Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2019	Oct. 22, 2019
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-38373
Entity Registrant Name	Transocean Ltd
Entity Incorporation, State or Country Code	V8
Entity Tax Identification Number	98-0599916
Entity Address, Address Line One	Turmstrasse 30
Entity Address, City or Town	Steinhausen
Entity Address, Country	CH
Entity Address, Postal Zip Code	6312
City Area Code	+41 (41)
Local Phone Number	749-0500
Title of 12(b) Security	Shares
Trading Symbol	RIG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		611,861,630
Entity Central Index Key	0001451505
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating revenues
Revenues	$ 784	$ 816	$ 2,296	$ 2,270
Revenue from Contract with Customer, Product and Service [Extensible List]	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember
Costs and expenses
Operating and maintenance	$ 547	$ 447	$ 1,565	$ 1,302
Cost, Product and Service [Extensible List]	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember
Depreciation and amortization	$ 212	$ 201	$ 648	$ 614
General and administrative	45	35	139	134
Total costs and expenses	804	683	2,352	2,050
Loss on impairment	(583)	(432)	(584)	(1,446)
Loss on disposal of assets, net	(4)	(6)	(7)
Operating loss	(607)	(305)	(647)	(1,226)
Other income (expense), net
Interest income	11	11	33	36
Interest expense, net of amounts capitalized	(166)	(160)	(500)	(455)
Loss on retirement of debt	(12)	(1)	(39)	(3)
Other, net	3	16	34	6
Total other income (expense), net	(164)	(134)	(472)	(416)
Loss before income tax expense	(771)	(439)	(1,119)	(1,642)
Income tax expense (benefit)	54	(30)	83	118
Net loss	(825)	(409)	(1,202)	(1,760)
Net income (loss) attributable to noncontrolling interest			2	(6)
Net loss attributable to controlling interest	$ (825)	$ (409)	$ (1,204)	$ (1,754)
Loss per share
Basic (in dollars per share)	$ (1.35)	$ (0.88)	$ (1.97)	$ (3.86)
Diluted (in dollars per share)	$ (1.35)	$ (0.88)	$ (1.97)	$ (3.86)
Weighted-average shares outstanding
Basic (in shares)	613	463	612	454
Diluted (in shares)	613	463	612	454

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME LOSS
Net loss	$ (825)	$ (409)	$ (1,202)	$ (1,760)
Net income (loss) attributable to noncontrolling interest			2	(6)
Net loss attributable to controlling interest	(825)	(409)	(1,204)	(1,754)
Components of net periodic benefit costs before reclassifications		(1)	7	(4)
Components of net periodic benefit costs reclassified to net loss		2	1	4
Other comprehensive income before income taxes		1	8
Other comprehensive income		1	8
Other comprehensive income attributable to controlling interest		1	8
Total comprehensive loss	(825)	(408)	(1,194)	(1,760)
Total comprehensive income (loss) attributable to noncontrolling interest			2	(6)
Total comprehensive loss attributable to controlling interest	$ (825)	$ (408)	$ (1,196)	$ (1,754)

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 1,906	$ 2,160
Accounts receivable, net of allowance for doubtful accounts of less than $1 at December 31, 2018	639	604
Materials and supplies, net of allowance for obsolescence of $123 and $134 at September 30, 2019 and December 31, 2018, respectively	475	474
Restricted cash accounts and investments	551	551
Other current assets	200	159
Total current assets	3,771	3,948
Property and equipment	24,203	25,811
Less accumulated depreciation	(5,255)	(5,403)
Property and equipment, net	18,948	20,408
Contract intangible assets	655	795
Deferred income taxes, net	21	66
Other assets	1,054	448
Total assets	24,449	25,665
Liabilities and equity
Accounts payable	308	269
Accrued income taxes	35	70
Debt due within one year	349	373
Other current liabilities	797	746
Total current liabilities	1,489	1,458
Long-term debt	9,041	9,605
Deferred income taxes, net	193	64
Other long-term liabilities	1,784	1,424
Total long-term liabilities	11,018	11,093
Commitments and contingencies
Shares, CHF 0.10 par value, 639,674,422 authorized, 142,365,398 conditionally authorized, 617,970,525 issued and 611,849,468 outstanding at September 30, 2019, and 638,285,574 authorized, 143,754,246 conditionally authorized, 610,581,677 issued and 609,649,291 outstanding at December 31, 2018	59	59
Additional paid-in capital	13,415	13,394
Accumulated deficit	(1,246)	(67)
Accumulated other comprehensive loss	(295)	(279)
Total controlling interest shareholders' equity	11,933	13,107
Noncontrolling interest	9	7
Total equity	11,942	13,114
Total liabilities and equity	$ 24,449	$ 25,665

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Millions	Sep. 30, 2019 SFr / shares	Sep. 30, 2019 USD ($) shares	Dec. 31, 2018 SFr / shares	Dec. 31, 2018 USD ($) shares
Materials and supplies, allowance for obsolescence (in dollars) \| $		$ 123		$ 134
Shares, CHF par value (in Swiss francs per share) \| SFr / shares	SFr 0.10		SFr 0.10
Shares, authorized		639,674,422		638,285,574
Shares, conditionally authorized		142,365,398		143,754,246
Shares, issued		617,970,525		610,581,677
Shares, outstanding		611,849,468		609,649,291
Maximum
Allowance for doubtful accounts \| $				$ 1

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total controlling interest shareholders' equity	Shares	Additional paid-in capital	Retained earnings (accumulated deficit)	Accumulated other comprehensive loss	Noncontrolling interest	Total
Balance at Dec. 31, 2017	$ 12,707	$ 37	$ 11,031	$ 1,929	$ (290)	$ 4	$ 12,711
Increase (Decrease) in Shareholders' Equity
Share-based compensation	36		36				36
Issuance of shares in acquisition transactions	746	7	739				746
Equity component of convertible debt instruments	172		172				172
Acquisition of redeemable noncontrolling interest	53		53				53
Allocated capital for transactions with holders of noncontrolling interest	5		5			(5)
Net loss attributable to controlling interest				(1,754)			(1,754)
Total comprehensive loss attributable to controlling interest	(1,754)						(1,754)
Total comprehensive income (loss) attributable to noncontrolling interest						(2)
Total comprehensive loss							(1,756)
Recognition of noncontrolling interest in business combination						33	33
Acquisition of noncontrolling interest						(31)	(31)
Other, net	(3)		(3)				(3)
Balance at Sep. 30, 2018	11,962	44	12,033	175	(290)	(1)	11,961
Balance at Jun. 30, 2018	12,359	44	12,022	584	(291)	3	12,362
Increase (Decrease) in Shareholders' Equity
Share-based compensation	8		8				8
Allocated capital for transactions with holders of noncontrolling interest	2		2			(2)
Net loss attributable to controlling interest				(409)			(409)
Other comprehensive income attributable to controlling interest					1		1
Total comprehensive loss attributable to controlling interest	(408)						(408)
Total comprehensive income (loss) attributable to noncontrolling interest						(1)
Total comprehensive loss							(409)
Acquisition of noncontrolling interest						(1)	(1)
Other, net	1		1				1
Balance at Sep. 30, 2018	11,962	44	12,033	175	(290)	(1)	11,961
Balance at Dec. 31, 2018	13,107	59	13,394	(67)	(279)	7	13,114
Increase (Decrease) in Shareholders' Equity
Share-based compensation	28		28				28
Net loss attributable to controlling interest				(1,204)			(1,204)
Other comprehensive income attributable to controlling interest					8		8
Total comprehensive loss attributable to controlling interest	(1,196)						(1,196)
Total comprehensive income (loss) attributable to noncontrolling interest						2
Total comprehensive loss							(1,194)
Other, net	(6)		(7)				(6)
Balance at Sep. 30, 2019	11,933	59	13,415	(1,246)	(295)	9	11,942
Balance at Jun. 30, 2019	12,748	59	13,405	(421)	(295)	9	12,757
Increase (Decrease) in Shareholders' Equity
Share-based compensation	9		9				9
Net loss attributable to controlling interest				(825)			(825)
Total comprehensive loss attributable to controlling interest	(825)						(825)
Total comprehensive loss							(825)
Other, net	1		1				1
Balance at Sep. 30, 2019	$ 11,933	$ 59	$ 13,415	(1,246)	(295)	$ 9	$ 11,942
Increase (Decrease) in Shareholders' Equity
Effect of adopting accounting standards update				$ 25	$ (24)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net loss	$ (1,202)	$ (1,760)
Adjustments to reconcile to net cash provided by operating activities:
Contract intangible asset amortization	140	78
Depreciation and amortization	648	614
Share-based compensation expense	28	36
Loss on impairment	584	1,446
Loss on disposal of assets, net	7
Loss on retirement of debt	39	3
Deferred income tax expense	139	50
Other, net	28	12
Changes in deferred revenues, net	19	(127)
Changes in deferred costs, net	(21)	23
Changes in other operating assets and liabilities, net	(216)	(55)
Net cash provided by operating activities	193	320
Cash flows from investing activities
Capital expenditures	(259)	(140)
Proceeds from disposal of assets, net	52	37
Investments in unconsolidated affiliates	(77)	(107)
Unrestricted and restricted cash acquired in business combination		131
Proceeds from maturities of unrestricted and restricted investments	123	500
Deposits to unrestricted investments		(50)
Other, net	3
Net cash provided by (used in) investing activities	(158)	371
Cash flows from financing activities
Proceeds from issuance of debt, net of discount and issue costs	1,056	1,319
Repayments of debt	(1,189)	(2,015)
Proceeds from investments restricted for financing activities		26
Payments to terminate derivative instruments		(92)
Other, net	(34)	(29)
Net cash used in financing activities	(167)	(791)
Net decrease in unrestricted and restricted cash and cash equivalents	(132)	(100)
Unrestricted and restricted cash and cash equivalents, beginning of period	2,589	2,975
Unrestricted and restricted cash and cash equivalents, end of period	$ 2,457	$ 2,875

Significant Accounting Policies

9 Months Ended

Sep. 30, 2019

Significant Accounting Policies

Significant Accounting Policies

Note 2—Significant Accounting Policies

Presentation—We 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 (the “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 nine months ended September 30, 2019, are not necessarily indicative of the results that may be expected for the year ending December 31, 2019, 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, 2018 and 2017, and for each of the three years in the period ended December 31, 2018, included in our annual report on Form 10-K filed on February 19, 2019.

Accounting estimates—To prepare financial statements in accordance with accounting principles generally accepted in the U.S., we must 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, assets held for sale, property and equipment, intangibles, leases, income taxes, contingencies, share-based compensation and postemployment benefit plans. We base our estimates and assumptions on historical experience and other factors that we believe are reasonable. 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) significant observable inputs, including unadjusted quoted prices for identical assets or liabilities in active markets (“Level 1”), (2) significant other observable inputs, including direct or indirect market data for similar assets or liabilities in active markets or identical assets or liabilities in less active markets (“Level 2”) and (3) significant unobservable inputs, including those that require considerable judgment for which there is little or no market data (“Level 3”). When a valuation requires multiple input levels, 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.

Accounting Standards Updates

9 Months Ended

Sep. 30, 2019

Accounting Standards Updates

Accounting Standards Updates

Note 3—Accounting Standards Updates

Recently adopted accounting standards

Leases—Effective January 1, 2019, we adopted the accounting standards update that requires lessees to recognize a right-of-use asset and lease liability for virtually all leases and updates previous accounting standards for lessors to align certain requirements with the updates to the revenue recognition accounting standards. We applied the transition method that required us to recognize right-of-use assets and lease liabilities as of the date of our adoption with no adjustment to prior periods. We applied the package of practical expedients that permitted us to carry forward historical lease classifications. For our drilling contracts, we recognize revenues based on the predominant component, which is the service component. As of January 1, 2019, for the finance leases under which we are the lessee, we reclassified to other assets $528 million, representing the unamortized right-of-use asset previously recorded in property and equipment, and we reclassified an aggregate remaining lease liability of $511 million, including $32 million and $479 million recorded in other current liabilities and other long-term liabilities, respectively, previously recorded in debt due within one year and debt. As of January 1, 2019, for operating leases under which we are the lessee, we recorded a non-cash adjustment to recognize an aggregate right-of-use asset of $95 million, recorded in other assets, and a corresponding aggregate remaining lease liability of $133 million, including $15 million and $118 million recorded in other current liabilities and other long-term liabilities, respectively. We have accounted for lease and non-lease components of our operating leases as a single component. We have not recognized right-of-use assets or lease liabilities for our short-term leases. Our adoption did not have and is not expected in the future to have a material effect on our condensed consolidated statements of financial position, operations or cash flows. See Note 9—Leases.

Other comprehensive income—Effective January 1, 2019, we adopted the accounting standards update that allows for a reclassification from accumulated other comprehensive loss to accumulated deficit for stranded tax effects resulting from the Tax Cuts and

Jobs Act of 2017. As of January 1, 2019, as a result of our adoption, we recorded an increase of $24 million to accumulated deficit with a corresponding decrease to accumulated other comprehensive loss.

Statements of equity—Effective January 1, 2019, we adopted the SEC’s final rule that requires a reconciliation of the changes in shareholders’ equity to be presented for the current and comparative quarter and year-to-date periods, together with subtotals for each interim period. The final rule permits the disclosure requirements to be made either in a separate financial statement or in a note to the financial statements. Our adoption did not have a material effect on our condensed consolidated statements of financial position, operations or cash flows or on the disclosures contained in our notes to condensed consolidated financial statements.

Recently issued accounting standards

Financial instruments – credit losses—Effective no later than January 1, 2020, we will adopt the accounting standards update that requires entities to estimate an expected lifetime credit loss on financial assets ranging from short-term trade accounts receivable to long-term financings. The update, which permits early adoption, is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual periods. We continue to evaluate the requirements and do not expect our adoption to have a material effect on our condensed consolidated statements of financial position, operations or cash flows or on the disclosures contained in our notes to condensed consolidated financial statements.

Business Combinations

9 Months Ended

Sep. 30, 2019

Business Combinations

Business Combinations

Note 4—Business Combinations

Overview

In the year ended December 31, 2018, we completed the acquisitions of Songa Offshore SE, a European public company limited by shares, or societas Europaea, existing under the laws of Cyprus (“Songa”) and Ocean Rig UDW Inc., a Cayman Islands exempted company with limited liability (“Ocean Rig”). In the three and nine months ended September 30, 2018, we incurred acquisition costs of $4 million and $11 million, respectively, recorded in general and administrative costs and expenses, related to these acquisitions.

Ocean Rig UDW Inc.

Consideration—To complete the Ocean Rig acquisition, we issued 147.7 million shares with a per share market value of $9.32, based on the market value of our shares on the acquisition date, and made an aggregate cash payment of $1.2 billion. The aggregate fair value of the consideration transferred in the business combination was as follows (in millions):


	Total
Consideration transferred
Aggregate fair value of shares issued as partial consideration for Ocean Rig shares	$	1,377
Aggregate cash paid as partial consideration for Ocean Rig shares		1,168
Total consideration transferred in business combination	$	2,545

Assets and liabilities—In the three months ended September 30, 2019, we completed our estimates of the fair values of the assets acquired and liabilities assumed. At September 30, 2019, the fair values of assets acquired and liabilities assumed, measured as of December 5, 2018, were as follows (in millions):


	Total
Assets acquired
Cash and cash equivalents	$	152
Accounts receivable		76
Property and equipment		2,205
Drilling contract intangible assets		275
Other assets		115

Liabilities assumed
Accounts payable and other current liabilities		71
Construction contract intangible liabilities		132
Other long-term liabilities		54
Net assets acquired	$	2,566

In the nine months ended September 30, 2019, as a result of adjustments to assets acquired and liabilities assumed in the Ocean Rig acquisition, we recognized a gain of $11 million, recorded in other, net, as an adjustment to the previously recognized gain on bargain purchase. Including this adjustment, we have recognized a cumulative net gain of $21 million associated with the bargain purchase, primarily due to the decline in the market value of our shares between the announcement date and the closing date. We estimated the fair value of the rigs and related equipment by applying a combination of income and market approaches, using projected discounted cash flows and estimates of the exchange price that would be received for the assets in the principal or most advantageous markets for the assets in an orderly transaction between participants as of the acquisition date. We estimated the fair value of the drilling contracts by comparing the contractual dayrates over the remaining firm contract term and option periods relative to the projected market dayrates as of the acquisition

date. We estimated the fair value of the construction contracts by comparing the contractual future payments and terms relative to the market payments and terms as of the acquisition date. Our estimates of fair value for the drilling units and contract intangibles required us to use significant unobservable inputs, representative of a Level 3 fair value measurement, including assumptions related to the future performance of the assets, such as future commodity prices, projected demand for our services, rig availability, rig utilization, dayrates, remaining useful lives of the rigs and discount rates.

Unconsolidated Affiliates

9 Months Ended

Sep. 30, 2019

Unconsolidated Affiliates

Unconsolidated Affiliates

Note 5—Unconsolidated Affiliates

We hold investments in various partially owned, unconsolidated companies, including a 33.0 percent ownership interest in Orion Holdings (Cayman) Limited (“Orion”), a Cayman Islands company formed to construct and own the newbuild harsh environment floater Transocean Norge through its wholly owned subsidiary. In the nine months ended September 30, 2019 and 2018, we made an aggregate cash contribution of $74 million and $91 million, respectively, to Orion. We have agreed to contribute $33 million to Orion in January 2020. At September 30, 2019 and December 31, 2018, the aggregate carrying amount of our investment in Orion was $163 million and $91 million, respectively, recorded in other assets.

In the three and nine months ended September 30, 2019, we earned income of $1 million and $3 million, recorded in other income, for agent fees to procure equipment and services on behalf of Orion or its subsidiary under management services and shipyard care agreements. In the three and nine months ended September 30, 2019, we received an aggregate cash payment of $41 million and $74 million, respectively, as reimbursement, together with the agent fees, for equipment and services procured on behalf of Orion or its subsidiary.

In the three and nine months ended September 30, 2019, we recognized rental expense of $3 million, recorded in operating and maintenance costs and expenses, and made an aggregate cash payment of $2 million to lease the harsh environment floater Transocean Norge under a short-term bareboat charter agreement, which is expected to expire in May 2020. In the three and nine months ended September 30, 2019, we made an aggregate cash payment of $9 million to acquire materials and supplies and other equipment from Orion. At September 30, 2019, we had receivables of $35 million and payables of $4 million, recorded in other current assets and other current liabilities, respectively, due from or to Orion or its subsidiary.

Revenues

9 Months Ended

Sep. 30, 2019

Revenues

Revenues

Note 6—Revenues

Overview—The duration of our performance obligation varies by contract. As of September 30, 2019, the drilling contract with the longest expected remaining duration, excluding unexercised options, extends through February 2028. In the nine months ended September 30, 2019, we recognized revenues of $10 million for performance obligations satisfied in previous periods due to certain revenues recognized on a cash basis. In the three and nine months ended September 30, 2018, we recognized revenues of $54 million and $147 million, respectively, for performance obligations satisfied in previous periods, primarily related to revenues for a customer’s contract termination and certain revenues recognized on a cash basis.

To obtain contracts with our customers, we incur pre-operating costs to prepare a rig for contract and deliver or mobilize a rig to the drilling location. We defer such pre-operating costs and recognize the costs on a straight-line basis, consistent with the general pace of activity, in operating and maintenance costs over the estimated firm period of drilling. In the three and nine months ended September 30, 2019, we recognized pre-operating costs of $4 million and $10 million, respectively. In the three and nine months ended September 30, 2018, we recognized pre-operating costs of $14 million and $36 million, respectively. At September 30, 2019 and December 31, 2018, the unrecognized pre-operating costs to obtain contracts was $21 million and $2 million, respectively, recorded in other assets.

Disaggregation—We recognized revenues as follows (in millions):


	Three months ended September 30, 2019										Three months ended September 30, 2018
	U.S.		Norway		Brazil		Other		Total		U.S.		Norway		Brazil		Other		Total

Ultra-deepwater floaters	$	317	$	—	$	27	$	149	$	493	$	396	$	—	$	1	$	86	$	483
Harsh environment floaters		4		200		—		77		281		—		174		—		91		265
Deepwater floaters		—		—		—		—		—		—		—		25		11		36
Midwater floaters		—		—		—		10		10		—		—		—		19		19
High-specification jackups		—		—		—		—		—		—		—		—		13		13
Total revenues	$	321	$	200	$	27	$	236	$	784	$	396	$	174	$	26	$	220	$	816


	Nine months ended September 30, 2019										Nine months ended September 30, 2018
	U.S.		Norway		Brazil		Other		Total		U.S.		Norway		Brazil		Other		Total

Ultra-deepwater floaters	$	940	$	—	$	81	$	434	$	1,455	$	1,162	$	—	$	1	$	168	$	1,331
Harsh environment floaters		4		554		—		232		790		—		467		—		254		721
Deepwater floaters		—		—		6		1		7		—		—		74		32		106
Midwater floaters		—		—		—		44		44		—		—		—		57		57
High-specification jackups		—		—		—		—		—		—		—		—		55		55
Total revenues	$	944	$	554	$	87	$	711	$	2,296	$	1,162	$	467	$	75	$	566	$	2,270

Contract liabilities—We recognize contract liabilities, recorded in other current liabilities and other long-term liabilities, for mobilization, contract preparation and capital upgrades using the straight-line method over the remaining contract term. Contract liabilities for our contracts with customers were as follows (in millions):


	September 30,		December 31,
	2019		2018
Deferred contract revenues, recorded in other current liabilities	$	108	$	87
Deferred contract revenues, recorded in other long-term liabilities		397		399
Total contract liabilities	$	505	$	486

Significant changes in contract liabilities were as follows (in millions):


	Nine months ended
	September 30,
	2019		2018
Total contract liabilities, beginning of period	$	486	$	625
Decrease due to recognition of revenues for goods and services		(83)		(192)
Increase due to goods and services transferred over time		102		65
Total contract liabilities, end of period	$	505	$	498

Drilling Fleet

9 Months Ended

Sep. 30, 2019

Drilling Fleet

Drilling Fleet

Note 7—Drilling Fleet

Construction work in progress—The changes in our construction work in progress, including capital expenditures and other capital additions, were as follows (in millions):


	Nine months ended
	September 30,
	2019		2018
Construction work in progress, beginning of period	$	632	$	1,392

Capital expenditures
Newbuild construction program		90		64
Other equipment and construction projects		169		76
Total capital expenditures		259		140
Changes in accrued capital additions		32		(6)
Construction work in progress impaired		(5)		—
Construction work in progress acquired in business combination		—		26

Property and equipment placed into service
Newbuild construction program		—		(903)
Other property and equipment		(151)		(61)
Construction work in progress, end of period	$	767	$	588

Impairments of assets held for sale—In September 2019, we announced our intent to retire in an environmentally responsible way the ultra-deepwater floaters Discoverer Deep Seas, Discoverer Enterprise and Discoverer Spirit, along with related assets. In the three and nine months ended September 30, 2019, we recognized an aggregate loss of $578 million ($0.96 per diluted share), which had no tax effect, associated with the impairment of these assets and other equipment, which we determined were impaired at the time we classified the assets as held for sale.

During the nine months ended September 30, 2018, we announced our intent to retire in an environmentally responsible way the ultra-deepwater floaters Deepwater Discovery, Deepwater Frontier, Deepwater Millennium and GSF C.R. Luigs and the midwater floaters Songa Delta and Songa Trym, along with related assets. In the three and nine months ended September 30, 2018, we recognized an aggregate loss of $433 million ($0.93 per diluted share) and $981 million ($2.15 per diluted share), respectively, which had no tax effect, associated with the impairment of these assets, which we determined were impaired at the time we classified the assets as held for sale.

We measured the impairment of the drilling units and related assets as the amount by which the carrying amount exceeded the estimated fair value less costs to sell. We estimated the fair value of the assets using significant other observable inputs, representative of a Level 2 fair value measurement, including indicative market values for the drilling units and related assets to be sold for scrap value.

Dispositions—During the nine months ended September 30, 2019, in connection with our efforts to dispose of non-strategic assets, we completed the sale of the ultra-deepwater floaters Deepwater Frontier, Deepwater Millennium and Ocean Rig Paros, the harsh environment floater Eirik Raude, the deepwater floaters Jack Bates and Transocean 706 and the midwater floaters Actinia and Songa Delta, along with related assets. In the nine months ended September 30, 2019, we received aggregate net cash proceeds of $47 million and recognized an aggregate net gain of $2 million, which had no tax effect, associated with the disposal of these assets. In the nine months

ended September 30, 2019, we received aggregate net cash proceeds of $5 million and recognized an aggregate net loss of $9 million associated with the disposal of assets unrelated to rig sales.

During the nine months ended September 30, 2018, we completed the sale of the ultra-deepwater floaters Cajun Express, Deepwater Discovery, Deepwater Pathfinder, Sedco Energy and Sedco Express, the deepwater floater Transocean Marianas and the midwater floater Songa Trym, along with related assets. In the nine months ended September 30, 2018, we received aggregate net cash proceeds of $31 million and recognized an aggregate net gain of $6 million ($0.02 per diluted share), which had no tax effect, associated with the disposal of these assets. In the nine months ended September 30, 2018, we received aggregate net cash proceeds of $6 million and recognized an aggregate net loss of $6 million associated with the disposal of assets unrelated to rig sales.

Assets held for sale—At September 30, 2019, the aggregate carrying amount of our assets held for sale, including the ultra-deepwater floaters Discoverer Deep Seas, Discoverer Enterprise and Discoverer Spirit and related assets, was $15 million, recorded in other current assets. At December 31, 2018, the aggregate carrying amount of our assets held for sale, including the ultra-deepwater floaters Deepwater Frontier and Deepwater Millennium, the deepwater floaters Jack Bates and Transocean 706 and the midwater floater Songa Delta, along with related assets, was $25 million, recorded in other current assets.

Leases

9 Months Ended

Sep. 30, 2019

Leases

Leases

Note 9—Leases

Our operating leases are principally for office space, real estate, storage facilities and operating equipment. At September 30, 2019, our operating leases had a weighted average discount rate of 6.3 percent and a weighted-average remaining lease term of 13.9 years.

Our finance lease of the ultra-deepwater drillship Petrobras 10000, which is scheduled to expire in August 2029, has an implicit interest rate of 7.8 percent and requires scheduled monthly payments of $6 million through lease expiration, after which we will have the right and obligation to acquire the drillship from the lessor for one dollar. In the nine months ended September 30, 2019, we recognized expense of $15 million, recorded in depreciation and amortization, associated with the amortization of the right-of-use asset.

The components of our lease costs were as follows (in millions):


	Three months		Nine months
	ended		ended
	September 30,		September 30,
	2019		2019
Lease costs
Operating lease costs	$	6	$	19
Short-term lease costs		3		4
Finance lease costs, amortization of right-of-use assets		5		15
Finance lease costs, interest on lease liabilities		9		29
Total lease costs	$	23	$	67

Supplemental cash flow information for our leases was as follows (in millions):


	Nine months
	ended
	September 30,
	2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	14
Operating cash flows from finance lease		29
Financing cash flows from finance lease		24

At September 30, 2019, the aggregate future minimum rental payments for our leases were as follows (in millions):


	Operating		Finance
	leases		lease
Twelve months ending September 30,
2020	$	18	$	71
2021		11		71
2022		12		71
2023		12		71
2024		11		71
Thereafter		132		345
Total future minimum rental payment		196		700
Less amount representing imputed interest		(72)		(213)
Present value of future minimum rental payments		124		487
Less current portion, recorded in other current liabilities		(14)		(34)
Long-term lease liabilities, recorded in other long-term liabilities	$	110	$	453

Debt

9 Months Ended

Sep. 30, 2019

Debt

Debt

Note 10—Debt

Overview

Outstanding debt—The aggregate principal amounts and aggregate carrying amounts, net of debt-related balances, including unamortized discounts, premiums, issue costs and fair value adjustments of our debt, were as follows (in millions):


	Principal amount				Carrying amount
	September 30,		December 31,		September 30,		December 31,
	2019		2018		2019		2018
6.50% Senior Notes due November 2020	$	208	$	286	$	209	$	288
6.375% Senior Notes due December 2021		224		328		224		327
5.52% Senior Secured Notes due May 2022		221		282		219		280
3.80% Senior Notes due October 2022		199		411		198		408
0.50% Exchangeable Bonds due January 2023		863		863		862		862
5.375% Senior Secured Notes due May 2023		525		—		517		—
9.00% Senior Notes due July 2023		753		1,250		738		1,221
5.875% Senior Secured Notes due January 2024		667		750		655		735
7.75% Senior Secured Notes due October 2024		450		480		441		469
6.25% Senior Secured Notes due December 2024		469		500		460		489
6.125% Senior Secured Notes due August 2025		534		600		524		588
7.25% Senior Notes due November 2025		750		750		737		736
7.50% Senior Notes due January 2026		750		750		743		742
6.875% Senior Secured Notes due February 2027		550		—		541		—
7.45% Notes due April 2027		88		88		86		86
8.00% Debentures due April 2027		57		57		57		57
7.00% Notes due June 2028		300		300		306		306
Finance lease contract due August 2029		—		511		—		511
7.50% Notes due April 2031		588		588		585		585
6.80% Senior Notes due March 2038		1,000		1,000		991		991
7.35% Senior Notes due December 2041		300		300		297		297
Total debt		9,496		10,094		9,390		9,978
Less debt due within one year
5.52% Senior Secured Notes due May 2022		87		83		86		81
9.00% Senior Notes due July 2023		3		—		3		—
5.875% Senior Secured Notes due January 2024		83		83		79		79
7.75% Senior Secured Notes due October 2024		60		60		58		58
6.25% Senior Secured Notes due December 2024		62		62		60		60
6.125% Senior Secured Notes due August 2025		66		66		63		63
Finance lease contract due August 2029		—		32		—		32
Total debt due within one year		361		386		349		373
Total long-term debt	$	9,135	$	9,708	$	9,041	$	9,605

Scheduled maturities—At September 30, 2019, the scheduled maturities of our debt were as follows (in millions):


	Total
Twelve months ending September 30,
2020	$	361
2021		602
2022		669
2023		2,582
2024		609
Thereafter		4,673
Total principal amount of debt		9,496
Total debt-related balances, net		(106)
Total carrying amount of debt	$	9,390

Interest rate adjustments—The interest rates for certain of our notes are subject to adjustment from time to time upon a change to the credit rating of our non-credit enhanced senior unsecured long-term debt. As of September 30, 2019, the interest rate in effect for the 6.375% senior notes due December 2021, 3.80% senior notes due October 2022 and the 7.35% senior notes due December 2041 was 8.375 percent, 5.80 percent and 9.35 percent, respectively.

Secured Credit Facility—In June 2018, we entered into a bank credit agreement, which established a $1.0 billion secured revolving credit facility (the “Secured Credit Facility”), and in May, July and September 2019, we amended the terms of the Secured Credit Facility to, among other changes, increase the borrowing capacity to $1.3 billion and add to and clarify the lender parties and their respective commitments under the facility. The Secured Credit Facility is scheduled to expire on the earlier of (i) June 22, 2023 or (ii) if greater than $300 million aggregate principal amount of our 9.00% senior notes due July 2023 remain outstanding in April 2023, such date. The Secured Credit Facility is guaranteed by Transocean Ltd. and certain wholly owned subsidiaries and is secured by, among other things, a lien on the ultra-deepwater floaters Deepwater Asgard, Deepwater Invictus, Deepwater Skyros, Dhirubhai Deepwater KG2 and Discoverer Inspiration and the harsh environment floaters Transocean Barents and Transocean Spitsbergen, the aggregate carrying amount of which was $4.1 billion at September 30, 2019. We may borrow under the Secured Credit Facility at either (1) the reserve adjusted London interbank offered rate plus a margin (the “Secured Credit Facility Margin”), which ranges from 2.625 percent to 3.375 percent based on the credit rating of the Secured Credit Facility, or (2) the base rate specified in the credit agreement plus the Secured Credit Facility Margin, minus one percent per annum. Throughout the term of the Secured Credit Facility, we pay a facility fee on the amount of the underlying commitment which ranges from 0.375 percent to 1.00 percent based on the credit rating of the Secured Credit Facility. At September 30, 2019, based on the credit rating of the Secured Credit Facility on that date, the Secured Credit Facility Margin was 2.875 percent and the facility fee was 0.625 percent. At September 30, 2019, we had no borrowings outstanding, $15 million of letters of credit issued, and we had $1.3 billion of available borrowing capacity under the Secured Credit Facility.

Debt issuances

Senior secured notes—On February 1, 2019, we issued $550 million aggregate principal amount of 6.875% senior secured notes due February 2027 (the “6.875% Senior Secured Notes”), and we received approximately $539 million aggregate cash proceeds, net of discount and issue costs. The 6.875% Senior Secured Notes are secured by the assets and earnings associated with the ultra-deepwater floater Deepwater Poseidon and the equity of the wholly owned subsidiaries that own or operate the collateral rig. Additionally, we were required to deposit $19 million in restricted cash accounts to satisfy debt service requirements. We are required to pay semiannual installments of (a) interest only through August 2021 and (b) principal and interest thereafter. We may redeem all or a portion of the 6.875% Senior Secured Notes on or prior to February 1, 2022 at a price equal to 100 percent of the aggregate principal amount plus a make-whole provision, and subsequently, at specified redemption prices. We will be required to redeem the notes at a price equal to 100 percent of the aggregate principal amount, without a make-whole provision, upon the occurrence of certain events related to the collateral rig and the related drilling contract. The indenture that governs the 6.875% Senior Secured Notes contains covenants that limit the ability of our subsidiaries that own or operate the collateral rig to declare or pay dividends to their affiliates. The indenture also imposes a maximum collateral rig leverage ratio (the “Maximum Collateral Ratio”), represented by the net earnings of the rig relative to the debt balance, that changes over the term of the notes. Through December 31, 2020, the Maximum Collateral Ratio under the indenture is 5.75 to 1.00.

On May 24, 2019, we issued $525 million aggregate principal amount of 5.375% senior secured notes due May 2023 (the “5.375% Senior Secured Notes”), and we received approximately $517 million aggregate cash proceeds, net of discount and issue costs. The 5.375% Senior Secured Notes are secured by the assets and earnings associated with the ultra-deepwater floaters Transocean Endurance and Transocean Equinox and the equity of the wholly owned subsidiaries that own or operate the collateral rigs. Additionally, we were required to deposit $14 million in restricted cash accounts to satisfy debt service requirements. We are required to pay semiannual installments of (a) interest only through May 2020 and (b) principal and interest thereafter. We may redeem all or a portion of the 5.375% Senior Secured Notes on or prior to May 15, 2021 at a price equal to 100 percent of the aggregate principal amount plus a make-whole provision, and subsequently, at specified redemption prices. We will be required to redeem the notes at a price equal to 100 percent of the aggregate principal amount, without a make-whole provision, upon the occurrence of certain events related to the collateral rigs and the related drilling contracts. The indenture that governs the 5.375% Senior Secured Notes contains covenants that limit the ability

of our subsidiaries that own or operate the collateral rigs to declare or pay dividends to their affiliates. The indenture also imposes a Maximum Collateral Ratio, represented by the net earnings of the rig relative to the debt balance, that changes over the term of the notes. Through March 31, 2021, the Maximum Collateral Ratio under the indenture is 4.50 to 1.00.

On July 13, 2018, we issued $750 million aggregate principal amount of 5.875% senior secured notes due January 2024 (the “5.875% Senior Secured Notes”) and received aggregate cash proceeds of $733 million, net of discount and issue costs. In connection with the issuance of such notes, we were required to deposit $63 million in restricted cash accounts to satisfy debt service and reserve requirements. We are required to pay semiannual installments of principal and interest. The 5.875% Senior Secured Notes are secured by the assets and earnings associated with the harsh environment floaters Transocean Enabler and Transocean Encourage and the equity of the wholly owned subsidiaries that own or operate the collateral rigs.

On July 20, 2018, we issued $600 million aggregate principal amount of 6.125% senior secured notes due August 2025 (the “6.125% Senior Secured Notes” and, together with the 5.875% Senior Secured Notes, the “2018 Senior Secured Notes”), and we received aggregate cash proceeds of $586 million, net of discount and issue costs. In connection with the issuance of such notes, we were required to deposit $51 million in restricted cash accounts to satisfy debt service and reserve requirements. We are required to pay semiannual installments of principal and interest. The 6.125% Senior Secured Notes are secured by the assets and earnings associated with the ultra-deepwater floater Deepwater Pontus and the equity of the wholly owned subsidiaries that own or operate the collateral rig.

Exchangeable bonds—In the nine months ended September 30, 2018, we issued $863 million aggregate principal amount of 0.50% exchangeable senior bonds due January 30, 2023 (the “Exchangeable Bonds”), as partial consideration for the acquisition of Songa shares and as consideration for refinancing certain Songa indebtedness. The Exchangeable Bonds may be converted at any time prior to the maturity date at an exchange rate of 97.29756 shares per $1,000 note, equivalent to a conversion price of $10.28 per share, subject to adjustment upon the occurrence of certain events. We recorded the Exchangeable Bonds at the aggregate fair value of $1.0 billion, measured as of the issuance date, and recorded to additional paid-in capital the amount above par value, representing a substantial premium of $172 million. We estimated the fair value using significant other observable inputs, representative of a Level 2 fair value measurement, including the terms and credit spreads for the instruments.

Debt retirements

Tender offers—On February 5, 2019, we completed cash tender offers to purchase certain notes (the “2019 Tendered Notes”). We received valid tenders from holders of aggregate principal amounts of the 2019 Tendered Notes as follows (in millions):


	Nine months
	ended
	September 30,
	2019
6.50% Senior Notes due November 2020	$	57
6.375% Senior Notes due December 2021		63
3.80% Senior Notes due October 2022		190
9.00% Senior Notes due July 2023		200
Aggregate principal amount retired	$	510

Aggregate cash payment	$	522
Aggregate net loss	$	(18)

Repurchases—We repurchased in the open market our debt securities with aggregate principal amounts as follows (in millions):


	Nine months ended September 30,
		2019		2018
6.50% Senior Notes due November 2020	$	21	$	—
6.375% Senior Notes due December 2021		41		—
3.80% Senior Notes due October 2022		22		95
9.00% Senior Notes due July 2023		297		—
Aggregate principal amount retired	$	381	$	95

Aggregate cash payment	$	395	$	95
Aggregate net loss for the three months ended September 30	$	(12)	$	—
Aggregate net loss for the nine months ended September 30	$	(21)	$	(1)

Other repayments—During the nine months ended September 30, 2018, in connection with the Songa acquisition, we assumed the rights and obligations under certain credit agreements, a subscription agreement and bond loan agreements. In the three and nine months ended September 30, 2018, we made an aggregate cash payment equivalent to $1.59 billion and $1.65 billion, respectively, to repay the debt obligations outstanding under these agreements, and we terminated the underlying agreements.

Income Taxes

9 Months Ended

Sep. 30, 2019

Income Taxes

Income Taxes

Note 12—Income Taxes

Tax provision and rate—In the nine months ended September 30, 2019 and 2018, our effective tax rate was (7.4) percent and (7.2) percent, respectively, based on income or loss before income tax expense. In the nine months ended September 30, 2019 and 2018, the effect of various discrete period tax items was a net tax benefit of $40 million and a net tax expense of $91 million, respectively. In the nine months ended September 30, 2019, such discrete items were related to various items, including settlements and expirations of various uncertain tax positions and adjustments to our deferred taxes for operating structural changes made in the U.S. In the nine months ended September 30, 2018, such discrete items were primarily related to the U.S. transition tax on non-U.S. earnings. In the nine months ended September 30, 2019 and 2018, our effective tax rate, excluding discrete items, was (24.7) percent and (15.6) percent, respectively, based on income or loss before income tax expense. Our effective tax rate in the nine months ended September 30, 2019 compared to the nine months ended September 30, 2018, decreased primarily due to the adoption of a new operating structure, which reduces our exposure to the U.S. base erosion and anti-abuse tax and other cash taxes in the U.S. in the current and future years. To a lesser extent, our effective tax rate decreased due to changes in the relative blend of income from operations in certain jurisdictions.

Included in our tax provision for the nine months ended September 30, 2019, we recognized a tax benefit of $112 million, including interest and penalties, as a result of changes to our unrecognized tax benefits related to settlements that were closed in our favor, which was partially offset by tax expense of $94 million for unrecognized tax benefits related to new positions. See Note 17—Subsequent Events.

Tax returns—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 timing or the outcome of these proceedings, we do not expect the ultimate liability to have a material adverse effect on our condensed consolidated statement of financial position or results of operations, although it may have a material adverse effect on our condensed consolidated statement of cash flows.

Brazil tax investigations—In December 2005, the Brazilian tax authorities began issuing tax assessments with respect to our tax returns for the years 2000 through 2004. In January 2008, we filed a protest letter with the Brazilian tax authorities for these tax assessments, and we are currently engaged in the appeals process. In May 2014, the Brazilian tax authorities issued an additional tax assessment for the years 2009 and 2010, and in June 2014, we filed protests with the Brazilian tax authorities for these tax assessments. In September 2018 and in the first half of 2019, a portion of one of the cases was favorably closed. As of September 30, 2019, the remaining aggregate tax assessment was for BRL 672 million, equivalent to approximately $162 million, including penalties and interest. We believe our returns are materially correct as filed, and we are vigorously contesting these assessments. An unfavorable outcome on these proposed assessments could result in a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Other tax matters—We conduct operations through our various subsidiaries in 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. It is reasonably possible that we may release certain liabilities for uncertain tax positions in the year ending December 31, 2019, primarily due to resolution of certain tax settlements. Although we are unable to predict the outcome of our tax positions, we do not expect the effect, if any, resulting from these adjustments to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Loss Per Share

9 Months Ended

Sep. 30, 2019

Loss Per Share

Loss Per Share

Note 13—Loss Per Share

The numerator and denominator used to compute per share loss were as follows (in millions, except per share data):


	Three months ended September 30,								Nine months ended September 30,
	2019				2018				2019				2018
	Basic		Diluted		Basic		Diluted		Basic		Diluted		Basic		Diluted
Numerator for loss per share
Net loss attributable to controlling interest	$	(825)	$	(825)	$	(409)	$	(409)	$	(1,204)	$	(1,204)	$	(1,754)	$	(1,754)

Denominator for loss per share
Weighted-average shares outstanding		612		612		463		463		611		611		454		454
Effect of share-based awards and other equity instruments		1		1		—		—		1		1		—		—
Weighted-average shares for per share calculation		613		613		463		463		612		612		454		454

Loss per share	$	(1.35)	$	(1.35)	$	(0.88)	$	(0.88)	$	(1.97)	$	(1.97)	$	(3.86)	$	(3.86)

In the three and nine months ended September 30, 2019, we excluded from the calculation 12.2 million share-based awards since the effect would have been anti-dilutive. In the three and nine months ended September 30, 2018, we excluded from the calculation 10.7 million share-based awards since the effect would have been anti-dilutive. In the three and nine months ended September 30, 2019, we excluded from the calculation 84.0 million shares issuable upon conversion of the Exchangeable Bonds, since the effect would have been anti-dilutive. In the three and nine months ended September 30, 2018, we excluded from the calculation 84.0 million and 74.9 million shares issuable upon conversion of the Exchangeable Bonds, respectively, since the effect would have been anti-dilutive.

Contingencies

9 Months Ended

Sep. 30, 2019

Contingencies

Contingencies

Note 14—Contingencies

Legal proceedings

Macondo well incident—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 off the coast of Louisiana. At the time of the explosion, Deepwater Horizon was contracted to an affiliate of BP plc. Following the incident, we have been subject to civil and criminal claims, as well as causes of action, fines and penalties by local, state and federal governments. Litigation commenced shortly after the incident, and most claims against us were consolidated by the U.S. Judicial Panel on Multidistrict Litigation and transferred to the U.S. District Court for the Eastern District of Louisiana (the “MDL Court”). We recognized a liability for the remaining estimated loss contingencies associated with litigation resulting from the Macondo well incident that we believe are probable and for which a reasonable estimate can be made. At September 30, 2019 and December 31, 2018, the liability for estimated loss contingencies that we believe are probable and for which a reasonable estimate can be made was $124 million and $158 million, respectively, recorded in other current liabilities, the majority of which is related to the settlement agreement that we and the Plaintiff Steering Committee filed with the MDL Court in May 2015 (the “PSC Settlement Agreement”). A significant portion of the contingencies arising from the Macondo well incident has now been resolved or is pending release of funds from escrow. As for any actions not resolved by our previous settlements, we will vigorously defend those claims and pursue any and all defenses available.

On February 15, 2017, the MDL Court entered a final order and judgment approving the PSC Settlement Agreement. Through the PSC Settlement Agreement, we agreed to pay a total of $212 million to be allocated between two classes of plaintiffs in exchange for a release of all respective claims each class has against us. As required under the PSC Settlement Agreement, we deposited the settlement amount into an escrow account established by the MDL Court. In August 2019 and November 2018, the MDL Court released $33 million and $58 million, respectively, from the escrow account to make payments to the plaintiffs. At September 30, 2019 and December 31, 2018, the remaining cash balance in the escrow account was $124 million and $156 million, respectively, recorded in restricted cash accounts and investments.

Asbestos litigation—In 2004, several of our subsidiaries were named, along with numerous other unaffiliated defendants in complaints filed in the Circuit Courts of the State of Mississippi, and in 2014, a group of similar complaints were filed in Louisiana. The plaintiffs, former employees of some of the defendants, generally allege that the defendants used or manufactured asbestos containing drilling mud additives for use in connection with drilling operations, claiming 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, but the court-appointed special master has ruled that a Jones Act employer defendant, such as us, cannot be sued for punitive damages. At September 30, 2019, nine plaintiffs have claims pending in Louisiana, in which we have or may have an interest. We intend to defend these lawsuits vigorously, although we can provide no assurance as to the 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 related to the complaints, we do not expect the liability, if any, resulting from these claims to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

One of our subsidiaries has been named as a defendant, along with numerous other companies, in lawsuits arising out of the subsidiary’s manufacture and sale of heat exchangers, and involvement in the construction and refurbishment of major industrial complexes

alleging bodily injury or personal injury as a result of exposure to asbestos. As of September 30, 2019, the subsidiary was a defendant in approximately 192 lawsuits with a corresponding number of plaintiffs. For many of these lawsuits, we have not been provided 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 operating assets of the subsidiary were sold in 1989. In September 2018, the subsidiary and certain insurers agreed to a settlement of outstanding disputes that leaves the subsidiary with funding, including cash, annuities and coverage in place settlement, that we believe will be sufficient to respond to both the current lawsuits as well as future lawsuits of a similar nature. While we cannot predict or provide assurance as to the outcome of these matters, we do not expect the ultimate liability, if any, resulting from these claims to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Nigerian Cabotage Act litigation—In October 2007, three of our subsidiaries were each served a Notice and Demand from the Nigeria Maritime Administration and Safety Agency (“NIMASA”), imposing a two percent surcharge on the value of all contracts performed by us in Nigeria pursuant to the Coastal and Inland Shipping (Cabotage) Act 2003 (the “Cabotage Act”). Our subsidiaries each filed an originating summons in the Federal High Court in Lagos challenging the imposition of this surcharge on the basis that the Cabotage Act and associated levy is not applicable to offshore drilling rigs. The respondents challenged the competence of the suits on several procedural grounds. The court upheld the objections and dismissed the suits. In December 2010, our subsidiaries filed a new joint Cabotage Act suit. In June 2019, the Court of Appeal of Nigeria ruled the suits had been properly dismissed, confirming that offshore drilling rigs are not subject to the surcharges of the Cabotage Act. NIMASA has not indicated whether it intends to appeal. While we cannot predict or provide assurance as to the outcome of these proceedings, we do not expect the proceedings to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Other matters—We are involved in various tax matters, various regulatory matters and a number of claims and lawsuits, asserted and unasserted, 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 condensed 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, threatened, or possible litigation or liability. We can provide no assurance that our beliefs or expectations as to the outcome or effect of any tax, regulatory, lawsuit or other litigation matter will prove correct and the eventual outcome of these matters could materially differ from management’s current estimates.

Environmental matters

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.

One of our subsidiaries has 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 agreed, under a participation agreement with the U.S. Environmental Protection Agency (the “EPA”) and the U.S. Department of Justice, to settle our potential liabilities by remediating the site, and we have completed the required remediation. Our share of the ongoing operation and maintenance costs has been insignificant. We have no reason to believe that any additional potential liabilities for the site will be material.

One of our subsidiaries was ordered by the California Regional Water Quality Control Board to develop a testing plan for a site known as Campus 1000 Fremont in Alhambra, California, which is now a part of the San Gabriel Valley, Area 3, Superfund site. The current property owner, an unrelated party, performed the required testing and detected no contaminants, and based on such results, we would contest any potential liability. We have no knowledge of the potential cost of any remediation, who has been 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. It is difficult to quantify the potential cost of environmental matters and remediation obligations. Nevertheless, based on the available information, we do not expect the ultimate liability, if any, resulting from all environmental matters, including the liability for all related pending legal proceedings, asserted legal claims and known potential legal claims that are likely to be asserted, to have a material adverse effect on our condensed consolidated statement of financial position, results of operations or cash flows.

Financial Instruments

9 Months Ended

Sep. 30, 2019

Financial Instruments

Financial Instruments

Note 16—Financial Instruments

Overview—The carrying amounts and fair values of our financial instruments were as follows (in millions):


	September 30, 2019				December 31, 2018
	Carrying		Fair		Carrying		Fair
	amount		value		amount		value
Cash and cash equivalents	$	1,906	$	1,906	$	2,160	$	2,160
Restricted cash and cash equivalents		551		551		429		429
Restricted investments		—		—		123		123
Long-term debt, including current maturities		9,390		8,569		9,978		9,212
Derivative instruments, liabilities		3		3		6		6

We estimated 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 our cash and cash equivalents represents the historical cost, plus accrued interest. Our cash equivalents are primarily invested in short-term time deposits and money market funds. The carrying amount of our cash and cash equivalents approximates fair value because of the short maturities of the instruments.

Restricted cash and cash equivalents—The carrying amount of our restricted cash and cash equivalents, which are subject to restrictions due to collateral requirements, legislation, regulation or court order, approximates fair value because of the near-term maturities of the instruments in which the restricted balances are held. At September 30, 2019, the aggregate carrying amount of such restricted cash and cash equivalents was $551 million, recorded in current assets. At December 31, 2018, the aggregate carrying amount of such restricted cash and cash equivalents was $429 million, including $428 million and $1 million recorded in current assets and other assets, respectively.

Restricted investments—The carrying amount of our restricted investments, which were held in escrow by court order, represents the amortized historical cost of the time deposits in which they are invested. The carrying amount of such restricted investments approximates fair value because of the near-term maturities of the instruments.

Debt—The carrying amount of our debt represents the principal amount, net of unamortized discounts, premiums, debt issue costs and fair value adjustments. We measured the estimated fair value of our debt using significant other observable inputs, representative of a Level 2 fair value measurement, including the terms and credit spreads for the instruments.

Derivative instruments—The carrying amount of our derivative instruments represents the estimated fair value of such instruments. We measured the estimated fair value of our derivative instruments using significant other observable inputs, representative of a Level 2 fair value measurement, including the terms and credit spreads for the instruments.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial 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 entity 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 risks 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)	9 Months Ended
Significant Accounting Policies (Policies)	Sep. 30, 2019
Significant Accounting Policies
Presentation	Presentation—We 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 (the “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 nine months ended September 30, 2019, are not necessarily indicative of the results that may be expected for the year ending December 31, 2019, 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, 2018 and 2017, and for each of the three years in the period ended December 31, 2018, included in our annual report on Form 10-K filed on February 19, 2019.
Accounting estimates	Accounting estimates—To prepare financial statements in accordance with accounting principles generally accepted in the U.S., we must 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, assets held for sale, property and equipment, intangibles, leases, income taxes, contingencies, share-based compensation and postemployment benefit plans. We base our estimates and assumptions on historical experience and other factors that we believe are reasonable. Actual results could differ from such estimates.
Fair value measurements	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) significant observable inputs, including unadjusted quoted prices for identical assets or liabilities in active markets (“Level 1”), (2) significant other observable inputs, including direct or indirect market data for similar assets or liabilities in active markets or identical assets or liabilities in less active markets (“Level 2”) and (3) significant unobservable inputs, including those that require considerable judgment for which there is little or no market data (“Level 3”). When a valuation requires multiple input levels, 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

Business Combinations (Tables) - Ocean Rig

9 Months Ended

Sep. 30, 2019

Business Combination

Schedule of consideration transferred


	Total
Consideration transferred
Aggregate fair value of shares issued as partial consideration for Ocean Rig shares	$	1,377
Aggregate cash paid as partial consideration for Ocean Rig shares		1,168
Total consideration transferred in business combination	$	2,545

Schedule of assets acquired and liabilities assumed


	Total
Assets acquired
Cash and cash equivalents	$	152
Accounts receivable		76
Property and equipment		2,205
Drilling contract intangible assets		275
Other assets		115

Liabilities assumed
Accounts payable and other current liabilities		71
Construction contract intangible liabilities		132
Other long-term liabilities		54
Net assets acquired	$	2,566

Revenues (Tables)

9 Months Ended

Sep. 30, 2019

Revenues

Schedule of revenue disaggregation


	Three months ended September 30, 2019										Three months ended September 30, 2018
	U.S.		Norway		Brazil		Other		Total		U.S.		Norway		Brazil		Other		Total

Ultra-deepwater floaters	$	317	$	—	$	27	$	149	$	493	$	396	$	—	$	1	$	86	$	483
Harsh environment floaters		4		200		—		77		281		—		174		—		91		265
Deepwater floaters		—		—		—		—		—		—		—		25		11		36
Midwater floaters		—		—		—		10		10		—		—		—		19		19
High-specification jackups		—		—		—		—		—		—		—		—		13		13
Total revenues	$	321	$	200	$	27	$	236	$	784	$	396	$	174	$	26	$	220	$	816


	Nine months ended September 30, 2019										Nine months ended September 30, 2018
	U.S.		Norway		Brazil		Other		Total		U.S.		Norway		Brazil		Other		Total

Ultra-deepwater floaters	$	940	$	—	$	81	$	434	$	1,455	$	1,162	$	—	$	1	$	168	$	1,331
Harsh environment floaters		4		554		—		232		790		—		467		—		254		721
Deepwater floaters		—		—		6		1		7		—		—		74		32		106
Midwater floaters		—		—		—		44		44		—		—		—		57		57
High-specification jackups		—		—		—		—		—		—		—		—		55		55
Total revenues	$	944	$	554	$	87	$	711	$	2,296	$	1,162	$	467	$	75	$	566	$	2,270

Schedule of contract balances and changes


	September 30,		December 31,
	2019		2018
Deferred contract revenues, recorded in other current liabilities	$	108	$	87
Deferred contract revenues, recorded in other long-term liabilities		397		399
Total contract liabilities	$	505	$	486

Significant changes in contract liabilities were as follows (in millions):


	Nine months ended
	September 30,
	2019		2018
Total contract liabilities, beginning of period	$	486	$	625
Decrease due to recognition of revenues for goods and services		(83)		(192)
Increase due to goods and services transferred over time		102		65
Total contract liabilities, end of period	$	505	$	498

Drilling Fleet (Tables)

9 Months Ended

Sep. 30, 2019

Drilling Fleet

Changes in our construction work in progress, including capital expenditures and capitalized interest


	Nine months ended
	September 30,
	2019		2018
Construction work in progress, beginning of period	$	632	$	1,392

Capital expenditures
Newbuild construction program		90		64
Other equipment and construction projects		169		76
Total capital expenditures		259		140
Changes in accrued capital additions		32		(6)
Construction work in progress impaired		(5)		—
Construction work in progress acquired in business combination		—		26

Property and equipment placed into service
Newbuild construction program		—		(903)
Other property and equipment		(151)		(61)
Construction work in progress, end of period	$	767	$	588

Leases (Tables)

9 Months Ended

Sep. 30, 2019

Leases

Schedule of lease costs

The components of our lease costs were as follows (in millions):


	Three months		Nine months
	ended		ended
	September 30,		September 30,
	2019		2019
Lease costs
Operating lease costs	$	6	$	19
Short-term lease costs		3		4
Finance lease costs, amortization of right-of-use assets		5		15
Finance lease costs, interest on lease liabilities		9		29
Total lease costs	$	23	$	67

Schedule of lease cash flow information

Supplemental cash flow information for our leases was as follows (in millions):


	Nine months
	ended
	September 30,
	2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	14
Operating cash flows from finance lease		29
Financing cash flows from finance lease		24

Schedule of future minimum payments on operating leases


	Operating		Finance
	leases		lease
Twelve months ending September 30,
2020	$	18	$	71
2021		11		71
2022		12		71
2023		12		71
2024		11		71
Thereafter		132		345
Total future minimum rental payment		196		700
Less amount representing imputed interest		(72)		(213)
Present value of future minimum rental payments		124		487
Less current portion, recorded in other current liabilities		(14)		(34)
Long-term lease liabilities, recorded in other long-term liabilities	$	110	$	453

Schedule of future minimum payments on finance leases

At September 30, 2019, the aggregate future minimum rental payments for our leases were as follows (in millions):


	Operating		Finance
	leases		lease
Twelve months ending September 30,
2020	$	18	$	71
2021		11		71
2022		12		71
2023		12		71
2024		11		71
Thereafter		132		345
Total future minimum rental payment		196		700
Less amount representing imputed interest		(72)		(213)
Present value of future minimum rental payments		124		487
Less current portion, recorded in other current liabilities		(14)		(34)
Long-term lease liabilities, recorded in other long-term liabilities	$	110	$	453

Debt (Tables)

9 Months Ended

Sep. 30, 2019

Debt

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


	Principal amount				Carrying amount
	September 30,		December 31,		September 30,		December 31,
	2019		2018		2019		2018
6.50% Senior Notes due November 2020	$	208	$	286	$	209	$	288
6.375% Senior Notes due December 2021		224		328		224		327
5.52% Senior Secured Notes due May 2022		221		282		219		280
3.80% Senior Notes due October 2022		199		411		198		408
0.50% Exchangeable Bonds due January 2023		863		863		862		862
5.375% Senior Secured Notes due May 2023		525		—		517		—
9.00% Senior Notes due July 2023		753		1,250		738		1,221
5.875% Senior Secured Notes due January 2024		667		750		655		735
7.75% Senior Secured Notes due October 2024		450		480		441		469
6.25% Senior Secured Notes due December 2024		469		500		460		489
6.125% Senior Secured Notes due August 2025		534		600		524		588
7.25% Senior Notes due November 2025		750		750		737		736
7.50% Senior Notes due January 2026		750		750		743		742
6.875% Senior Secured Notes due February 2027		550		—		541		—
7.45% Notes due April 2027		88		88		86		86
8.00% Debentures due April 2027		57		57		57		57
7.00% Notes due June 2028		300		300		306		306
Finance lease contract due August 2029		—		511		—		511
7.50% Notes due April 2031		588		588		585		585
6.80% Senior Notes due March 2038		1,000		1,000		991		991
7.35% Senior Notes due December 2041		300		300		297		297
Total debt		9,496		10,094		9,390		9,978
Less debt due within one year
5.52% Senior Secured Notes due May 2022		87		83		86		81
9.00% Senior Notes due July 2023		3		—		3		—
5.875% Senior Secured Notes due January 2024		83		83		79		79
7.75% Senior Secured Notes due October 2024		60		60		58		58
6.25% Senior Secured Notes due December 2024		62		62		60		60
6.125% Senior Secured Notes due August 2025		66		66		63		63
Finance lease contract due August 2029		—		32		—		32
Total debt due within one year		361		386		349		373
Total long-term debt	$	9,135	$	9,708	$	9,041	$	9,605

Scheduled maturities of debt


	Total
Twelve months ending September 30,
2020	$	361
2021		602
2022		669
2023		2,582
2024		609
Thereafter		4,673
Total principal amount of debt		9,496
Total debt-related balances, net		(106)
Total carrying amount of debt	$	9,390

Schedule of tender offers


	Nine months
	ended
	September 30,
	2019
6.50% Senior Notes due November 2020	$	57
6.375% Senior Notes due December 2021		63
3.80% Senior Notes due October 2022		190
9.00% Senior Notes due July 2023		200
Aggregate principal amount retired	$	510

Aggregate cash payment	$	522
Aggregate net loss	$	(18)

Schedule of debt repurchases


	Nine months ended September 30,
		2019		2018
6.50% Senior Notes due November 2020	$	21	$	—
6.375% Senior Notes due December 2021		41		—
3.80% Senior Notes due October 2022		22		95
9.00% Senior Notes due July 2023		297		—
Aggregate principal amount retired	$	381	$	95

Aggregate cash payment	$	395	$	95
Aggregate net loss for the three months ended September 30	$	(12)	$	—
Aggregate net loss for the nine months ended September 30	$	(21)	$	(1)

Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2019

Loss Per Share

Loss Per Share

The numerator and denominator used to compute per share loss were as follows (in millions, except per share data):


	Three months ended September 30,								Nine months ended September 30,
	2019				2018				2019				2018
	Basic		Diluted		Basic		Diluted		Basic		Diluted		Basic		Diluted
Numerator for loss per share
Net loss attributable to controlling interest	$	(825)	$	(825)	$	(409)	$	(409)	$	(1,204)	$	(1,204)	$	(1,754)	$	(1,754)

Denominator for loss per share
Weighted-average shares outstanding		612		612		463		463		611		611		454		454
Effect of share-based awards and other equity instruments		1		1		—		—		1		1		—		—
Weighted-average shares for per share calculation		613		613		463		463		612		612		454		454

Loss per share	$	(1.35)	$	(1.35)	$	(0.88)	$	(0.88)	$	(1.97)	$	(1.97)	$	(3.86)	$	(3.86)

Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2019

Financial Instruments

Carrying amounts and fair values of the financial instruments


	September 30, 2019				December 31, 2018
	Carrying		Fair		Carrying		Fair
	amount		value		amount		value
Cash and cash equivalents	$	1,906	$	1,906	$	2,160	$	2,160
Restricted cash and cash equivalents		551		551		429		429
Restricted investments		—		—		123		123
Long-term debt, including current maturities		9,390		8,569		9,978		9,212
Derivative instruments, liabilities		3		3		6		6

Accounting Standards Updates (Details) - USD ($) $ in Millions		9 Months Ended
	Jan. 01, 2019	Sep. 30, 2018	Sep. 30, 2019
Recently issued accounting standards
Lease, Practical Expedients, Package [true false]	true
Finance Lease, Liability			$ 487
Finance lease current			34
Finance lease noncurrent			453
Operating lease liability			124
Operating leases current			14
Operating leases noncurrent			$ 110
Loss on impairment of goodwill		$ 462
Loss on impairment of goodwill, tax effect		$ 0
ASU-Leases \| Reclassifications
Recently issued accounting standards
Right-to-use asset, Finance lease	$ 528
Finance Lease, Liability	511
Finance lease current	32
Finance lease noncurrent	479
Right-to-use asset, Operating lease	95
Operating lease liability	133
Operating leases current	15
Operating leases noncurrent	118
ASU-Reclassification of certain tax effects \| Reclassifications
Recently issued accounting standards
Effect of adopting accounting standards update	$ 24

Business Combinations (Consideration and Allocation) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	9 Months Ended
	Dec. 05, 2018	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 28, 2018
Aggregate consideration
Acquisition costs		$ 4		$ 11
Songa
Aggregate consideration
Business combination consideration (per share)					$ 10.99
Ocean Rig
Aggregate consideration
Newly issued shares (in shares)	147.7
Business combination consideration (per share)	$ 9.32
Aggregate fair value of shares issued as partial consideration	$ 1,377
Aggregate cash paid as partial consideration	1,168
Total consideration transferred in business combination	2,545
Acquisition price allocation
Cash and cash equivalents	152
Accounts receivable	76
Property and equipment	2,205
Drilling contract intangible assets	275
Other current assets	115
Accounts payable and other current liabilities	71
Construction contract intangible liabilities	132
Other long-term liabilities	54
Net assets acquired	$ 2,566
Bargain purchase gain			$ 11
Cumulative gain on bargain purchase			$ 21

Unconsolidated Affiliates (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Unconsolidated Affiliates (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Investments
Investment in unconsolidated affiliate		$ 77	$ 107
Transocean Norge
Investments
Ownership percentage	33.00%	33.00%
Equity method investment		$ 74	$ 91
Aggregate carrying amount of investment	$ 163	163		$ 91
Revenue from affiliates	(1)	(3)
Affiliate costs	3	3
Related party receivable	35	35
Related party payable	4	4
Transocean Norge \| Reimbursements, Agent Fees and Other Receipts
Investments
Related party transaction	(41)	(74)
Transocean Norge \| Bareboat Charter Lease
Investments
Related party transaction	2	2
Transocean Norge \| Materials and Supplies and Other Equipment
Investments
Related party transaction	$ 9	9
January 2020 payment \| Transocean Norge
Investments
Investment in unconsolidated affiliate		$ 33

Revenues (Disaggregation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Revenues (Disaggregation) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Revenue
Performance obligations satisfied in previous periods		$ 54	$ 10	$ 147
Recognized pre-operating costs	$ 4	14	10	36
Unrecognized pre-operating costs	21		21		$ 2
Contract drilling revenues	784	816	2,296	2,270
Ultra-deepwater floaters
Revenue
Contract drilling revenues	493	483	1,455	1,331
Harsh environment floaters
Revenue
Contract drilling revenues	281	265	790	721
Deepwater floaters
Revenue
Contract drilling revenues		36	7	106
Midwater floaters
Revenue
Contract drilling revenues	10	19	44	57
High specification jackups
Revenue
Contract drilling revenues		13		55
U.S.
Revenue
Contract drilling revenues	321	396	944	1,162
U.S. \| Ultra-deepwater floaters
Revenue
Contract drilling revenues	317	396	940	1,162
U.S. \| Harsh environment floaters
Revenue
Contract drilling revenues	4		4
Norway
Revenue
Contract drilling revenues	200	174	554	467
Norway \| Harsh environment floaters
Revenue
Contract drilling revenues	200	174	554	467
Brazil
Revenue
Contract drilling revenues	27	26	87	75
Brazil \| Ultra-deepwater floaters
Revenue
Contract drilling revenues	27	1	81	1
Brazil \| Deepwater floaters
Revenue
Contract drilling revenues		25	6	74
Other
Revenue
Contract drilling revenues	236	220	711	566
Other \| Ultra-deepwater floaters
Revenue
Contract drilling revenues	149	86	434	168
Other \| Harsh environment floaters
Revenue
Contract drilling revenues	77	91	232	254
Other \| Deepwater floaters
Revenue
Contract drilling revenues		11	1	32
Other \| Midwater floaters
Revenue
Contract drilling revenues	$ 10	19	$ 44	57
Other \| High specification jackups
Revenue
Contract drilling revenues		$ 13		$ 55

Revenues (Contract liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Contract balances
Deferred contract revenues, recorded in other current liabilities	$ 108	$ 87
Deferred contract revenues, recorded in other long-term liabilities	397	399
Total contract liabilities	$ 505	$ 486	$ 498	$ 625

Drilling Fleet (Details) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
Drilling Fleet (Details) $ in Millions	Sep. 30, 2019 USD ($) item	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures				$ 259	$ 140
Construction work in progress impaired		$ (583)	$ (432)	(584)	(1,446)
Number of ultra deepwater drillships construction contracts canceled \| item	2
Construction in Progress
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Construction work in progress, at beginning of period				632	1,392
Total capital expenditures				259	140
Changes in accrued capital additions				32	(6)
Construction work in progress impaired				(5)
Construction work in progress acquired in business combination					26
Construction work in progress, at end of period	$ 767	$ 767	$ 588	767	588
New builds
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures				90	64
Property and equipment placed into service					(903)
Other property and equipment
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures				169	76
Property and equipment placed into service				$ (151)	$ (61)

Drilling Fleet (Disposal) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Dispositions
Net cash proceeds from sale of assets			$ 52	$ 37
Gain (loss) on the sale of assets	$ (4)	$ (6)	(7)
Assets held for sale, included in other current assets	$ 15		15		$ 25
Assets sold, not discontinued operations \| Rig sales
Dispositions
Net cash proceeds from sale of assets			47	31
Gain (loss) on the sale of assets			2	$ 6
Gain (loss) on the sale of assets per diluted share				$ 0.02
Gain (loss) on disposal of assets, tax effect			0	$ 0
Assets sold, not discontinued operations \| Other property and equipment
Dispositions
Net cash proceeds from sale of assets			5	6
Gain (loss) on the sale of assets			$ (9)	$ (6)

Goodwill (Details) $ / shares in Units, $ in Millions	9 Months Ended
Goodwill (Details) $ / shares in Units, $ in Millions	Sep. 30, 2018 USD ($) item $ / shares
Goodwill
Number of impaired ultra-deepwater floaters \| item	3
Loss on impairment of goodwill	$ 462
Loss on impairment of goodwill per diluted share from continuing operations \| $ / shares	$ 1.02
Loss on impairment of goodwill, tax effect	$ 0

Leases (Lease costs) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Leases (Lease costs) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2019
Leases
Operating lease costs	$ 6	$ 19
Short-term lease costs	3	4
Finance lease costs, amortization of right-of-use assets	5	15
Finance lease costs, interest on lease liabilities	9	29
Total lease costs	$ 23	$ 67

Leases (Maturity) (Details) $ in Millions	Sep. 30, 2019 USD ($)
Operating lease maturity
2020	$ 18
2021	11
2022	12
2023	12
2024	11
Thereafter	132
Total future minimum rental payment	196
Operating leases amount representing imputed interest	(72)
Present value of future minimum rental payments under operating leases	124
Operating leases current portion, recorded in other current liabilities	(14)
Operating leases long-term lease liabilities, recorded in other long-term liabilities	110
Finance lease maturity
2020	71
2021	71
2022	71
2023	71
2024	71
Thereafter	345
Total future minimum rental payment	700
Less amount representing imputed interest	(213)
Present value of future minimum rental payments under finance leases	487
Finance lease current portion, recorded in other current liabilities	(34)
Finance lease long-term lease liabilities, recorded in other long-term liabilities	$ 453

Debt (Details) - USD ($) $ in Millions	Sep. 30, 2019	May 24, 2019	Feb. 01, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 20, 2018	Jul. 13, 2018	Jun. 30, 2018
Principal amount
Total principal amount of debt	$ 9,496			$ 10,094
Debt due within one year	361			386
Long-term debt	9,135			9,708
Carrying amount
Total debt	9,390			9,978
Debt due within one year	349			373
Long-term debt	9,041			9,605
6.50% Senior Notes due November 2020
Principal amount
Total principal amount of debt	208			286
Carrying amount
Total debt	$ 209			288
Debt instrument interest rate stated percentage	6.50%
6.375% Senior Notes due December 2021
Principal amount
Total principal amount of debt	$ 224			328
Carrying amount
Total debt	$ 224			327
Debt instrument interest rate stated percentage	6.375%
5.52% Senior Notes due May 2022
Principal amount
Total principal amount of debt	$ 221			282
Debt due within one year	87			83
Carrying amount
Total debt	219			280
Debt due within one year	$ 86			81
Debt instrument interest rate stated percentage	5.52%
3.80% Senior Notes due October 2022
Principal amount
Total principal amount of debt	$ 199			411
Carrying amount
Total debt	$ 198			408
Debt instrument interest rate stated percentage	3.80%
0.50% Exchangeable Bonds due January 2023
Principal amount
Total principal amount of debt	$ 863			863	$ 863
Carrying amount
Total debt	$ 862			862
Debt instrument interest rate stated percentage	0.50%				0.50%
5.375% Senior Secured Notes due May 2023
Principal amount
Total principal amount of debt	$ 525
Carrying amount
Total debt	$ 517
Debt instrument interest rate stated percentage	5.375%	5.375%
9.00% Senior Notes due July 2023
Principal amount
Total principal amount of debt	$ 753			1,250
Debt due within one year	3
Carrying amount
Total debt	738			1,221
Debt due within one year	$ 3
Debt instrument interest rate stated percentage	9.00%							9.00%
5.875% Senior Secured Notes due January 2024
Principal amount
Total principal amount of debt	$ 667			750
Debt due within one year	83			83
Carrying amount
Total debt	655			735
Debt due within one year	$ 79			79
Debt instrument interest rate stated percentage	5.875%						5.875%
7.75% Senior Secured Notes due October 2024
Principal amount
Total principal amount of debt	$ 450			480
Debt due within one year	60			60
Carrying amount
Total debt	441			469
Debt due within one year	$ 58			58
Debt instrument interest rate stated percentage	7.75%
6.25% Senior Notes due December 2024
Principal amount
Total principal amount of debt	$ 469			500
Debt due within one year	62			62
Carrying amount
Total debt	460			489
Debt due within one year	$ 60			60
Debt instrument interest rate stated percentage	6.25%
6.125% Senior Secured Notes due August 2025
Principal amount
Total principal amount of debt	$ 534			600
Debt due within one year	66			66
Carrying amount
Total debt	524			588
Debt due within one year	$ 63			63
Debt instrument interest rate stated percentage	6.125%					6.125%
7.25% Senior Notes due November 2025
Principal amount
Total principal amount of debt	$ 750			750
Carrying amount
Total debt	$ 737			736
Debt instrument interest rate stated percentage	7.25%
7.50% Senior Notes due January 2026
Principal amount
Total principal amount of debt	$ 750			750
Carrying amount
Total debt	$ 743			742
Debt instrument interest rate stated percentage	7.50%
6.875% Senior Secured Notes due February 2027
Principal amount
Total principal amount of debt	$ 550
Carrying amount
Total debt	$ 541
Debt instrument interest rate stated percentage	6.875%		6.875%
7.45% Notes due April 2027
Principal amount
Total principal amount of debt	$ 88			88
Carrying amount
Total debt	$ 86			86
Debt instrument interest rate stated percentage	7.45%
8.00% Debentures due April 2027
Principal amount
Total principal amount of debt	$ 57			57
Carrying amount
Total debt	$ 57			57
Debt instrument interest rate stated percentage	8.00%
7.00% Notes due June 2028
Principal amount
Total principal amount of debt	$ 300			300
Carrying amount
Total debt	$ 306			306
Debt instrument interest rate stated percentage	7.00%
Finance lease contract due August 2029
Principal amount
Total principal amount of debt				511
Debt due within one year				32
Carrying amount
Total debt				511
Debt due within one year				32
7.50% Notes due April 2031
Principal amount
Total principal amount of debt	$ 588			588
Carrying amount
Total debt	$ 585			585
Debt instrument interest rate stated percentage	7.50%
6.80% Senior Notes due March 2038
Principal amount
Total principal amount of debt	$ 1,000			1,000
Carrying amount
Total debt	$ 991			991
Debt instrument interest rate stated percentage	6.80%
7.35% Senior Notes due December 2041
Principal amount
Total principal amount of debt	$ 300			300
Carrying amount
Total debt	$ 297			$ 297
Debt instrument interest rate stated percentage	7.35%

Debt (Maturities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Scheduled maturities of debt
2020	$ 361
2021	602
2022	669
2023	2,582
2024	609
Thereafter	4,673
Total principal amount of debt	9,496	$ 10,094
Total debt-related balances, net	(106)
Total carrying amount of debt	$ 9,390

Debt (Issued) (Details) $ / shares in Units, $ in Millions					1 Months Ended	9 Months Ended
Debt (Issued) (Details) $ / shares in Units, $ in Millions	May 24, 2019 USD ($)	Feb. 01, 2019 USD ($)	Jul. 20, 2018 USD ($)	Jul. 13, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($) $ / shares	May 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt
Proceeds from issuance of debt						$ 1,056	$ 1,319
Aggregate principal amount outstanding						9,496			$ 10,094
Restricted cash and cash equivalents						$ 551			429
Equity component of convertible debt instruments							$ 172
6.375% Senior Notes due December 2021
Debt
Debt instrument interest rate stated percentage						6.375%
Interest rate, as adjusted (as a percent)						8.375%
Aggregate principal amount outstanding						$ 224			328
3.80% Senior Notes due October 2022
Debt
Debt instrument interest rate stated percentage						3.80%
Interest rate, as adjusted (as a percent)						5.80%
Aggregate principal amount outstanding						$ 199			411
7.35% Senior Notes due December 2041
Debt
Debt instrument interest rate stated percentage						7.35%
Interest rate, as adjusted (as a percent)						9.35%
Aggregate principal amount outstanding						$ 300			300
Five-Year Revolving Credit Facility
Debt
Borrowing capacity, maximum					$ 1,000			$ 1,300
Aggregate minimum principal amount impacting maturity					$ 300
Aggregate carrying amount assets pledged						$ 4,100
Commitment fee percentage at period end						0.625%
Credit facility amount outstanding						$ 0
Letters of credit issued and outstanding						15
Credit facility available borrowing capacity						$ 1,300
Five-Year Revolving Credit Facility \| Minimum
Debt
Commitment fee percentage at period end					0.375%
Five-Year Revolving Credit Facility \| Maximum
Debt
Commitment fee percentage at period end					1.00%
Five-Year Revolving Credit Facility \| Adjusted LIBOR
Debt
Spread on variable rate basis (as a percent)						2.875%
Percentage reduction to the calculated variable rate					1.00%
Five-Year Revolving Credit Facility \| Adjusted LIBOR \| Minimum
Debt
Spread on variable rate basis (as a percent)					2.625%
Five-Year Revolving Credit Facility \| Adjusted LIBOR \| Maximum
Debt
Spread on variable rate basis (as a percent)					3.375%
9.00% Senior Notes due July 2023
Debt
Debt instrument interest rate stated percentage					9.00%	9.00%
Aggregate principal amount outstanding						$ 753			1,250
6.875% Senior Secured Notes due February 2027
Debt
Debt instrument interest rate stated percentage		6.875%				6.875%
Debt instrument face value		$ 550
Proceeds from issuance of debt		$ 539
Redemption price of debt instrument (as a percent)		100.00%
Percentage of principal amount that the holder of the note may require the entity to repurchase upon the occurrence of certain events		100
Maximum Collateral Ratio		5.75
Aggregate principal amount outstanding						$ 550
Restricted cash and cash equivalents		$ 19
5.375% Senior Secured Notes due May 2023
Debt
Debt instrument interest rate stated percentage	5.375%					5.375%
Debt instrument face value	$ 525
Proceeds from issuance of debt	$ 517
Redemption price of debt instrument (as a percent)	100.00%
Percentage of principal amount that the holder of the note may require the entity to repurchase upon the occurrence of certain events	100
Maximum Collateral Ratio	4.50
Aggregate principal amount outstanding						$ 525
Restricted cash and cash equivalents	$ 14
5.875% Senior Secured Notes due January 2024
Debt
Debt instrument interest rate stated percentage				5.875%		5.875%
Debt instrument face value				$ 750
Proceeds from issuance of debt				733
Aggregate principal amount outstanding						$ 667			750
Restricted cash and cash equivalents				$ 63
6.125% Senior Secured Notes due August 2025
Debt
Debt instrument interest rate stated percentage			6.125%			6.125%
Debt instrument face value			$ 600
Proceeds from issuance of debt			586
Aggregate principal amount outstanding						$ 534			600
Restricted cash and cash equivalents			$ 51
0.50% Exchangeable Bonds due January 2023
Debt
Debt instrument interest rate stated percentage						0.50%	0.50%
Aggregate principal amount outstanding						$ 863	$ 863		$ 863
Debt conversion ratio							0.09729756
Debt conversion (in dollars per share) \| $ / shares							$ 10.28
Fair value of debt							$ 1,000
Equity component of convertible debt instruments							$ 172

Debt (Settled) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Debt (Settled) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Debt
Aggregate cash payment			$ 522
Aggregate net loss	$ (12)	$ (1)	(39)	$ (3)
6.50% Senior Notes due November 2020
Debt
Aggregate debt repurchase	57		57
Aggregate principal amount repaid			21
6.375% Senior Notes due December 2021
Debt
Aggregate debt repurchase	63		63
Aggregate principal amount repaid			41
3.80% Senior Notes due October 2022
Debt
Aggregate debt repurchase	190		190
Aggregate principal amount repaid			22	95
9.00% Senior Notes due July 2023
Debt
Aggregate debt repurchase	200		200
Aggregate principal amount repaid			297
Tendered Notes
Debt
Aggregate debt repurchase	$ 510		510
Aggregate net loss			(18)
Debt Repurchases
Debt
Aggregate principal amount repaid			381	95
Aggregate cash payment			395	95
Aggregate net loss			$ (21)	(1)
Songa
Debt
Aggregate cash payment		$ 1,590		$ 1,650

Derivative Instruments (Details) - Undesignated derivative instruments kr in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2019 NOK (kr)	Dec. 31, 2018 USD ($)
Forward exchange contracts
Derivatives
Exchange rate (as a percent)		8.74	8.74
Derivative instruments, liabilities		$ 3		$ 6
Forward exchange contracts \| Pay
Derivatives
Aggregate notional amount		$ 93
Forward exchange contracts \| Receive
Derivatives
Aggregate notional amount \| kr			kr 810
Currency swaps
Derivatives
Cash payment for termination of derivatives	$ 92
Loss associated with derivative sale	$ (11)

Income Taxes (Provision) (Details) - USD ($) $ in Millions	9 Months Ended
Income Taxes (Provision) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Income Taxes
Effective tax rate	(7.40%)	(7.20%)
Various discrete tax items expense (benefit)	$ (40)	$ 91
Annual effective tax rate excluding discrete items (as a percent)	(24.70%)	(15.60%)
Reductions due to settlements	$ 112
Additions for current year tax positions	$ 94

Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator for loss per share, basic
Net loss attributable to controlling interest	$ (825)	$ (409)	$ (1,204)	$ (1,754)
Denominator for loss per share, basic
Weighted-average shares outstanding	612.0	463.0	611.0	454.0
Effect of share-based awards and other equity instruments	1.0		1.0
Weighted-average shares for per share calculation, basic	613.0	463.0	612.0	454.0
Loss per share, basic (in dollars per share)	$ (1.35)	$ (0.88)	$ (1.97)	$ (3.86)
Numerator for loss per share, diluted
Net loss attributable to controlling interest	$ (825)	$ (409)	$ (1,204)	$ (1,754)
Denominator for loss per share, diluted
Weighted-average shares outstanding	612.0	463.0	611.0	454.0
Effect of share-based awards and other equity instruments	1.0		1.0
Weighted-average shares for per share calculation, diluted	613.0	463.0	612.0	454.0
Loss per share, diluted (in dollars per share)	$ (1.35)	$ (0.88)	$ (1.97)	$ (3.86)
Share-based awards
Anti-dilutive securities
Securities excluded from earnings per share calculation (in shares)	12.2	10.7	12.2	10.7
0.50% Exchangeable Bonds due January 2023
Anti-dilutive securities
Securities excluded from earnings per share calculation (in shares)	84.0	84.0	84.0	74.9

Contingencies (Details) $ in Millions		1 Months Ended			9 Months Ended
Contingencies (Details) $ in Millions	Feb. 15, 2017 USD ($) item	Aug. 31, 2019 USD ($)	Nov. 30, 2018 USD ($)	Oct. 31, 2007 subsidiary	Sep. 30, 2019 USD ($) lawsuit plaintiff subsidiary	Dec. 31, 2018 USD ($)
Macondo well incident
Contingencies
Amount of fines, recoveries and civil penalties					$ 124	$ 158
PSC Settlement Agreement
Contingencies
Settlement Agreement	$ 212
Number of classes of plaintiffs \| item	2
Payment of contingency accrual		$ 33	$ 58
Cash payment into an escrow account pending approval by MDL Court					$ 124	$ 156
Asbestos litigation
Contingencies
Number of subsidiaries \| subsidiary					1
Number of claims \| lawsuit					192
Asbestos litigation \| LA
Contingencies
Number of claims \| plaintiff					9
Nigerian Cabotage Act litigation
Contingencies
Number of subsidiaries \| subsidiary				3
Percentage of surcharge on the value of contracts performed in Nigeria pursuant to the Coastal and Inland Shipping (Cabotage) Act 2003 (the Cabotage Act)				2.00%

Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	9 Months Ended
	Mar. 28, 2018	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 30, 2018
Variable Interest Entity
Recognition of noncontrolling interest in business combination				$ 33
Payment to acquire interest			$ 77	107
Acquisition of noncontrolling interest in compulsory acquisition		$ 1		31
Songa
Variable Interest Entity
Ownership interest (as a percent)					97.70%
Issuance of shares in acquisition transactions (in shares)	66.9
Business combination consideration (per share)	$ 10.99
Recognition of noncontrolling interest in business combination	$ 33
Cash payment to acquire noncontrolling interest	8
Acquisition of noncontrolling interest in compulsory acquisition	30
Songa \| 0.50% Exchangeable Bonds due January 2023
Variable Interest Entity
Convertible debt	$ 854
Noncontrolling interest
Variable Interest Entity
Recognition of noncontrolling interest in business combination				33
Acquisition of noncontrolling interest in compulsory acquisition		$ 1		$ 31
Noncontrolling interest \| Songa
Variable Interest Entity
Issuance of shares in acquisition transactions (in shares)	1.1
Business combination consideration (per share)	$ 9.76
Noncontrolling interest \| Songa \| 0.50% Exchangeable Bonds due January 2023
Variable Interest Entity
Convertible debt	$ 9
Noncontrolling interest \| Songa \| Songa
Variable Interest Entity
Ownership interest held by minority interest (as a percent)	2.30%

Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Financial instruments
Restricted cash and cash equivalents	$ 551	$ 429
Long-term debt, including current maturities	9,390	9,978
Carrying amount
Financial instruments
Cash and cash equivalents	1,906	2,160
Restricted cash and cash equivalents	551	429
Restricted investments		123
Long-term debt, including current maturities	9,390	9,978
Derivative instruments, liabilities	3	6
Fair value
Financial instruments
Cash and cash equivalents	1,906	2,160
Restricted cash and cash equivalents	551	429
Restricted investments		123
Long-term debt, including current maturities	8,569	9,212
Derivative instruments, liabilities	$ 3	6
Other current assets
Financial instruments
Restricted cash and cash equivalents		428
Other assets
Financial instruments
Restricted cash and cash equivalents		$ 1

Business (Details)	Sep. 30, 2019 item
Number of mobile offshore drilling units	45
Ultra-deepwater floaters
Number of mobile offshore drilling units	28
Number of mobile offshore drilling units under construction	2
Harsh environment floaters
Number of mobile offshore drilling units	14
Midwater floaters
Number of mobile offshore drilling units	3

Drilling Fleet (Impairment held for sale) (Details) - Rig sales - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Assets held for sale
Aggregate loss on impairment of assets held for sale	$ 578.0	$ 433.0	$ 578.0	$ 981.0
Loss associated with impairment, net of tax (per share)	$ 0.96	$ 0.93	$ 0.96	$ 2.15
Aggregate loss on impairment of assets held for sale, tax effect	$ 0.0	$ 0.0	$ 0.0	$ 0.0

Leases (Operating leases) (Details)	Sep. 30, 2019
Leases
Weighted average discount rate, operating leases (as a percent)	6.30%
Weighted-average remaining lease term, operating leases	13 years 10 months 24 days

Leases (Finance lease) (Details)	3 Months Ended	9 Months Ended
Leases (Finance lease) (Details)	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Leases
Implicit interest rate (as a percent)		7.80%
Scheduled monthly payments under finance lease obligation	$ 6,000,000	$ 6,000,000
End of lease obligation	1	1
Recognized expense associated with amortization of right-of-use asset from finance lease	$ 5,000,000	$ 15,000,000

Income Taxes (Tax Returns) (Details) - 9 months ended Sep. 30, 2019 R$ in Millions, $ in Millions	BRL (R$)	USD ($)
Brazil
Income Tax Examination
Net adjustments of additional taxes, including interest and penalties	R$ 672	$ 162

Revenues (Changes) (Details) - USD ($) $ in Millions	9 Months Ended
Revenues (Changes) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Significant changes to contract liabilities
Total contract liabilities, at beginning of period	$ 486	$ 625
Decrease due to recognition of revenues for goods and services	(83)	(192)
Increase due to goods and services transferred over time	102	65
Total contract liabilities, at end of period	$ 505	$ 498

Leases - (Cash flow) (Details) $ in Millions	9 Months Ended
Leases - (Cash flow) (Details) $ in Millions	Sep. 30, 2019 USD ($)
Leases
Operating cash flows from operating leases	$ 14
Operating cash flows from finance lease	29
Financing cash flows from finance lease	$ 24

Subsequent Events (Details) $ in Millions	1 Months Ended	3 Months Ended
Subsequent Events (Details) $ in Millions	Sep. 30, 2019 item	Dec. 31, 2019 USD ($)
Subsequent events
Number of ultra deepwater drillships construction contracts canceled \| item	2
Subsequent Event
Subsequent events
Tax Cuts and Jobs Act benefit		$ 90
Construction contract intangible liability		$ 132