues	$	9,576	$	11,556	$	12,674

______________________________

(a)	Other countries represents countries in which we operate that individually had operating revenues representing less than 10 percent of total operating revenues earned.

Long-lived assets by country

Long-lived assets by country were as follows (in millions):

	December 31,
	2010		2009
Long-lived assets
U.S.	$	5,573	$	6,203
India		2,632		1,358
Brazil		2,472		1,433
South Korea		820		3,128
Other countries (a)		9,961		10,896
Total long-lived assets	$	21,458	$	23,018

______________________________

(a)	Other countries represents countries in which we operate that individually had long-lived assets representing less than 10 percent of total long-lived assets.

Quarterly Results (Tables)

12 Months Ended

Dec. 31, 2010

Selected unaudited quarterly data

Shown below are selected unaudited quarterly data. Amounts are rounded for consistency in presentation with no effect to the results of operations previously reported on Form 10-Q or Form 10-K.

	Three months ended
	March 31,		June 30,		September 30,		December 31,
	(In millions, except per share data)
2010
Operating revenues	$	2,602	$	2,505	$	2,309	$	2,160
Operating income (loss) (a)		926		957		645		(662	)
Net income (loss) attributable to controlling interest (a)		677		715		368		(799	)
Earnings (loss) per share
Basic	$	2.10	$	2.23	$	1.15	$	(2.51	)
Diluted	$	2.09	$	2.22	$	1.15	$	(2.51	)
Weighted-average shares outstanding
Basic		321		319		319		319
Diluted		322		320		319		319

2009
Operating revenues	$	3,118	$	2,882	$	2,823	$	2,733
Operating income (b)		1,319		1,121		957		1,003
Net income attributable to controlling interest (b)		942		806		710		723
Earnings per share
Basic	$	2.94	$	2.50	$	2.20	$	2.24
Diluted	$	2.93	$	2.49	$	2.19	$	2.24
Weighted-average shares outstanding
Basic		319		320		321		321
Diluted		320		321		322		322

______________________________

(a)	First quarter included loss on impairment of $2 million. Second quarter included gain on the loss of Deepwater Horizon of $267 million. Fourth quarter included loss on impairment of $1.0 billion. See Note 5-Impairments and Note 9-Drilling Fleet.

(b)	First quarter included loss on impairment of $221 million. Second quarter included loss on impairment of $67 million. Third quarter included loss on impairment of $46 million and settlement charges related to litigation matters of $132 million. See Note 5-Impairments.

Nature of Business (Details)	12 Months Ended
Nature of Business (Details)	Dec. 31, 2010	Dec. 31, 2008
Notes to Financial Statements [Abstract]
Number of mobile offshore drilling units	139
Number of High-Specification Floaters	47
Number of Midwater Floaters	25
Number of High-Specification Jackups	10
Number of Standard Jackups	54
Number of Other Rigs	3
Number of Ultra-Deepwater Floaters under construction	1
Number of High-Specification Jackups under construction	3
Number of shares issued by Transocean Ltd. in exchange for each ordinary share of Transocean Inc. (in shares)		1
Number of shares issued by Transocean Ltd. to Transocean Inc. for future use to satisfy obligations to deliver or acquire shares (in shares)	16,000,000

Significant Accounting Policies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Principles of consolidation [Abstract]
Carrying amounts of investments in and advances to unconsolidated affiliates	$ 19	$ 11
Equity in earnings of unconsolidated affiliates	8	2	2
Allowance for doubtful accounts [Abstract]
Allowance for doubtful accounts	38	65
Materials and supplies [Abstract]
Materials and supplies, allowance for obsolescence	70	66
Property and equipment [Abstract]
Property and equipment as a percentage of total assets (in hundredths)	58.00%
Assets held for sale [Abstract]
Assets held for sale	0	186
Contract drilling intangible revenues [Abstract]
Contract drilling intangible revenues	98	281	690
Share-based compensation [Abstract]
Number Of Trading Days Used To Calculate Average Stock Price	30
Share-based compensation expense	102	81	64
Income tax benefit on share-based compensation expense	10	8	8
Pension and other postretirement benefits [Abstract]
Aggregate liability of pension and other postretirement benefit plan obligations	469	514
Net periodic benefit costs	91	87	47
Capitalized interest [Abstract]
Capitalized interest costs on construction work in progress	89	182	147
Foreign currency [Abstract]
Net foreign currency exchange gains (losses)	1	(34)	(3)
Buildings and Improvements [Member]
Estimated useful lives [Abstract]
Estimated original useful life, minimum (in years)	10Y
Estimated original useful life, maximum (in years)	30Y
Machinery and Equipment [Member]
Estimated useful lives [Abstract]
Estimated original useful life, minimum (in years)	4Y
Estimated original useful life, maximum (in years)	12Y
Drilling Rigs [Member]
Estimated useful lives [Abstract]
Estimated original useful life, minimum (in years)	18Y
Estimated original useful life, maximum (in years)	35Y
Number of rigs whose useful life was adjusted	5	10	5
Estimated useful life before adjustment, minimum (in years)	20Y	30Y	30Y
Estimated useful life before adjustment, maximum (in years)	36Y	35Y	35Y
Estimated useful life after adjustment, minimum (in years)	25Y	33Y	34Y
Estimated useful life after adjustment, maximum (in years)	39Y	50Y	50Y
Increase (decrease) in depreciation expense due to changes in estimated useful lives	23	23	6
Increase (decrease) in earnings per diluted share due to changes in estimated useful lives (in dollars per share)	$ 0.07	$ 0.07	$ 0.02
Drilling Rigs Acquired Through Merger Transaction [Member]
Estimated useful lives [Abstract]
Number of rigs whose useful life was adjusted			4
Estimated useful life before adjustment, minimum (in years)			8Y
Estimated useful life before adjustment, maximum (in years)			16Y
Estimated useful life after adjustment, minimum (in years)			3Y
Estimated useful life after adjustment, maximum (in years)			9Y
Increase (decrease) in depreciation expense due to changes in estimated useful lives			$ 46
Increase (decrease) in earnings per diluted share due to changes in estimated useful lives (in dollars per share)			$ 0.14

Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	11 Months Ended	12 Months Ended
	Jan. 31, 2010	Nov. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Variable Interest, Carrying Amount [Abstract]
Assets			$ 2,462	$ 2,082
Liabilities			1,108	1,245
Net carrying amount			1,354	837
Consolidated variable interest entities [Abstract]
Aggregate carrying amount of assets pledged as security got outstanding debt			2,191	1,975
Unconsolidated variable interest entities [Abstract]
Number of Midwater Floaters sold	2
Net cash proceeds from sale of Midwater Floaters	38
Number of notes receivable from sale of Midwater Floaters	2
Non-cash proceeds in the form of notes receivable from sale of Midwater Floaters	165
Stated interest rate on notes receivable received from sale of Midwater Floaters (in hundredths)	9.00%
Maturity date of notes receivable received from sale of Midwater Floaters		2015-01-31
Maximum borrowing amount of working capital loan in connection with sale of Midwater Floaters				35
Aggregate carrying amounts of notes receivable in connection with sale of Midwater Floaters			109
Aggregate carrying amounts of working capital loan receivable in connection with sale of Midwater Floaters			6
TPDI [Member]
Variable Interest, Carrying Amount [Abstract]
Assets			1,598	1,500
Liabilities			763	763
Net carrying amount			835	737
ADDCL [Member]
Variable Interest, Carrying Amount [Abstract]
Assets			864	582
Liabilities			345	482
Net carrying amount			$ 519	$ 100

Impairments (Details) (USD $)	12 Months Ended
Impairments (Details) (USD $)	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Long-lived assets [Abstract]
Loss on impairment of long-lived assets	$ 1,000,000,000
Loss on impairment of long-lived assets per diluted share (in dollars per share)	$ 3.15
Goodwill and other indefinite-lived intangible assets [Abstract]
Loss on impairment of goodwill associated with oil and gas properties	2,000,000
Loss on impairment of goodwill associated with oil and gas properties per diluted share (in dollars per share)	$ 0.01
Loss on impairment of goodwill associated with drilling management services			176,000,000
Loss on impairment of goodwill associated with drilling management services per diluted share (in dollars per share)			$ 0.55
Loss on impairment of trade name intangible asset		6,000,000	31,000,000
Loss on impairment of trade name intangible asset, net of tax			20,000,000
Loss on impairment of trade name intangible asset per diluted share (in dollars per share)		$ 0.02	$ 0.06
Carrying amount of the trade name intangible asset associated with drilling management services	39,000,000	39,000,000
Definite-lived intangible assets [Abstract]
Loss on impairment of customer relationships intangible asset		49,000,000	16,000,000
Loss on impairment of customer relationships intangible asset, net of tax			11,000,000
Loss on impairment of customer relationships intangible asset per diluted share (in dollars per share)		0.15	0.04
Carry amount of the customer relationship intangible asset	59,000,000	64,000,000
Assets held for sale [Abstract]
Loss on impairment of assets		279,000,000	97,000,000
Loss on impairment of assets per diluted share (in dollars per share)		$ 0.87	$ 0.30
Carrying amount of assets held for sale	$ 0	$ 186,000,000

Income Taxes (Details) (USD $)	12 Months Ended
Income Taxes (Details) (USD $)	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Components of provision (benefit) for income taxes [Abstract]
Current tax expense	$ 456,000,000	$ 741,000,000	$ 735,000,000
Deferred tax expense (benefit)	(145,000,000)	13,000,000	8,000,000
Income tax expense	311,000,000	754,000,000	743,000,000
Effective tax rate (in hundredths)	23.90%	19.20%	15.60%
Swiss holding company statutory rate (in hundredths)	7.83%	7.83%
Reconciliation of income tax expense at the Swiss holding company statutory rate and the reported provision for income taxes [Abstract]
Income tax expense at the federal statutory rate	102,000,000	307,000,000
Taxes on earnings subject to rates greater than the Swiss rate	89,000,000	321,000,000
Taxes on impairment loss subject to rates less than the Swiss rate	79,000,000	0
Changes in unrecognized tax benefits	71,000,000	135,000,000
Change in valuation allowance	(4,000,000)	46,000,000
Benefit from foreign tax credits	(23,000,000)	(49,000,000)
Other, net	(3,000,000)	(6,000,000)
Income tax expense	311,000,000	754,000,000	743,000,000
Deferred tax assets [Abstract]
Drilling contract intangibles	6,000,000	14,000,000
Net operating loss carryforwards	114,000,000	135,000,000
Tax credit carryforwards	29,000,000	29,000,000
Accrued payroll expenses not currently deductible	72,000,000	74,000,000
Deferred income	84,000,000	74,000,000
Other	61,000,000	29,000,000
Valuation allowance	(94,000,000)	(98,000,000)	(52,000,000)
Total deferred tax assets	272,000,000	257,000,000
Deferred tax liabilities [Abstract]
Depreciation and amortization	(699,000,000)	(834,000,000)
Drilling management services intangibles	(26,000,000)	(27,000,000)
Other	(26,000,000)	(18,000,000)
Total deferred tax liabilities	(751,000,000)	(879,000,000)
Net deferred tax liabilities	(479,000,000)	(622,000,000)
U.S. foreign tax credit carryforwards	29,000,000
Expiration date range of U.S. foreign tax credit carryforwards	between 2015 and 2020
Tax effect of Brazilian NOLs	53,000,000	59,000,000
Indefinitely reinvested earnings	2,000,000,000
Range of taxes that would be payable upon distribution of all previously unremitted earnings, lower range limit	150,000,000
Range of taxes that would be payable upon distribution of all previously unremitted earnings, upper range limit	200,000,000
Reconciliation of unrecognized tax benefits, excluding interest and penalties [Roll Forward]
Balance, beginning of period	460,000,000	372,000,000	299,000,000
Additions for current year tax positions	46,000,000	64,000,000	46,000,000
Additions for prior year tax positions	9,000,000	62,000,000	67,000,000
Reductions for prior year tax positions	(11,000,000)	(22,000,000)	(36,000,000)
Settlements	(17,000,000)	(3,000,000)	(3,000,000)
Reductions related to statute of limitation expirations	(2,000,000)	(13,000,000)	(1,000,000)
Balance, end of period	485,000,000	460,000,000	372,000,000
Liabilities Related To Unrecognized Tax Benefits: [Abstract]
Unrecognized tax benefits, excluding interest and penalties	485,000,000	460,000,000
Interest and penalties	235,000,000	200,000,000
Unrecognized tax benefits, including interest and penalties	720,000,000	660,000,000
Interest and penalties related to unrecognized tax benefits recorded as a component of income tax expense	35,000,000	51,000,000	24,000,000
Unrecognized tax benefits, including interest and penalties, that would favorably impact effective tax rate	693,000,000
Tax Positions [Abstract]
2004 and 2005 transfer pricing adjustment	79,000,000
2006 and 2007 income tax adjustments	278,000,000
2006 through 2009 restructuring transactions tax adjustments	295,000,000
2006 through 2009 withholding and other tax adjustments	166,000,000
Assessed penalties associated with the various adjustments	92,000,000
Norway tax assessment due to restructuring transactions	268,000,000
Norway tax assessment due to migration of subsidiary	117,000,000
Norway tax assessment due 2001 dividend payment	71,000,000
Norway tax assessment due foreign exchange deductions	7,000,000
Norway tax financial security	1,000,000,000
Percentage of penalties to be assessed by Norway tax authorities (in hundredths)	60.00%
Brazil tax assessment for income tax returns 2000 to 2004	115,000,000
Percentage of penalties to be assessed by Brazil tax authorities (in hundredths)	75.00%
Brazil tax assessment penalty	86,000,000
Brazil tax assessment interest	$ 138,000,000

Earnings Per Share (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified

3 Months Ended

12 Months Ended

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

Dec. 31, 2009

Sep. 30, 2009

Jun. 30, 2009

Mar. 31, 2009

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Numerator for earnings per share, basic [Abstract]

Net income attributable to controlling interest

$ (799)

^[1]

$ 368

$ 715

^[1]

$ 677

^[1]

$ 723

$ 710

^[2]

$ 806

^[2]

$ 942

^[2]

$ 961

$ 3,181

$ 4,031

Undistributed net income allocable to participating securities

(5)

(18)

(10)

Net income available to shareholders

956

3,163

4,021

Denominator for earnings per share, basic [Abstract]

Weighted-average shares outstanding (in shares)

319

321

320

319

320

318

Earnings per share, basic (in dollars per share)

$ (2.51)

$ 1.15

$ 2.23

$ 2.10

$ 2.24

$ 2.20

$ 2.50

$ 2.94

$ 2.99

$ 9.87

$ 12.63

Numerator for earnings per share, diluted [Abstract]

Net income attributable to controlling interest

(799)

^[1]

368

715

^[1]

677

^[1]

723

710

^[2]

806

^[2]

942

^[2]

961

3,181

4,031

Undistributed net income allocable to participating securities

(5)

(18)

(10)

Net income available to shareholders

$ 956

$ 3,163

$ 4,021

Denominator for earnings per share, diluted [Abstract]

Weighted-average shares outstanding (in shares)

319

321

320

319

320

318

Effect of dilutive securities [Abstract]

Stock options and other share-based awards (in shares)

Stock warrants (in shares)

Weighted-average shares per calculation (in shares)

319

320

322

321

320

321

Earnings per share, diluted (in dollars per share)

$ (2.51)

$ 1.15

$ 2.22

$ 2.09

$ 2.24

$ 2.19

$ 2.49

$ 2.93

$ 2.99

$ 9.84

$ 12.53

Antidilutive securities excluded from computation of earnings per share [Abstract]

Antidilutive share-based awards excluded from the calculation of earnings per share (in shares)

2.2

1.7

0.4

1.625% Series A Convertible Senior Notes, stated interest rate (in hundredths)

1.625%

1.50% Series B Convertible Senior Notes, stated interest rate (in hundredths)

1.50%

1.50% Series C Convertible Senior Notes, stated interest rate (in hundredths)

1.50%

[1]	First quarter included loss on impairment of $2 million. Second quarter included gain on the loss of Deepwater Horizon of $267 million. Fourth quarter included loss on impairment of $1.0 billion. See Note [5]-Impairments and Note [9]-Drilling Fleet.
[2]	First quarter included loss on impairment of $221 million. Second quarter included loss on impairment of $67 million. Third quarter included loss on impairment of $46 million and settlement charges related to litigation matters of $132 million. See Note [5]-Impairments.

Other Comprehensive Income (Details) (USD $)
In Millions, unless otherwise specified

12 Months Ended

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Other comprehensive income (loss) attributable to controlling interest [Abstract]

Unrecognized components of net periodic benefit costs

$ (8)

$ 37

$ (388)

Recognized components of net periodic benefit costs

Unrealized gain (loss) on derivative instruments

(10)

(4)

(1)

Recognized (gain) loss on derivative instruments

Other, net

(3)

Other comprehensive income (loss) before income taxes

(387)

(9)

Other comprehensive income (loss), net of tax

(378)

Other comprehensive income (loss) attributable to non-controlling interest [Abstract]

Unrecognized components of net periodic benefit costs

^[1]

Recognized components of net periodic benefit costs

^[1]

Unrealized gain (loss) on derivative instruments

(19)

^[1]

Recognized (gain) loss on derivative instruments

(2)

^[1]

Other, net

^[1]

Other comprehensive income (loss) before income taxes

(21)

^[1]

Other comprehensive income (loss), net of tax

(21)

^[1]

Other comprehensive income (loss) total [Abstract]

Unrecognized components of net periodic benefit costs

(37)

388

Recognized components of net periodic benefit costs

(16)

(24)

(5)

Recognized (gain) loss on derivative instruments

Other, net

(1)

Other comprehensive loss before income taxes

(9)

(387)

(9)

Other comprehensive loss, net of income taxes

(18)

(378)

Accumulated other comprehensive income (loss), net of tax attributable to controlling interest [Abstract]

Unrecognized components of net period benefit costs

(335)

^[2]

(334)

^[2]

Unrecognized gain on derivative investments

Unrealized loss on securities held for sale

(2)

Accumulated other comprehensive income (loss)

(332)

(335)

Accumulated other comprehensive income (loss), net of tax attributable to non-controlling interest [Abstract]

Unrecognized components of net period benefit costs

^[2]

Unrecognized gain (loss) on derivative investments

(3)

Unrealized loss on marketable securities

Accumulated other comprehensive income (loss)

(3)

Accumulated other comprehensive income (loss), net of tax, attributable to redeemable non-controlling interest [Abstract]

Unrecognized components of net period benefit costs

^[2]

Unrecognized gain (loss) on derivative investments

(13)

Unrealized loss on marketable securities

Accumulated other comprehensive income (loss)

(13)

$ 36

$ 45

[1]	Includes amounts attributable to noncontrolling interest and redeemable noncontrolling interest.
[2]	Amounts are net of income tax effect of $36 million and $45 million for December 31, 2010 and 2009, respectively.

Drilling Fleet (Details) (USD $)	1 Months Ended		12 Months Ended			24 Months Ended	12 Months Ended											12 Months Ended			24 Months Ended		12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended		12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended		12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended		12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended	12 Months Ended			24 Months Ended
Drilling Fleet (Details) (USD $)	Mar. 31, 2010	Jan. 31, 2010	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2010 Sale of Two Midwater Floaters [Member]	Dec. 31, 2010 Disposal of Other Unrelated Assets [Member]	Dec. 31, 2009 Disposal of Other Unrelated Assets [Member]	Dec. 31, 2009 Sale of Sedco 135-D [Member]	Dec. 31, 2009 Caspian Drilling Company Limited [Member]	Dec. 31, 2009 Arab Drilling & Workover Company [Member]	Dec. 31, 2008 Sale of Three Standard Jackups [Member]	Apr. 22, 2010 Sale of Three Standard Jackups [Member]	Dec. 31, 2010 Sale of Transocean Mercury and Related Equipment [Member]	Dec. 31, 2010 TPDI [Member]	Dec. 31, 2010 ADDCL [Member]	Dec. 31, 2010 Deepwater Champion [Member]	Dec. 31, 2009 Deepwater Champion [Member]	Dec. 31, 2008 Deepwater Champion [Member]	Dec. 31, 2007 Deepwater Champion [Member]	Nov. 30, 2007 Deepwater Champion [Member]	Dec. 31, 2010 Discoverer India [Member]	Dec. 31, 2009 Discoverer India [Member]	Dec. 31, 2008 Discoverer India [Member]	Dec. 31, 2007 Discoverer India [Member]	Dec. 31, 2010 Discoverer Luanda [Member]	Dec. 31, 2009 Discoverer Luanda [Member]	Dec. 31, 2008 Discoverer Luanda [Member]	Dec. 31, 2007 Discoverer Luanda [Member]	Dec. 31, 2010 Transocean Honor [Member]	Dec. 31, 2009 Transocean Honor [Member]	Dec. 31, 2008 Transocean Honor [Member]	Dec. 31, 2007 Transocean Honor [Member]	Nov. 30, 2010 Transocean Honor [Member]	Dec. 31, 2010 Dhirubhai Deepwater KG2 [Member]	Dec. 31, 2009 Dhirubhai Deepwater KG2 [Member]	Dec. 31, 2008 Dhirubhai Deepwater KG2 [Member]	Dec. 31, 2007 Dhirubhai Deepwater KG2 [Member]	Dec. 31, 2010 Development Driller III [Member]	Dec. 31, 2009 Development Driller III [Member]	Dec. 31, 2008 Development Driller III [Member]	Dec. 31, 2007 Development Driller III [Member]	Nov. 30, 2007 Development Driller III [Member]	Dec. 31, 2010 Discoverer Inspiration [Member]	Dec. 31, 2009 Discoverer Inspiration [Member]	Dec. 31, 2008 Discoverer Inspiration [Member]	Dec. 31, 2007 Discoverer Inspiration [Member]	Dec. 31, 2010 High-Specification Jackup TBN1 [Member]	Dec. 31, 2009 High-Specification Jackup TBN1 [Member]	Dec. 31, 2008 High-Specification Jackup TBN1 [Member]	Dec. 31, 2007 High-Specification Jackup TBN1 [Member]	Dec. 31, 2010 High-Specification Jackup TBN2 [Member]	Dec. 31, 2009 High-Specification Jackup TBN2 [Member]	Dec. 31, 2008 High-Specification Jackup TBN2 [Member]	Dec. 31, 2007 High-Specification Jackup TBN2 [Member]	Dec. 31, 2010 Discoverer Americas [Member]	Dec. 31, 2009 Discoverer Americas [Member]	Dec. 31, 2008 Discoverer Americas [Member]	Dec. 31, 2007 Discoverer Americas [Member]	Dec. 31, 2010 Discoverer Clear Leader [Member]	Dec. 31, 2009 Discoverer Clear Leader [Member]	Dec. 31, 2008 Discoverer Clear Leader [Member]	Dec. 31, 2007 Discoverer Clear Leader [Member]	Dec. 31, 2010 Petrobras 10000 [Member]	Dec. 31, 2009 Petrobras 10000 [Member]	Dec. 31, 2008 Petrobras 10000 [Member]	Dec. 31, 2007 Petrobras 10000 [Member]	Aug. 04, 2009 Petrobras 10000 [Member]	Dec. 31, 2010 Dhirubhai Deepwater KG1 [Member]	Dec. 31, 2009 Dhirubhai Deepwater KG1 [Member]	Dec. 31, 2008 Dhirubhai Deepwater KG1 [Member]	Dec. 31, 2007 Dhirubhai Deepwater KG1 [Member]	Dec. 31, 2010 Sedco 700-series Upgrades [Member]	Dec. 31, 2009 Sedco 700-series Upgrades [Member]	Dec. 31, 2008 Sedco 700-series Upgrades [Member]	Dec. 31, 2007 Sedco 700-series Upgrades [Member]	Dec. 31, 2010 Capitalized interest [Member]	Dec. 31, 2009 Capitalized interest [Member]	Dec. 31, 2008 Capitalized interest [Member]	Dec. 31, 2007 Capitalized interest [Member]	Dec. 31, 2010 Mobilization costs [Member]	Dec. 31, 2009 Mobilization costs [Member]	Dec. 31, 2008 Mobilization costs [Member]	Dec. 31, 2007 Mobilization costs [Member]
Actual Capital Expenditures And Other Capital Additions Including Capitalized Interest [Line Items]
Actual capital expenditures and other capital additions, including capitalized interest			$ 966,000,000	$ 3,187,000,000	$ 1,692,000,000	$ 2,471,000,000												$ 206,000,000	$ 263,000,000	$ 155,000,000	$ 109,000,000		$ 203,000,000	$ 291,000,000	$ 250,000,000	$ 0	$ 174,000,000	$ 220,000,000	$ 208,000,000	$ 107,000,000	$ 97,000,000	$ 0	$ 0	$ 0		$ 36,000,000	$ 371,000,000	$ 91,000,000	$ 179,000,000	$ 24,000,000	$ 117,000,000	$ 133,000,000	$ 350,000,000		$ 12,000,000	$ 224,000,000	$ 205,000,000	$ 238,000,000	$ 9,000,000	$ 0	$ 0	$ 0	$ 9,000,000	$ 0	$ 0	$ 0	$ 6,000,000	$ 148,000,000	$ 167,000,000	$ 311,000,000	$ 6,000,000	$ 115,000,000	$ 107,000,000	$ 409,000,000	$ 6,000,000	$ 735,000,000	$ 0	$ 0		$ 0	$ 295,000,000	$ 105,000,000	$ 279,000,000	$ 0	$ 71,000,000	$ 124,000,000	$ 396,000,000	$ 89,000,000	$ 182,000,000	$ 147,000,000	$ 93,000,000	$ 89,000,000	$ 155,000,000	$ 0	$ 0
Total capital expenditures and other capital additions, including capitalized interest			8,316,000,000															733,000,000					744,000,000				709,000,000				97,000,000					677,000,000				624,000,000					679,000,000				9,000,000				9,000,000				632,000,000				637,000,000				741,000,000					679,000,000				591,000,000				511,000,000				244,000,000
Initial investment in construction project																						109,000,000													195,000,000									350,000,000
Initial installment payment																																			97,000,000														9,000,000				9,000,000
Total purchase price of completed construction project																																																	186,000,000				186,000,000
Percentage of costs in construction project incurred by joint venture (in hundredths)																											100.00%									100.00%																																		100.00%
Ownership interest in joint venture (in hundredths)											45.00%					50.00%	65.00%
Percentage interest in joint venture held by an unaffiliated party (in hundredths)																50.00%	35.00%
Name of joint venture company																											ADDCL									TPDI																																		TPDI
Non-cash net additions to property and equipment for the delivery of Petrobras 10000																																																																					716,000,000
Capital costs incurred by Petrobras and Mitsui for the construction of the Petrobras 10000																																																																		716,000,000
Other capital expenditures for the construction of the Petrobras 10000																																																																		19,000,000
Term of capital lease agreement for the Petrobras 10000 (in years)																																																																		20Y
Bargain purchase price for the Petrobras 10000																																																																		1
Expansion [Abstract]
Construction work in progress			1,500,000,000	3,700,000,000
Acquisition cost for GSF Explorer, formerly held under capital lease	15,000,000
Dispositions [Line Items]
Number of Midwater Floaters sold		2					2
Net cash proceeds from sale of assets			60,000,000	18,000,000	348,000,000		38,000,000			10,000,000			320,000,000
Non-cash proceeds in the form of notes receivable from sale of assets							165,000,000
Gain (loss) on the sale of assets			257,000,000	(9,000,000)	(7,000,000)		(15,000,000)	5,000,000	9,000,000
Gain (loss) on the sale of assets per diluted share (in dollars per share)							$ (0.040000000)
Net proceeds received for the exchange of the company's ownership interest											4,000,000	38,000,000
Maximum carrying value of Transocean Mercury classified as asset held for sale															1,000,000
Deepwater Horizon [Abstract]
Insured value of drilling unit lost														560,000,000
Proceeds from insurance recoveries for loss of drilling unit			560,000,000	0	0
Recognized gain on loss of drilling unit			$ 267,000,000
Recognized gain on loss of drilling unit per dilutive share (in dollars per share)			$ 0.8300000

Goodwill and Other Intangibles Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Goodwill [Roll Forward]
Gross carrying amount before purchase price adjustment	$ 10,810	$ 10,798
Accumulated impairment before purchase price adjustment	(2,670)	(2,670)
Net carrying amount before purchase price adjustment	8,134	8,128
Gross carrying amount, purchase price adjustment	0
Accumulated impairment, purchase price adjustment	0	0
Net carrying amount, purchase price adjustment	0	6
Goodwill Gross Carrying Amount Impairment	0	0
Accumulated impairment, impairment	(2)	0
Net carrying amount, impairment	(2)	0
Gross carrying amount after purchase price adjustment and impairment	10,804	10,810	10,798
Accumulated impairment after purchase price adjustment and impairment	(2,672)	(2,670)	(2,670)
Net carrying amount after purchase price adjustment and impairment	8,132	8,134	8,128
Acquired finite-lived intangible assets, net [Abstract]
Net carrying amount, beginning of period	64
Accumulated amortization and impairment, impairment		49	16
Net carrying amount, end of period	59	64
Estimated net future amortization expense (income) [Abstract]
Amortization period for customer relationships (in years)	15Y
Drilling Contract Intangible Assets [Member]
Acquired finite-lived intangible assets, net [Abstract]
Gross carrying amount beginning of period	191	191	191
Accumulated amortization and impairment, beginning of period	(167)	(123)
Net carrying amount, beginning of period	24	68
Gross carrying amount, amortization	0	0
Accumulated amortization and impairment, amortization	(18)	(44)
Net carrying amount, amortization	(18)	(44)
Gross carrying amount, end of period	191	191	191
Accumulated amortization and impairment, end of period	(185)	(167)
Net carrying amount, end of period	6	24
Estimated net future amortization expense (income) [Abstract]
2011	(45)
2012	(42)
2013	(25)
2014	(15)
2015	(14)
Thereafter	(6)
Total estimated net future amortization expense (income)	(147)
Customer Relationships [Member]
Acquired finite-lived intangible assets, net [Abstract]
Gross carrying amount beginning of period	148	148	148
Accumulated amortization and impairment, beginning of period	(84)	(27)
Net carrying amount, beginning of period	64	121
Gross carrying amount, amortization	0	0
Accumulated amortization and impairment, amortization	(5)	(8)
Net carrying amount, amortization	(5)	(8)
Gross carrying amount, impairment	0	0
Accumulated amortization and impairment, impairment	0	(49)
Net carrying amount, impairment	0	(49)
Gross carrying amount, end of period	148	148	148
Accumulated amortization and impairment, end of period	(89)	(84)
Net carrying amount, end of period	59	64
Estimated net future amortization expense (income) [Abstract]
2011	5
2012	5
2013	5
2014	5
2015	5
Thereafter	34
Total estimated net future amortization expense (income)	59
Total Intangible Assets [Member]
Acquired finite-lived intangible assets, net [Abstract]
Gross carrying amount beginning of period	339	339	339
Accumulated amortization and impairment, beginning of period	(252)	(150)
Net carrying amount, beginning of period	87	189
Gross carrying amount, amortization	0	0
Accumulated amortization and impairment, amortization	(23)	(53)
Net carrying amount, amortization	(23)	(53)
Gross carrying amount, impairment	0	0
Accumulated amortization and impairment, impairment	0	(49)
Net carrying amount, impairment	0	(49)
Gross carrying amount, end of period	339	339	339
Accumulated amortization and impairment, end of period	(275)	(252)
Net carrying amount, end of period	64	87
Drilling Contract Intangible Liabilities [Member]
Acquired finite-lived intangible assets, net [Abstract]
Gross carrying amount beginning of period	1,494	1,494	1,494
Accumulated amortization and impairment, beginning of period	(1,226)	(901)
Net carrying amount, beginning of period	268	593
Gross carrying amount, amortization	0	0
Accumulated amortization and impairment, amortization	(116)	(325)
Net carrying amount, amortization	(116)	(325)
Gross carrying amount, end of period	1,494	1,494	1,494
Accumulated amortization and impairment, end of period	(1,342)	(1,226)
Net carrying amount, end of period	152	268
ADTI Trade name [Member]
Indefinite-lived intangible asset, net [Abstract]
Gross carrying amount, beginning balance	76	76
Accumulated impairment, beginning balance	(37)	(31)
Net carrying amount, beginning balance	39	45
Gross carrying amount, impairment	0	0
Accumulated impairment, impairment	0	(6)
Net carrying amount, impairment	0	(6)
Gross carrying amount, ending balance	76	76
Accumulated impairment, ending balance	(37)	(37)
Net carrying amount, ending balance	39	39
Contract Drilling Services [Member]
Goodwill [Roll Forward]
Gross carrying amount before purchase price adjustment	10,626	10,620
Accumulated impairment before purchase price adjustment	(2,494)	(2,494)
Net carrying amount before purchase price adjustment	8,132	8,126
Gross carrying amount, purchase price adjustment	0	6
Accumulated impairment, purchase price adjustment	0	0
Net carrying amount, purchase price adjustment	0	6
Gross carrying amount after purchase price adjustment and impairment	10,626	10,626
Accumulated impairment after purchase price adjustment and impairment	(2,494)	(2,494)
Net carrying amount after purchase price adjustment and impairment	8,132	8,132
Drilling Management Services [Member]
Goodwill [Roll Forward]
Gross carrying amount after purchase price adjustment and impairment	176	176	176
Accumulated impairment after purchase price adjustment and impairment	(176)	(176)	(176)
Net carrying amount after purchase price adjustment and impairment	0	0	0
Oil and Gas Properties [Member]
Goodwill [Roll Forward]
Gross carrying amount before purchase price adjustment	2	2
Accumulated impairment before purchase price adjustment	0	0
Net carrying amount before purchase price adjustment	2	2
Goodwill Gross Carrying Amount Impairment	0	0
Accumulated impairment, impairment	(2)	0
Net carrying amount, impairment	(2)	0
Gross carrying amount after purchase price adjustment and impairment	2	2
Accumulated impairment after purchase price adjustment and impairment	(2)	0
Net carrying amount after purchase price adjustment and impairment	$ 0	$ 2

Debt (Details) (USD $)

1 Months Ended

12 Months Ended

Mar. 31, 2010

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Long-term debt by current and noncurrent [Abstract]

$ 11,221,000,000

$ 11,717,000,000

Percentage ownership interest in Transocean Inc. by Transocean Ltd. (in hundredths)

2,012,000,000

1,868,000,000

Long-term debt

9,209,000,000

9,849,000,000

100.00%

Independent assets and operations of Transocean Inc. as a percentage of total consolidated assets and operations of Transocean Ltd.

2.00%

Total debt, excluding unamortized discounts, premiums and fair value adjustments

2,065,000,000

1,838,000,000

868,000,000

122,000,000

1,463,000,000

5,017,000,000

11,373,000,000

Total unamortized discounts, premiums and fair value adjustments

(152,000,000)

Cash payment to acquire asset formerly held under capital lease

11,221,000,000

11,717,000,000

15,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

Gain (loss) on retirement of debt

11,221,000,000

11,717,000,000

(33,000,000)

(29,000,000)

(3,000,000)

ODL Loan Facility [Member]

Long-term debt by current and noncurrent [Abstract]

10,000,000

10,000,000

10,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

10,000,000

Long-term debt by current and noncurrent [Abstract]

10,000,000

Commercial paper program [Member]

88,000,000

^[1]

281,000,000

^[1]

88,000,000

^[1]

281,000,000

^[1]

88,000,000

^[1]

281,000,000

^[1]

Credit facility weighted-average interest rate (in hundredths)

1,500,000,000

1.00%

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

88,000,000

^[1]

281,000,000

^[1]

Notes Due April 2011 [Member]

167,000,000

^[1]

170,000,000

^[1]

Debt instrument interest rate stated percentage (in hundredths)

167,000,000

^[1]

6.625%

2011-04

167,000,000

^[1]

170,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

700,000,000

166,000,000

Long-term debt by current and noncurrent [Abstract]

167,000,000

^[1]

170,000,000

^[1]

Notes Due February 2013 [Member]

Debt instrument interest rate stated percentage (in hundredths)

255,000,000

247,000,000

5.00%

2013-02

Debt redemption percentage of principal to be repaid (in hundredths)

255,000,000

247,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

250,000,000

Long-term debt by current and noncurrent [Abstract]

255,000,000

247,000,000

Senior Notes Due March 2013 [Member]

Debt instrument interest rate stated percentage (in hundredths)

511,000,000

^[1]

496,000,000

^[1]

5.25%

2013-03

511,000,000

^[1]

496,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

500,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

500,000,000

Long-term debt by current and noncurrent [Abstract]

511,000,000

^[1]

496,000,000

^[1]

TPDI Credit Facilities Due March 2015 [Member]

560,000,000

581,000,000

70,000,000

52,000,000

2015-03

560,000,000

581,000,000

560,000,000

581,000,000

Credit facility weighted-average interest rate (in hundredths)

1,265,000,000

1.90%

Letters of credit issued and outstanding

60,000,000

Aggregate commitment of subsidiary in secured term loan

595,000,000

Credit facility amount outstanding

1,100,000,000

TPDI debt due to a subsidiary and eliminated in consolidation

543,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

560,000,000

581,000,000

Senior Notes Due November 2015 [Member]

Debt instrument interest rate stated percentage (in hundredths)

1,099,000,000

^[1]

4.95%

2015-11

1,099,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

1,100,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

1,100,000,000

Long-term debt by current and noncurrent [Abstract]

1,099,000,000

^[1]

ADDCL Credit Facilities Due November 2017 [Member]

242,000,000

454,000,000

25,000,000

248,000,000

2017-11

Carrying amounts of Convertible Senior Notes [Abstract]

242,000,000

454,000,000

Long-term debt by current and noncurrent [Abstract]

242,000,000

454,000,000

Senior Notes Due March 2018 [Member]

Debt instrument interest rate stated percentage (in hundredths)

997,000,000

^[1]

997,000,000

^[1]

6.00%

2018-03

997,000,000

^[1]

997,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

1,000,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

1,000,000,000

Long-term debt by current and noncurrent [Abstract]

997,000,000

^[1]

997,000,000

^[1]

Senior Notes Due April 2018 [Member]

Debt instrument interest rate stated percentage (in hundredths)

247,000,000

^[1]

247,000,000

^[1]

7.375%

2018-04

247,000,000

^[1]

247,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

247,000,000

246,000,000

Long-term debt by current and noncurrent [Abstract]

247,000,000

^[1]

247,000,000

^[1]

TPDI Notes Due October 2019 [Member]

148,000,000

2019-10

Credit facility weighted-average interest rate (in hundredths)

148,000,000

2.60%

TPDI debt due to a subsidiary and eliminated in consolidation

148,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

296,000,000

Long-term debt by current and noncurrent [Abstract]

148,000,000

Senior Notes Due November 2020 [Member]

Debt instrument interest rate stated percentage (in hundredths)

899,000,000

^[1]

6.50%

2020-11

899,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

900,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

900,000,000

Long-term debt by current and noncurrent [Abstract]

899,000,000

^[1]

Capital lease Obligation Due July 2026 [Member]

15,000,000

2026-07

Cash payment to acquire asset formerly held under capital lease

15,000,000

15,000,000

Gain on debt retirement from termination of capital lease obligation

2,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

15,000,000

Debentures Due April 2027 [Member]

Debt instrument interest rate stated percentage (in hundredths)

57,000,000

^[1]

57,000,000

^[1]

8.00%

2027-04

57,000,000

^[1]

57,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

200,000,000

57,000,000

Long-term debt by current and noncurrent [Abstract]

57,000,000

^[1]

57,000,000

^[1]

Notes Due April 2027 [Member]

Debt instrument interest rate stated percentage (in hundredths)

96,000,000

^[1]

96,000,000

^[1]

7.45%

2027-04

96,000,000

^[1]

96,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

100,000,000

100,000,000

Long-term debt by current and noncurrent [Abstract]

96,000,000

^[1]

96,000,000

^[1]

Senior Notes Due June 2028 [Member]

Debt instrument interest rate stated percentage (in hundredths)

313,000,000

7.00%

2028-06

313,000,000

Debt redemption percentage of principal to be repaid (in hundredths)

300,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

300,000,000

Long-term debt by current and noncurrent [Abstract]

313,000,000

Capital Lease Contract Due August 2029 [Member]

694,000,000

711,000,000

16,000,000

2029-08

Carrying amounts of Convertible Senior Notes [Abstract]

694,000,000

711,000,000

Long-term debt by current and noncurrent [Abstract]

694,000,000

711,000,000

Notes Due April 2031 [Member]

Debt instrument interest rate stated percentage (in hundredths)

598,000,000

^[1]

598,000,000

^[1]

7.50%

2031-04

598,000,000

^[1]

598,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

600,000,000

Long-term debt by current and noncurrent [Abstract]

598,000,000

^[1]

598,000,000

^[1]

Series A Convertible Senior Notes Due December 2037 [Member]

11,000,000

^[1]

1,261,000,000

^[1]

Debt instrument interest rate stated percentage (in hundredths)

11,000,000

^[1]

1,261,000,000

^[1]

1.625%

2037-12

11,000,000

^[1]

1,261,000,000

^[1]

Number of shares received upon conversion of Convertible Senior Notes

2,200,000,000

5.931

Principal amount of Convertible Senior Notes that can be converted

1,000

Conversion price per share (in dollars per share)

$ 168.61

Convertible Senior Notes terms of conversion

Carrying amounts of Convertible Senior Notes [Abstract]

11,000,000

1,299,000,000

Unamortized discount

(38,000,000)

Carrying amount of equity component

11,000,000

^[1]

1,261,000,000

^[1]

964,000,000

215,000,000

Interest expense

58,000,000

85,000,000

97,000,000

Aggregate principal amount of debt repurchased

1,288,000,000

901,000,000

Aggregate cash payment made for debt repurchased

1,288,000,000

865,000,000

Gain (loss) on retirement of debt

(28,000,000)

Adjustment to additional paid-in capital associated with equity component of debt retired

22,000,000

Series B Convertible Senior Notes Due December 2037 [Member]

Long-term debt by current and noncurrent [Abstract]

1,625,000,000

^[1]

2,057,000,000

^[1]

Debt instrument interest rate stated percentage (in hundredths)

1,625,000,000

^[1]

1.50%

2037-12

1,625,000,000

^[1]

2,057,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

2,200,000,000

100.00%

Number of shares received upon conversion of Convertible Senior Notes

5.931

Principal amount of Convertible Senior Notes that can be converted

1,000

Conversion price per share (in dollars per share)

$ 168.61

Convertible Senior Notes assumed repurchase date

2011-12-20

Convertible Senior Notes terms of conversion

Carrying amounts of Convertible Senior Notes [Abstract]

1,680,000,000

2,200,000,000

Unamortized discount

(55,000,000)

(143,000,000)

Carrying amount of equity component

1,625,000,000

^[1]

2,057,000,000

^[1]

210,000,000

275,000,000

Interest expense

98,000,000

100,000,000

97,000,000

Aggregate principal amount of debt repurchased

520,000,000

Aggregate cash payment made for debt repurchased

505,000,000

Series C Convertible Senior Notes Due December 2037 [Member]

Long-term debt by current and noncurrent [Abstract]

Debt instrument interest rate stated percentage (in hundredths)

1,605,000,000

^[1]

1,979,000,000

^[1]

1.50%

2037-12

1,605,000,000

^[1]

1,979,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

2,200,000,000

100.00%

Number of shares received upon conversion of Convertible Senior Notes

5.931

Principal amount of Convertible Senior Notes that can be converted

1,000

Conversion price per share (in dollars per share)

$ 168.61

Convertible Senior Notes assumed repurchase date

2012-12-20

Convertible Senior Notes terms of conversion

Carrying amounts of Convertible Senior Notes [Abstract]

1,722,000,000

2,200,000,000

Unamortized discount

(117,000,000)

(221,000,000)

Carrying amount of equity component

1,605,000,000

^[1]

1,979,000,000

^[1]

276,000,000

352,000,000

Interest expense

98,000,000

100,000,000

97,000,000

Aggregate principal amount of debt repurchased

478,000,000

Aggregate cash payment made for debt repurchased

453,000,000

Gain (loss) on retirement of debt

35,000,000

Gain (loss) on retirement of debt per diluted share (in dollars per share)

$ 0.110000000

Adjustment to additional paid-in capital associated with equity component of debt retired

14,000,000

Senior Notes Due March 2038 [Member]

Long-term debt by current and noncurrent [Abstract]

Debt instrument interest rate stated percentage (in hundredths)

999,000,000

^[1]

999,000,000

^[1]

6.80%

2038-03

999,000,000

^[1]

999,000,000

^[1]

Debt redemption percentage of principal to be repaid (in hundredths)

1,000,000,000

100.00%

Carrying amounts of Convertible Senior Notes [Abstract]

1,000,000,000

Long-term debt by current and noncurrent [Abstract]

999,000,000

^[1]

999,000,000

^[1]

Five - Year Revolving Credit Facility Due November 2012 [Member]

2012-11

2,000,000,000

2,000,000,000

Minimum facility fee on the daily amount of five-year revolving credit facility (in hundredths)

We may borrow under the Five-Year Revolving Credit Facility at either (1) the adjusted London Interbank Offered Rate ("LIBOR") plus a margin (the "Five-Year Revolving Credit Facility Margin") based on our Debt Rating (based on our current Debt Rating, a margin of 1.1 percent) or (2) the Base Rate plus the Five-Year Revolving Credit Facility Margin, less one percent per annum.

We may borrow under the Five-Year Revolving Credit Facility at either (1) the adjusted London Interbank Offered Rate ("LIBOR") plus a margin (the "Five-Year Revolving Credit Facility Margin") based on our Debt Rating (based on our current Debt Rating, a margin of 1 percent) or (2) the Base Rate plus the Five-Year Revolving Credit Facility Margin, less one percent per annum.

0.10%

Maximum facility fee on the daily amount of five-year revolving credit facility (in hundredths)

0.30%

Facility fee on the daily amount of the five-year revolving credit facility (in hundredths)

0.175%

Maximum debt to tangible capitalization ratio

0.6 to 1.0

Letters of credit issued and outstanding

81,000,000

Credit facility available borrowing capacity

1,900,000,000

Credit facility amount outstanding

TPDI Credit Facilities Senior Term Loan Due March 2015 [Member]

Long-term debt by current and noncurrent [Abstract]

2015-03

1,000,000,000

1,000,000,000

Long-term debt by current and noncurrent [Abstract]

LIBOR plus the applicable margin of 1.45%.

TPDI Credit Facilities Junior Term Loan Due March 2015 [Member]

2015-03

190,000,000

190,000,000

Long-term debt by current and noncurrent [Abstract]

LIBOR plus the applicable margin of 2.25%.

TPDI Credit Facilities Revolving Credit Facility Due March 2015 [Member]

2015-03

75,000,000

75,000,000

Long-term debt by current and noncurrent [Abstract]

LIBOR plus the applicable margin of 1.45%.

ADDCL Credit Facilities Tranche A Due November 2017 [Member]

2017-12

215,000,000

Credit facility weighted-average interest rate (in hundredths)

215,000,000

1.20%

Tranche A bears interest at LIBOR plus the applicable margin of 0.425 percent until the first well commencement date, currently expected to be in the first quarter of 2011, following which the applicable margin will increase to 0.725 percent.

Tranche A bears interest at LIBOR plus the applicable margin of 0.425 percent until the first well commencement date, currently expected to be in the [first quarter of 2011], following which the applicable margin will increase to 0.725 percent.

ADDCL Credit Facilities Tranche B Due November 2017 [Member]

270,000,000

Repayments under credit facility

270,000,000

235,000,000

ADDCL Credit Facilities Tranche C Due November 2017 [Member]

399,000,000

Long-term debt by current and noncurrent [Abstract]

399,000,000

ADDCL Secondary Loan Facility Due December 2015 [Member]

2015-12

90,000,000

Credit facility weighted-average interest rate (in hundredths)

90,000,000

3.40%

Credit facility amount outstanding

The facility bears interest at LIBOR plus the applicable margin, ranging from 3.125 percent to 5.125 percent, depending on certain milestones.

77,000,000

Percent of total commitment under ADDCL secondary bank credit agreement provided by subsidiary (in hundredths)

65.00%

ADDCL debt provided by a subsidiary and eliminated in consolidation

50,000,000

Transocean Ltd. and Subsidiaries [Member]

Long-term debt by current and noncurrent [Abstract]

10,271,000,000

10,534,000,000

1,917,000,000

1,568,000,000

Long-term debt

8,354,000,000

8,966,000,000

Total debt, excluding unamortized discounts, premiums and fair value adjustments

1,970,000,000

1,741,000,000

770,000,000

22,000,000

1,123,000,000

4,797,000,000

10,423,000,000

Total unamortized discounts, premiums and fair value adjustments

(152,000,000)

Carrying amounts of Convertible Senior Notes [Abstract]

10,271,000,000

10,534,000,000

Long-term debt by current and noncurrent [Abstract]

10,271,000,000

10,534,000,000

Transocean Ltd. and Subsidiaries [Member] | ODL Loan Facility [Member]

10,000,000

10,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

10,000,000

Long-term debt by current and noncurrent [Abstract]

10,000,000

Transocean Ltd. and Subsidiaries [Member] | Commercial paper program [Member]

88,000,000

^[1]

281,000,000

^[1]

88,000,000

^[1]

281,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

88,000,000

^[1]

281,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

88,000,000

^[1]

281,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Notes Due April 2011 [Member]

167,000,000

^[1]

170,000,000

^[1]

167,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

167,000,000

^[1]

170,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

167,000,000

^[1]

170,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Notes Due February 2013 [Member]

255,000,000

247,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

255,000,000

247,000,000

Long-term debt by current and noncurrent [Abstract]

255,000,000

247,000,000

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due March 2013 [Member]

511,000,000

^[1]

496,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

511,000,000

^[1]

496,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

511,000,000

^[1]

496,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | TPDI Credit Facilities Due March 2015 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due November 2015 [Member]

1,099,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

1,099,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

1,099,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | ADDCL Credit Facilities Due November 2017 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due March 2018 [Member]

997,000,000

^[1]

997,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

997,000,000

^[1]

997,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

997,000,000

^[1]

997,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due April 2018 [Member]

247,000,000

^[1]

247,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

247,000,000

^[1]

247,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

247,000,000

^[1]

247,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | TPDI Notes Due October 2019 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due November 2020 [Member]

899,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

899,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

899,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Capital lease Obligation Due July 2026 [Member]

15,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

15,000,000

Long-term debt by current and noncurrent [Abstract]

15,000,000

Transocean Ltd. and Subsidiaries [Member] | Debentures Due April 2027 [Member]

57,000,000

^[1]

57,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

57,000,000

^[1]

57,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

57,000,000

^[1]

57,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Notes Due April 2027 [Member]

96,000,000

^[1]

96,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

96,000,000

^[1]

96,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

96,000,000

^[1]

96,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due June 2028 [Member]

313,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

313,000,000

Long-term debt by current and noncurrent [Abstract]

313,000,000

Transocean Ltd. and Subsidiaries [Member] | Capital Lease Contract Due August 2029 [Member]

694,000,000

711,000,000

16,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

694,000,000

711,000,000

Long-term debt by current and noncurrent [Abstract]

694,000,000

711,000,000

Transocean Ltd. and Subsidiaries [Member] | Notes Due April 2031 [Member]

598,000,000

^[1]

598,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

598,000,000

^[1]

598,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

598,000,000

^[1]

598,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Series A Convertible Senior Notes Due December 2037 [Member]

11,000,000

^[1]

1,261,000,000

^[1]

11,000,000

^[1]

1,261,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

11,000,000

^[1]

1,261,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

11,000,000

^[1]

1,261,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Series B Convertible Senior Notes Due December 2037 [Member]

1,625,000,000

^[1]

2,057,000,000

^[1]

1,625,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

1,625,000,000

^[1]

2,057,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

1,625,000,000

^[1]

2,057,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Series C Convertible Senior Notes Due December 2037 [Member]

1,605,000,000

^[1]

1,979,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

1,605,000,000

^[1]

1,979,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

1,605,000,000

^[1]

1,979,000,000

^[1]

Transocean Ltd. and Subsidiaries [Member] | Senior Notes Due March 2038 [Member]

999,000,000

^[1]

999,000,000

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

999,000,000

^[1]

999,000,000

^[1]

Long-term debt by current and noncurrent [Abstract]

999,000,000

^[1]

999,000,000

^[1]

Consolidated variable interest entities [Member]

950,000,000

1,183,000,000

95,000,000

300,000,000

Long-term debt

855,000,000

883,000,000

Total debt, excluding unamortized discounts, premiums and fair value adjustments

95,000,000

97,000,000

98,000,000

100,000,000

340,000,000

220,000,000

950,000,000

Total unamortized discounts, premiums and fair value adjustments

Carrying amounts of Convertible Senior Notes [Abstract]

950,000,000

1,183,000,000

Long-term debt by current and noncurrent [Abstract]

950,000,000

1,183,000,000

Consolidated variable interest entities [Member] | ODL Loan Facility [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Consolidated variable interest entities [Member] | Commercial paper program [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Notes Due April 2011 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Notes Due February 2013 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Consolidated variable interest entities [Member] | Senior Notes Due March 2013 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | TPDI Credit Facilities Due March 2015 [Member]

560,000,000

581,000,000

70,000,000

52,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

560,000,000

581,000,000

Long-term debt by current and noncurrent [Abstract]

560,000,000

581,000,000

Consolidated variable interest entities [Member] | Senior Notes Due November 2015 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | ADDCL Credit Facilities Due November 2017 [Member]

242,000,000

454,000,000

25,000,000

248,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

242,000,000

454,000,000

Long-term debt by current and noncurrent [Abstract]

242,000,000

454,000,000

Consolidated variable interest entities [Member] | Senior Notes Due March 2018 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Senior Notes Due April 2018 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | TPDI Notes Due October 2019 [Member]

148,000,000

Carrying amounts of Convertible Senior Notes [Abstract]

148,000,000

Long-term debt by current and noncurrent [Abstract]

148,000,000

Consolidated variable interest entities [Member] | Senior Notes Due November 2020 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Capital lease Obligation Due July 2026 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Consolidated variable interest entities [Member] | Debentures Due April 2027 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Notes Due April 2027 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Senior Notes Due June 2028 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Consolidated variable interest entities [Member] | Capital Lease Contract Due August 2029 [Member]

Carrying amounts of Convertible Senior Notes [Abstract]

Long-term debt by current and noncurrent [Abstract]

Consolidated variable interest entities [Member] | Notes Due April 2031 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Series A Convertible Senior Notes Due December 2037 [Member]

^[1]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Series B Convertible Senior Notes Due December 2037 [Member]

^[1]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Series C Convertible Senior Notes Due December 2037 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | Senior Notes Due March 2038 [Member]

^[1]

Carrying amounts of Convertible Senior Notes [Abstract]

^[1]

Long-term debt by current and noncurrent [Abstract]

^[1]

Consolidated variable interest entities [Member] | ADDCL Credit Facilities Tranche A Due November 2017 [Member]

$ 0

^[1]

[1]

Derivatives and Hedging (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009
Derivative [Line Items]
Notional value of interest rate swaps attributable to subsidiary	$ 543
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate cash flow hedge ineffectiveness	(1)	(1)
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Interest rate cash flow hedge derivative at fair value, net		6
Interest rate fair value hedge derivative at fair value, net	17
Other Long Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Interest rate cash flow hedge derivative at fair value, net	(11)	(1)
Interest rate fair value hedge derivative at fair value, net		(4)
Interest Rate Swap 1 [Member]
Derivative [Line Items]
Derivative, underlying risk	interest rate
Derivative, hedge designation	cash flow
Derivative, description of hedged item	borrowings under the TPDI Credit Facilities
Derivative, notional amount	1,100
Derivative, weighted-average fixed interest rate (in hundredths)	2.30%
Derivative, average variable interest rate (in hundredths)	0.30%
Interest Rate Swap 2 [Member]
Derivative [Line Items]
Derivative, underlying risk	interest rate
Derivative, hedge designation	fair value
Derivative, description of hedged item	5.25% Senior Notes
Derivative, notional amount	500
Derivative, average variable interest rate (in hundredths)	3.50%
Interest Rate Swap 3 [Member]
Derivative [Line Items]
Derivative, underlying risk	interest rate
Derivative, hedge designation	fair value
Derivative, description of hedged item	5.00% Notes
Derivative, notional amount	250
Derivative, average variable interest rate (in hundredths)	3.50%
Interest Rate Swap 4 [Member]
Derivative [Line Items]
Derivative, underlying risk	interest rate
Derivative, hedge designation	cash flow
Derivative, description of hedged item	cash interest payments on the borrowings under the Term Loan
Derivative, notional amount	$ 1,000
Derivative, weighted-average fixed interest rate (in hundredths)	0.768%
Derivative, description of variable rate basis	one-month LIBOR

Postemployment Benefit Plans (Details) (USD $)	12 Months Ended
Postemployment Benefit Plans (Details) (USD $)	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Defined benefit pension plans and other postretirement employee benefit plans [Abstract]
Number of other unfunded supplemental benefit plans	2
Number of funded defined benefit plans	2
Number of unfunded defined benefit plans	2
Number of unfunded plans covering eligible Norway employees and former employees	2
Change in projected benefit obligation [Roll Forward]
Projected benefit obligation, beginning of period	$ 1,389,000,000	$ 1,214,000,000
Plan amendments	0	5,000,000
Actuarial (gains) losses, net	45,000,000	39,000,000
Service cost	63,000,000	63,000,000
Interest cost	77,000,000	70,000,000
Foreign currency exchange rate	(13,000,000)	40,000,000
Benefits paid	(70,000,000)	(47,000,000)
Participant contributions	3,000,000	3,000,000
Special termination benefits	3,000,000	0	3,000,000
Settlements and curtailments	1,000,000	2,000,000
Projected benefit obligation, end of period	1,498,000,000	1,389,000,000	1,214,000,000
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	875,000,000	663,000,000
Actual return on plan assets	114,000,000	152,000,000
Foreign currency exchange rate changes	(11,000,000)	31,000,000
Employer contributions	118,000,000	73,000,000
Participant contributions	3,000,000	3,000,000
Benefits paid	(70,000,000)	(47,000,000)
Fair value of plan assets, end of period	1,029,000,000	875,000,000	663,000,000
Funded status, end of period	(469,000,000)	(514,000,000)
Balance sheet classification, end of period [Abstract]
Pension asset, non-current	(8,000,000)	0
Accrued pension liability, current	9,000,000	10,000,000
Accrued pension liability, non-current	468,000,000	504,000,000
Accumulated other comprehensive income (loss)	(371,000,000)	(379,000,000)
Aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets [Abstract]
Projected benefit obligation	1,414,000,000	1,389,000,000
Fair value of plan assets	945,000,000	875,000,000
Accumulated benefit obligation for all defined benefit pension plans	1,300,000,000	1,100,000,000
Aggregate accumulated benefit obligation and fair value of plan assets for plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Accumulated benefit obligation	1,246,000,000	1,187,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	1,029,000,000	875,000,000	663,000,000
Net periodic benefit costs, before tax [Abstract]
Service cost	62,000,000	62,000,000	46,000,000
Interest cost	74,000,000	67,000,000	64,000,000
Expected return on plan assets	(75,000,000)	(71,000,000)	(74,000,000)
Settlements and curtailments	8,000,000	6,000,000	(1,000,000)
Special termination benefits	3,000,000	0	3,000,000
Actuarial losses, net	17,000,000	20,000,000	4,000,000
Prior service cost, net	(1,000,000)	0	1,000,000
Transition obligation, net	1,000,000	0	1,000,000
Net periodic benefit costs	89,000,000	84,000,000	44,000,000
Unrecognized accumulated other comprehensive income, before tax [Abstract]
Actuarial loss, net	378,000,000	399,000,000
Prior service credit, net	(8,000,000)	(22,000,000)
Transition obligation, net	1,000,000	2,000,000
Total	371,000,000	379,000,000
Accumulated other comprehensive income expected to be recognized during the next fiscal year [Abstract]
Actuarial loss, net	24,000,000
Prior service credit, net	(2,000,000)
Transition obligation, net	0
Total amount expected to be recognized	22,000,000
Funding contributions [Abstract]
Defined benefit plan contributions	115,000,000	73,000,000	78,000,000
Expected defined plan contributions in 2011	93,000,000
Projected pension benefits payments [Abstract]
2011	48,000,000
2012	51,000,000
2013	54,000,000
2014	57,000,000
2015	60,000,000
2016-2020	364,000,000
Defined contribution plans [Abstract]
Total number of defined contribution plans sponsored	3
Number of qualified defined contribution savings plans covering certain employees working in the U.S.	1
Number of defined contribution savings plans covering certain employees working outside the U.S. and U.K.	1
Number of defined contribution pension plans that covers certain employees working outside the U.S.	1
Maximum matching contribution percentage of each covered employee's base salary for the U.S. Savings Plan and the Non U.S. Savings Plan (in hundredths)	6.00%
Minimum contribution percentage of each covered employee's base salary for the Non-U.S. Pension Plan (in hundredths)	4.50%
Maximum contribution percentage of each covered employee's base salary for the Non-U.S. Pension Plan (in hundredths)	6.50%
Expense related to defined contribution plans	69,000,000	67,000,000	51,000,000
Severance plan [Abstract]
Number of employees involuntarily terminated			377
Severance expense	5,000,000	17,000,000	5,000,000
Liability associated with severance plan	1,000,000	17,000,000
Cumulative termination benefits paid under the severance plan	74,000,000
Termination benefits paid under the severance plan	21,000,000	18,000,000	33,000,000
Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	726,000,000	594,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	726,000,000	594,000,000
Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	303,000,000	281,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	303,000,000	281,000,000
U.S. Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	387,000,000	366,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	387,000,000	366,000,000
U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	359,000,000	341,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	359,000,000	341,000,000
U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	28,000,000	25,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	28,000,000	25,000,000
Non-U.S. Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	241,000,000	226,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	241,000,000	226,000,000
Non-U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	91,000,000	88,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	91,000,000	88,000,000
Non-U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	150,000,000	138,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	150,000,000	138,000,000
Total Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	628,000,000	592,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	628,000,000	592,000,000
Total Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	450,000,000	429,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	450,000,000	429,000,000
Total Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	178,000,000	163,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	178,000,000	163,000,000
U.S. Government Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	59,000,000	109,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	59,000,000	109,000,000
U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	59,000,000	109,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	59,000,000	109,000,000
U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non-U.S. Government Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	34,000,000	30,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000	30,000,000
Non-U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non-U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	34,000,000	30,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000	30,000,000
U.S. Corporate Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	175,000,000	38,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	175,000,000	38,000,000
U.S. Corporate Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	175,000,000	38,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	175,000,000	38,000,000
U.S. Corporate Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non-U.S. Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	12,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	12,000,000
Non-U.S. Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	12,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	12,000,000
Non-U.S. Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Total Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	275,000,000	189,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	275,000,000	189,000,000
Total Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	241,000,000	159,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	241,000,000	159,000,000
Total Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	34,000,000	30,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000	30,000,000
Cash [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	35,000,000	6,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	35,000,000	6,000,000
Cash [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	35,000,000	6,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	35,000,000	6,000,000
Cash [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Property [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	11,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	11,000,000
Property [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Property [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	11,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	11,000,000
Investment Contracts [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	84,000,000	77,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	84,000,000	77,000,000
Investment Contracts [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Investment Contracts [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	84,000,000	77,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	84,000,000	77,000,000
Total Other Investments [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	126,000,000	94,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	126,000,000	94,000,000
Total Other Investments [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	35,000,000	6,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	35,000,000	6,000,000
Total Other Investments [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	91,000,000	88,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	91,000,000	88,000,000
U. S. Plans [Member]
Weighted average assumptions used to determine benefit obligations [Abstract]
Discount rate (in hundredths)	5.48%	5.84%
Compensation trend rate (in hundredths)	4.24%	4.21%
Weighted average assumptions used to determine net periodic benefit costs [Abstract]
Discount rate (in hundredths)	5.86%	5.41%	6.14%
Expected rate of return (in hundredths)	8.49%	8.50%	8.50%
Compensation trend rate (in hundredths)	4.21%	4.21%	4.57%
Change in projected benefit obligation [Roll Forward]
Projected benefit obligation, beginning of period	932,000,000	900,000,000
Plan amendments	0	0
Actuarial (gains) losses, net	89,000,000	(31,000,000)
Service cost	42,000,000	44,000,000
Interest cost	54,000,000	50,000,000
Foreign currency exchange rate	0	0
Benefits paid	(51,000,000)	(32,000,000)
Participant contributions	0	0
Special termination benefits	3,000,000	0
Settlements and curtailments	(1,000,000)	1,000,000
Projected benefit obligation, end of period	1,068,000,000	932,000,000	900,000,000
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	594,000,000	455,000,000
Actual return on plan assets	85,000,000	121,000,000
Foreign currency exchange rate changes	0	0
Employer contributions	69,000,000	50,000,000
Participant contributions	0	0
Benefits paid	(51,000,000)	(32,000,000)
Fair value of plan assets, end of period	697,000,000	594,000,000	455,000,000
Funded status, end of period	(371,000,000)	(338,000,000)
Balance sheet classification, end of period [Abstract]
Pension asset, non-current	0	0
Accrued pension liability, current	3,000,000	5,000,000
Accrued pension liability, non-current	368,000,000	333,000,000
Accumulated other comprehensive income (loss)	(308,000,000)	(264,000,000)
Aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets [Abstract]
Projected benefit obligation	1,068,000,000	932,000,000
Fair value of plan assets	697,000,000	594,000,000
Aggregate accumulated benefit obligation and fair value of plan assets for plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Accumulated benefit obligation	921,000,000	789,000,000
Fair value of plan assets	697,000,000	594,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Total target allocation percentage (in hundredths)	100.00%
Actual allocation percentage (in hundredths)	100.00%	100.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	697,000,000	594,000,000	455,000,000
Net periodic benefit costs, before tax [Abstract]
Service cost	42,000,000	44,000,000	30,000,000
Interest cost	54,000,000	50,000,000	47,000,000
Expected return on plan assets	(58,000,000)	(55,000,000)	(53,000,000)
Settlements and curtailments	5,000,000	4,000,000	(1,000,000)
Special termination benefits	3,000,000	0
Actuarial losses, net	13,000,000	18,000,000	4,000,000
Prior service cost, net	(1,000,000)	(1,000,000)	0
Transition obligation, net	0	0	0
Net periodic benefit costs	58,000,000	60,000,000	30,000,000
Unrecognized accumulated other comprehensive income, before tax [Abstract]
Actuarial loss, net	319,000,000	277,000,000
Prior service credit, net	(11,000,000)	(13,000,000)
Transition obligation, net	0	0
Total	308,000,000	264,000,000
Accumulated other comprehensive income expected to be recognized during the next fiscal year [Abstract]
Actuarial loss, net	22,000,000
Prior service credit, net	(1,000,000)
Transition obligation, net	0
Total amount expected to be recognized	21,000,000
Funding contributions [Abstract]
Expected defined plan contributions in 2011	56,000,000
Projected pension benefits payments [Abstract]
2011	37,000,000
2012	40,000,000
2013	42,000,000
2014	45,000,000
2015	47,000,000
2016-2020	285,000,000
U. S. Plans [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	695,000,000	592,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	695,000,000	592,000,000
U. S. Plans [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	2,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	2,000,000	2,000,000
U. S. Plans [Member] \| U.S. Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	359,000,000	341,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	359,000,000	341,000,000
U. S. Plans [Member] \| U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	359,000,000	341,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	359,000,000	341,000,000
U. S. Plans [Member] \| U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Non-U.S. Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	93,000,000	90,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	93,000,000	90,000,000
U. S. Plans [Member] \| Non-U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	91,000,000	88,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	91,000,000	88,000,000
U. S. Plans [Member] \| Non-U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	2,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	2,000,000	2,000,000
U. S. Plans [Member] \| Total Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	431,000,000
Fair value of plan assets, end of period	452,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Target allocation percentage, equity securities (in hundredths)	65.00%
Actual allocation percentage (in hundredths)	65.00%	72.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	452,000,000
U. S. Plans [Member] \| Total Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	450,000,000	429,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	450,000,000	429,000,000
U. S. Plans [Member] \| Total Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	2,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	2,000,000	2,000,000
U. S. Plans [Member] \| U.S. Government Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	59,000,000	109,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	59,000,000	109,000,000
U. S. Plans [Member] \| U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	59,000,000	109,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	59,000,000	109,000,000
U. S. Plans [Member] \| U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Non-U.S. Government Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Non-U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Non-U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| U.S. Corporate Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	175,000,000	38,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	175,000,000	38,000,000
U. S. Plans [Member] \| U.S. Corporate Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	175,000,000	38,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	175,000,000	38,000,000
U. S. Plans [Member] \| U.S. Corporate Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Non-U.S. Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	12,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	12,000,000
U. S. Plans [Member] \| Non-U.S. Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	12,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	12,000,000
U. S. Plans [Member] \| Non-U.S. Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Total Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	159,000,000
Fair value of plan assets, end of period	241,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Target allocation percentage, fixed income securities (in hundredths)	35.00%
Actual allocation percentage (in hundredths)	34.00%	27.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	241,000,000
U. S. Plans [Member] \| Total Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	241,000,000	159,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	241,000,000	159,000,000
U. S. Plans [Member] \| Total Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0
U. S. Plans [Member] \| Cash [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	4,000,000	4,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	4,000,000	4,000,000
U. S. Plans [Member] \| Cash [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	4,000,000	4,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	4,000,000	4,000,000
U. S. Plans [Member] \| Cash [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Property [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Property [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Property [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Investment Contracts [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Investment Contracts [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
U. S. Plans [Member] \| Total Other Investments [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	4,000,000
Fair value of plan assets, end of period	4,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Target allocation percentage, other investments (in hundredths)	0.00%
Actual allocation percentage (in hundredths)	1.00%	1.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	4,000,000
U. S. Plans [Member] \| Total Other Investments [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	4,000,000	4,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	4,000,000	4,000,000
U. S. Plans [Member] \| Total Other Investments [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member]
Weighted average assumptions used to determine benefit obligations [Abstract]
Discount rate (in hundredths)	5.81%	5.59%
Compensation trend rate (in hundredths)	4.65%	4.73%
Weighted average assumptions used to determine net periodic benefit costs [Abstract]
Discount rate (in hundredths)	5.67%	6.06%	5.97%
Expected rate of return (in hundredths)	6.65%	6.59%	7.16%
Compensation trend rate (in hundredths)	4.77%	4.55%	4.64%
Change in projected benefit obligation [Roll Forward]
Projected benefit obligation, beginning of period	403,000,000	250,000,000
Plan amendments	0	0
Actuarial (gains) losses, net	(46,000,000)	86,000,000
Service cost	20,000,000	18,000,000
Interest cost	20,000,000	17,000,000
Foreign currency exchange rate	(13,000,000)	40,000,000
Benefits paid	(14,000,000)	(11,000,000)
Participant contributions	2,000,000	2,000,000
Special termination benefits	0	0	0
Settlements and curtailments	2,000,000	1,000,000
Projected benefit obligation, end of period	374,000,000	403,000,000	250,000,000
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	281,000,000	208,000,000
Actual return on plan assets	29,000,000	31,000,000
Foreign currency exchange rate changes	(11,000,000)	31,000,000
Employer contributions	45,000,000	20,000,000
Participant contributions	2,000,000	2,000,000
Benefits paid	(14,000,000)	(11,000,000)
Fair value of plan assets, end of period	332,000,000	281,000,000	208,000,000
Funded status, end of period	(42,000,000)	(122,000,000)
Balance sheet classification, end of period [Abstract]
Pension asset, non-current	(8,000,000)	0
Accrued pension liability, current	2,000,000	2,000,000
Accrued pension liability, non-current	48,000,000	120,000,000
Accumulated other comprehensive income (loss)	(61,000,000)	(117,000,000)
Aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets [Abstract]
Projected benefit obligation	290,000,000	403,000,000
Fair value of plan assets	248,000,000	281,000,000
Aggregate accumulated benefit obligation and fair value of plan assets for plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Accumulated benefit obligation	269,000,000	344,000,000
Fair value of plan assets	428,000,000	281,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Total target allocation percentage (in hundredths)	100.00%
Actual allocation percentage (in hundredths)	100.00%	100.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	332,000,000	281,000,000	208,000,000
Net periodic benefit costs, before tax [Abstract]
Service cost	20,000,000	18,000,000	16,000,000
Interest cost	20,000,000	17,000,000	17,000,000
Expected return on plan assets	(17,000,000)	(16,000,000)	(21,000,000)
Settlements and curtailments	3,000,000	2,000,000	0
Special termination benefits	0	0	0
Actuarial losses, net	4,000,000	2,000,000	0
Prior service cost, net	0	1,000,000	1,000,000
Transition obligation, net	1,000,000	0	1,000,000
Net periodic benefit costs	31,000,000	24,000,000	14,000,000
Unrecognized accumulated other comprehensive income, before tax [Abstract]
Actuarial loss, net	52,000,000	117,000,000
Prior service credit, net	8,000,000	(2,000,000)
Transition obligation, net	1,000,000	2,000,000
Total	61,000,000	117,000,000
Accumulated other comprehensive income expected to be recognized during the next fiscal year [Abstract]
Actuarial loss, net	2,000,000
Prior service credit, net	1,000,000
Transition obligation, net	0
Total amount expected to be recognized	3,000,000
Projected pension benefits payments [Abstract]
2011	7,000,000
2012	7,000,000
2013	8,000,000
2014	8,000,000
2015	9,000,000
2016-2020	57,000,000
Non U. S. Plans [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	31,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	31,000,000	2,000,000
Non U. S. Plans [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	301,000,000	279,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	301,000,000	279,000,000
Non U. S. Plans [Member] \| U.S. Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	28,000,000	25,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	28,000,000	25,000,000
Non U. S. Plans [Member] \| U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	28,000,000	25,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	28,000,000	25,000,000
Non U. S. Plans [Member] \| Non-U.S. Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	148,000,000	136,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	148,000,000	136,000,000
Non U. S. Plans [Member] \| Non-U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| Non-U.S. Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	148,000,000	136,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	148,000,000	136,000,000
Non U. S. Plans [Member] \| Total Equity Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	161,000,000
Fair value of plan assets, end of period	176,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Target allocation percentage, equity securities (in hundredths)	52.00%
Actual allocation percentage (in hundredths)	53.00%	57.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	176,000,000
Non U. S. Plans [Member] \| Total Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| Total Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	176,000,000	161,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	176,000,000	161,000,000
Non U. S. Plans [Member] \| Non-U.S. Government Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	34,000,000	30,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000	30,000,000
Non U. S. Plans [Member] \| Non-U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| Non-U.S. Government Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	34,000,000	30,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000	30,000,000
Non U. S. Plans [Member] \| Total Fixed Income Securities [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	30,000,000
Fair value of plan assets, end of period	34,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Target allocation percentage, fixed income securities (in hundredths)	15.00%
Actual allocation percentage (in hundredths)	10.00%	11.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000
Non U. S. Plans [Member] \| Total Fixed Income Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| Total Fixed Income Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	34,000,000	30,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	34,000,000	30,000,000
Non U. S. Plans [Member] \| Cash [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	31,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	31,000,000	2,000,000
Non U. S. Plans [Member] \| Cash [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	31,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	31,000,000	2,000,000
Non U. S. Plans [Member] \| Cash [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| Property [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	11,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	11,000,000
Non U. S. Plans [Member] \| Property [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Non U. S. Plans [Member] \| Property [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	7,000,000	11,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	7,000,000	11,000,000
Non U. S. Plans [Member] \| Investment Contracts [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	84,000,000	77,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	84,000,000	77,000,000
Non U. S. Plans [Member] \| Investment Contracts [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	84,000,000	0
Fair value of plan assets [Abstract]
Fair value of plan assets	84,000,000	0
Non U. S. Plans [Member] \| Investment Contracts [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	84,000,000	77,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	84,000,000	77,000,000
Non U. S. Plans [Member] \| Total Other Investments [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	90,000,000
Fair value of plan assets, end of period	122,000,000
Actual and targeted weighted-average asset percentage allocations for funded Transocean Plans by asset category [Abstract]
Target allocation percentage, other investments (in hundredths)	33.00%
Actual allocation percentage (in hundredths)	37.00%	32.00%
Fair value of plan assets [Abstract]
Fair value of plan assets	122,000,000
Non U. S. Plans [Member] \| Total Other Investments [Member] \| Fair Value, Inputs, Level 1 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	31,000,000	2,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	31,000,000	2,000,000
Non U. S. Plans [Member] \| Total Other Investments [Member] \| Fair Value, Inputs, Level 2 [Member]
Change in plan assets [Rollforward]
Fair value of plan assets, end of period	91,000,000	88,000,000
Fair value of plan assets [Abstract]
Fair value of plan assets	91,000,000	88,000,000
OPEB Plans [Member]
Weighted average assumptions used to determine benefit obligations [Abstract]
Discount rate (in hundredths)	4.92%	5.52%
Weighted average assumptions used to determine net periodic benefit costs [Abstract]
Discount rate (in hundredths)	5.51%	5.34%	5.96%
Health care cost trend rate, initial (in hundredths)	8.00%	8.99%	8.55%
Health care cost trend rate, ultimate (in hundredths)	5.00%	5.00%	5.00%
Year the ultimate health care cost trend rate is reached	2016	2016	2014
Change in projected benefit obligation [Roll Forward]
Projected benefit obligation, beginning of period	54,000,000
Plan amendments	0	5,000,000
Actuarial (gains) losses, net	2,000,000	(16,000,000)
Service cost	1,000,000	1,000,000
Interest cost	3,000,000	3,000,000
Foreign currency exchange rate	0	0
Benefits paid	(5,000,000)	(4,000,000)
Participant contributions	1,000,000	1,000,000
Special termination benefits	0	0
Settlements and curtailments	0	0
Projected benefit obligation, end of period	56,000,000	54,000,000
Change in plan assets [Rollforward]
Fair value of plan assets, beginning of period	0
Actual return on plan assets	0	0
Foreign currency exchange rate changes	0	0
Employer contributions	4,000,000	3,000,000
Participant contributions	1,000,000	1,000,000
Benefits paid	(5,000,000)	(4,000,000)
Fair value of plan assets, end of period	0	0
Funded status, end of period	(56,000,000)	(54,000,000)
Balance sheet classification, end of period [Abstract]
Pension asset, non-current	0	0
Accrued pension liability, current	4,000,000	3,000,000
Accrued pension liability, non-current	52,000,000	51,000,000
Accumulated other comprehensive income (loss)	(2,000,000)	2,000,000
Aggregate projected benefit obligation and fair value of plan assets for plans with a projected benefit obligation in excess of plan assets [Abstract]
Projected benefit obligation	56,000,000	54,000,000
Fair value of plan assets	0	0
Aggregate accumulated benefit obligation and fair value of plan assets for plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Accumulated benefit obligation	56,000,000	54,000,000
Fair value of plan assets	0	0
Fair value of plan assets [Abstract]
Fair value of plan assets	0	0
Net periodic benefit costs, before tax [Abstract]
Special termination benefits	0	0
Net periodic benefit costs for OPEB plans	2,000,000	3,000,000	3,000,000
Unrecognized accumulated other comprehensive income, before tax [Abstract]
Actuarial loss, net	7,000,000	5,000,000
Prior service credit, net	(5,000,000)	(7,000,000)
Transition obligation, net	0	0
Total	2,000,000	(2,000,000)
Accumulated other comprehensive income expected to be recognized during the next fiscal year [Abstract]
Actuarial loss, net	0
Prior service credit, net	(2,000,000)
Transition obligation, net	0
Total amount expected to be recognized	(2,000,000)
Funding contributions [Abstract]
Expected defined plan contributions in 2011	4,000,000
Projected pension benefits payments [Abstract]
2011	4,000,000
2012	4,000,000
2013	4,000,000
2014	4,000,000
2015	4,000,000
2016-2020	$ 22,000,000

Commitments and Contingencies (Details) (USD $)	12 Months Ended
Commitments and Contingencies (Details) (USD $)	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Apr. 22, 2010
Notes to Financial Statements [Abstract]
Cash payment amount terminating the capital lease obligation for GSF Explorer	$ 15,000,000
Rental expenses for all leases, including leases with terms of less than one year	98,000,000	99,000,000	89,000,000
Capital leases, future minimum rental payments [Abstract]
2011	66,000,000
2012	72,000,000
2013	72,000,000
2014	73,000,000
2015	73,000,000
Thereafter	990,000,000
Total future minimum rental payment	1,346,000,000
Operating leases, future minimum rental payments [Abstract]
2011	36,000,000
2012	31,000,000
2013	23,000,000
2014	16,000,000
2015	12,000,000
Thereafter	32,000,000
Total future minimum rental payment	150,000,000
Less amount representing imputed interest	(652,000,000)
Present value of future minimum rental payments under capital leases	694,000,000
Less current portion included in debt due within one year	(16,000,000)
Long-term capital lease obligation	678,000,000
Aggregate carrying amount of assets held under capital lease [Abstract]
Property and equipment, cost	740,000,000	982,000,000
Accumulated depreciation	(20,000,000)	(27,000,000)
Property and equipment, net	720,000,000	955,000,000
Depreciation expense for GSF Explorer and Petrobras 10000	23,000,000	14,000,000	12,000,000
Months of depreciation expense included in costs and expenses for GSF Explorer (in months)	3
Macondo well incident [Abstract]
Number of persons declared dead				11
Number of miles Deepwater Horizon was off coast of Louisiana				41
Liability recorded based on probable losses related to the rig explosion and fire incident	135,000,000
Portion of liability related to the rig explosion and fire incident recoverable from insurance and recognized as a receivable	94,000,000
Number of actions and/or claims filed in state and federal courts	304
Number of subsidiaries entities named in numerous complaints that allege wrongful death and other personal injuries	we and one or more of our subsidiaries
Number of complaints filed in state and federal courts in Louisiana and Texas involving multiple plaintiffs that allege wrongful death and other personal injuries arising out of the Macondo well incident	30
Number of subsidiaries named in numerous complaints that allege potential economic loss as a result of environmental pollution	we and one or more of our subsidiaries
Number of individual complaints filed alleging, among other things, economic losses as a result of environmental pollution arising out of the Macondo well incident	70
Number of putative class action complaints filed alleging, among other things, economic losses as a result of environmental pollution arising out of the Macondo well incident	185
Number of complaints that alleges violation of RICO Act	1
Number of federal securities law class actions filed	3
Number of federal securities law class actions filed which generally allege violations of Section 10(b) of the Securities Exchange Act of 1934	2
Number of shareholder derivative suits filed	2
Number of schemes under which environmental claims were filed	2
Number of regimes under which environmental claims were filed	2
Number of invoices issued by National Pollution Funds Center to BP, Anadarko and Mitsui as operators and owners of well	9
Number of invoices issued by National Pollution Funds Center paid by BP	9
Number of Gulf Coast states Attorneys General seeking recovery of clean up costs and damages	5
Number of Atlantic Coast states Attorneys General wanting assurances of financial responsibility for potential damages	11
Percentage of asset value covered by wreck removal insurance (in hundredths)	25.00%
Asset value covered by wreck removal insurance	140,000,000
Amount agreed to indemnify and defend operator of rig	15,000,000
Asbestos litigation [Abstract]
Number of complaints filed in 2004 in Mississippi regarding asbestos litigation	21
Number of plaintiffs covered by complaints filed in 2004 in Mississippi regarding asbestos litigation	769
Number of subsidiaries named as a direct defendant in amended asbestos complaints	1
Number of cases filed under amended complaint in Mississippi regarding asbestos litigation	7
Number of additional cases in which there may be an indirect interest regarding asbestos litigation	12
Number of cases in which subsidiary is a named defendant that are scheduled for trial in 2010	two
Number of cases from original asbestos claim in 2004 that went to trial in 2009 against unaffiliated defendant companies	2
Number of cases from original asbestos claim in 2004 that went to trial in 2009 that received verdict in favor of plaintiff	1
Number of cases from original asbestos claim in 2004 that went to trial in 2009 that received verdict in favor of defendant	second case
Number of subsidiaries involved in lawsuits arising from design, construction and refurbishment of major industrial complexes	1
Number of lawsuits alleging personal injury from asbestos exposure for subsidiary involved in design, construction and refurbishment of major industrial complexes	1,037
Estimated number of plaintiffs in lawsuits alleging personal injury from asbestos exposure for subsidiary involved in design, construction and refurbishment of major industrial complexes	2,440
Insurance limits potentially available for damages in lawsuits regarding personal injury from asbestos exposure for subsidiary involved in design, construction and refurbishment of major industrial complexes	1,000,000,000
Rio de Janeiro Tax Assessment [Abstract]
Tax assessment from state tax authorities of Rio de Janeiro in Brazil	188,000,000
Number of subsidiaries involved in Rio de Janeiro tax assessment	1
Brazilian import license assessment [Abstract]
Tax assessment from federal tax authorities of Rio de Janeiro in Brazil relating to import license	235,000,000
Number of subsidiaries involved in Rio de Janeiro federal tax assessment relating to import license	1
Hazardous waste disposal sites [Abstract]
Percentage of liability for remediation and related costs from hazardous waste disposal site (in hundredths)	8.00%
Number of subsidiaries ordered by California Regional Water Quality Control Board to develop testing plan for Alhambra, California site	1
Number of subsidiaries likely to be named potentially responsible party by US Environmental Protection Agency for superfund site	one or more
Contamination litigation [Abstract]
Number of subsidiaries served with a lawsuit alleging property contamination in Louisiana	1
Number of landowners who filed a lawsuit alleging property contamination in Louisiana	3
Number of other defendants involved in lawsuit alleging property contamination in Louisiana	19
Amount claimed by plaintiffs' experts as required remediation costs for property contamination in Louisiana	300,000,000
Amount claimed by defendants' experts as required remediation costs for property contamination in Louisiana	2,500,000
Number of additional subsidiaries plaintiff attempted to add as defendant for lawsuit alleging property contamination in Louisiana	2
Amount of settlement by codefendant for property contamination in Louisiana	20,000,000
Retained risk [Abstract]
Per occurrence insurance deductible on hull and machinery	125,000,000
Maximum aggregate insurance deductible on hull and machinery per year	250,000,000
Percentage of asset value covered by wreck removal insurance (in hundredths)	25.00%
Percentage of asset value covered by damage mitigation insurance (in hundredths)	25.00%
Shared deductible in the event of a total loss or a constructive total loss of a drilling unit	0
Commercial market excess liability coverage	950,000,000
Per occurrence deductible on crew personal injury liability and collision liability claims	10,000,000
Per occurrence deductible on other third-party non-crew claims	5,000,000
Aggregate per occurrence deductible on other third party non-crew claims	50,000,000
Liability loss limit for commercial market excess liability coverage	1,000,000,000
Additional insurance that covers expenses that would otherwise be assumed by the well owner	100,000,000
Aggregate value of drilling rig fleet	38,500,000,000
Maximum liability amount for well control and redrilling liability related to blowouts	50,000,000
Letters of credit and surety bonds [Abstract]
Letters of credit outstanding	595,000,000	567,000,000
Amount of letter of credit issued on behalf of TPDI	60,000,000
Number of subsidiaries that established the letter of credit on behalf of TPDI	1
Surety bonds outstanding	27,000,000	31,000,000
Newbuilds [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2011	381,000,000
2012	149,000,000
2013	0
2014	0
2015	0
Thereafter	0
Total purchase obligations	$ 530,000,000

Redeemable Noncontrolling Interest (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Notes to Financial Statements [Abstract]
Balance, beginning of period	$ 0	$ 0	$ 0
Reclassification from noncontrolling interest	26	0	0
Net income attributable to noncontrolling interest	13	0	0
Other comprehensive income attributable to noncontrolling interest	(14)	0	0
Balance, end of period	$ 25	$ 0	$ 0

Equity (Details)	12 Months Ended
Equity (Details)	Dec. 31, 2010 USD ($)	Dec. 31, 2010 CHF	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)	Aug. 13, 2010	May 30, 2010 USD ($)	May 30, 2010 CHF
Shares held by subsidiary [Abstract]
Number of shares held by subsidiary (in shares)	13,291,353	13,291,353	14,011,416
Share repurchase program [Abstract]
Authorized aggregate purchase price of shares for cancellation	$ 3,800,000,000	3,500,000,000
Share repurchase USD exchange rate	1
Share repurchase CHF exchange rate		0.93
Shares repurchased under share repurchase program (in shares)	2,863,267	2,863,267
Purchases of shares held in treasury	(240,000,000)		0	0
Shares repurchased under share repurchase program held as treasury shares (in shares)	2,863,267	2,863,267
Distribution [Abstract]
Cash distribution approved in the form of a par value reduction (in CHF or dollars per share)						$ 3.7	3.44
Share repurchase USD Exchange Rate	1
Share Repurchase CHF Exchange Rate		0.93
Number of planned partial par value reductions previously approved by shareholders					4

Share based compensation (Details) (USD $)

12 Months Ended

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Authorized shares for employee grants (in shares)

36,000,000

Shares available to be granted

16,000,000

577,537

Number of shares issued to Transocean Inc. in connection with the Redomestication Transaction (in shares)

16,000,000

Number of available shares issued to Transocean Inc. in connection with the Redomestication Transaction (in shares)

13,000,000

Total unrecognized compensation costs related to unvested share-based awards

$ 99,000,000

Weighted-average period to recognize unrecognized compensation costs related to unvested share-based awards (in years)

1.8

Modifications to unrecognized compensation costs related to unvested share-based awards

12,000,000

8,000,000

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan, additional disclosures [Abstract]

Minimum percentage of annual base earnings full-time employees can have withheld to purchase shares (in hundredths)

2.00%

Maximum percentage of annual base earnings full-time employees can have withheld to purchase shares (in hundredths)

20.00%

Maximum annual base earnings full-time employees can have withheld to purchase shares

21,150

Percentage discount from market price of shares (in hundredths)

85.00%

Time Based Award Plan [Member]

Vesting rights for share-based payment awards

three equal annual installments

Time Based Award Plan [Member] | Stock Options [Member]

Expiration term for stock options and stock appreciation rights from date of grant (in years)

10Y

Option valuation assumptions [Abstract]

Fair value assumptions, method used

Black-Scholes-Merton option pricing model

Dividend yield (in hundredths)

4.00%

0.00%

Expected price volatility (in hundredths)

39.00%

49.00%

36.00%

Risk free interest rate (in hundredths)

2.30%

1.80%

3.00%

Expected life of options (in years)

4.70

4.80

4.40

Weighted-average grant date fair value (in dollars per share)

$ 30.03

$ 26.07

$ 49.32

Stock options [Roll Forward]

1,828,655

253,288

597,898

276,281

(289,445)

980,105

1,066,173

(138,815)

Vested and exercisable at end of period (in shares)

1,653,683

1,828,655

1,183,283

Stock options, additional disclosures [Abstract]

Balance at beginning of period, weighted-average exercise price per share (in dollars per share)

$ 60.69

Granted, weighted-average exercise price per share (in dollars per share)

$ 82.55

Exercised, weighted-average exercise price per share (in dollars per share)

$ 42.26

Forfeited, weighted-average exercise price per share (in dollars per share)

$ 71.37

Balance at end of period, weighted-average exercise price per share (in dollars per share)

$ 66.37

$ 60.69

Vested and exercisable at end of period, weighted-average exercise price per share (in dollars per share)

$ 61.28

Balance at beginning of period, weighted-average remaining contractual term (in years)

4.96

Balance at end of period, weighted-average remaining contractual term (in years)

5.29

4.96

Options exercisable at end of period, weighted-average remaining contractual term (in years)

3.99

Balance at beginning of period, aggregate intrinsic value

40,000,000

Balance at end of period, aggregate intrinsic value

5,000,000

40,000,000

Options vested and exercisable at end of period, aggregate intrinsic value

10,000,000

Weighted-average grant-date fair value per share of options granted (in dollars per share)

$ 30.03

$ 26.07

$ 49.32

Total pretax intrinsic value of options exercised

11,000,000

43,000,000

101,000,000

Unvested options outstanding at end of period (in shares)

470,400

656,790

273,314

Time Based Award Plan [Member] | Restricted Shares [Member]

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan [Roll Forward]

98,386

259,057

Vested (in shares)

(92,573)

320,782

129,979

(1,874)

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan, additional disclosures [Abstract]

3,939

98,386

Balance at beginning of period, weighted-average grant-date fair value per share (in dollars per share)

$ 112.14

Vested, weighted-average grant-date fair value per share (in dollars per share)

$ 111.32

$ 126.26

Forfeited, weighted-average grant-date fair value per share (in dollars per share)

$ 109.97

Balance at end of period, weighted-average grant-date fair value per share (in dollars per share)

$ 132.32

$ 112.14

Grant-date fair value of vested shares

10,000,000

39,000,000

14,000,000

Time Based Award Plan [Member] | Deferred Units [Member]

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan [Roll Forward]

1,455,447

1,055,367

1,287,893

498,216

Vested (in shares)

(559,339)

282,543

25,740

(106,691)

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan, additional disclosures [Abstract]

1,844,784

1,455,447

Balance at beginning of period, weighted-average grant-date fair value per share (in dollars per share)

$ 76.58

Granted, weighted-average grant-date fair value per share (in dollars per share)

$ 76.83

$ 60.53

$ 143.85

Vested, weighted-average grant-date fair value per share (in dollars per share)

$ 81.11

Forfeited, weighted-average grant-date fair value per share (in dollars per share)

$ 78.65

Balance at end of period, weighted-average grant-date fair value per share (in dollars per share)

$ 75.23

$ 76.58

Grant-date fair value of vested shares

45,000,000

33,000,000

3,000,000

Time Based Award Plan [Member] | Stock Appreciation Rights [Member]

Expiration term for stock options and stock appreciation rights from date of grant (in years)

10Y

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan [Roll Forward]

189,139

224

315,408

Vested and exercisable at end of period (in shares)

189,139

189,139

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan, additional disclosures [Abstract]

Balance at beginning of period, weighted-average exercise price per share (in dollars per share)

$ 93.28

Balance at end of period, weighted-average exercise price per share (in dollars per share)

$ 93.28

Vested and exercisable at end of period, weighted-average exercise price per share (in dollars per share)

$ 93.28

Balance at beginning of period, weighted-average remaining contractual term (in years)

6.76

Balance at end of period, weighted-average remaining contractual term (in years)

5.76

6.76

Vested and exercisable at end of period, weighted-average remaining contractual term (in years)

5.76

Balance at beginning of period, aggregate intrinsic value

$ 0

Balance at end of period, aggregate intrinsic value

$ 0

Vested and exercisable at end of period, aggregate intrinsic value

Performance Based Award Plan [Member]

Vesting rights for share-based payment awards

two year award over three annual installments three year award in one installment

Measurement period for performance-based and market-based awards (in years)

2 or 3 year measurement period

Performance Based Award Plan [Member] | Stock Options [Member]

Stock options [Roll Forward]

179,262

212,840

Vested and exercisable at end of period (in shares)

179,262

179,262

Stock options, additional disclosures [Abstract]

Balance at beginning of period, weighted-average exercise price per share (in dollars per share)

$ 75.30

Balance at end of period, weighted-average exercise price per share (in dollars per share)

$ 75.30

Vested and exercisable at end of period, weighted-average exercise price per share (in dollars per share)

$ 75.30

Balance at beginning of period, weighted-average remaining contractual term (in years)

6.22

Balance at end of period, weighted-average remaining contractual term (in years)

5.22

Options exercisable at end of period, weighted-average remaining contractual term (in years)

5.22

Balance at beginning of period, aggregate intrinsic value

1,000,000

Balance at end of period, aggregate intrinsic value

Options vested and exercisable at end of period, aggregate intrinsic value

Total pretax intrinsic value of options exercised

$ 22,000,000

Market Based Award Plan [Member]

Measurement period for performance-based and market-based awards (in years)

2 or 3 year measurement period

Market Based Award Plan [Member] | Deferred Units [Member]

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan [Roll Forward]

330,870

122,934

285,012

99,464

(30,898)

Restricted shares, deferred units, stock appreciation rights, and employee stock purchase plan, additional disclosures [Abstract]

422,906

330,870

Balance at beginning of period, weighted-average grant-date fair value per share (in dollars per share)

$ 93.70

Granted, weighted-average grant-date fair value per share (in dollars per share)

$ 82.55

$ 75.98

$ 144.32

Forfeited, weighted-average grant-date fair value per share (in dollars per share)

$ 84.48

Balance at end of period, weighted-average grant-date fair value per share (in dollars per share)

$ 89.14

$ 93.70

Market Based Award Plan [Member] | Employee Stock Purchase Plan [Member]

Option valuation assumptions [Abstract]

Dividend yield (in hundredths)

0.00%

^[1]

0.00%

^[1]

0.00%

^[1]

Expected price volatility (in hundredths)

0.00%

^[1]

0.00%

^[1]

31.00%

^[1]

Risk free interest rate (in hundredths)

0.00%

^[1]

0.00%

^[1]

3.15%

^[1]

Expected life of options (in years)

^[1]

1.00

^[1]

Weighted-average grant date fair value (in dollars per share)

$ 0

^[1]

$ 0

^[1]

$ 41.39

^[1]

Stock options, additional disclosures [Abstract]

Weighted-average grant-date fair value per share of options granted (in dollars per share)

$ 0

^[1]

$ 0

^[1]

$ 41.39

^[1]

[1]	As of January 1, 2009, we discontinued offering the ESPP.

Supplemental Balance Sheet Information (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2010	Dec. 31, 2009
Other current liabilities [Abstract]
Accrued payroll and employee benefits	$ 272	$ 263
Deferred revenue	150	147
Accrued taxes, other than income	123	102
Accrued interest	97	83
Unearned income	15	15
Other	204	120
Total other current liabilities	861	730
Other long-term liabilities [Abstract]
Long-term income taxes payable	655	594
Accrued pension liabilities	416	453
Deferred revenue	393	214
Drilling contract intangibles	152	268
Accrued retiree life insurance and medical benefits	53	51
Other	103	104
Total other long-term liabilities	$ 1,772	$ 1,684

Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2010	Dec. 31, 2009
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Derivative financial instruments, assets	$ 17	$ 5
Derivative financial instruments, liabilities	13	5
Carrying Amount [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Short-term investments		38
Notes receivable	115
Notes receivable, current	4
Notes receivable, noncurrent	111
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Long-term debt, including current maturities	10,271	10,534
Long-term debt of consolidated variable interest entities, including current maturities	950	1,183
Fair Value [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
TPDI Notes and Overseas Drilling Limited Loan Facility	158	158
Long-term debt, including current maturities	10,562	11,218
Long-term debt of consolidated variable interest entities, including current maturities	$ 964	$ 1,178

Supplemental Cash Flow Information (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified

12 Months Ended

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Supplemental Cash Flow [Line Items]

Impairment loss associated with proportional interest in the debt instruments of Lehman Holdings held by the funds

$ 1

$ 16

Distributions received from fund

296

Aggregate investment in the Reserve Funds

408

Changes in operating assets and liabilities[Abstract]

Decrease (increase) in accounts receivable

386

504

(501)

Increase in other current assets

(75)

(50)

(118)

Increase in other assets

(40)

(30)

(8)

Increase (decrease) in accounts payable and other current liabilities

227

(60)

Decrease in other long-term liabilities

(52)

(7)

(43)

Change in income taxes receivable / payable, net

(37)

274

Total changes in operating assets and liabilities

409

434

(321)

Certain cash operating activities[Abstract]

Cash payments for interest

641

683

545

Cash payments for income taxes

493

663

461

Non-cash investing and financing activities[Abstract]

Capital expenditures, accrued at end of period

^[1]

139

^[1]

268

^[1]

Asset capitalized under capital leases

^[2]

716

^[2]

Non-cash proceeds received for the sale of assets

134

^[3]

Number of rigs sold

Net cash proceeds received from the sale of two rigs

Number of notes received from the sale of two rigs

Aggregate face value of notes received

$ 165

The Reserve Primary Fund [Member]

Supplemental Cash Flow [Line Items]

Net asset value per share (in dollars per share)

$ 1.00000000

The Reserve International Liquidity Fund Ltd. [Member]

Supplemental Cash Flow [Line Items]

Net asset value per share (in dollars per share)

$ 1.00

[1]	These amounts represent additions to property and equipment for which we had accrued a corresponding liability in accounts payable.
[2]	On August 4, 2009, we accepted delivery of Petrobras 10000 and recorded non cash additions of $716 million to property and equipment, net along with a corresponding increase to long term debt. See Note 11-Debt and Note 14-Commitments and Contingencies.
[3]	During the year ended December 31, 2010, we completed the sale of two Midwater Floaters, GSF Arctic II and GSF Arctic IV. In connection with the sale, we received net cash proceeds of $38 million and non cash proceeds in the form of two notes receivable in the aggregate face value amount of $165 million. We recognized the notes receivable at their estimated fair value, in the aggregate amount of $134 million, measured at the time of the sale. See Note 4-Variable Interest Entities and Note 9-Drilling Fleet.

Segments, Geographical Analysis and Major Customers (Details) (USD $)
In Millions, unless otherwise specified

12 Months Ended

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Number of reportable segments

Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries [Line Items]

Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries [Line Items]

$ 9,576

^[1]

$ 11,556

^[1]

$ 12,674

^[1]

Threshold for disclosing operating revenues or long-lived assets by individual country

21,458

23,018

10.00%

Long-lived assets in Switzerland

BP [Member]

Entity-Wide Revenue, Major Customer [Line Items]

Percent of operating revenues from major customer (in hundredths)

10.00%

12.00%

11.00%

United States [Member]

Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries [Line Items]

Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries [Line Items]

5,573

6,203

Brazil [Member]

Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries [Line Items]

2,472

1,433

India [Member]

Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries [Line Items]

2,632

1,358

Other Countries [Member]

Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries [Line Items]

9,961

^[2]

10,896

^[2]

South Korea [Member]

Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries [Line Items]

820

3,128

United States [Member]

Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries [Line Items]

2,117

2,239

2,578

Brazil [Member]

Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries [Line Items]

1,288

1,108

547

United Kingdom [Member]

Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries [Line Items]

1,183

1,563

2,012

India [Member]

Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries [Line Items]

828

1,084

890

Other Countries [Member]

$ 4,160

$ 5,562

$ 6,647

[1]	Other countries represents countries in which we operate that individually had operating revenues representing less than 10 percent of total operating revenues earned.
[2]	Other countries represents countries in which we operate that individually had long-lived assets representing less than 10 percent of total long-lived assets.

Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Pacific Drilling Limited [Member]
Related Party Transactions [Line Items]
Ownership interest in joint venture (in hundredths)	50.00%
Name of joint venture company	TPDI
Aggregate outstanding principal amount of TPDI notes	$ 296	$ 296
Oustanding balance of aggregate commitment of subidiary in TPDI notes	148	148
Angco Cayman Limited [Member]
Related Party Transactions [Line Items]
Ownership interest in joint venture (in hundredths)	65.00%
Name of joint venture company	ADDCL
Overseas Drilling Limited [Member]
Related Party Transactions [Line Items]
Ownership interest in joint venture (in hundredths)	50.00%
Name of joint venture company	ODL
Revenue from operational and management services	2	2	2
Loan facility, maximum borrowing capacity	10
Loan facility, amount outstanding	$ 10	$ 10
Loan facility repayment, number of business days from written notice	five business days

Quarterly Results (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified

3 Months Ended

12 Months Ended

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

Mar. 31, 2010

Dec. 31, 2009

Sep. 30, 2009

Jun. 30, 2009

Mar. 31, 2009

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Quarterly financial data [Abstract]