Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2019	Apr. 23, 2019
Document and Entity Information
Entity Registrant Name	Transocean Ltd.
Entity Central Index Key	0001451505
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		611,631,548
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Entity Small Business	false
Entity Emerging Growth Company	false

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating revenues
Revenues	$ 754	$ 664
Type of Revenue [Extensible List]	us-gaap:OilAndGasServiceMember	us-gaap:OilAndGasServiceMember
Costs and expenses
Operating and maintenance	$ 508	$ 424
Depreciation and amortization	217	202
General and administrative	49	47
Total costs and expenses	774	673
Gain on disposal of assets, net	7	5
Operating loss	(13)	(4)
Other income (expense), net
Interest income	10	12
Interest expense, net of amounts capitalized	(166)	(147)
Loss on retirement of debt	(18)
Other, net	8	(10)
Total other income (expense), net	(166)	(145)
Loss before income tax expense	(179)	(149)
Income tax expense (benefit)	(8)	63
Net loss	(171)	(212)
Net loss attributable to noncontrolling interest		(2)
Net loss attributable to controlling interest	$ (171)	$ (210)
Loss per share
Basic (in dollars per share)	$ (0.28)	$ (0.48)
Diluted (in dollars per share)	$ (0.28)	$ (0.48)
Weighted-average shares outstanding
Basic (in shares)	611	438
Diluted (in shares)	611	438

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net loss	$ (171)	$ (212)
Net loss attributable to noncontrolling interest		(2)
Net loss attributable to controlling interest	(171)	(210)
Components of net periodic benefit costs before reclassifications	7	(4)
Components of net periodic benefit costs reclassified to net loss		2
Other comprehensive income (loss) before income taxes	7	(2)
Other comprehensive income (loss)	7	(2)
Other comprehensive income (loss) attributable to controlling interest	7	(2)
Total comprehensive loss	(164)	(214)
Total comprehensive loss attributable to noncontrolling interest		(2)
Total comprehensive loss attributable to controlling interest	$ (164)	$ (212)

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 1,886	$ 2,160
Accounts receivable, net of allowance for doubtful accounts of less than $1 at March 31, 2019 and December 31, 2018	665	604
Materials and supplies, net of allowance for obsolescence of $135 and $134 at March 31, 2019 and December 31, 2018, respectively	488	474
Restricted cash accounts and investments	583	551
Other current assets	170	159
Total current assets	3,792	3,948
Property and equipment	25,118	25,811
Less accumulated depreciation	(5,427)	(5,403)
Property and equipment, net	19,691	20,408
Contract intangible assets	750	795
Deferred income taxes, net	58	66
Other assets	1,159	448
Total assets	25,450	25,665
Liabilities and equity
Accounts payable	212	269
Accrued income taxes	50	70
Debt due within one year	343	373
Other current liabilities	791	746
Total current liabilities	1,396	1,458
Long-term debt	9,071	9,605
Deferred income taxes, net	62	64
Other long-term liabilities	1,968	1,424
Total long-term liabilities	11,101	11,093
Commitments and contingencies
Shares, CHF 0.10 par value, 639,674,422 authorized, 142,365,398 conditionally authorized, 611,970,525 issued and 611,614,353 outstanding at March 31, 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	13,396	13,394
Accumulated deficit	(213)	(67)
Accumulated other comprehensive loss	(296)	(279)
Total controlling interest shareholders' equity	12,946	13,107
Noncontrolling interest	7	7
Total equity	12,953	13,114
Total liabilities and equity	$ 25,450	$ 25,665

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Millions	Mar. 31, 2019 SFr / shares	Mar. 31, 2019 USD ($) shares	Dec. 31, 2018 SFr / shares	Dec. 31, 2018 USD ($) shares
Materials and supplies, allowance for obsolescence (in dollars) \| $		$ 135		$ 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		611,970,525		610,581,677
Shares, outstanding		611,614,353		609,649,291
Maximum
Allowance for doubtful accounts \| $		$ 1		$ 1

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Millions, $ 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
Balance (in shares) at Dec. 31, 2017		391
Increase (Decrease) in Shareholders' Equity
Share-based compensation	10		10				10
Issuance of shares under share-based compensation plans (in shares)		3
Issuance of shares in acquisition transactions	746	$ 7	739				746
Issuance of shares in acquisition transactions (in shares)		68
Equity component of convertible debt instruments	172		172				172
Allocated capital for transactions with holders of noncontrolling interest	3		3			(3)
Net loss attributable to controlling interest				(210)			(210)
Other comprehensive income (loss) attributable to controlling interest					(2)		(2)
Total comprehensive loss attributable to controlling interest	(212)						(212)
Total comprehensive loss attributable to noncontrolling interest						(1)
Total comprehensive loss							(213)
Recognition of noncontrolling interest in business combination						33	33
Acquisition of noncontrolling interest						(30)	(30)
Other, net	(2)		(2)				(2)
Balance at Mar. 31, 2018	13,424	$ 44	11,953	1,719	(292)	3	13,427
Balance (in shares) at Mar. 31, 2018		462
Balance at Dec. 31, 2018	13,107	$ 59	13,394	(67)	(279)	7	13,114
Balance (in shares) at Dec. 31, 2018		610
Increase (Decrease) in Shareholders' Equity
Share-based compensation	9		9				9
Issuance of shares under share-based compensation plans (in shares)		2
Net loss attributable to controlling interest				(171)			(171)
Other comprehensive income (loss) attributable to controlling interest					7		7
Total comprehensive loss attributable to controlling interest	(164)						(164)
Total comprehensive loss							(164)
Other, net	(6)		(7)				(6)
Balance at Mar. 31, 2019	$ 12,946	$ 59	$ 13,396	(213)	(296)	$ 7	$ 12,953
Balance (in shares) at Mar. 31, 2019		612
Increase (Decrease) in Shareholders' Equity
Effect of adopting accounting standards update				$ 25	$ (24)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (171)	$ (212)
Adjustments to reconcile to net cash provided by (used in) operating activities:
Contract intangible asset amortization	45	19
Depreciation and amortization	217	202
Share-based compensation expense	9	10
Gain on disposal of assets, net	(7)	(5)
Loss on retirement of debt	18
Deferred income tax benefit	(19)	(3)
Other, net	11	13
Changes in deferred revenues, net	1	(20)
Changes in deferred costs, net	(1)	1
Changes in other operating assets and liabilities, net	(154)	98
Net cash provided by (used in) operating activities	(51)	103
Cash flows from investing activities
Capital expenditures	(52)	(53)
Proceeds from disposal of assets, net	12	13
Investment in unconsolidated affiliates	(60)	(15)
Unrestricted and restricted cash acquired in business combination		131
Proceeds from maturities of unrestricted and restricted investments	123	350
Deposits to unrestricted investments		(50)
Net cash provided by investing activities	23	376
Cash flows from financing activities
Proceeds from issuance of debt, net of discount and issue costs	540
Repayments of debt	(616)	(168)
Proceeds from investments restricted for financing activities		26
Payments to terminate derivative instruments		(92)
Other, net	(15)	(14)
Net cash provided by (used in) financing activities	(91)	(248)
Net increase (decrease) in unrestricted and restricted cash and cash equivalents	(119)	231
Unrestricted and restricted cash and cash equivalents, beginning of period	2,589	2,975
Unrestricted and restricted cash and cash equivalents, end of period	$ 2,470	$ 3,206

Business	3 Months Ended
Business	Mar. 31, 2019
Business
Business	Note 1—Business Transocean Ltd. (together with its subsidiaries and predecessors, unless the context requires otherwise, “Transocean,” “we,” “us” or “our”) is a leading international provider of offshore contract drilling services for oil and gas wells. We specialize in technically demanding sectors of the offshore drilling business with a particular focus on ultra‑deepwater and harsh environment drilling services. Our mobile offshore drilling fleet is considered one of the most versatile fleets in the world. We contract our drilling rigs, related equipment and work crews predominantly on a dayrate basis to drill oil and gas wells. As of March 31, 2019, we owned or had partial ownership interests in and operated 48 mobile offshore drilling units, including 31 ultra‑deepwater floaters, 13 harsh environment floaters and four midwater floaters. As of March 31, 2019, we were constructing (i) four additional ultra‑deepwater drillships and (ii) one harsh environment semisubmersible, in which we hold a partial ownership interest.

Significant Accounting Policies	3 Months Ended
Significant Accounting Policies	Mar. 31, 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 months ended March 31, 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	3 Months Ended
Accounting Standards Updates	Mar. 31, 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 lessee accounting standards and 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, which contain a lease component, we applied the practical expedient to recognize revenues based on the service component, which we determined is predominant. 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 to other current liabilities and other long‑term liabilities $511 million, representing the remaining lease liability 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 lease liability of $133 million, recorded in other current liabilities and other long‑term liabilities. 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 8—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 (the “2017 Tax Act”). 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 fiscal years. 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

3 Months Ended

Mar. 31, 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 months ended March 31, 2018, in connection with the Songa acquisition, we incurred acquisition costs of $7 million, recorded in general and administrative costs and expenses.

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—We estimated the fair value of assets acquired and liabilities assumed, measured as of December 5, 2018, as follows (in millions):


	Total
Assets acquired
Cash and cash equivalents	$	152
Accounts receivable		74
Property and equipment		2,205
Drilling contract intangible assets		275
Other assets		116

Liabilities assumed
Accounts payable and other current liabilities		72
Construction contract intangible liabilities		132
Other long-term liabilities		61
Net assets acquired	$	2,557

In the three months ended March 31, 2019, as a result of adjustments to assets acquired and liabilities assumed in the Ocean Rig acquisition, we recognized a gain of $2 million, recorded in other, net, as an adjustment to the previously recognized gain on bargain purchase. As a result of the acquisition, we recognized a cumulative net gain of $12 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.

We have not completed our estimates of the fair values of assets acquired and liabilities assumed. We continue to review the estimated fair values of property and equipment, intangible assets, and other assets and liabilities, and to evaluate the assumed tax positions and contingencies. Our estimates of the fair value for such assets and liabilities require significant assumptions and judgment. Until we complete our evaluation, we may be required to adjust our original estimates, and such adjustments could be material.

Unconsolidated Affiliates	3 Months Ended
Unconsolidated Affiliates	Mar. 31, 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 semisubmersible Transocean Norge. We expect to operate Transocean Norge through one of our wholly owned subsidiaries, and the rig has been awarded a drilling contract that is expected to commence in July 2019. In the three months ended March 31, 2019, we made a $59 million cash contribution to Orion. We have agreed to contribute $33 million to Orion in January 2020. At March 31, 2019 and December 31, 2018, the aggregate carrying amount of our investment in Orion was $150 million and $91 million, respectively, recorded in other assets.

Revenues

3 Months Ended

Mar. 31, 2019

Revenues

Revenues

Note 6—Revenues

Overview—The duration of our performance obligation varies by contract. As of March 31, 2019, the drilling contract with the longest expected remaining duration, excluding unexercised options, extends through February 2028. In the three months ended March 31, 2019 and 2018, we recognized revenues of $10 million and $48 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 costs to prepare a rig for contract and deliver or mobilize a rig to the drilling location. We defer pre‑operating costs, including contract preparation and mobilization costs, and recognize such 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 months ended March 31, 2019 and 2018, we recognized costs of $2 million and $12 million, respectively, associated with pre‑operating costs for contracts with customers. At March 31, 2019 and December 31, 2018, the unrecognized pre‑operating costs to obtain contracts was $3 million and $2 million, respectively, recorded in other assets.

Disaggregation—In the three months ended March 31, 2019 and 2018, we recognized revenues as follows (in millions):


	Three months ended March 31, 2019										Three months ended March 31, 2018
	U.S.		Norway		Brazil		Other		Total		U.S.		Norway		Brazil		Other		Total

Ultra-deepwater floaters	$	314	$	—	$	26	$	136	$	476	$	349	$	—	$	—	$	29	$	378
Harsh environment floaters		—		181		—		77		258		—		122		—		82		204
Deepwater floaters		—		—		6		—		6		—		—		24		11		35
Midwater floaters		—		—		—		14		14		—		—		—		20		20
High-specification jackups		—		—		—		—		—		—		—		—		27		27
Total revenues	$	314	$	181	$	32	$	227	$	754	$	349	$	122	$	24	$	169	$	664

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):


	March 31,		December 31,
	2019		2018
Deferred contract revenues, recorded in other current liabilities	$	88	$	87
Deferred contract revenues, recorded in other long-term liabilities		399		399
Total contract liabilities	$	487	$	486

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


	Three months ended
	March 31,
	2019		2018
Total contract liabilities, beginning of period	$	486	$	625
Decrease due to recognition of revenues for goods and services		(37)		(65)
Increase due to goods and services transferred over time		38		45
Total contract liabilities, end of period	$	487	$	605

Drilling Fleet

3 Months Ended

Mar. 31, 2019

Drilling Fleet

Drilling Fleet

Note 7—Drilling Fleet

Construction work in progress—For the three months ended March 31, 2019 and 2018, the changes in our construction work in progress, including capital expenditures and other capital additions, were as follows (in millions):


	Three months ended
	March 31,
	2019		2018
Construction work in progress, beginning of period	$	632	$	1,392

Capital expenditures
Newbuild construction program		14		30
Other equipment and construction projects		38		23
Total capital expenditures		52		53
Changes in accrued capital additions		(17)		1
Construction work in progress acquired in business combination		—		26

Property and equipment placed into service
Newbuild construction program		—		(903)
Other property and equipment		(20)		(3)
Construction work in progress, end of period	$	647	$	566

Dispositions—During the three months ended March 31, 2019, in connection with our efforts to dispose of non‑strategic assets, we completed the sale of the deepwater floaters Jack Bates and Transocean 706, and the midwater floater Songa Delta, along with related assets. In the three months ended March 31, 2019, we received aggregate net cash proceeds of $11 million and recognized an aggregate net gain of $1 million, which had no tax effect, associated with the disposal of these assets. In the three months ended March 31, 2019, we received aggregate net cash proceeds of $1 million and recognized an aggregate net gain of $6 million associated with the disposal of assets unrelated to rig sales.

During the three months ended March 31, 2018, in connection with our efforts to dispose of non‑strategic assets, we completed the sale of the ultra‑deepwater floaters Cajun Express, Sedco Energy and Sedco Express, along with related assets. In the three months ended March 31, 2018, we received aggregate net cash proceeds of $12 million associated with the disposal of these assets. In the three months ended March 31, 2018, we received aggregate net cash proceeds of $1 million and recognized an aggregate net gain of $5 million associated with the disposal of assets unrelated to rig sales.

Assets held for sale—At March 31, 2019, the aggregate carrying amount of our assets held for sale, including the ultra‑deepwater floaters Deepwater Frontier, Deepwater Millennium and Ocean Rig Paros and the harsh environment floater Eirik Raude, along with related assets, was $26 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

3 Months Ended

Mar. 31, 2019

Leases

Leases

Note 8—Leases

We have operating leases expiring at various dates, principally for real estate, office space, storage facilities and operating equipment. For one operating lease that commences in July 2019, we are managing the construction of certain improvements to the leased facility, and we expect to complete the improvements in the year ending December 31, 2019. For this operating lease, we recognized a right‑of‑use asset and lease liability of $33 million and $65 million, respectively. We also recognized a receivable from the lessor for $31 million as reimbursement for certain leasehold improvements. At March 31, 2019, supplemental information for our operating leases were as follows:


	March 31,
	2019
Weighted-average remaining lease term, operating leases (years)		13.6
Weighted average discount rate, operating leases		6.3	%

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 three months ended March 31, 2019, amortization expense associated with right‑of‑use asset was $5 million, recorded in depreciation and amortization.

At March 31, 2019, the aggregate future minimum rental payments for our leases were as follows (in millions):


	Finance		Operating
	lease		leases
For the twelve months ending March 31,
2020	$	72	$	23
2021		72		11
2022		71		11
2023		71		12
2024		72		11
Thereafter		389		141
Total future minimum rental payment		747		209
Less amount representing imputed interest		(244)		(78)
Present value of future minimum rental payments		503		131
Less current portion, recorded in other current liabilities		(33)		(18)
Long-term lease liabilities, recorded in other long-term liabilities	$	470	$	113

In the three months ended March 31, 2019, the components of lease costs were as follows (in millions):


	Three months
	ended
	March 31,
	2019
Lease costs
Operating lease costs	$	6
Short-term lease costs		1
Finance lease costs
Amortization of right-of-use assets		5
Interest on lease liabilities		10
Total lease costs	$	22

In the three months ended March 31, 2019, the supplemental cash flow information for our leases were as follows (in millions):


	Three months
	ended
	March 31,
	2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	6
Operating cash flows from finance lease		10
Financing cash flows from finance lease		8

Debt

3 Months Ended

Mar. 31, 2019

Debt

Debt

Note 9—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
	March 31,		December 31,		March 31,		December 31,
	2019		2018		2019		2018
6.50% Senior Notes due November 2020	$	229	$	286	$	230	$	288
6.375% Senior Notes due December 2021		265		328		264		327
5.52% Senior Secured Notes due May 2022		263		282		260		280
3.80% Senior Notes due October 2022		221		411		220		408
0.50% Exchangeable Bonds due January 2023		863		863		862		862
9.00% Senior Notes due July 2023		1,050		1,250		1,027		1,221
5.875% Senior Secured Notes due January 2024		708		750		694		735
7.75% Senior Secured Notes due October 2024		480		480		470		469
6.25% Senior Secured Notes due December 2024		500		500		490		489
6.125% Senior Secured Notes due August 2025		567		600		555		588
7.25% Senior Notes due November 2025		750		750		736		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		9,529		10,094		9,414		9,978
Less debt due within one year
5.52% Senior Secured Notes due May 2022		85		83		84		81
5.875% Senior Secured Notes due January 2024		82		83		79		79
7.75% Senior Secured Notes due October 2024		60		60		57		58
6.25% Senior Secured Notes due December 2024		63		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		356		386		343		373
Total long-term debt	$	9,173	$	9,708	$	9,071	$	9,605

Scheduled maturities—At March 31, 2019, the scheduled maturities of our debt were as follows (in millions):


	Total
Twelve months ending March 31,
2020	$	356
2021		589
2022		641
2023		1,442
2024		1,693
Thereafter		4,808
Total principal amount of debt		9,529
Total debt-related balances, net		(115)
Total carrying amount of debt	$	9,414

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 March 31, 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”), which is scheduled to expire on the earlier of (i) June 22, 2023 and (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. 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 March 31, 2019, based on the credit rating of the Secured Credit Facility on that date, the Secured Credit Facility Margin was 2.75 percent and the facility fee was 0.50 percent. At March 31, 2019, we had no borrowings outstanding, $25 million of letters of credit issued, and we had $1.0 billion of available borrowing capacity under the Secured Credit Facility. See Note 13—Contingencies—Global Marine litigation.

Debt issuances

Senior secured notes issuance—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 $538 million aggregate cash proceeds, net of discount and issue costs. In connection with the issuance of such notes, we were required to deposit $19 million in restricted cash accounts to satisfy debt service requirements. We are required to pay semiannual installments of interest only through August 2021, after which we will pay semiannual installments of principal and interest. We may redeem all or a portion of the 6.875% Senior Secured Notes at any time prior to February 1, 2022 at a price equal to 100 percent of the aggregate principal amount plus a make whole provision, and on or after February 1, 2022 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 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. 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.

Exchangeable bonds—In the three months ended March 31, 2018, in connection with the Songa acquisition transactions, 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 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):


	Three months
	ended
	March 31,
	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	$	521
Aggregate net gain (loss)	$	(18)

Repayments—In the three months ended March 31, 2018, in connection with the Songa acquisition, we assumed the indebtedness related to two bond loans and we assumed the rights and obligations under a credit agreement for a secured borrowing facility. In the three months ended March 31, 2018, we made an aggregate cash payment equivalent to $67 million to repay the two bond loans and borrowings outstanding under the secured borrowing facility, and we terminated the underlying credit agreement.

Derivative Instruments	3 Months Ended
Derivative Instruments	Mar. 31, 2019
Derivative Instruments
Derivatives instruments	Note 10—Derivative Instruments Forward exchange contracts—At March 31, 2019, we held undesignated forward exchange contracts, extending through December 2019, with an aggregate notional payment amount of $132 million and an aggregate notional receive amount of NOK 1.1 billion, representing a weighted average exchange rate of NOK 8.41 to $1. At March 31, 2019 and December 31, 2018, the net carrying amount of our undesignated forward exchange contracts was a liability of $3 million and $6 million, respectively, recorded in other current liabilities. Currency swaps—In connection with the Songa acquisition, we acquired undesignated currency swaps to receive Norwegian kroner in exchange for U.S. dollars. In the three months ended March 31, 2018, we made an aggregate cash payment of $92 million to terminate the currency swaps and we recognized a loss of $11 million, recorded in other, net.

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2019
Income Taxes
Income Taxes	Note 11—Income Taxes Tax provision and rate—In the three months ended March 31, 2019 and 2018, our estimated annual effective tax rate, excluding discrete items, was (10.6) percent and (42.8) percent, respectively, based on estimated annual income or loss before income taxes. In the three months ended March 31, 2019, such discrete items included losses on retirement of debt and changes in estimates related to taxes in prior years, as described below. In the three months ended March 31, 2018, such discrete items included acquisition costs. In the three months ended March 31, 2019, compared to the three months ended March 31, 2018, our effective tax rate increased primarily due to the increased tax expense related to the U.S. base erosion and anti‑abuse tax and changes in the relative blend of income from operations in certain jurisdictions and the loss before income taxes. Certain changes to our operating structures in the U.S. could reduce the effect of the base erosion and anti‑abuse tax in future periods. We consider the tax effect, if any, of the excluded items noted below, as well as settlements of prior year tax estimates, to be discrete period tax expenses or benefits. In the three months ended March 31, 2019 and 2018, the effect of the various discrete period tax items was a net tax benefit of $25 million and $1 million, respectively. In the three months ended March 31, 2019, such discrete items were primarily related to the reversal of various uncertain tax provisions and adjustments to our valuation allowance. In the three months ended March 31, 2018, such discrete items were primarily related to the tax benefit of changes in unrecognized tax benefits associated with tax positions taken in prior years and remeasurement of the deferred tax assets for a tax rate change. For the three months ended March 31, 2019 and 2018, our effective tax rate, including these discrete tax items, and the excluded income and expense items noted above, was 4.5 percent and (42.2) percent, respectively, based on income or loss before income tax expense. 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 consolidated statement of financial position or results of operations, although it may have a material adverse effect on our 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, a portion of one of the cases was favorably closed. As of March 31, 2019, the remaining aggregate tax assessment was for BRL 657 million, equivalent to approximately $168 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 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

3 Months Ended

Mar. 31, 2019

Loss Per Share

Loss Per Share

Note 12—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 March 31,
	2019				2018
	Basic		Diluted		Basic		Diluted
Numerator for loss per share
Net loss available to shareholders	$	(171)	$	(171)	$	(210)	$	(210)

Denominator for loss per share
Weighted-average shares outstanding		610		610		438		438
Effect of share-based awards and other equity instruments		1		1		—		—
Weighted-average shares for per share calculation		611		611		438		438

Loss per share	$	(0.28)	$	(0.28)	$	(0.48)	$	(0.48)

In the three months ended March 31, 2019 and 2018, we excluded from the calculation 12.1 million and 11.0 million share‑based awards, respectively, since the effect would have been anti‑dilutive. In the three months ended March 31, 2019 and 2018, we excluded from the calculation 84.0 million and 56.3 million shares issuable upon conversion of the Exchangeable Bonds, respectively, since the effect would have been anti‑dilutive.

Contingencies	3 Months Ended
Contingencies	Mar. 31, 2019
Contingencies
Contingencies	Note 13—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 (together with its affiliates, “BP”). 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 March 31, 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 $158 million, recorded in other current liabilities, the majority of which is related to the settlement agreement that we and the Plaintiff Steering Committee (the “PSC”) 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, including any claims by the 30 claimants who opted out of the PSC Settlement Agreement, 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 judgement 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 November 2018, the MDL Court released $58 million from the escrow account as the first installment to the plaintiffs. At March 31, 2019 and December 31, 2018, the remaining cash balance in the escrow account was $156 million, 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 March 31, 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 to date, 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 March 31, 2019, the subsidiary was a defendant in approximately 184 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, 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 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. 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. Global Marine litigation—On November 28, 2017, Wilmington Trust Company, in its capacity as trustee, filed a lawsuit in the Supreme Court of the State of New York, County of New York, against Global Marine Inc. (“Global Marine”), one of our wholly owned, indirect subsidiaries, seeking a declaratory judgment that Global Marine is in default under the indenture governing its $300 million of outstanding 7.00% Notes due June 2028. We disagree with the assertions in the lawsuit and believe that Global Marine is in compliance with the indenture and has meritorious defenses against these allegations, although it can make no assurance regarding the outcome of the lawsuit, including the actual amount that would be due in the event that the lawsuit is successful. The notes are neither guaranteed by, nor recourse to, Transocean Ltd. or our other subsidiaries. The claimants seek payment prior to the scheduled maturity of the principal amount of notes outstanding and accrued but unpaid interest as well as make whole amounts under the indenture. In addition, the acceleration of the amounts due under the indenture could, absent our payment of the amounts due or otherwise staying any judgment therefrom, result in an event of default under our currently undrawn Secured Credit Facility. We intend to vigorously defend the lawsuit. 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. Nigerian customer arbitration—One of our customers in Nigeria owes us approximately $80 million for drilling services performed in 2014 and 2015. The customer has not disputed the services rendered and we have remained engaged in discussions with the customer about collection of this overdue balance. In September 2018, we notified the customer of our intentions to enter into arbitration. We intend to vigorously pursue full recovery of this receivable. While we cannot predict or provide assurance as to its outcome, we do not expect it 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 with the Environmental Protection Agency (the “EPA”) and the Department of Justice to settle our potential liabilities by remediating the site. Under a participation agreement, the parties to the settlement completed the required remediation, and we believe our share, approximately eight percent, of the ongoing future operation and maintenance costs is not material. We have no reason to believe that any additional potential liabilities for the site will be material. One of our subsidiaries has been ordered by the California Regional Water Quality Control Board (“CRWQCB”) to develop a testing plan for a site known as Campus 1000 Fremont in Alhambra, California, which is now a part of the San Gabriel Valley, Area 3, Superfund site. We were also advised that one or more of our subsidiaries that formerly owned and operated the site would likely be named as a PRP. 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. In discussions with CRWQCB staff, we were advised of their intent to issue us a “no further action” letter, but it has not yet been received. We have no knowledge of the potential cost of any remediation, who else will be named as PRPs, and whether in fact any of our subsidiaries is a responsible party. The subsidiaries in question do not own any operating assets and have limited ability to respond to any liabilities. Resolutions of other claims by the EPA, the involved state agency or PRPs are at various stages of investigation. 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.

Equity	3 Months Ended
Equity	Mar. 31, 2019
Equity
Equity	Note 14—Equity On January 30, 2018, we acquired an approximate 97.7 percent ownership interest in Songa. To complete the acquisition, we issued 66.9 million shares with a weighted average per share market value of $10.99 and $854 million aggregate principal amount of the Exchangeable Bonds. On the date of the Songa acquisition, we recognized noncontrolling interest of $33 million, representing the estimated fair value of the 2.3 percent ownership interest not owned by us. On March 28, 2018, we acquired the remaining Songa shares through a compulsory acquisition under Cyprus law, and as a result, Songa became our wholly owned subsidiary. As consideration, we issued 1.1 million shares with a weighted average per share market value of $9.76 and $9 million aggregate principal amount of Exchangeable Bonds and we made an aggregate cash payment of $8 million to the Songa shareholders who elected to receive a cash payment or failed to make an election, for an aggregate fair value of $30 million.

Financial Instruments

3 Months Ended

Mar. 31, 2019

Financial Instruments

Financial Instruments

Note 15—Financial Instruments

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


	March 31, 2019				December 31, 2018
	Carrying		Fair		Carrying		Fair
	amount		value		amount		value
Cash and cash equivalents	$	1,886	$	1,886	$	2,160	$	2,160
Restricted cash and cash equivalents		584		584		429		429
Restricted investments		—		—		123		123
Long-term debt, including current maturities		9,414		9,423		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 due to the near‑term maturities of the instruments in which the restricted balances are held. At March 31, 2019, the aggregate carrying amount of such restricted cash and cash equivalents was $584 million, including $583 million and less than $1 million recorded in current assets and other assets, respectively. 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 are 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)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 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 months ended March 31, 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

3 Months Ended

Mar. 31, 2019

Business Combination

Schedule of consideration transferred

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

Schedule of assets acquired and liabilities assumed

We estimated the fair value of assets acquired and liabilities assumed, measured as of December 5, 2018, as follows (in millions):


	Total
Assets acquired
Cash and cash equivalents	$	152
Accounts receivable		74
Property and equipment		2,205
Drilling contract intangible assets		275
Other assets		116

Liabilities assumed
Accounts payable and other current liabilities		72
Construction contract intangible liabilities		132
Other long-term liabilities		61
Net assets acquired	$	2,557

Revenues (Tables)

3 Months Ended

Mar. 31, 2019

Revenues

Schedule of revenue disaggregation

In the three months ended March 31, 2019 and 2018, we recognized revenues as follows (in millions):


	Three months ended March 31, 2019										Three months ended March 31, 2018
	U.S.		Norway		Brazil		Other		Total		U.S.		Norway		Brazil		Other		Total

Ultra-deepwater floaters	$	314	$	—	$	26	$	136	$	476	$	349	$	—	$	—	$	29	$	378
Harsh environment floaters		—		181		—		77		258		—		122		—		82		204
Deepwater floaters		—		—		6		—		6		—		—		24		11		35
Midwater floaters		—		—		—		14		14		—		—		—		20		20
High-specification jackups		—		—		—		—		—		—		—		—		27		27
Total revenues	$	314	$	181	$	32	$	227	$	754	$	349	$	122	$	24	$	169	$	664

Schedule of contract balances and changes

Contract liabilities for our contracts with customers were as follows (in millions):


	March 31,		December 31,
	2019		2018
Deferred contract revenues, recorded in other current liabilities	$	88	$	87
Deferred contract revenues, recorded in other long-term liabilities		399		399
Total contract liabilities	$	487	$	486

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


	Three months ended
	March 31,
	2019		2018
Total contract liabilities, beginning of period	$	486	$	625
Decrease due to recognition of revenues for goods and services		(37)		(65)
Increase due to goods and services transferred over time		38		45
Total contract liabilities, end of period	$	487	$	605

Drilling Fleet (Tables)

3 Months Ended

Mar. 31, 2019

Drilling Fleet

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

For the three months ended March 31, 2019 and 2018, the changes in our construction work in progress, including capital expenditures and other capital additions, were as follows (in millions):


	Three months ended
	March 31,
	2019		2018
Construction work in progress, beginning of period	$	632	$	1,392

Capital expenditures
Newbuild construction program		14		30
Other equipment and construction projects		38		23
Total capital expenditures		52		53
Changes in accrued capital additions		(17)		1
Construction work in progress acquired in business combination		—		26

Property and equipment placed into service
Newbuild construction program		—		(903)
Other property and equipment		(20)		(3)
Construction work in progress, end of period	$	647	$	566

Leases (Tables)

3 Months Ended

Mar. 31, 2019

Leases

Schedule of supplemental information for our operating leases


	March 31,
	2019
Weighted-average remaining lease term, operating leases (years)		13.6
Weighted average discount rate, operating leases		6.3	%

Schedule of future minimum payments on finance leases

At March 31, 2019, the aggregate future minimum rental payments for our leases were as follows (in millions):


	Finance		Operating
	lease		leases
For the twelve months ending March 31,
2020	$	72	$	23
2021		72		11
2022		71		11
2023		71		12
2024		72		11
Thereafter		389		141
Total future minimum rental payment		747		209
Less amount representing imputed interest		(244)		(78)
Present value of future minimum rental payments		503		131
Less current portion, recorded in other current liabilities		(33)		(18)
Long-term lease liabilities, recorded in other long-term liabilities	$	470	$	113

Schedule of future minimum payments on operating leases


	Finance		Operating
	lease		leases
For the twelve months ending March 31,
2020	$	72	$	23
2021		72		11
2022		71		11
2023		71		12
2024		72		11
Thereafter		389		141
Total future minimum rental payment		747		209
Less amount representing imputed interest		(244)		(78)
Present value of future minimum rental payments		503		131
Less current portion, recorded in other current liabilities		(33)		(18)
Long-term lease liabilities, recorded in other long-term liabilities	$	470	$	113

Schedule of lease costs

In the three months ended March 31, 2019, the components of lease costs were as follows (in millions):


	Three months
	ended
	March 31,
	2019
Lease costs
Operating lease costs	$	6
Short-term lease costs		1
Finance lease costs
Amortization of right-of-use assets		5
Interest on lease liabilities		10
Total lease costs	$	22

Schedule of lease cash flow information

In the three months ended March 31, 2019, the supplemental cash flow information for our leases were as follows (in millions):


	Three months
	ended
	March 31,
	2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	6
Operating cash flows from finance lease		10
Financing cash flows from finance lease		8

Debt (Tables)

3 Months Ended

Mar. 31, 2019

Debt

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

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
	March 31,		December 31,		March 31,		December 31,
	2019		2018		2019		2018
6.50% Senior Notes due November 2020	$	229	$	286	$	230	$	288
6.375% Senior Notes due December 2021		265		328		264		327
5.52% Senior Secured Notes due May 2022		263		282		260		280
3.80% Senior Notes due October 2022		221		411		220		408
0.50% Exchangeable Bonds due January 2023		863		863		862		862
9.00% Senior Notes due July 2023		1,050		1,250		1,027		1,221
5.875% Senior Secured Notes due January 2024		708		750		694		735
7.75% Senior Secured Notes due October 2024		480		480		470		469
6.25% Senior Secured Notes due December 2024		500		500		490		489
6.125% Senior Secured Notes due August 2025		567		600		555		588
7.25% Senior Notes due November 2025		750		750		736		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		9,529		10,094		9,414		9,978
Less debt due within one year
5.52% Senior Secured Notes due May 2022		85		83		84		81
5.875% Senior Secured Notes due January 2024		82		83		79		79
7.75% Senior Secured Notes due October 2024		60		60		57		58
6.25% Senior Secured Notes due December 2024		63		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		356		386		343		373
Total long-term debt	$	9,173	$	9,708	$	9,071	$	9,605

Scheduled maturities of debt


	Total
Twelve months ending March 31,
2020	$	356
2021		589
2022		641
2023		1,442
2024		1,693
Thereafter		4,808
Total principal amount of debt		9,529
Total debt-related balances, net		(115)
Total carrying amount of debt	$	9,414

Schedule of tender offers

We received valid tenders from holders of aggregate principal amounts of the 2019 Tendered Notes as follows (in millions):


	Three months
	ended
	March 31,
	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	$	521
Aggregate net gain (loss)	$	(18)

Loss Per Share (Tables)

3 Months Ended

Mar. 31, 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 March 31,
	2019				2018
	Basic		Diluted		Basic		Diluted
Numerator for loss per share
Net loss available to shareholders	$	(171)	$	(171)	$	(210)	$	(210)

Denominator for loss per share
Weighted-average shares outstanding		610		610		438		438
Effect of share-based awards and other equity instruments		1		1		—		—
Weighted-average shares for per share calculation		611		611		438		438

Loss per share	$	(0.28)	$	(0.28)	$	(0.48)	$	(0.48)

Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2019

Financial Instruments

Carrying amounts and fair values of the financial instruments


	March 31, 2019				December 31, 2018
	Carrying		Fair		Carrying		Fair
	amount		value		amount		value
Cash and cash equivalents	$	1,886	$	1,886	$	2,160	$	2,160
Restricted cash and cash equivalents		584		584		429		429
Restricted investments		—		—		123		123
Long-term debt, including current maturities		9,414		9,423		9,978		9,212
Derivative instruments, liabilities		3		3		6		6

Business (Details)	Mar. 31, 2019 item
Number of mobile offshore drilling units	48
Ultra-deepwater floaters
Number of mobile offshore drilling units	31
Number of mobile offshore drilling units under construction	4
Harsh environment floaters
Number of mobile offshore drilling units	13
Number of mobile offshore drilling units under construction	1
Midwater floaters
Number of mobile offshore drilling units	4

Accounting Standards Updates (Details) - USD ($) $ in Millions	Jan. 01, 2019	Mar. 31, 2019
Recently issued accounting standards
Lease, Practical Expedients, Package [true false]	true
Finance Lease, Liability		$ 503
Operating lease liability		$ 131
ASU-Leases \| Reclassifications
Recently issued accounting standards
Right-to-use asset, Finance lease	$ 528
Finance Lease, Liability	511
Right-to-use asset, Operating lease	95
Operating lease liability	133
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
	Dec. 05, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 28, 2018
Songa
Aggregate consideration
Acquisition costs			$ 7
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	74
Property and equipment	2,205
Drilling contract intangible assets	275
Other current assets	116
Accounts payable and other current liabilities	72
Construction contract intangible liabilities	132
Other long-term liabilities	61
Net assets acquired	$ 2,557
Adjustment to previously recognized gain on bargain purchase		$ 2
Bargain purchase gain		$ 12

Unconsolidated Affiliates (Details) - USD ($) $ in Millions	3 Months Ended
Unconsolidated Affiliates (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Investments
Investment in unconsolidated affiliate	$ 60	$ 15
Transocean Norge
Investments
Ownership percentage	33.00%
Equity method investment	$ 59
Aggregate carrying amount of investment	150		$ 91
January 2020 payment \| Transocean Norge
Investments
Investment in unconsolidated affiliate	$ 33

Revenues (Disaggregation) (Details) - USD ($) $ in Millions	3 Months Ended
Revenues (Disaggregation) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Revenue
Performance obligations satisfied in previous periods	$ 10	$ 48
Recognized pre-operating costs	2	12
Unrecognized pre-operating costs	3		$ 2
Contract drilling revenues	754	664
Ultra-deepwater floaters
Revenue
Contract drilling revenues	476	378
Harsh environment floaters
Revenue
Contract drilling revenues	258	204
Deepwater floaters
Revenue
Contract drilling revenues	6	35
Midwater floaters
Revenue
Contract drilling revenues	14	20
High specification jackups
Revenue
Contract drilling revenues		27
U.S.
Revenue
Contract drilling revenues	314	349
U.S. \| Ultra-deepwater floaters
Revenue
Contract drilling revenues	314	349
Norway
Revenue
Contract drilling revenues	181	122
Norway \| Harsh environment floaters
Revenue
Contract drilling revenues	181	122
Brazil
Revenue
Contract drilling revenues	32	24
Brazil \| Ultra-deepwater floaters
Revenue
Contract drilling revenues	26
Brazil \| Deepwater floaters
Revenue
Contract drilling revenues	6	24
Other
Revenue
Contract drilling revenues	227	169
Other \| Ultra-deepwater floaters
Revenue
Contract drilling revenues	136	29
Other \| Harsh environment floaters
Revenue
Contract drilling revenues	77	82
Other \| Deepwater floaters
Revenue
Contract drilling revenues		11
Other \| Midwater floaters
Revenue
Contract drilling revenues	$ 14	20
Other \| High specification jackups
Revenue
Contract drilling revenues		$ 27

Revenues (Contract liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Contract balances
Deferred contract revenues, recorded in other current liabilities	$ 88	$ 87
Deferred contract revenues, recorded in other long-term liabilities	399	399
Total contract liabilities	$ 487	$ 486	$ 605	$ 625

Revenues (Changes) (Details) - USD ($) $ in Millions	3 Months Ended
Revenues (Changes) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 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	(37)	(65)
Increase due to goods and services transferred over time	38	45
Total contract liabilities, at end of period	$ 487	$ 605

Drilling Fleet (Details) - USD ($) $ in Millions	3 Months Ended
Drilling Fleet (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures	$ 52	$ 53
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	52	53
Changes in accrued capital additions	(17)	1
Construction work in progress acquired in business combination		26
Construction work in progress, at end of period	647	566
New builds
Changes in construction work in progress, including capital expenditures and other capital additions, such as capitalized interest
Total capital expenditures	14	30
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	38	23
Property and equipment placed into service	$ (20)	$ (3)

Drilling Fleet (Disposal) (Details) - USD ($) $ in Millions	3 Months Ended
Drilling Fleet (Disposal) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Dispositions
Net cash proceeds from sale of assets	$ 12	$ 13
Gain (loss) on the sale of assets	7	5
Assets held for sale, included in other current assets	26		$ 25
Assets sold, not discontinued operations \| Rig sales
Dispositions
Net cash proceeds from sale of assets	11	12
Gain (loss) on the sale of assets	1
Gain (loss) on disposal of assets, tax effect	0
Assets sold, not discontinued operations \| Other property and equipment
Dispositions
Net cash proceeds from sale of assets	1	1
Gain (loss) on the sale of assets	$ 6	$ 5

Leases (Operating leases) (Details) $ in Millions	Mar. 31, 2019 USD ($)
Leases
Right of use asset for operating lease not yet commenced	$ 33
Lease liability for operating leases not yet commenced	65
Receivable from lessor	$ 31
Weighted-average remaining lease term, operating leases	13 years 7 months 6 days
Weighted average discount rate, operating leases (as a percent)	6.30%

Leases (Finance lease) (Details)	3 Months Ended
Leases (Finance lease) (Details)	Mar. 31, 2019 USD ($)
Leases
Implicit interest rate (as a percent)	7.80%
Scheduled monthly payments under finance lease obligation	$ 6,000,000
End of lease obligation	1
Amortization expense for right-of-use asset from finance lease	$ 5,000,000

Leases (Maturity) (Details) $ in Millions	Mar. 31, 2019 USD ($)
Finance lease maturity
2020	$ 72
2021	72
2022	71
2023	71
2024	72
Thereafter	389
Total future minimum rental payment	747
Less amount representing imputed interest	(244)
Present value of future minimum rental payments under finance leases	503
Finance lease current portion, recorded in other current liabilities	(33)
Finance lease long-term lease liabilities, recorded in other long-term liabilities	470
Operating lease maturity
2020	23
2021	11
2022	11
2023	12
2024	11
Thereafter	141
Total future minimum rental payment	209
Operating leases amount representing imputed interest	(78)
Present value of future minimum rental payments under operating leases	131
Operating leases current portion, recorded in other current liabilities	(18)
Operating leases long-term lease liabilities, recorded in other long-term liabilities	$ 113

Leases (Lease costs) (Details) $ in Millions	3 Months Ended
Leases (Lease costs) (Details) $ in Millions	Mar. 31, 2019 USD ($)
Leases
Operating lease costs	$ 6
Short-term lease costs	1
Finance lease costs
Amortization of right-of-use assets	5
Interest on lease liabilities	10
Total lease costs	$ 22

Leases - (Cash flow) (Details) $ in Millions	3 Months Ended
Leases - (Cash flow) (Details) $ in Millions	Mar. 31, 2019 USD ($)
Leases
Operating cash flows from operating leases	$ 6
Operating cash flows from finance lease	10
Financing cash flows from finance lease	$ 8

Debt (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018
Principal amount
Total principal amount of debt	$ 9,529	$ 10,094
Debt due within one year	356	386
Long-term debt	9,173	9,708
Carrying amount
Total debt	9,414	9,978
Debt due within one year	343	373
Long-term debt	9,071	9,605
6.50% Senior Notes due November 2020
Principal amount
Total principal amount of debt	229	286
Carrying amount
Total debt	$ 230	288
Debt instrument interest rate stated percentage	6.50%
6.375% Senior Notes due December 2021
Principal amount
Total principal amount of debt	$ 265	328
Carrying amount
Total debt	$ 264	327
Debt instrument interest rate stated percentage	6.375%
5.52% Senior Notes due May 2022
Principal amount
Total principal amount of debt	$ 263	282
Debt due within one year	85	83
Carrying amount
Total debt	260	280
Debt due within one year	$ 84	81
Debt instrument interest rate stated percentage	5.52%
3.80% Senior Notes due October 2022
Principal amount
Total principal amount of debt	$ 221	411
Carrying amount
Total debt	$ 220	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%
9.00% Senior Notes due July 2023
Principal amount
Total principal amount of debt	$ 1,050	1,250
Carrying amount
Total debt	$ 1,027	1,221
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	$ 708	750
Debt due within one year	82	83
Carrying amount
Total debt	694	735
Debt due within one year	$ 79	79
Debt instrument interest rate stated percentage	5.875%
7.75% Senior Secured Notes due October 2024
Principal amount
Total principal amount of debt	$ 480	480
Debt due within one year	60	60
Carrying amount
Total debt	470	469
Debt due within one year	$ 57	58
Debt instrument interest rate stated percentage	7.75%
6.25% Senior Notes due December 2024
Principal amount
Total principal amount of debt	$ 500	500
Debt due within one year	63	62
Carrying amount
Total debt	490	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	$ 567	600
Debt due within one year	66	66
Carrying amount
Total debt	555	588
Debt due within one year	$ 63	63
Debt instrument interest rate stated percentage	6.125%
7.25% Senior Notes due November 2025
Principal amount
Total principal amount of debt	$ 750	750
Carrying amount
Total debt	$ 736	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%
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	Mar. 31, 2019	Dec. 31, 2018
Scheduled maturities of debt
2020	$ 356
2021	589
2022	641
2023	1,442
2024	1,693
Thereafter	4,808
Total principal amount of debt	9,529	$ 10,094
Total debt-related balances, net	(115)
Total carrying amount of debt	$ 9,414

Debt (Issued) (Details) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended
Debt (Issued) (Details) $ / shares in Units, $ in Millions	Feb. 01, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($) $ / shares	Dec. 31, 2018 USD ($)
Debt
Proceeds from issuance of debt			$ 540
Aggregate principal amount outstanding			9,529		$ 10,094
Restricted cash and cash equivalents			$ 584		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			$ 265		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			$ 221		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
Aggregate minimum principal amount impacting maturity		$ 300
Commitment fee percentage at period end			0.50%
Credit facility amount outstanding			$ 0
Letters of credit issued and outstanding			25
Credit facility available borrowing capacity			$ 1,000
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)			2.75%
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			$ 1,050		1,250
6.875% Senior Secured Notes due February 2027
Debt
Debt instrument interest rate stated percentage			6.875%
Debt instrument face value	$ 550
Proceeds from issuance of debt	$ 538
Redemption price of debt instrument (as a percent)	100.00%
Maximum Collateral Ratio	5.75
Aggregate principal amount outstanding			$ 550
Restricted cash and cash equivalents	$ 19
0.50% Exchangeable Bonds due January 2023
Debt
Debt instrument interest rate stated percentage			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
Debt (Settled) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Debt
Aggregate cash payment made for debt redemption	$ 521
Loss on retirement of debt	(18)
Tendered Notes
Debt
Aggregate debt repurchase	510
Loss on retirement of debt	(18)
6.50% Senior Notes due November 2020
Debt
Aggregate debt repurchase	57
6.375% Senior Notes due December 2021
Debt
Aggregate debt repurchase	63
3.80% Senior Notes due October 2022
Debt
Aggregate debt repurchase	190
9.00% Senior Notes due July 2023
Debt
Aggregate debt repurchase	$ 200
Secured Borrowing Facility
Debt
Aggregate cash payment made for debt redemption		$ 67

Derivative Instruments (Details) - Undesignated derivative instruments $ in Millions, kr in Billions	3 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2019 NOK (kr)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Forward exchange contracts
Derivatives
Exchange rate (as a percent)		8.41	8.41
Derivative instruments, liabilities			$ 3	$ 6
Forward exchange contracts \| Pay
Derivatives
Aggregate notional amount			$ 132
Forward exchange contracts \| Receive
Derivatives
Aggregate notional amount \| kr		kr 1.1
Currency swaps
Derivatives
Cash payment for termination of derivatives	$ 92
Loss associated with derivative sale	$ (11)

Income Taxes (Provision) (Details) - USD ($) $ in Millions	3 Months Ended
Income Taxes (Provision) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Income Taxes
Annual effective tax rate excluding discrete items (as a percent)	(10.60%)	(42.80%)
Various discrete tax items	$ 25	$ 1
Effective tax rate	4.50%	(42.20%)

Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator for loss per share, basic
Net loss available to shareholders	$ (171)	$ (210)
Denominator for loss per share, basic
Weighted-average shares outstanding	610.0	438.0
Effect of share-based awards and other equity instruments	1.0
Weighted-average shares for per share calculation, basic	611.0	438.0
Loss per share, basic (in dollars per share)	$ (0.28)	$ (0.48)
Numerator for loss per share, diluted
Net loss available to shareholders	$ (171)	$ (210)
Denominator for loss per share, diluted
Weighted-average shares outstanding	610.0	438.0
Effect of share-based awards and other equity instruments	1.0
Weighted-average shares for per share calculation, diluted	611.0	438.0
Loss per share, diluted (in dollars per share)	$ (0.28)	$ (0.48)
Share-based awards
Anti-dilutive securities
Securities excluded from earnings per share calculation (in shares)	12.1	11.0
0.50% Exchangeable Bonds due January 2023
Anti-dilutive securities
Securities excluded from earnings per share calculation (in shares)	84.0	56.3

Contingencies (Details) $ in Millions		1 Months Ended			3 Months Ended
Contingencies (Details) $ in Millions	Feb. 15, 2017 USD ($) item	Nov. 30, 2018 USD ($)	May 31, 2015 item	Oct. 31, 2007 subsidiary	Mar. 31, 2019 USD ($) plaintiff lawsuit subsidiary	Dec. 31, 2018 USD ($)	Nov. 28, 2017 USD ($)
7.00% Notes due June 2028
Contingencies
Debt instrument interest rate stated percentage					7.00%
Macondo well incident
Contingencies
Amount of fines, recoveries and civil penalties					$ 158	$ 158
PSC Settlement Agreement
Contingencies
Number of claimants \| item			30
Settlement Agreement	$ 212
Number of classes of plaintiffs \| item	2
Payment of contingency accrual		$ 58
Cash payment into an escrow account pending approval by MDL Court					$ 156	$ 156
Asbestos litigation
Contingencies
Number of subsidiaries \| subsidiary					1
Number of claims \| lawsuit					184
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%
Global Marine Litigation \| 7.00% Notes due June 2028
Contingencies
Debt instrument face value							$ 300
Debt instrument interest rate stated percentage							7.00%
Nigerian customer arbitration
Contingencies
Uncertain collectability of drilling service receivable					$ 80
Hazardous waste disposal sites
Contingencies
Number of subsidiaries \| subsidiary					1
Percentage of liability for remediation and related costs					8.00%
Minimum number of subsidiaries likely to be named potentially responsible party by US Environmental Protection Agency for superfund site (in counts) \| subsidiary					1

Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
	Mar. 28, 2018	Mar. 31, 2019	Mar. 31, 2018	Jan. 30, 2018
Variable Interest Entity
Recognition of noncontrolling interest in business combination			$ 33
Payment to acquire interest		$ 60	15
Acquisition of noncontrolling interest in compulsory acquisition			30
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			$ 30
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	Mar. 31, 2019	Dec. 31, 2018
Financial instruments
Restricted cash and cash equivalents	$ 584	$ 429
Long-term debt, including current maturities	9,414	9,978
Carrying amount
Financial instruments
Cash and cash equivalents	1,886	2,160
Restricted cash and cash equivalents	584	429
Restricted investments		123
Long-term debt, including current maturities	9,414	9,978
Derivative instruments, liabilities	3	6
Fair value
Financial instruments
Cash and cash equivalents	1,886	2,160
Restricted cash and cash equivalents	584	429
Restricted investments		123
Long-term debt, including current maturities	9,423	9,212
Derivative instruments, liabilities	3	6
Other current assets
Financial instruments
Restricted cash and cash equivalents	583	428
Other assets
Financial instruments
Restricted cash and cash equivalents		$ 1
Other assets \| Maximum
Financial instruments
Restricted cash and cash equivalents	$ 1

Income Taxes (Tax Returns) (Details) - 3 months ended Mar. 31, 2019 R$ in Millions, $ in Millions	BRL (R$)	USD ($)
Brazil
Income Tax Examination
Net adjustments of additional taxes, including interest and penalties	R$ 657	$ 168