CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Operating revenues
Contract drilling revenues	$ 2,086	$ 2,272	$ 4,036	$ 4,697
Contract drilling intangible revenues	10	29	20	62
Other revenues	238	178	422	299
Total operating revenues	2,334	2,479	4,478	5,058
Costs and expenses
Operating and maintenance	1,492	1,347	2,851	2,533
Depreciation and amortization	359	393	713	767
General and administrative	66	58	133	121
Total costs and expenses	1,917	1,798	3,697	3,421
Loss on impairment	(25)		(25)
Gain (loss) on disposal of assets, net	(1)	268	7	254
Operating income	391	949	763	1,891
Other income (expense), net
Interest income	5	5	20	10
Interest expense, net of amounts capitalized	(147)	(141)	(292)	(273)
Other, net	(5)	(3)	(2)	12
Total other income (expense), net	(147)	(139)	(274)	(251)
Income from continuing operations before income tax expense	244	810	489	1,640
Income tax expense	82	98	163	245
Income from continuing operations	162	712	326	1,395
Income from discontinued operations, net of tax	2	8	178	10
Net income	164	720	504	1,405
Net income attributable to noncontrolling interest	9	5	39	13
Net income attributable to controlling interest	$ 155	$ 715	$ 465	$ 1,392
Earnings per share-basic
Earnings from continuing operations (in dollars per share)	$ 0.47	$ 2.20	$ 0.89	$ 4.29
Earnings from discontinued operations (in dollars per share)	$ 0.01	$ 0.03	$ 0.55	$ 0.03
Earnings per share (in dollars per share)	$ 0.48	$ 2.23	$ 1.44	$ 4.32
Earnings per share-diluted
Earnings from continuing operations (in dollars per share)	$ 0.47	$ 2.20	$ 0.89	$ 4.28
Earnings from discontinued operations (in dollars per share)	$ 0.01	$ 0.02	$ 0.55	$ 0.03
Earnings per share (in dollars per share)	$ 0.48	$ 2.22	$ 1.44	$ 4.31
Weighted-average shares outstanding
Basic (in shares)	320	319	319	320
Diluted (in shares)	320	320	320	321

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net income	$ 164	$ 720	$ 504	$ 1,405
Other comprehensive income (loss) before income taxes
Unrecognized components of net periodic benefit costs			(6)	(10)
Recognized components of net periodic benefit costs	6		12	6
Unrecognized loss on derivative instruments	(8)	(13)	(7)	(23)
Recognized loss on derivative instruments	3	2	5	6
Other comprehensive income (loss) before income taxes	1	(11)	4	(21)
Income taxes related to other comprehensive income (loss)		(1)	(2)	(1)
Other comprehensive income (loss), net of income taxes	1	(12)	2	(22)
Total comprehensive income	165	708	506	1,383
Total comprehensive income (loss) attributable to noncontrolling interest	3	(9)	37	(8)
Total comprehensive income attributable to controlling interest	$ 162	$ 717	$ 469	$ 1,391

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 3,389	$ 3,394
Accounts receivable, net of allowance for doubtful accounts of $30 and $38 at June 30, 2011 and December 31, 2010, respectively	2,114	1,843
Materials and supplies, net of allowance for obsolescence of $73 and $70 at June 30, 2011 and December 31, 2010, respectively	546	514
Deferred income taxes, net	112	115
Assets held for sale	139
Other current assets	438	329
Total current assets	6,738	6,195
Property and equipment	26,897	26,721
Property and equipment of consolidated variable interest entities	2,243	2,214
Less accumulated depreciation	8,144	7,616
Property and equipment, net	20,996	21,319
Goodwill	8,132	8,132
Other assets	1,070	1,165
Total assets	36,936	36,811
Liabilities and equity
Accounts payable	742	832
Accrued income taxes	26	109
Debt due within one year	1,820	1,917
Debt of consolidated variable interest entities due within one year	96	95
Other current liabilities	1,800	883
Total current liabilities	4,484	3,836
Long-term debt	8,375	8,354
Long-term debt of consolidated variable interest entities	790	855
Deferred income taxes, net	594	575
Other long-term liabilities	1,754	1,791
Total long-term liabilities	11,513	11,575
Commitments and contingencies
Redeemable noncontrolling interest	66	25
Shares, CHF 15.00 par value, 335,235,298 authorized, 167,617,649 conditionally authorized, 335,235,298 issued at June 30, 2011 and December 31, 2010; 319,639,362 and 319,080,678 outstanding at June 30, 2011 and December 31, 2010, respectively	4,490	4,482
Additional paid-in capital	6,529	7,504
Treasury shares, at cost, 2,863,267 held at June 30, 2011 and December 31, 2010	(240)	(240)
Retained earnings	10,434	9,969
Accumulated other comprehensive loss	(328)	(332)
Total controlling interest shareholders' equity	20,885	21,383
Noncontrolling interest	(12)	(8)
Total equity	20,873	21,375
Total liabilities and equity	$ 36,936	$ 36,811

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) In Millions, except Share data, unless otherwise specified	Jun. 30, 2011 USD ($)	Jun. 30, 2011 CHF	Dec. 31, 2010 USD ($)	Dec. 31, 2010 CHF
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts	$ 30		$ 38
Materials and supplies, allowance for obsolescence	$ 73		$ 70
Shares, CHF par value (in Swiss Francs per share)		15.00		15.00
Shares, authorized shares (in shares)	335,235,298	335,235,298	335,235,298	335,235,298
Shares, conditionally authorized shares (in shares)	167,617,649	167,617,649	167,617,649	167,617,649
Shares, issued shares (in shares)	335,235,298	335,235,298	335,235,298	335,235,298
Shares, outstanding shares (in shares)	319,639,362	319,639,362	319,080,678	319,080,678
Treasury shares (in shares)	2,863,267	2,863,267	2,863,267	2,863,267

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Millions, unless otherwise specified	Total	Total controlling interest shareholders' equity	Common Shares	Additional paid-in capital	Treasury shares, at cost	Retained earnings	Accumulated other comprehensive loss	Noncontrolling interest
Balance at Dec. 31, 2009	$ 20,559	$ 20,552	$ 4,472	$ 7,407		$ 9,008	$ (335)	$ 7
Balance (in shares) at Dec. 31, 2009			321
Increase (Decrease) in Stockholders' Equity
Share-based compensation	53	53		53
Issuance of shares under share-based compensation plans	(2)	(2)	7	(9)
Issuance of shares under share-based compensation plans (in shares)			1
Purchases of shares held in treasury	(240)	(240)			(240)
Purchases of shares held in treasury (in shares)			(3)
Net income attributable to controlling interest	1,392					1,392
Other comprehensive income (loss) attributable to controlling interest	(22)						(1)
Total comprehensive income attributable to controlling interest	1,391	1,391
Total comprehensive loss attributable to noncontrolling interest	(8)							(8)
Total comprehensive income	1,383
Other, net	(2)	(6)		(6)				4
Balance at Jun. 30, 2010	21,751	21,748	4,479	7,445	(240)	10,400	(336)	3
Balance (in shares) at Jun. 30, 2010			319
Balance at Dec. 31, 2010	21,375	21,383	4,482	7,504	(240)	9,969	(332)	(8)
Balance (in shares) at Dec. 31, 2010			319
Increase (Decrease) in Stockholders' Equity
Share-based compensation	54	54		54
Issuance of shares under share-based compensation plans	(7)	(7)	8	(15)
Issuance of shares under share-based compensation plans (in shares)			1
Obligation for distribution of qualifying additional paid-in capital	(1,016)	(1,016)		(1,016)
Net income attributable to controlling interest	465					465
Other comprehensive income (loss) attributable to controlling interest	2						4
Total comprehensive income attributable to controlling interest	469	469
Total comprehensive loss attributable to noncontrolling interest	37							(4)
Total comprehensive income	506
Other, net	2	2		2
Balance at Jun. 30, 2011	$ 20,873	$ 20,885	$ 4,490	$ 6,529	$ (240)	$ 10,434	$ (328)	$ (12)
Balance (in shares) at Jun. 30, 2011			320

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities
Net income	$ 164	$ 720	$ 504	$ 1,405
Adjustments to reconcile to net cash provided by operating activities
Amortization of drilling contract intangibles	(10)	(29)	(20)	(62)
Depreciation and amortization	359	393	713	767
Share-based compensation expense	27	18	54	53
Loss on impairment	25		25
Gain on disposal of discontinued operations			(173)
(Gain) loss on disposal of assets, net	1	(268)	(7)	(254)
Amortization of debt issue costs, discounts and premiums, net	36	51	62	100
Deferred income taxes	5	(12)	16	(34)
Other, net	14	1	11	32
Deferred revenue, net	(3)	7	43	158
Deferred expenses, net	(48)	(23)	(84)	(37)
Changes in operating assets and liabilities	(230)	411	(414)	313
Net cash provided by operating activities	340	1,269	730	2,441
Cash flows from investing activities
Capital expenditures	(293)	(300)	(533)	(669)
Proceeds from disposal of assets, net	5	10	18	51
Proceeds from disposal of discontinued operations			259
Proceeds from insurance recoveries for loss of drilling unit		560		560
Other, net	(27)	10	(33)	15
Net cash provided by (used in) investing activities	(315)	280	(289)	(43)
Cash flows from financing activities
Change in short-term borrowings, net	5	(46)	56	(177)
Proceeds from debt			5	54
Repayments of debt	(202)	(22)	(249)	(275)
Distribution of qualifying additional paid-in capital	(254)		(254)
Purchases of shares held in treasury		(180)		(240)
Other, net	3	1	(4)	(2)
Net cash used in financing activities	(448)	(247)	(446)	(640)
Net increase (decrease) in cash and cash equivalents	(423)	1,302	(5)	1,758
Cash and cash equivalents at beginning of period	3,812	1,586	3,394	1,130
Cash and cash equivalents at end of period	$ 3,389	$ 2,888	$ 3,389	$ 2,888

Significant Accounting Policies

6 Months Ended

Jun. 30, 2011

Significant Accounting Policies

Significant Accounting Policies

Note 2—Significant Accounting Policies

Basis of presentation—We have prepared our accompanying unaudited condensed consolidated financial statements in accordance with accounting principles generally accepted in the United States (“U.S.”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the U.S. Securities and Exchange Commission (“SEC”). Pursuant to such rules and regulations, these financial statements do not include all disclosures required by accounting principles generally accepted in the U.S. for complete financial statements. The condensed consolidated financial statements reflect all adjustments, which are, in the opinion of management, necessary for a fair presentation of financial position, results of operations and cash flows for the interim periods. Such adjustments are considered to be of a normal recurring nature unless otherwise noted. Operating results for the three and six months ended June 30, 2011 are not necessarily indicative of the results that may be expected for the year ending December 31, 2011 or for any future period. The accompanying condensed consolidated financial statements and notes thereto should be read in conjunction with the audited consolidated financial statements and notes thereto as of December 31, 2010 and 2009 and for each of the three years in the period ended December 31, 2010 included in our annual report on Form 10-K filed on February 28, 2011.

Accounting estimates—To prepare financial statements in accordance with accounting principles generally accepted in the U.S., we are required 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, defined benefit pension plans and other postretirement benefits, contingencies and share-based compensation. 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 the entity, which either (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 entity. See Note 4—Variable Interest Entities.

Share-based compensation—Share-based compensation expense was $27 million and $54 million for the three and six months ended June 30, 2011, respectively. Share-based compensation expense was $18 million and $53 million for the three and six months ended June 30, 2010, respectively.

Capitalized interest—We capitalize interest costs for qualifying construction and upgrade projects. We capitalized interest costs on construction work in progress of $10 million and $25 million for the three and six months ended June 30, 2011, respectively. We capitalized interest costs for construction work in progress of $19 million and $47 million for the three and six months ended June 30, 2010, respectively.

Reclassifications—We have made certain reclassifications, which did not have an effect on net income, to prior period amounts to conform with the current period’s presentation, including certain reclassifications to our condensed consolidated statement of financial position, results of operations and cash flows to present our oil and gas properties operating segment and our Caspian Sea operations as discontinued operations (see Note 6—Discontinued Operations). Other reclassifications did not have a material effect on our condensed 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 16—Subsequent Events.

Variable Interest Entities

6 Months Ended

Jun. 30, 2011

Variable Interest Entities

Variable Interest Entities

Note 4—Variable Interest Entities

Consolidated variable interest entities—We consolidate the assets and liabilities of Transocean Pacific Drilling Inc. (“TPDI”), a consolidated British Virgin Islands joint venture company, and Angola Deepwater Drilling Company Limited (“ADDCL”), a consolidated Cayman Islands joint venture company, which are two variable interest entities for which we are the primary beneficiary. The carrying amounts associated with our consolidated variable interest entities, after eliminating the effect of intercompany transactions, were as follows (in millions):

	June 30, 2011						December 31, 2010
	Assets		Liabilities		Net carrying amount		Assets		Liabilities		Net carrying amount
Variable interest entity
TPDI	$	1,573	$	712	$	861	$	1,598	$	763	$	835
ADDCL	881		333		548		864		345		519
Total	$	2,454	$	1,045	$	1,409	$	2,462	$	1,108	$	1,354

Unconsolidated variable interest entity—As holder of two notes receivable and a lender under a working capital loan, we hold a variable interest in Awilco Drilling plc (“Awilco”), a U.K. company (see Note 8—Drilling Fleet). The notes receivable, originally issued in exchange for and secured by two drilling units, have stated interest rates of nine percent and are payable in scheduled quarterly installments of principal and interest through maturity in January 2015. Additionally, we provide Awilco with a working capital loan, also secured by the drilling units, that has a stated interest rate of 10 percent and a maximum borrowing amount of $35 million. We evaluate the credit quality and financial condition of Awilco quarterly. The aggregate carrying amount of the notes receivable was $108 million and $109 million at June 30, 2011 and December 31, 2010, respectively. The aggregate carrying amount of the working capital loan receivable was $35 million and $6 million at June 30, 2011 and December 31, 2010, respectively.

- Definition

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

Income Taxes

6 Months Ended

Jun. 30, 2011

Income Taxes

Income Taxes

Note 5—Income Taxes

Tax rate—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.

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 rather than income before taxes, (b) rig movements between taxing jurisdictions and (c) our rig operating structures.

Our estimated annual effective tax rates were 22.6 percent and 16.2 percent for the six months ended June 30, 2011 and June 30, 2010, respectively. These rates were based on estimated annual income before income taxes for each period after adjusting for various discrete items, including certain immaterial adjustments to prior period tax expense.

Deferred taxes—The valuation allowance for our non-current deferred tax assets was as follows (in millions):

	June 30, 2011		December 31, 2010
Valuation allowance for non-current deferred tax assets	$	169	$	164

Unrecognized tax benefits—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):

	June 30, 2011		December 31, 2010
Unrecognized tax benefits, excluding interest and penalties	$	506	$	485
Interest and penalties	250		235
Unrecognized tax benefits, including interest and penalties	$	756	$	720

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 2000. For the six months ended June 30, 2011 and June 30, 2010, 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 major jurisdictions in which we operate, other than the U.S., Norway and Brazil which are mentioned below, are generally subject to examination for periods ranging from three to six years. We have agreed to extensions beyond the statute of limitations 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.

U.S. tax investigations—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, exclusive of 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. This matter will be heard in U.S. Tax Court in January 2012.

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 responding to 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 $163 million, exclusive of interest. In addition, the tax authorities assessed penalties associated with the various tax adjustments for the 2006 and 2007 audits 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.

Norway tax investigations—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 employees of our former external tax advisors on these transactions. The authorities issued tax assessments of (a) approximately $290 million plus interest, related to certain restructuring transactions, (b) approximately $127 million plus interest, related to the migration of a subsidiary that was previously subject to tax in Norway, (c) approximately $76 million plus interest, related to a 2001 dividend payment and (d) approximately $8 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 $1.1 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 most but not 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. In June 2011, the Norwegian authorities issued criminal indictments against two of our subsidiaries alleging misleading or incomplete disclosures in Norwegian tax returns for the years 1999 through 2002, as well as inaccuracies in Norwegian statutory financial statements for the years ended December 31, 1996 through 2001. Two employees of our former external tax advisors were also issued indictments with respect to the disclosures in our tax returns. We believe these charges are without merit and plan to vigorously defend our subsidiaries to the fullest extent. We intend to vigorously contest any assertions by the Norwegian civil and criminal authorities in connection with the various transactions being investigated. An unfavorable outcome on these Norwegian civil and criminal tax matters could result in a material adverse effect on our consolidated statement of financial position, results of operations or cash flows. However, 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.

Brazil tax investigations—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 $125 million, plus a 75 percent penalty of $94 million and $159 million of interest through June 30, 2011. 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.

Other tax matters—We conduct operations through our various subsidiaries in a number of countries throughout the world. Each country has its own tax regimes with varying nominal rates, deductions and tax attributes. From time to time, we may identify changes to previously evaluated tax positions that could result in adjustments to our recorded assets and liabilities. Although we are unable to predict the outcome of these changes, we do not expect the effect, if any, resulting from these assessments to have a material adverse effect on our consolidated statement of financial position, results of operations or cash flows.

Discontinued Operations

6 Months Ended

Jun. 30, 2011

Discontinued Operations

Discontinued Operations

Note 6—Discontinued Operations

Oil and gas properties—In March 2011, in connection with our efforts to dispose of non-strategic assets, we engaged an unaffiliated advisor to coordinate the sale of the assets of our oil and gas properties reporting unit, a component of our other operations segment, which comprises the exploration, development and production activities performed by Challenger Minerals Inc. and Challenger Minerals (North Sea) Limited, our wholly owned oil and gas subsidiaries. At June 30, 2011, the oil and gas properties and related assets of this reporting unit were classified as assets held for sale.

Caspian Sea operations—In February 2011, in connection with our efforts to dispose of non-strategic assets, we sold the subsidiary that owns the High-Specification Jackup Trident 20, located in the Caspian Sea. The disposal of this subsidiary, a component of our contract drilling services segment, reflects our decision to discontinue operations in the Caspian Sea. As a result of the sale, we received net cash proceeds of $259 million and recognized a gain on the disposal of the discontinued operations of $173 million ($0.54 per diluted share from discontinued operations), which had no tax effect. Through June 2011, we continued to operate Trident 20 under a bareboat charter to perform services for the customer and the buyer reimbursed us for the approximate cost of providing these services. Additionally, we have agreed to provide certain transition services to the buyer through September 2011.

Summarized results of discontinued operations—The summarized results of operations included in income from discontinued operations, were as follows (in millions):

	Three months ended June 30,					Six months ended June 30,
	2011			2010		2011			2010
Operating revenues	$	22		$	26	$	48		$	49
Costs and expenses	18			18		41			57
Income (loss) from discontinued operations before income tax expense	4			8		7			(8		)
Income tax benefit (expense)	(2		)	—		(2		)	18
Gain on disposal of discontinued operations	—			—		173			—

Income from discontinued operations, net of tax	$	2		$	8	$	178		$	10

Assets and liabilities of discontinued operations—As of June 30, 2011, our oil and gas properties and related assets were classified as assets held for sale. As a result of our decision to discontinue these operations and the operations of our Caspian Sea subsidiary, we also reclassified the assets and liabilities associated with our discontinued operations to other current assets, other assets, other current liabilities and other long-term liabilities as of December 31, 2010. The carrying amounts of the major classes of assets and liabilities associated with these operations were classified as follows (in millions):

	June 30, 2011		December 31, 2010
Assets
Oil and gas properties, net	$	57	$	—
Other related assets	11		—
Assets held for sale	$	68	$	—

Accounts receivable	$	16	$	22
Other assets	5		17
Other current assets	$	21	$	39

Rig and related equipment, net	$	—	$	86
Oil and gas properties, net	—		53
Other assets	$	—	$	139

Liabilities
Accounts payable	$	22	$	15
Other liabilities	25		13
Other current liabilities	$	47	$	28

Asset retirement obligation	$	—	$	9
Deferred taxes	—		19
Other long-term liabilities	$	—	$	28

Earnings Per Share

6 Months Ended

Jun. 30, 2011

Earnings Per Share

Earnings Per Share

Note 7—Earnings Per Share

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

	Three months ended June 30,												Six months ended June 30,
	2011						2010						2011						2010
	Basic			Diluted			Basic			Diluted			Basic			Diluted			Basic			Diluted
	(As adjusted)												(As adjusted)
Numerator for earnings per share
Income from continuing operations attributable to controlling interest	$	153		$	153		$	707		$	707		$	287		$	287		$	1,382		$	1,382
Undistributed earnings allocable to participating securities	(1		)	(1		)	(4		)	(4		)	(2		)	(2		)	(8		)	(8		)
Income from continuing operations available to shareholders	$	152		$	152		$	703		$	703		$	285		$	285		$	1,374		$	1,374

Denominator for earnings per share
Weighted-average shares outstanding	320			320			319			319			319			319			320			320
Effect of stock options and other share-based awards	—			—			—			1			—			1			—			1
Weighted-average shares for per share calculation	320			320			319			320			319			320			320			321

Per share earnings from continuing operations	$	0.47		0.47			$	2.20		$	2.20		$	0.89		$	0.89		$	4.29		$	4.28

For the three and six months ended June 30, 2011, respectively, 1.5 million and 1.7 million share-based awards were excluded from the calculation since the effect would have been anti-dilutive. For the three and six months ended June 30, 2010, respectively, 2.3 million and 1.6 million share-based awards were excluded 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 9—Debt).

Drilling Fleet

6 Months Ended

Jun. 30, 2011

Drilling Fleet

Drilling Fleet

Note 8—Drilling Fleet

Expansion—Construction work in progress, recorded in property and equipment, was $843 million and $1.5 billion at June 30, 2011 and December 31, 2010, respectively. Capital expenditures and other capital additions, including capitalized interest, for our major construction projects that were ongoing during the six months ended June 30, 2011 or during the year ended December 31, 2010 were as follows (in millions):

	Six months ended June 30, 2011		Through December 31, 2010		Total costs
Transocean Honor (a)	$	72	$	97	$	169
High-Specification Jackup TBN1 (b)	69		9		78
High-Specification Jackup TBN2 (b)	69		9		78
Deepwater Champion (c)(d)	49		733		782
High-Specification Jackup TBN3 (e)	10		—		10
Discoverer Luanda (d)(f)	8		709		717
Discoverer India (d)	—		744		744
Discoverer Inspiration (d)	—		679		679
Dhirubhai Deepwater KG2 (d)(g)	—		677		677
Capitalized interest	24		273		297
Mobilization costs	7		100		107
Total	$	308	$	4,030	$	4,338

(a) In November 2010, we purchased a PPL Pacific Class 400 design jackup, to be named Transocean Honor. 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.

(b) In December 2010, we purchased two Keppel FELS Super B class design jackups. The two High-Specification Jackups TBN1 and TBN2 are under construction at Keppel FELS’ yard in Singapore and are expected for delivery in the fourth quarter of 2012 and first quarter of 2013, respectively.

(c) These costs include our initial investment in Deepwater Champion of $109 million, representing the estimated fair value of the rig at the time of our merger with GlobalSantaFe Corporation (“GlobalSantaFe”) in November 2007.

(d) 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 June 30, 2011.

(e) In June 2011, we purchased a Keppel FELS Super B class design jackup. The High-Specification Jackup TBN3 is under construction at Keppel FELS’ yard in Singapore and is expected for delivery in the third quarter of 2013.

(f) 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 the ADDCL joint venture, and Angco Cayman Limited holds the remaining 35 percent interest.

(g) The costs for 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 the TPDI joint venture, and Quantum Pacific Management Limited, a Cypriot company and successor in interest to Pacific Drilling Limited (“Quantum”), holds the remaining 50 percent interest.

Dispositions—During the six months ended June 30, 2011, in connection with our efforts to dispose of non-strategic assets, we sold the High-Specification Jackup Trident 20 and the Standard Jackup Transocean Mercury. The sale of Trident 20 reflected our decision to discontinue operations in the Caspian Sea (see Note 6—Discontinued Operations). In connection with the sale of Transocean Mercury, we received net cash proceeds of $10 million and recognized a gain on disposal of the drilling unit of $9 million ($0.03 per diluted share from continuing operations), which had no tax effect. For the three and six months ended June 30, 2011, we recognized a net loss on disposal of other unrelated assets in the amounts of $1 million and $2 million, respectively.

During the six months ended June 30, 2010, we sold two Midwater Floaters, GSF Arctic II and GSF Arctic IV. In connection with the sales, 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). 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 sales, we recognized a loss on disposal of assets in the amount of $15 million ($0.04 per diluted share from continuing operations), which had no tax effect for the six months ended June 30, 2010. For the three and six months ended June 30, 2010, we recognized gains on disposal of unrelated assets in the amounts of $1 million and $2 million, respectively.

Assets held for sale— During the six months ended June 30, 2011, in addition to our plan to sell the assets associated with our oil and gas properties operating segment (see Note 6—Discontinued Operations), we also committed to plans to sell our Standard Jackups GSF Britannia, George H. Galloway and GSF Labrador and related equipment. In the three months ended June 30, 2011, we recognized a $25 million loss on impairment associated with GSF Britannia, George H. Galloway and GSF Labrador since the carrying amounts of these rigs and related assets exceeded the estimated fair values less costs to sell. We estimated the fair values of the rigs and related assets using significant observable inputs, including binding sale and purchase agreements for the assets. At June 30, 2011, GSF Britannia, George H. Galloway and GSF Labrador were classified as held for sale with an aggregate net carrying amount of $71 million. At December 31, 2010, Transocean Mercury was classified as held for sale with a net carrying amount of less than $1 million. See Note 16—Subsequent Events.

Debt

6 Months Ended

Jun. 30, 2011

Debt.

Debt

Note 9—Debt

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

	June 30, 2011						December 31, 2010
	Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total		Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total
ODL Loan Facility	$	5	$	—	$	5	$	10	$	—	$	10
Commercial paper program (a)	144		—		144		88		—		88
6.625% Notes due April 2011 (a)	—		—		—		167		—		167
5% Notes due February 2013	255		—		255		255		—		255
5.25% Senior Notes due March 2013 (a)	511		—		511		511		—		511
TPDI Credit Facilities due March 2015	—		508		508		—		560		560
4.95% Senior Notes due November 2015 (a)	1,101		—		1,101		1,099		—		1,099
ADDCL Credit Facilities due December 2017	—		230		230		—		242		242
6.00% Senior Notes due March 2018 (a)	998		—		998		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		899		—		899
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	686		—		686		694		—		694
7.5% Notes due April 2031 (a)	598		—		598		598		—		598
1.625% Series A Convertible Senior Notes due December 2037 (a)	—		—		—		11		—		11
1.50% Series B Convertible Senior Notes due December 2037 (a)	1,653		—		1,653		1,625		—		1,625
1.50% Series C Convertible Senior Notes due December 2037 (a)	1,633		—		1,633		1,605		—		1,605
6.80% Senior Notes due March 2038 (a)	999		—		999		999		—		999
Total debt	10,195		886		11,081		10,271		950		11,221
Less debt due within one year
ODL Loan Facility	5		—		5		10		—		10
Commercial paper program (a)	144		—		144		88		—		88
6.625% Notes due April 2011 (a)	—		—		—		167		—		167
TPDI Credit Facilities due March 2015	—		70		70		—		70		70
ADDCL Credit Facilities due December 2017	—		26		26		—		25		25
Capital lease contract due August 2029	18		—		18		16		—		16
1.625% Series A Convertible Senior Notes due December 2037 (a)	—		—		—		11		—		11
1.50% Series B Convertible Senior Notes due December 2037 (a)	1,653		—		1,653		1,625		—		1,625
Total debt due within one year	1,820		96		1,916		1,917		95		2,012
Total long-term debt	$	8,375	$	790	$	9,165	$	8,354	$	855	$	9,209

(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 one 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 June 30, 2011, the scheduled maturities of our debt were as follows (in millions):

	Transocean Ltd. and subsidiaries			Consolidated variable interest entities		Consolidated total
Twelve months ending June 30,
2012	$	1,847		$	96	$	1,943
2013	2,491			98		2,589
2014	21			99		120
2015	23			329		352
2016	1,124			61		1,185
Thereafter	4,785			203		4,988
Total debt, excluding unamortized discounts, premiums and fair value adjustments	10,291			886		11,177
Total unamortized discounts, premiums and fair value adjustments	(96		)	—		(96		)
Total debt	$	10,195		$	886	$	11,081

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 June 30, 2011, $144 million in commercial paper was outstanding at a weighted-average interest rate of 0.9 percent, including commissions.

6.625% Notes—In April 2001, we issued $700 million aggregate principal amount of 6.625% Notes due April 2011. On April 15, 2011, we repaid the 6.625% Notes at maturity.

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 (the “Five-Year Revolving Credit Facility”). 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 June 30, 2011. At June 30, 2011, we had $41 million in letters of credit issued and outstanding, we had $1.9 billion available borrowing capacity and we had no borrowings outstanding under the Five-Year Revolving Credit Facility.

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 term loans with an aggregate commitment of $595 million. At June 30, 2011, $1.0 billion was outstanding under the TPDI Credit Facilities, of which $508 million was due to one of our subsidiaries and was eliminated in consolidation. The weighted-average interest rate on June 30, 2011 was 1.8 percent. See Note 10—Derivatives and Hedging and Note 12—Contingencies.

ADDCL Credit Facilities—ADDCL has a senior secured bank credit agreement for a credit facility (the “ADDCL Primary Loan Facility”) comprised of Tranche A and Tranche C for $215 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 the borrowings under Tranche A. One of our subsidiaries provides the commitment for and the borrowings under Tranche C. At June 30, 2011, $203 million was outstanding under Tranche A at a weighted-average interest rate of 1.12 percent. At June 30, 2011, $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. At June 30, 2011, $78 million was outstanding under the ADDCL Secondary Loan Facility, of which $51 million was provided by one of our subsidiaries and has been eliminated in consolidation. The weighted-average interest rate on June 30, 2011 was 3.4 percent.

TPDI Notes—TPDI has issued promissory notes (the “TPDI Notes”) payable to its shareholders, including Quantum and one of our subsidiaries, which have maturities through October 2019. At June 30, 2011, 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 June 30, 2011 was 2.4 percent.

1.625% Series A, 1.50% Series B and 1.50% Series C Convertible Senior Notes—The carrying amounts of the liability components of the Convertible Senior Notes were as follows (in millions):

	June 30, 2011							December 31, 2010
	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
Series B Convertible Senior Notes due 2037	1,680		(27		)	1,653		1,680		(55		)	1,625
Series C Convertible Senior Notes due 2037	1,722		(89		)	1,633		1,722		(117		)	1,605

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

	June 30, 2011		December 31, 2010
Carrying amount of equity component
Series A Convertible Senior Notes due 2037	$	—	$	1
Series B Convertible Senior Notes due 2037	210		210
Series C Convertible Senior Notes due 2037	276		276

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 June 30, 2011, the remaining period over which the discount will be amortized was less than one year for the Series B Convertible Senior Notes and 1.3 years for the Series C Convertible Senior Notes. Interest expense, excluding amortization of debt issue costs, was as follows (in millions):

	Three months ended June 30,				Six months ended June 30,
	2011		2010		2011		2010
Interest expense
Series A Convertible Senior Notes due 2037	$	—	$	15	$	—	$	30
Series B Convertible Senior Notes due 2037	20		26		40		52
Series C Convertible Senior Notes due 2037	21		26		41		52

During the six months ended June 30, 2011, we redeemed the remaining aggregate principal amount of $11 million of the Series A Convertible Senior Notes.

Derivatives and Hedging

6 Months Ended

Jun. 30, 2011

Derivatives and Hedging

Derivatives and Hedging

Note 10—Derivatives and Hedging

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 4.95% Senior Notes, 5.25% Senior Notes and the 5.00% Notes. The interest rate swaps have aggregate notional amounts equal to the corresponding 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. Accordingly, changes in the fair value of the interest rate swaps recognized in interest expense perfectly offset changes in the fair value of the hedged fixed-rate notes. Through the stated maturities of the interest rate swaps we receive semi-annual interest at a fixed rate equal to that of the underlying debt instrument and pay variable interest semi-annually at three-month LIBOR plus a margin.

Additionally, 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.

At June 30, 2011, the aggregate notional amounts and the weighted average interest rates associated with our derivatives were as follows (in millions):

	Aggregate notional amount		Weighted average variable rate		Weighted average fixed rates
Interest rate swaps, fair value hedges	$	1,400	3.4	%	5.1	%
Interest rate swaps, cash flow hedges	490		0.2	%	2.3	%

The balance sheet classification and aggregate carrying amount of our derivatives, measured at fair value, were as follows (in millions):

	Balance sheet classification	June 30, 2011		December 31, 2010
Interest rate swaps, fair value hedges	Other current assets	$	5	$	4
Interest rate swaps, fair value hedges	Other assets	20		17
Interest rate swaps, fair value hedges	Other long-term liabilities	1		—
Interest rate swaps, cash flow hedges	Other long-term liabilities	15		13

The effect on our condensed consolidated statement of operations resulting from changes in the fair values of derivatives designated as cash flow hedges was as follows (in millions):

		Three months ended June 30,					Six months ended June 30,
	Statement of operations classification	2011		2010			2011		2010
Gain associated with effective portion	Interest expense, net of amounts capitalized	$	3	$	3		$	5	$	6
Loss associated with ineffective portion	Interest expense, net of amounts capitalized	—		(1		)	—		—

Postemployment Benefit Plans

6 Months Ended

Jun. 30, 2011

Postemployment Benefit Plans

Postemployment Benefit Plans

Note 11—Postemployment Benefit Plans

Defined benefit pension plans and other postretirement employee benefit plans—We have several defined benefit pension plans, both funded and unfunded, covering substantially all of our U.S. employees, including certain frozen plans, assumed in connection with our mergers, that cover certain current employees and certain former employees and directors of our predecessors (the “U.S. Plans”). We also have various defined benefit plans in the U.K., Norway, Nigeria, Egypt and Indonesia that cover our employees in those areas (the “Non-U.S. Plans”). Additionally, we offer several unfunded contributory and noncontributory other postretirement employee benefit plans covering substantially all of our U.S. employees (the “OPEB Plans”).

The components of net periodic benefit costs, before tax, and funding contributions for these plans were as follows (in millions):

	Three months ended June 30, 2011												Three months ended June 30, 2010
	U.S. Plans			Non-U.S. Plans			OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans		Total
Net periodic benefit costs
Service cost	$	11		$	5		$	1		$	17		$	11		$	4		$	1	$	16
Interest cost	15			6			—			21			14			5			—		19
Expected return on plan assets	(16		)	(7		)	—			(23		)	(15		)	(3		)	—		(18		)
Settlements and curtailments	1			—			—			1			2			—			—		2
Actuarial losses, net	6			—			—			6			3			(2		)	—		1
Prior service cost, net	(1		)	—			(1		)	(2		)	(1		)	—			—		(1		)
Transition obligation, net	—			1			—			1			—			—			—		—
Net periodic benefit costs	$	16		$	5		$	—		$	21		$	14		$	4		$	1	$	19

Funding contributions	$	55		$	6		$	2		$	63		$	49		$	4		$	1	$	54

	Six months ended June 30, 2011												Six months ended June 30, 2010
	U.S. Plans			Non-U.S. Plans			OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans			Total
Net periodic benefit costs
Service cost	$	22		$	10		$	1		$	33		$	21		$	10		$	1		$	32
Interest cost	29			11			1			41			27			8			1			36
Expected return on plan assets	(32		)	(12		)	—			(44		)	(29		)	(8		)	—			(37		)
Settlements and curtailments	1			—			—			1			2			1			—			3
Actuarial losses, net	12			—			—			12			7			1			—			8
Prior service cost, net	(1		)	—			(1		)	(2		)	(1		)	—			(1		)	(2		)
Transition obligation, net	—			1			—			1			—			—			—			—
Net periodic benefit costs	$	31		$	10		$	1		$	42		$	27		$	12		$	1		$	40

Funding contributions	$	68		$	13		$	3		$	84		$	51		$	8		$	3		$	62

- Definition

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

Contingencies

6 Months Ended

Jun. 30, 2011

Contingencies

Contingencies

Note 12—Contingencies

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.

Although we cannot predict the final outcome or estimate the reasonably possible range of loss in connection with the incident, 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 an asset associated with a portion of this liability that we believe is recoverable from insurance. As of June 30, 2011, the amount of the estimated liability was approximately $217 million, and the corresponding estimated recoverable amount was $183 million. As of December 31, 2010, the amount of the estimated liability was approximately $135 million, and the corresponding estimated recoverable amount was $94 million. New information or future developments could require us to adjust our disclosures and our estimated liabilities and insurance recoveries. See “—Contractual indemnity”.

In April 2011, several defendants in the Macondo litigation before the Multi-District Litigation Panel (the “MDL”) filed cross-claims or third-party claims against Transocean entities and other defendants. BP Exploration and Production or its affiliates (“BP”) filed a claim seeking contribution under the Oil Pollution Act of 1990 (“OPA”) and maritime law, subrogation and claimed breach of contract, unseaworthiness, negligence and gross negligence. Anadarko Petroleum Corporation (“Anadarko”), which owns a 25 percent non-operating interest in the Macondo well, asserted claims of negligence, gross negligence, and willful misconduct and is seeking indemnity under state and maritime law and contribution under maritime and state law as well as OPA. MOEX Offshore 2007 LLC (“MOEX”), which owns a 10 percent non-operating interest in the Macondo well, filed claims of negligence under state and maritime law, gross negligence under state law, gross negligence and willful misconduct under maritime law and is seeking indemnity under state and maritime law and contribution under maritime law and OPA. Cameron International Corporation (“Cameron”), the manufacturer and designer of the blowout preventer, asserted multiple claims for contractual indemnity and declarations regarding contractual obligations under various contracts and quotes and is also seeking non-contractual indemnity and contribution under maritime law and OPA. Halliburton Company (“Halliburton”), which provided cementing and mud-logging services to the operator, filed a claim seeking contribution and indemnity under maritime law, contractual indemnity and alleging negligence and gross negligence. Additionally, certain other third parties filed claims for indemnity and contribution.

On April 20, 2011, we filed cross-claims and counter-claims against BP, Halliburton, Cameron, Anadarko, MOEX, certain of these parties’ affiliates, the U.S. and certain other third parties. We seek indemnity, contribution (including contribution under OPA), and subrogation under OPA, and we have asserted claims for breach of warranty of workmanlike performance, strict liability for manufacturing and design defect, breach of express contract, and damages for the difference between the fair market value of Deepwater Horizon and the amount received from insurance proceeds. Additionally, we have preserved our right to arbitration under our contract with BP in each of the relevant filings. With regard to the U.S., we are not seeking recovery of monetary damages, but rather a declaration regarding relative fault and contribution via credit, setoff, or recoupment.

The Department of Justice (“DOJ”) convened a grand jury in Louisiana to investigate potential criminal conduct in connection with the Macondo well incident, and on April 13, 2011, the grand jury issued a subpoena requesting documents from us.

Insurance coverage—In May 2010, we received notice from BP maintaining that it believes that it is entitled to additional insured status under our excess liability insurance program. In response, many of our insurers filed declaratory judgment actions in the Houston Division of the U.S. District Court for the Southern District of Texas in May 2010 seeking a judgment declaring that they have limited additional insured obligation to the operator. Our insurers have also received notices from Anadarko and MOEX advising of their intent to preserve any rights they may have to our insurance policies as an additional insured under the drilling contract. We, Anadarko and MOEX have each entered into the declaratory judgment actions. The actions have been transferred to the MDL for discovery purposes in the U.S. District Court, Eastern District of Louisiana.

At the time of the Macondo well incident, our excess liability insurance program offered aggregate insurance coverage of $950 million, exclusive of a $15 million deductible and a $50 million self-insured layer, consisted of two $150 million first and second layers, two $200 million third and fourth layers and a $250 million fifth layer. The $250 million fifth layer contains different contractual terms, compared to the first four layers, with regard to additional insured status, such that we believe with reasonable certainty that BP, Anadarko and MOEX do not have contractual right to additional insured status under the fifth layer of our insurance program.

On June 17, 2011, certain insurance companies of our excess liability policies filed a complaint for interpleader with the MDL regarding the insurance proceeds to be paid pursuant to the $150 million first layer of our excess liability coverage to ensure that correct payments are made to the proper persons and entities according to the court’s oversight. In their complaint for interpleader, the insurers state that we have a right to coverage (subject to certain terms, conditions, limitations and exclusions) and that they specifically dispute that BP, Anadarko and MOEX are unrestricted additional insured parties under the policy. The insurers further request relief from the court to, among other things, reimburse us for properly submitted, reasonable and covered claims submitted to date and in the future. While we cannot predict or provide assurance as to the final outcome of our insurers’ interpleader action or the court’s ultimate decision as to insured status, we do not expect these proceedings to have a material adverse effect on our consolidated statement of financial position.

Litigation—Numerous actions or claims are 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 unreasonable claims and pursue any and all appropriate 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. Third parties have also, based on contractual arrangements, 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 third parties. See “—Contractual indemnity.”

Wrongful death and personal injury—As of June 30, 2011, we and one or more of our subsidiaries have been named, along with other unaffiliated defendants, in 17 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. The complaints generally allege negligence and seek awards of unspecified economic damages and punitive damages. See “—Contractual indemnity.”

Environmental pollution and economic loss—As of June 30, 2011, we and one or more of our subsidiaries were named, along with other unaffiliated defendants, in 94 individual complaints as well as 188 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 OPA and state OPA analogues. The plaintiffs are generally seeking awards of unspecified economic, compensatory and punitive damages, as well as injunctive relief. See “—Contractual indemnity.”

Federal securities claims—Two 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. One 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 other 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 certain of 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. The cases have been consolidated. By agreement of the parties, the time for the defendants to respond has been extended by the Court with plaintiffs currently scheduled to file an amended consolidated complaint in September 2011.

Government claims—On December 15, 2010, 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 on December 8, 2010. These demands are part of an ongoing 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. See Note 16—Subsequent Events.

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. 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 for the discharges emanating from the Macondo well.

Additionally, suits have been filed by the States of Alabama and Louisiana; the cities of Greenville, Evergreen, Georgiana and McKenzie, Alabama; the city of New Orleans, Louisiana; the Town of Grand Isle, Grand Isle Independent Levee District, the town of Jean Lafitte, Lafitte Area Independent Levee District, and the cities of Gretna, Westwego, and Harahan, Louisiana; several Louisiana parishes; the Plaquemines Parish School Board; and the Mexican States of Veracruz, Quintana Roo and Tamaulipas. Other governmental entities have filed claims that have been consolidated into the MDL. Generally, these governmental entities allege economic losses under OPA and other statutory environmental state claims and also assert various common law state claims.

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 subsequent 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 have confirmed that no diesel fuel remains on the rig. 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. See Note 16—Subsequent Events.

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, but 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 yet been reviewed on appeal. The second case resulted in a verdict completely in favor of the defendants. Two cases went to trial 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 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 commutation 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 June 30, 2011, the subsidiary was a defendant in approximately 977 lawsuits. Some of these lawsuits include multiple plaintiffs and we estimate that there are approximately 2,147 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 June 30, 2011, 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 $211 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 these assessments are without merit. We have challenged the assessments and the cases are still pending a final decision at the administrative level. 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 in June 2011, a lower court ruled in our favor and reduced the assessment to approximately $15 million. We expect the taxing authorities to appeal the reduction, and we intend to appeal for a complete elimination of the remaining assessment. 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. As of June 30, 2011, 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 number 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 statement of financial position or 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 GlobalSantaFe and its two subsidiaries filed supervisory writs 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 of its subsidiaries served third-party demands joining various insurers in the Avoyelles Parish lawsuit seeking insurance coverage for the claims brought against GlobalSantaFe and such subsidiaries. Thereafter, on January 27, 2011, one of the recently joined insurers filed pleadings removing the Avoyelles Parish lawsuit to the United States District Court for the Western District of Louisiana, Alexandria Division (the “Western District Action”). On February 3, 2011, GlobalSantaFe and the two subsidiaries filed motions to dismiss the Western District Action, which are now pending. A motion to remand was filed by the codefendant and a hearing on the motion was held on April 5, 2011. A report and recommendations were issued on April 25, 2011 by the magistrate in favor of granting the motion to remand. Objections to this report were filed and these objections are now under advisement with the district court.

We believe that the legal theories advanced by the codefendant 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 these theories 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 policy periods, which commenced on May 1, 2011. As of June 30, 2011, the insured value of our drilling rig fleet was approximately $35 billion in the aggregate, excluding rigs under construction.

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, we generally retain the risk for all hull and machinery exposures for our Standard Jackups and drilling barges, which are self-insured through our wholly-owned captive insurance company.

We carry $793 million of commercial market excess liability coverage, exclusive of the 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. Through our wholly-owned captive insurance company, we have retained the risk of $157 million excess liability coverage, of which we have re-insured $25 million in the commercial market. Together, these components comprise our $950 million aggregate excess liability coverage, which is subject to a $50 million per occurrence deductible. Our excess liability coverage has (1) separate $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.

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 $557 million and $595 million at June 30, 2011 and December 31, 2010, respectively. These letters of credit guarantee various 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 June 30, 2011. The letter of credit was issued under an uncommitted credit facility that has been established by one of our subsidiaries. See Note 9—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 $24 million and $27 million at June 30, 2011 and December 31, 2010, respectively.

Shareholders' Equity

6 Months Ended

Jun. 30, 2011

Shareholders' Equity

Shareholders' Equity

Note 14—Shareholders’ Equity

Distribution of qualifying additional paid-in capital—In May 2011, at our annual general meeting, our shareholders approved the distribution of additional paid-in capital in the form of a U.S. dollar denominated dividend of $3.16 per outstanding share, payable in four equal installments of $0.79 per outstanding share, subject to certain limitations. In May 2011, we recognized a distribution payable in the amount of approximately $1.0 billion, recorded in other current liabilities, with a corresponding entry to additional paid-in capital. On June 15, 2011, we paid the first installment in the aggregate amount of $254 million to shareholders of record as of May 20, 2011. At June 30, 2011, the carrying amount of the unpaid distribution payable was $762 million.

Distribution in the form of a par value reduction—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 $4.10, using an exchange rate of USD 1.00 to CHF 0.84 as of June 30, 2011. 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 par value reduction distribution, as adjusted on our condensed consolidated statements of equity.

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. 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 believed it was in our best interest to discontinue with the disputed 2010 distribution. We filed a request to stay the pending appeal with the Swiss Federal Supreme Court against the decision of the Administrative Court until shareholders voted on the proposed rescission, and such stay was granted on March 7, 2011. In May 2011, at our annual general meeting, our shareholders approved the rescission of the previously approved distribution in the form of a par value reduction. On May 16, 2011 we withdrew our appeal and, on May 18, 2011, the Swiss Federal Supreme Court dismissed the appeal as a result of our withdrawal.

Shares held by subsidiary—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 both June 30, 2011 and December 31, 2010, our subsidiary held approximately 13 million shares.

- Definition

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.

+ References+ Details

Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2011

Fair Value of Financial Instruments

Fair Value of Financial Instruments

Note 15—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.

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 June 30, 2011, the aggregate carrying amount of our notes receivable and working capital loan receivable was $143 million, including $23 million and $120 million recorded in other current assets and other assets, respectively. 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.

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 Overseas Drilling Limited (“ODL”) Loan Facility are included in the fair values stated below at their aggregate carrying amount of $153 million and $158 million at June 30, 2011 and December 31, 2010, respectively, since there is no available market price for such related-party debt. The carrying amounts and estimated fair values of our long-term debt, including debt due within one year, were as follows (in millions):

	June 30, 2011				December 31, 2010
	Carrying amount		Fair value		Carrying amount		Fair value

Long-term debt, including current maturities	$	10,195	$	10,819	$	10,271	$	10,562
Long-term debt of consolidated variable interest entities, including current maturities	886		901		950		964

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 June 30, 2011, the carrying amounts of our derivative instruments were $20 million and $16 million, recorded in other assets and other long-term liabilities, respectively, on our condensed consolidated balance sheets. 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.

- Definition

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.

+ References+ Details

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2011

Significant Accounting Policies

Basis of presentation

Accounting estimates

Fair value measurements

Principles of consolidation

Share-based compensation

Capitalized interest

Reclassifications

Subsequent events

Subsequent events—We evaluate subsequent events through the time of our filing on the date we issue our financial statements. See Note 16—Subsequent Events.

Variable Interest Entities (Tables)

6 Months Ended

Jun. 30, 2011

Variable Interest Entities

Carrying Amounts of Variable Interest Entities

The carrying amounts associated with our consolidated variable interest entities, after eliminating the effect of intercompany transactions, were as follows (in millions):

	June 30, 2011						December 31, 2010
	Assets		Liabilities		Net carrying amount		Assets		Liabilities		Net carrying amount
Variable interest entity
TPDI	$	1,573	$	712	$	861	$	1,598	$	763	$	835
ADDCL	881		333		548		864		345		519
Total	$	2,454	$	1,045	$	1,409	$	2,462	$	1,108	$	1,354

Income Taxes (Tables)

6 Months Ended

Jun. 30, 2011

Income Taxes

Valuation allowance for non-current deferred tax assets

Deferred taxes—The valuation allowance for our non-current deferred tax assets was as follows (in millions):

		June 30, 2011			December 31, 2010
Valuation allowance for non-current deferred tax assets		$	169		$	164

	June 30, 2011		December 31, 2010
Unrecognized tax benefits, excluding interest and penalties	$	506	$	485
Interest and penalties	250		235
Unrecognized tax benefits, including interest and penalties	$	756	$	720

- Definition

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.

+ References+ Details

Discontinued Operations (Tables)

6 Months Ended

Jun. 30, 2011

Discontinued Operations

Summarized results of discontinued operations

Summarized results of discontinued operations—The summarized results of operations included in income from discontinued operations, were as follows (in millions):

	Three months ended June 30,					Six months ended June 30,
	2011			2010		2011			2010
Operating revenues	$	22		$	26	$	48		$	49
Costs and expenses	18			18		41			57
Income (loss) from discontinued operations before income tax expense	4			8		7			(8		)
Income tax benefit (expense)	(2		)	—		(2		)	18
Gain on disposal of discontinued operations	—			—		173			—

Income from discontinued operations, net of tax	$	2		$	8	$	178		$	10

Assets and liabilities of discontinued operations

The carrying amounts of the major classes of assets and liabilities associated with these operations were classified as follows (in millions):

	June 30, 2011		December 31, 2010
Assets
Oil and gas properties, net	$	57	$	—
Other related assets	11		—
Assets held for sale	$	68	$	—

Accounts receivable	$	16	$	22
Other assets	5		17
Other current assets	$	21	$	39

Rig and related equipment, net	$	—	$	86
Oil and gas properties, net	—		53
Other assets	$	—	$	139

Liabilities
Accounts payable	$	22	$	15
Other liabilities	25		13
Other current liabilities	$	47	$	28

Asset retirement obligation	$	—	$	9
Deferred taxes	—		19
Other long-term liabilities	$	—	$	28

Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2011

Earnings Per Share

Earnings Per Share

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

	Three months ended June 30,												Six months ended June 30,
	2011						2010						2011						2010
	Basic			Diluted			Basic			Diluted			Basic			Diluted			Basic			Diluted
	(As adjusted)												(As adjusted)
Numerator for earnings per share
Income from continuing operations attributable to controlling interest	$	153		$	153		$	707		$	707		$	287		$	287		$	1,382		$	1,382
Undistributed earnings allocable to participating securities	(1		)	(1		)	(4		)	(4		)	(2		)	(2		)	(8		)	(8		)
Income from continuing operations available to shareholders	$	152		$	152		$	703		$	703		$	285		$	285		$	1,374		$	1,374

Denominator for earnings per share
Weighted-average shares outstanding	320			320			319			319			319			319			320			320
Effect of stock options and other share-based awards	—			—			—			1			—			1			—			1
Weighted-average shares for per share calculation	320			320			319			320			319			320			320			321

Per share earnings from continuing operations	$	0.47		0.47			$	2.20		$	2.20		$	0.89		$	0.89		$	4.29		$	4.28

Drilling Fleet (Tables)

6 Months Ended

Jun. 30, 2011

Drilling Fleet

Actual capital expenditures and other capital additions, including capitalized interest

Capital expenditures and other capital additions, including capitalized interest, for our major construction projects that were ongoing during the six months ended June 30, 2011 or during the year ended December 31, 2010 were as follows (in millions):

	Six months ended June 30, 2011		Through December 31, 2010		Total costs
Transocean Honor (a)	$	72	$	97	$	169
High-Specification Jackup TBN1 (b)	69		9		78
High-Specification Jackup TBN2 (b)	69		9		78
Deepwater Champion (c)(d)	49		733		782
High-Specification Jackup TBN3 (e)	10		—		10
Discoverer Luanda (d)(f)	8		709		717
Discoverer India (d)	—		744		744
Discoverer Inspiration (d)	—		679		679
Dhirubhai Deepwater KG2 (d)(g)	—		677		677
Capitalized interest	24		273		297
Mobilization costs	7		100		107
Total	$	308	$	4,030	$	4,338

(d) 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 June 30, 2011.

Debt (Tables)

6 Months Ended

Jun. 30, 2011

Debt.

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):

	June 30, 2011						December 31, 2010
	Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total		Transocean Ltd. and subsidiaries		Consolidated variable interest entities		Consolidated total
ODL Loan Facility	$	5	$	—	$	5	$	10	$	—	$	10
Commercial paper program (a)	144		—		144		88		—		88
6.625% Notes due April 2011 (a)	—		—		—		167		—		167
5% Notes due February 2013	255		—		255		255		—		255
5.25% Senior Notes due March 2013 (a)	511		—		511		511		—		511
TPDI Credit Facilities due March 2015	—		508		508		—		560		560
4.95% Senior Notes due November 2015 (a)	1,101		—		1,101		1,099		—		1,099
ADDCL Credit Facilities due December 2017	—		230		230		—		242		242
6.00% Senior Notes due March 2018 (a)	998		—		998		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		899		—		899
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	686		—		686		694		—		694
7.5% Notes due April 2031 (a)	598		—		598		598		—		598
1.625% Series A Convertible Senior Notes due December 2037 (a)	—		—		—		11		—		11
1.50% Series B Convertible Senior Notes due December 2037 (a)	1,653		—		1,653		1,625		—		1,625
1.50% Series C Convertible Senior Notes due December 2037 (a)	1,633		—		1,633		1,605		—		1,605
6.80% Senior Notes due March 2038 (a)	999		—		999		999		—		999
Total debt	10,195		886		11,081		10,271		950		11,221
Less debt due within one year
ODL Loan Facility	5		—		5		10		—		10
Commercial paper program (a)	144		—		144		88		—		88
6.625% Notes due April 2011 (a)	—		—		—		167		—		167
TPDI Credit Facilities due March 2015	—		70		70		—		70		70
ADDCL Credit Facilities due December 2017	—		26		26		—		25		25
Capital lease contract due August 2029	18		—		18		16		—		16
1.625% Series A Convertible Senior Notes due December 2037 (a)	—		—		—		11		—		11
1.50% Series B Convertible Senior Notes due December 2037 (a)	1,653		—		1,653		1,625		—		1,625
Total debt due within one year	1,820		96		1,916		1,917		95		2,012
Total long-term debt	$	8,375	$	790	$	9,165	$	8,354	$	855	$	9,209

Scheduled maturities of debt

	Transocean Ltd. and subsidiaries			Consolidated variable interest entities		Consolidated total
Twelve months ending June 30,
2012	$	1,847		$	96	$	1,943
2013	2,491			98		2,589
2014	21			99		120
2015	23			329		352
2016	1,124			61		1,185
Thereafter	4,785			203		4,988
Total debt, excluding unamortized discounts, premiums and fair value adjustments	10,291			886		11,177
Total unamortized discounts, premiums and fair value adjustments	(96		)	—		(96		)
Total debt	$	10,195		$	886	$	11,081

Carrying amounts of liability components of convertible senior notes

1.625% Series A, 1.50% Series B and 1.50% Series C Convertible Senior Notes—The carrying amounts of the liability components of the Convertible Senior Notes were as follows (in millions):

	June 30, 2011							December 31, 2010
	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
Series B Convertible Senior Notes due 2037	1,680		(27		)	1,653		1,680		(55		)	1,625
Series C Convertible Senior Notes due 2037	1,722		(89		)	1,633		1,722		(117		)	1,605

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):

	June 30, 2011		December 31, 2010
Carrying amount of equity component
Series A Convertible Senior Notes due 2037	$	—	$	1
Series B Convertible Senior Notes due 2037	210		210
Series C Convertible Senior Notes due 2037	276		276

Interest expense, excluding amortization of debt issue costs

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

	Three months ended June 30,				Six months ended June 30,
	2011		2010		2011		2010
Interest expense
Series A Convertible Senior Notes due 2037	$	—	$	15	$	—	$	30
Series B Convertible Senior Notes due 2037	20		26		40		52
Series C Convertible Senior Notes due 2037	21		26		41		52

Derivatives and Hedging (Tables)

6 Months Ended

Jun. 30, 2011

Derivatives and Hedging

Schedule of aggregate notional amounts and the weighted average interest rates associated with derivatives

At June 30, 2011, the aggregate notional amounts and the weighted average interest rates associated with our derivatives were as follows (in millions):

	Aggregate notional amount		Weighted average variable rate		Weighted average fixed rates
Interest rate swaps, fair value hedges	$	1,400	3.4	%	5.1	%
Interest rate swaps, cash flow hedges	490		0.2	%	2.3	%

Schedule of balance sheet classification and aggregate carrying amount of the entity's derivatives, measured at fair value

The balance sheet classification and aggregate carrying amount of our derivatives, measured at fair value, were as follows (in millions):

	Balance sheet classification	June 30, 2011		December 31, 2010
Interest rate swaps, fair value hedges	Other current assets	$	5	$	4
Interest rate swaps, fair value hedges	Other assets	20		17
Interest rate swaps, fair value hedges	Other long-term liabilities	1		—
Interest rate swaps, cash flow hedges	Other long-term liabilities	15		13

Schedule of effect on the entity's condensed consolidated statement of operations resulting from changes in the fair values of derivatives designated as cash flow hedges

The effect on our condensed consolidated statement of operations resulting from changes in the fair values of derivatives designated as cash flow hedges was as follows (in millions):

		Three months ended June 30,					Six months ended June 30,
	Statement of operations classification	2011		2010			2011		2010
Gain associated with effective portion	Interest expense, net of amounts capitalized	$	3	$	3		$	5	$	6
Loss associated with ineffective portion	Interest expense, net of amounts capitalized	—		(1		)	—		—

Postemployment Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2011

Postemployment Benefit Plans

Net Periodic Benefit Costs Before Tax

The components of net periodic benefit costs, before tax, and funding contributions for these plans were as follows (in millions):

	Three months ended June 30, 2011												Three months ended June 30, 2010
	U.S. Plans			Non-U.S. Plans			OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans		Total
Net periodic benefit costs
Service cost	$	11		$	5		$	1		$	17		$	11		$	4		$	1	$	16
Interest cost	15			6			—			21			14			5			—		19
Expected return on plan assets	(16		)	(7		)	—			(23		)	(15		)	(3		)	—		(18		)
Settlements and curtailments	1			—			—			1			2			—			—		2
Actuarial losses, net	6			—			—			6			3			(2		)	—		1
Prior service cost, net	(1		)	—			(1		)	(2		)	(1		)	—			—		(1		)
Transition obligation, net	—			1			—			1			—			—			—		—
Net periodic benefit costs	$	16		$	5		$	—		$	21		$	14		$	4		$	1	$	19

Funding contributions	$	55		$	6		$	2		$	63		$	49		$	4		$	1	$	54

	Six months ended June 30, 2011												Six months ended June 30, 2010
	U.S. Plans			Non-U.S. Plans			OPEB Plans			Total			U.S. Plans			Non-U.S. Plans			OPEB Plans			Total
Net periodic benefit costs
Service cost	$	22		$	10		$	1		$	33		$	21		$	10		$	1		$	32
Interest cost	29			11			1			41			27			8			1			36
Expected return on plan assets	(32		)	(12		)	—			(44		)	(29		)	(8		)	—			(37		)
Settlements and curtailments	1			—			—			1			2			1			—			3
Actuarial losses, net	12			—			—			12			7			1			—			8
Prior service cost, net	(1		)	—			(1		)	(2		)	(1		)	—			(1		)	(2		)
Transition obligation, net	—			1			—			1			—			—			—			—
Net periodic benefit costs	$	31		$	10		$	1		$	42		$	27		$	12		$	1		$	40

Funding contributions	$	68		$	13		$	3		$	84		$	51		$	8		$	3		$	62

Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Consolidated variable interest entities
Variable interest entities for which we are the primary beneficiary	2
Carrying amounts associated with consolidated variable interest entities
Assets	$ 2,454	$ 2,462
Liabilities	1,045	1,108
Net carrying amount	1,409	1,354
Unconsolidated Variable interest entities
Number of notes receivable from sale of Midwater Floaters	2
Number of Midwater Floaters sold		2
Stated interest rate on notes receivable received from sale of Midwater Floaters (as a percent)	9.00%
Stated interest rate on working capital loan (as a percentage)	10.00%
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	108	109
Aggregate carrying amounts of working capital loan receivable in connection with sale of Midwater Floaters	35	6
TPDI
Carrying amounts associated with consolidated variable interest entities
Assets	1,573	1,598
Liabilities	712	763
Net carrying amount	861	835
ADDCL
Carrying amounts associated with consolidated variable interest entities
Assets	881	864
Liabilities	333	345
Net carrying amount	$ 548	$ 519

Income Taxes (Details) (USD $)	1 Months Ended	6 Months Ended
Income Taxes (Details) (USD $)	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	May 31, 2010
Tax rate
Annual effective tax rate (as a percent)		22.60%	16.20%
Deferred taxes
Valuation allowance for non-current deferred tax assets	$ 169,000,000	$ 169,000,000		$ 164,000,000
Unrecognized tax benefits
Unrecognized tax benefits, excluding interest and penalties	506,000,000	506,000,000		485,000,000
Interest and penalties	250,000,000	250,000,000		235,000,000
Unrecognized tax benefits, including interest and penalties	756,000,000	756,000,000		720,000,000
Tax returns
Minimum range tax returns are subject to examination (in years)	3	3
Maximum range tax returns are subject to examination (in years)	6	6
Number of jurisdictions with extensions beyond statute of limitations	4	4
Maximum number of years agreed to extensions beyond the statute of limitations (in years)	16	16
Tax investigations
2004 and 2005 transfer pricing adjustment	79,000,000	79,000,000
2006 and 2007 income tax adjustments	278,000,000	278,000,000
2006 through 2009 restructuring transactions tax adjustments	295,000,000	295,000,000
2006 through 2009 withholding and other tax adjustments					163,000,000
Assessed penalties associated with the various adjustments					92,000,000
Norway tax assessment due to restructuring transactions	290,000,000	290,000,000
Norway tax assessment due to migration of subsidiary	127,000,000	127,000,000
Norway tax assessment due 2001 dividend payment	76,000,000	76,000,000
Norway tax assessment due to foreign exchange deductions and dividend withholding taxes	8,000,000	8,000,000
Norway tax financial security	1,100,000,000	1,100,000,000
Percentage of penalties to be assessed by Norway tax authorities (as a percent)	60.00%	60.00%
Number of subsidiaries against which notification of criminal charges are issued	2	2
Number of former external tax advisors who issued indictments against the entity	2	2
Brazil tax assessment for income tax returns 2000 to 2004	125,000,000	125,000,000
Percentage of penalties to be assessed by Brazil tax authorities (as a percent)	75.00%	75.00%
Brazil tax assessment penalty	94,000,000	94,000,000
Brazil tax assessment interest	$ 159,000,000	$ 159,000,000

Discontinued Operations (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 Caspian Sea Operations	Dec. 31, 2010 Caspian Sea Operations
Discontinued Operations
Proceeds from sale of Trident 20			$ 259		$ 259
Gain on disposal of the discontinued operations per diluted share (in dollars per share)					$ 0.54
Summarized results of discontinued operations
Operating revenues	22	26	48	49
Costs and expenses	18	18	41	57
Income (loss) from discontinued operations before income tax expense	4	8	7	(8)
Income tax benefit (expense)	(2)		(2)	18
Gain on disposal of the discontinued operations			173		173
Income from discontinued operations, net of tax	2	8	178	10
Assets
Oil and gas properties, net					57
Other related assets					11
Assets held for sale					68
Accounts receivable					16	22
Other assets					5	17
Other current assets					21	39
Rig and related equipment, net						86
Oil and gas properties, net						53
Other assets						139
Liabilities
Accounts payable					22	15
Other liabilities					25	13
Other current liabilities					47	28
Asset retirement obligation						9
Deferred taxes						19
Other long-term liabilities						$ 28

Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Numerator for earnings per share, basic
Income from continuing operations attributable to controlling interest	$ 153	$ 707	$ 287	$ 1,382
Undistributed earnings allocable to participating securities	(1)	(4)	(2)	(8)
Income from continuing operations available to shareholders	152	703	285	1,374
Denominator for earnings per share, basic
Weighted-average shares outstanding (in shares)	320	319	319	320
Weighted-average shares for per share calculation, basic (in shares)	320	319	319	320
Per share earnings from continuing operations, basic (in dollars per share)	$ 0.47	$ 2.20	$ 0.89	$ 4.29
Numerator for earnings per share, diluted
Income from continuing operations attributable to controlling interest	153	707	287	1,382
Undistributed earnings allocable to participating securities	(1)	(4)	(2)	(8)
Income from continuing operations available to shareholders	$ 152	$ 703	$ 285	$ 1,374
Denominator for earnings per share, diluted
Weighted-average shares outstanding (in shares)	320	319	319	320
Effect of stock options and other share-based awards (in shares)		1	1	1
Weighted-average shares for per share calculation, diluted (in shares)	320	320	320	321
Per share earnings from continuing operations, diluted (in dollars per share)	$ 0.47	$ 2.20	$ 0.89	$ 4.28
1.625% Series A Convertible Senior Notes due December 2037
Anti-dilutive securities
Interest rate on convertible debt not having effect on earning per share calculation (as a percent)	1.625%		1.625%
1.50% Series B Convertible Senior Notes due December 2037
Anti-dilutive securities
Interest rate on convertible debt not having effect on earning per share calculation (as a percent)	1.50%		1.50%
1.50% Series C Convertible Senior Notes due December 2037
Anti-dilutive securities
Interest rate on convertible debt not having effect on earning per share calculation (as a percent)	1.50%		1.50%
Stock-based awards
Anti-dilutive securities
Share-based awards excluded from earnings per share calculation (in shares)	1.5	2.3	1.7	1.6

Drilling Fleet (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended	18 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2011	Nov. 30, 2007
Drilling Fleet
Construction work in progress, recorded in property and equipment	$ 843	$ 1,500	$ 843
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	308	4,030	4,338
Number of high-specification jackups purchased and under construction		2
Transocean Honor
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	72	97	169
High-Specification Jackup TBN1
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	69	9	78
High-Specification Jackup TBN2
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	69	9	78
Deepwater Champion
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	49	733	782
Initial investment in construction project				109
High Specification Jackup TBN3
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	10		10
Discoverer Luanda
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	8	709	717
Costs as a percentage of total expenditures incurred since inception (as a percent)	100.00%		100.00%
Discoverer India
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs		744	744
Discoverer Inspiration
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs		679	679
Dhirubhai Deepwater KG2
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs		677	677
Capitalized interest
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	24	273	297
Mobilization costs
Capital expenditures and other capital additions, including capitalized interest, for our major construction projects
Capital expenditures and other capital additions, including capitalized interest costs	$ 7	$ 100	$ 107

Drilling Fleet (Details 3) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Dispositions
Net cash proceeds from sale of assets	$ 5	$ 10	$ 18	$ 51
Gain (loss) on the sale of assets	(1)	268	7	254
Number of Midwater Floaters sold					2
Assets held for sale
Impairment loss recognized on assets held for sale	25		25
Carrying amount	139		139
High-Specification Jackup Trident 20 and the Standard Jackup Transocean Mercury
Dispositions
Net cash proceeds from sale of assets			10
Gain (loss) on the sale of assets			9
Gain (loss) on the sale of assets per diluted share (in dollars per share)			$ 0.03
Recognized gain (loss) on disposal of unrelated assets	1		2
Midwater Floaters
Dispositions
Net cash proceeds from sale of assets				38
Gain (loss) on the sale of assets				(15)
Gain (loss) on the sale of assets per diluted share (in dollars per share)				$ 0.04
Recognized gain (loss) on disposal of unrelated assets		1		2
Number of Midwater Floaters sold				2
Number of notes receivable provided as non-cash proceeds from sale of assets		2		2
Non-cash proceeds in the form of notes receivable from sale of assets		165		165
GSF Britannia, G.H. Galloway, and GSF Labrador
Assets held for sale
Impairment loss recognized on assets held for sale	25
Carrying amount	71		71
Transocean Mercury
Assets held for sale
Carrying amount					$ 1

Debt (Details) (USD $)					6 Months Ended									6 Months Ended										6 Months Ended																						6 Months Ended				6 Months Ended		6 Months Ended
Debt (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2011 ODL Loan Facility	Dec. 31, 2010 ODL Loan Facility	Jun. 30, 2011 Commercial paper program	Dec. 31, 2010 Commercial paper program	Jun. 30, 2011 6.625% Notes due April 2011	Apr. 30, 2011 6.625% Notes due April 2011	Dec. 31, 2010 6.625% Notes due April 2011	Jun. 30, 2011 5% Notes due February 2013	Dec. 31, 2010 5% Notes due February 2013	Jun. 30, 2011 5.25% Senior Notes due March 2013	Dec. 31, 2010 5.25% Senior Notes due March 2013	Jun. 30, 2011 TPDI Credit Facilities due March 2015	Dec. 31, 2010 TPDI Credit Facilities due March 2015	Jun. 30, 2011 4.95% Senior Notes due November 2015	Dec. 31, 2010 4.95% Senior Notes due November 2015	Jun. 30, 2011 ADDCL Credit Facilities due December 2017	Dec. 31, 2010 ADDCL Credit Facilities due December 2017	Jun. 30, 2011 6.00% Senior Notes due March 2018	Dec. 31, 2010 6.00% Senior Notes due March 2018	Jun. 30, 2011 7.375% Senior Notes due April 2018	Dec. 31, 2010 7.375% Senior Notes due April 2018	Jun. 30, 2011 TPDI Notes due October 2019	Dec. 31, 2010 TPDI Notes due October 2019	Jun. 30, 2011 6.50% Senior Notes due November 2020	Dec. 31, 2010 6.50% Senior Notes due November 2020	Jun. 30, 2011 8% Debentures due April 2027	Dec. 31, 2010 8% Debentures due April 2027	Jun. 30, 2011 7.45% Notes due April 2027	Dec. 31, 2010 7.45% Notes due April 2027	Jun. 30, 2011 7% Notes due June 2028	Dec. 31, 2010 7% Notes due June 2028	Jun. 30, 2011 Capital lease contract due August 2029	Dec. 31, 2010 Capital lease contract due August 2029	Jun. 30, 2011 7.5% Notes due April 2031	Dec. 31, 2010 7.5% Notes due April 2031	Jun. 30, 2011 1.625% Series A Convertible Senior Notes due December 2037	Dec. 31, 2010 1.625% Series A Convertible Senior Notes due December 2037	Jun. 30, 2011 1.50% Series B Convertible Senior Notes due December 2037	Dec. 31, 2010 1.50% Series B Convertible Senior Notes due December 2037	Jun. 30, 2011 1.50% Series C Convertible Senior Notes due December 2037	Dec. 31, 2010 1.50% Series C Convertible Senior Notes due December 2037	Jun. 30, 2011 6.80% Senior Notes due March 2038	Dec. 31, 2010 6.80% Senior Notes due March 2038	Jun. 30, 2011 Five Year Revolving Credit Facility Due November	Jun. 30, 2011 TPDI Credit Facilities Senior Term Loan Due March 2015	Jun. 30, 2011 TPDI Credit Facilities Junior Term Loan Due March 2015	Jun. 30, 2011 TPDI Credit Facilities Revolving Credit Facility Due March 2015	Jun. 30, 2011 ADDCL Credit Facilities Tranche A Due November 2017	Jun. 30, 2011 ADDCL Credit Facilities Tranche C Due November 2017	Jun. 30, 2011 ADDCL Secondary Loan Facility Due December 2015	Jun. 30, 2011 Transocean Ltd. and Subsidiaries	Dec. 31, 2010 Transocean Ltd. and Subsidiaries	Jun. 30, 2011 Transocean Ltd. and Subsidiaries ODL Loan Facility	Dec. 31, 2010 Transocean Ltd. and Subsidiaries ODL Loan Facility	Jun. 30, 2011 Transocean Ltd. and Subsidiaries Commercial paper program	Dec. 31, 2010 Transocean Ltd. and Subsidiaries Commercial paper program	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.625% Notes due April 2011	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 5% Notes due February 2013	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 5% Notes due February 2013	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 5.25% Senior Notes due March 2013	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 5.25% Senior Notes due March 2013	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 4.95% Senior Notes due November 2015	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 4.95% Senior Notes due November 2015	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 6.00% Senior Notes due March 2018	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.00% Senior Notes due March 2018	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 7.375% Senior Notes due April 2018	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7.375% Senior Notes due April 2018	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 6.50% Senior Notes due November 2020	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.50% Senior Notes due November 2020	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 8% Debentures due April 2027	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 8% Debentures due April 2027	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 7.45% Notes due April 2027	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7.45% Notes due April 2027	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 7% Notes due June 2028	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7% Notes due June 2028	Jun. 30, 2011 Transocean Ltd. and Subsidiaries Capital lease contract due August 2029	Dec. 31, 2010 Transocean Ltd. and Subsidiaries Capital lease contract due August 2029	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 7.5% Notes due April 2031	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 7.5% Notes due April 2031	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 1.625% Series A Convertible Senior Notes due December 2037	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 1.50% Series B Convertible Senior Notes due December 2037	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 1.50% Series B Convertible Senior Notes due December 2037	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 1.50% Series C Convertible Senior Notes due December 2037	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 1.50% Series C Convertible Senior Notes due December 2037	Jun. 30, 2011 Transocean Ltd. and Subsidiaries 6.80% Senior Notes due March 2038	Dec. 31, 2010 Transocean Ltd. and Subsidiaries 6.80% Senior Notes due March 2038	Jun. 30, 2011 Consolidated variable interest entities	Dec. 31, 2010 Consolidated variable interest entities	Jun. 30, 2011 Consolidated variable interest entities TPDI Credit Facilities due March 2015	Dec. 31, 2010 Consolidated variable interest entities TPDI Credit Facilities due March 2015	Jun. 30, 2011 Consolidated variable interest entities ADDCL Credit Facilities due December 2017	Dec. 31, 2010 Consolidated variable interest entities ADDCL Credit Facilities due December 2017	Jun. 30, 2011 Consolidated variable interest entities TPDI Notes due October 2019	Dec. 31, 2010 Consolidated variable interest entities TPDI Notes due October 2019
Long-term debt by current and noncurrent
Total debt	$ 11,081,000,000	$ 11,221,000,000	$ 5,000,000	$ 10,000,000	$ 144,000,000	$ 88,000,000			$ 167,000,000	$ 255,000,000	$ 255,000,000	$ 511,000,000	$ 511,000,000	$ 508,000,000	$ 560,000,000	$ 1,101,000,000	$ 1,099,000,000	$ 230,000,000	$ 242,000,000	$ 998,000,000	$ 997,000,000	$ 247,000,000	$ 247,000,000	$ 148,000,000	$ 148,000,000	$ 899,000,000	$ 899,000,000	$ 57,000,000	$ 57,000,000	$ 96,000,000	$ 96,000,000	$ 313,000,000	$ 313,000,000	$ 686,000,000	$ 694,000,000	$ 598,000,000	$ 598,000,000		$ 11,000,000	$ 1,653,000,000	$ 1,625,000,000	$ 1,633,000,000	$ 1,605,000,000	$ 999,000,000	$ 999,000,000								$ 10,195,000,000	$ 10,271,000,000	$ 5,000,000	$ 10,000,000	$ 144,000,000	$ 88,000,000	$ 167,000,000	$ 255,000,000	$ 255,000,000	$ 511,000,000	$ 511,000,000	$ 1,101,000,000	$ 1,099,000,000	$ 998,000,000	$ 997,000,000	$ 247,000,000	$ 247,000,000	$ 899,000,000	$ 899,000,000	$ 57,000,000	$ 57,000,000	$ 96,000,000	$ 96,000,000	$ 313,000,000	$ 313,000,000	$ 686,000,000	$ 694,000,000	$ 598,000,000	$ 598,000,000	$ 11,000,000	$ 1,653,000,000	$ 1,625,000,000	$ 1,633,000,000	$ 1,605,000,000	$ 999,000,000	$ 999,000,000	$ 886,000,000	$ 950,000,000	$ 508,000,000	$ 560,000,000	$ 230,000,000	$ 242,000,000	$ 148,000,000	$ 148,000,000
Debt due within one year	1,916,000,000	2,012,000,000	5,000,000	10,000,000	144,000,000	88,000,000			167,000,000					70,000,000	70,000,000			26,000,000	25,000,000															18,000,000	16,000,000				11,000,000	1,653,000,000	1,625,000,000												1,820,000,000	1,917,000,000	5,000,000	10,000,000	144,000,000	88,000,000	167,000,000																			18,000,000	16,000,000			11,000,000	1,653,000,000	1,625,000,000					96,000,000	95,000,000	70,000,000	70,000,000	26,000,000	25,000,000
Long-term debt	9,165,000,000	9,209,000,000																																																			8,375,000,000	8,354,000,000																																			790,000,000	855,000,000
Debt instrument interest rate stated percentage (as a percent)							6.625%			5.00%		5.25%				4.95%				6.00%		7.375%				6.50%		8.00%		7.45%		7.00%				7.50%		1.625%		1.50%		1.50%		6.80%
Debt instrument maturity date							April 2011			February 2013		March 2013		March 2015		November 2015		December 2017		March 2018		April 2018		October 2019		November 2020		April 2027		April 2027		June 2028		August 2029		April 2031		December 2037		December 2037		December 2037		March 2038
Percentage ownership interest in Transocean Inc. by Transocean Ltd. (as a percent)																																																					100.00%
Independent assets and operations of Transocean Inc. as a percentage of total consolidated assets and operations of Transocean Ltd. (as a percent)																																																					1.00%
Scheduled maturities of debt
2012	1,943,000,000																																																				1,847,000,000																																				96,000,000
2013	2,589,000,000																																																				2,491,000,000																																				98,000,000
2014	120,000,000																																																				21,000,000																																				99,000,000
2015	352,000,000																																																				23,000,000																																				329,000,000
2016	1,185,000,000																																																				1,124,000,000																																				61,000,000
Thereafter	4,988,000,000																																																				4,785,000,000																																				203,000,000
Total debt, excluding unamortized discounts, premiums and fair value adjustments	11,177,000,000																																																				10,291,000,000																																				886,000,000
Total unamortized discounts, premiums and fair value adjustments	(96,000,000)																																																				(96,000,000)
Total debt	11,081,000,000	11,221,000,000	5,000,000	10,000,000	144,000,000	88,000,000			167,000,000	255,000,000	255,000,000	511,000,000	511,000,000	508,000,000	560,000,000	1,101,000,000	1,099,000,000	230,000,000	242,000,000	998,000,000	997,000,000	247,000,000	247,000,000	148,000,000	148,000,000	899,000,000	899,000,000	57,000,000	57,000,000	96,000,000	96,000,000	313,000,000	313,000,000	686,000,000	694,000,000	598,000,000	598,000,000		11,000,000	1,653,000,000	1,625,000,000	1,633,000,000	1,605,000,000	999,000,000	999,000,000								10,195,000,000	10,271,000,000	5,000,000	10,000,000	144,000,000	88,000,000	167,000,000	255,000,000	255,000,000	511,000,000	511,000,000	1,101,000,000	1,099,000,000	998,000,000	997,000,000	247,000,000	247,000,000	899,000,000	899,000,000	57,000,000	57,000,000	96,000,000	96,000,000	313,000,000	313,000,000	686,000,000	694,000,000	598,000,000	598,000,000	11,000,000	1,653,000,000	1,625,000,000	1,633,000,000	1,605,000,000	999,000,000	999,000,000	886,000,000	950,000,000	508,000,000	560,000,000	230,000,000	242,000,000	148,000,000	148,000,000
Credit facility term (in years)					5
Credit facility maximum borrowing capacity					1,500,000,000									1,265,000,000																																2,000,000,000			75,000,000	215,000,000	399,000,000	90,000,000
Credit facility weighted-average interest rate (as a percent)					0.90%
Minimum facility fee on the daily amount of five-year revolving credit facility (as a percent)																																														0.10%
Maximum facility fee on the daily amount of five-year revolving credit facility (as a percent)																																														0.30%
Facility fee on the daily amount of the five-year revolving credit facility (as a percent)																																														0.175%
Letters of credit issued and outstanding																																														41,000,000
Credit facility available borrowing capacity																																														1,900,000,000
Debt instrument face amount								700,000,000																																							1,000,000,000	190,000,000
Aggregate commitment of subsidiary in secured term loan														595,000,000
Credit facility amount outstanding														1,000,000,000
Debt due to a subsidiary, eliminated in consolidation														508,000,000										148,000,000																												51,000,000
Principal amount outstanding																								$ 296,000,000															$ 11,000,000	$ 1,680,000,000	$ 1,680,000,000	$ 1,722,000,000	$ 1,722,000,000							$ 203,000,000	$ 399,000,000	$ 78,000,000
Weighted-average interest rate (as a percent)														1.80%										2.40%																										1.12%		3.40%
Percentage of total commitment under ADDCL secondary bank credit agreement provided by subsidiary (as a percent)																																																				65.00%

Debt (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Carrying amounts of Convertible Senior Notes
Carrying amount of liability component	$ 11,081		$ 11,081		$ 11,221
1.625% Series A Convertible Senior Notes due December 2037
Carrying amounts of Convertible Senior Notes
Principal amount outstanding					11
Carrying amount of liability component					11
Carrying amount of equity component					1
Interest expense		15		30
Redemption of remaining principal amount of Series A Convertible Senior Notes			11
1.50% Series B Convertible Senior Notes due December 2037
Carrying amounts of Convertible Senior Notes
Principal amount outstanding	1,680		1,680		1,680
Unamortized discount	(27)		(27)		(55)
Carrying amount of liability component	1,653		1,653		1,625
Carrying amount of equity component	210		210		210
Convertible debt instrument effective interest rate (as a percent)			5.08%
Remaining period over which discount will be amortized (in years)	1		1
Interest expense	20	26	40	52
1.50% Series C Convertible Senior Notes due December 2037
Carrying amounts of Convertible Senior Notes
Principal amount outstanding	1,722		1,722		1,722
Unamortized discount	(89)		(89)		(117)
Carrying amount of liability component	1,633		1,633		1,605
Carrying amount of equity component	276		276		276
Convertible debt instrument effective interest rate (as a percent)			5.28%
Remaining period over which discount will be amortized (in years)	1.3		1.3
Interest expense	$ 21	$ 26	$ 41	$ 52

Derivatives and Hedging (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011
4.95% Senior Notes due November 2015
Derivatives and Hedging
Interest rate on notes hedged to reduce exposure to changes in fair value (as a percent)	4.95%
5.25% Senior Notes due March 2013
Derivatives and Hedging
Interest rate on notes hedged to reduce exposure to changes in fair value (as a percent)	5.25%
5% Notes due February 2013
Derivatives and Hedging
Interest rate on notes hedged to reduce exposure to changes in fair value (as a percent)	5.00%
Interest rate swaps
Derivatives and Hedging
Number of wholly owned subsidiaries in interest rate swap agreements	2
Derivative, underlying risk	interest rate
Derivative, hedge designation	fair value
Interest rate description to determine the variable interest on debt hedged	three-month LIBOR
Interest rate swaps \| 4.95% Senior Notes due November 2015
Derivatives and Hedging
Interest rate on notes hedged to reduce exposure to changes in fair value (as a percent)	4.95%
Interest rate swaps \| 5.25% Senior Notes due March 2013
Derivatives and Hedging
Interest rate on notes hedged to reduce exposure to changes in fair value (as a percent)	5.25%
Interest rate swaps \| 5% Notes due February 2013
Derivatives and Hedging
Interest rate on notes hedged to reduce exposure to changes in fair value (as a percent)	5.00%
Interest rate swaps \| fair value hedges
Derivatives and Hedging
Aggregate notional amount	$ 1,400
Weighted average variable rate (as a percent)	3.40%
Weighted average fixed rates (as a percent)	5.10%
Interest rate swaps \| Cash flow hedges
Derivatives and Hedging
Aggregate notional amount	$ 490
Weighted average variable rate (as a percent)	0.20%
Weighted average fixed rates (as a percent)	2.30%

Postemployment Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net periodic benefit costs
Service cost	$ 17	$ 16	$ 33	$ 32
Interest cost	21	19	41	36
Expected return on plan assets	(23)	(18)	(44)	(37)
Settlements and curtailments	1	2	1	3
Actuarial losses, net	6	1	12	8
Prior service cost, net	(2)	(1)	(2)	(2)
Transition obligation, net	1		1
Net periodic benefit costs	21	19	42	40
Funding contributions	63	54	84	62
U.S. Plans
Net periodic benefit costs
Service cost	11	11	22	21
Interest cost	15	14	29	27
Expected return on plan assets	(16)	(15)	(32)	(29)
Settlements and curtailments	1	2	1	2
Actuarial losses, net	6	3	12	7
Prior service cost, net	(1)	(1)	(1)	(1)
Net periodic benefit costs	16	14	31	27
Funding contributions	55	49	68	51
Non-U.S. Plans
Net periodic benefit costs
Service cost	5	4	10	10
Interest cost	6	5	11	8
Expected return on plan assets	(7)	(3)	(12)	(8)
Settlements and curtailments				1
Actuarial losses, net		(2)		1
Transition obligation, net	1		1
Net periodic benefit costs	5	4	10	12
Funding contributions	6	4	13	8
OPEB Plans
Net periodic benefit costs
Service cost	1	1	1	1
Interest cost			1	1
Prior service cost, net	(1)		(1)	(1)
Net periodic benefit costs		1	1	1
Funding contributions	$ 2	$ 1	$ 3	$ 3

Contingencies (Details) (USD $)	6 Months Ended
Contingencies (Details) (USD $)	Jun. 30, 2011	Jan. 27, 2011	Dec. 31, 2010	Jun. 30, 2010	Jun. 21, 2010	May 31, 2010	May 05, 2010	Apr. 22, 2010	Sep. 30, 2006	Jul. 11, 2005
Macondo well incident
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	$ 217,000,000		$ 135,000,000
Portion of liability related to the rig explosion and fire incident recoverable from insurance and recognized as a receivable	183,000,000		94,000,000
Percentage of non-operating interest of Anadarko in the Macondo well (as a percent)	25.00%
Percentage of non-operating interest of MOEX in the Macondo well (as a percent)	10.00%
Number of subsidiaries entities named in numerous complaints that allege wrongful death and other personal injuries	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	17
Number of individual complaints filed alleging, among other things, economic losses as a result of environmental pollution arising out of the Macondo well incident	94
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	188
Number of federal securities law class actions filed	2
Number of federal securities law class actions filed which generally allege violations of Section 10(b) of the Securities Exchange Act of 1934	1
Number of shareholder derivative suits filed				2
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 (as a percent)	25.00%
Asset value covered by wreck removal insurance	140,000,000
Amount agreed to indemnify and defend operator of rig	15,000,000
Insurance coverage
Insured status under excess liability insurance program						950,000,000
Deductible amount under excess liability insurance program								15,000,000
Amount covered by self insured layer of excess liability insurance program								50,000,000
Amount covered by first layer of excess liability insurance program								150,000,000
Amount covered by second layer of excess liability insurance program								150,000,000
Amount covered by third layer of excess liability insurance program								200,000,000
Amount covered by fourth layer of excess liability insurance program								200,000,000
Amount covered by fifth layer of excess liability insurance program								250,000,000
Asbestos litigation
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 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
Additional trials in 2010	2
Substantial verdict for the plaintiff	1
Complete verdict for the defendants	1
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	977
Estimated number of plaintiffs in lawsuits alleging personal injury from asbestos exposure for subsidiary involved in design, construction and refurbishment of major industrial complexes	2,147
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	1,000,000,000
Rio de Janeiro Tax Assessment
Tax assessment from state tax authorities of Rio de Janeiro in Brazil									211,000,000
Number of subsidiaries involved in Rio de Janeiro federal tax assessment relating to import license									1
Brazilian import license assessment
Number of subsidiaries involved in Rio de Janeiro federal tax assessment relating to import license			1
Tax assessment from federal tax authorities of Rio de Janeiro in Brazil relating to import license			235,000,000
Reduced tax assessment by lower court of Rio de Janeiro in Brazil relating to import license			15,000,000
Hazardous waste disposal sites
Percentage of liability for remediation and related costs from hazardous waste disposal site (as a percent)	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
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
Number of insurers which filed pleadings to move lawsuit to United States District Court		1
Retained risk
Term of policy for commercial market and captive insurance policies	12 months
Aggregate value of drilling rig fleet	35,000,000,000
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 damage mitigation insurance (as a percent)	25.00%
Commercial market excess liability coverage	793,000,000
Excess liability coverage through wholly-owned captive insurance company	157,000,000
Re-insured portion of excess liability coverage through wholly-owned captive insurance company	25,000,000
Aggregate excess liability coverage	950,000,000
Per occurrence deductible on aggregate excess liability coverage	50,000,000
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
Maximum liability amount for well control and redrilling liability related to blowouts	50,000,000
Letters of credit and surety bonds
Letters of credit outstanding	557,000,000		595,000,000
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	$ 24,000,000		$ 27,000,000

Shareholders' Equity (Details) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Dec. 31, 2008	Jun. 30, 2011 CHF	May 31, 2011 USD ($)	Dec. 31, 2010	May 31, 2010 USD ($)	May 31, 2010 CHF
Distribution of qualifying additional paid-in capital
Cash distribution approved in the form of additional paid-in capital (in dollars per share)						$ 3.16
Number of quarterly installments						4
Amount of installment (in dollars per share)						$ 0.79
Proposed U.S. dollar-denominated dividend						$ 1,000,000,000
First installment of dividend paid	254,000,000	254,000,000	254,000,000
Unpaid distribution payable	762,000,000	762,000,000	762,000,000
Distribution in the form of a par value reduction
Cash distribution approved in the form of a par value reduction (in CHF or dollars per share)								$ 4.10	3.44
Share repurchase USD exchange rate	1	1	1
Share repurchase CHF exchange rate					0.84
Number of planned partial par value reductions previously approved by shareholders	4	4	4
Shares held by subsidiary
Number of issued shares held by subsidiary (in shares)				16
Number of subsidiaries to whom shares were issued				1
Number of shares held by subsidiary (in shares)	13	13	13				13

Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Carrying amount
Notes receivable and working capital loan receivable
Notes receivable	$ 143	$ 115
Notes receivable, current	23	4
Notes receivable, noncurrent	120	111
Debt
TPDI Notes and Overseas Drilling Limited Loan Facility	153	158
Long-term debt, including current maturities	10,195	10,271
Long-term debt of consolidated variable interest entities, including current maturities	886	950
Derivative instruments
Derivative financial instruments, assets	20	17
Derivative financial instruments, liabilities	16	13
Fair value
Debt
Long-term debt, including current maturities	10,819	10,562
Long-term debt of consolidated variable interest entities, including current maturities	$ 901	$ 964

Document and Entity Information	6 Months Ended
Document and Entity Information	Jun. 30, 2011	Jul. 26, 2011
Document and Entity Information
Entity Registrant Name	Transocean Ltd.
Entity Central Index Key	0001451505
Document Type	10-Q
Document Period End Date	Jun. 30, 2011
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		319,811,081
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2

Nature of Business (Details)	Jun. 30, 2011
Nature of Business
Number of mobile offshore drilling units	136
Number of High-Specification Floaters	48
Number of Midwater Floaters	25
Number of High-Specification Jackups	9
Number of Standard Jackups	51
Number of Other Rigs	3
Number of High-Specification Jackups under construction	4

Drilling Fleet (Details 2)	Jun. 30, 2011
Schedule of Variable Interest Entities
Noncontrolling owner's ownership interest in affiliate (as a percent)	50.00%
TPDI
Schedule of Variable Interest Entities
Ownership interest in affiliate (as a percent)	50.00%
Noncontrolling owner's ownership interest in affiliate (as a percent)	50.00%
ADDCL
Schedule of Variable Interest Entities
Ownership interest in affiliate (as a percent)	65.00%
Noncontrolling owner's ownership interest in affiliate (as a percent)	35.00%

Redeemable Noncontrolling Interest (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011
Redeemable Noncontrolling Interest
Percentage interest in joint venture (TPDI) that is held by an unaffiliated party (Quantum) (as a percent)	50.00%
Redeemable noncontrolling interest
Balance, beginning of period	$ 25
Net income attributable to noncontrolling interest	43
Other comprehensive loss attributable to noncontrolling interest	(2)
Balance, end of period	$ 66

Derivatives and Hedging (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Other current assets
Aggregate carrying amount of derivatives
Interest rate swaps, fair value hedges	$ 5	$ 4
Other assets
Aggregate carrying amount of derivatives
Interest rate swaps, fair value hedges	20	17
Other long-term liabilities
Aggregate carrying amount of derivatives
Interest rate swaps, fair value hedges	1
Interest rate swaps, cash flow hedges	$ 15	$ 13