Marathon Oil (MRO) 10-K 20 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Feb. 14, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Title of 12(b) Security	Common Stock, par value $1.00
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019
Amendment Flag	false
Entity Registrant Name	Marathon Oil Corporation
Entity Central Index Key	0000101778
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well Known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		795,849,999
Entity Public Float			$ 11,398
Entity Address, Address Line One	5555 San Felipe Street,
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77056-2723
City Area Code	(713)
Local Phone Number	629-6600
Entity Shell Company	false
Entity File Number	1-1513
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Tax Identification Number	25-0996816
Trading Symbol	MRO
Security Exchange Name	NYSE

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues and other income:
Revenues from contracts with customers	$ 5,063	$ 5,902	$ 4,247
Net loss on commodity derivatives	(72)	(14)	(36)
Income from equity method investments	87	225	256
Net gain on disposal of assets	50	319	58
Other income	62	150	78
Total revenues and other income	5,190	6,582	4,765
Costs and expenses:
Production	712	842	716
Shipping, handling and other operating	605	575	431
Exploration	149	289	409
Depreciation, depletion and amortization	2,397	2,441	2,372
Impairments	24	75	229
Taxes other than income	311	299	183
General and administrative	356	394	371
Total costs and expenses	4,554	4,915	4,879
Income (loss) from operations	636	1,667	(114)
Net interest and other	(244)	(226)	(270)
Other net periodic benefit costs	3	(14)	(19)
Loss on early extinguishment of debt	(3)	0	(51)
Income (loss) from continuing operations before income taxes	392	1,427	(454)
Provision (benefit) for income taxes	(88)	331	376
Income (loss) from continuing operations	480	1,096	(830)
Loss from discontinued operations	0	0	(4,893)
Net income (loss)	$ 480	$ 1,096	$ (5,723)
Basic:
Income from continuing operations (in dollars per basic share)	$ 0.59	$ 1.30	$ (0.97)
Discontinued operations (in dollars per basic share)	0	0	(5.76)
Net income (in dollars per basic share)	0.59	1.30	(6.73)
Diluted:
Income from continuing operations (in dollars per diluted share)	0.59	1.29	(0.97)
Discontinued operations (in dollars per diluted share)	0	0	(5.76)
Net income (in dollars per diluted share)	$ 0.59	$ 1.29	$ (6.73)
Weighted average shares:
Basic	810	846	850
Diluted	810	847	850
Marketing revenues
Revenues and other income:
Revenues from contracts with customers	$ 0	$ 0	$ 162
Costs and expenses:
Marketing, including purchases from related parties	$ 0	$ 0	$ 168

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 480	$ 1,096	$ (5,723)
Postretirement and postemployment plans
Change in actuarial loss and other	54	117	21
Income tax benefit (provision) on postretirement and postemployment plans	(38)	4	7
Postretirement and postemployment plans, net of tax	16	121	28
Derivative hedges
Net unrecognized gain (loss)	2	0	(13)
Reclassification of gains on terminated derivative hedges	0	0	(47)
Income tax provision on derivative hedges	0	0	21
Derivative hedges, net of tax	2	0	(39)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	30	0	0
Foreign currency translation adjustment related to sale of U.K. business	0	0	34
Income taxes related to sale of U.K. business (b)	(7)	0	(4)
Foreign currency translation, net of tax	23	0	30
Other, net of tax	1	4	2
Other comprehensive income (loss)	42	125	21
Comprehensive income (loss)	$ 522	$ 1,221	$ (5,702)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 858	$ 1,462
Receivables, less reserve of $11 and $11	1,122	1,079
Notes receivable	0	0
Inventories	72	96
Other current assets	83	257
Current assets held for sale	0	27
Total current assets	2,135	2,921
Equity method investments	663	745
Property, plant and equipment, less accumulated depreciation, depletion and amortization of $18,003 and $21,830	17,000	16,804
Goodwill	95	97
Other noncurrent assets	352	723
Noncurrent assets held for sale	0	31
Total assets	20,245	21,321
Current liabilities:
Accounts payable	1,307	1,320
Payroll and benefits payable	112	154
Accrued taxes	118	181
Other current liabilities	208	170
Current liabilities held for sale	0	7
Total current liabilities	1,745	1,832
Long-term debt	5,501	5,499
Deferred tax liabilities	186	199
Defined benefit postretirement plan obligations	183	195
Asset retirement obligations	243	1,081
Deferred credits and other liabilities	234	279
Noncurrent liabilities held for sale	0	108
Total liabilities	8,092	9,193
Commitments and contingencies
Stockholders’ Equity
Preferred stock – no shares issued or outstanding (no par value, 26 million shares authorized)	0	0
Issued – 937 million shares (par value $1 per share, 1.925 billion shares authorized at December 31, 2019 and December 31, 2018)	937	937
Held in treasury, at cost – 141 million shares and 118 million shares	(4,089)	(3,816)
Additional paid-in capital	7,207	7,238
Retained earnings	7,993	7,706
Accumulated other comprehensive loss	105	63
Total stockholders equity	12,153	12,128
Total liabilities and stockholders equity	$ 20,245	$ 21,321

Consolidated Balance Sheets Par

Consolidated Balance Sheets Parentheticals - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Consolidated Balance Sheets Parenthetical [Abstract]
Receivables, less reserve of $11 and $11	$ 11	$ 11
Less accumulated depreciation, depletion and amortization	$ (18,003)	$ (21,830)
Preferred stock, no par value	$ 0	$ 0
Preferred stock, shares authorized	26,000,000	26,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 1	$ 1
Common stock, shares authorized	1,925,000,000	1,925,000,000
Common stock, shares issued	937,000,000	937,000,000
Held in treasury, shares	141,000,000	118,000,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Cash Flows [Abstract]
Net income (loss)	$ 480	$ 1,096	$ (5,723)
Adjustments to reconcile net income to net cash provided by operating activities:
Discontinued operations	0	0	(4,893)
Depreciation, depletion and amortization	2,397	2,441	2,372
Impairments	24	75	229
Exploratory dry well costs and unproved property impairments	114	255	323
Net (gain) loss on disposal of assets	(50)	(319)	(58)
Loss on early extinguishment of debt	3	0	51
Deferred income taxes	(34)	52	(61)
Net loss on derivative instruments	72	14	36
Net settlements of derivative instruments	52	(281)	45
Pension and other post retirement benefits, net	(52)	(65)	(46)
Share-based Payment Arrangement, Noncash Expense	60	53	49
Equity method investments, net	18	45	20
Changes in:
Current receivables	52	(133)	(334)
Inventories	3	(1)	10
Current accounts payable and accrued liabilities	(187)	179	297
Other current assets and liabilities	(4)	(22)	1
All other operating, net	(199)	(155)	(116)
Net cash provided by continuing operations	2,749	3,234	1,988
Investing activities:
Additions to property, plant and equipment	(2,550)	(2,753)	(1,974)
Additions to other assets	36	(26)	(25)
Acquisitions, net of cash acquired	(293)	(25)	(1,891)
Disposal of assets, net of cash transferred to the buyer	(76)	1,264	1,787
Equity method investments - return of capital	64	57	64
All other investing, net	1	13	(5)
Net cash used in investing activities	(2,818)	(1,470)	(2,044)
Financing activities:
Borrowings	600	0	988
Debt repayments	(600)	0	(2,764)
Debt extinguishment costs	(2)	0	(46)
Purchases of common stock	(362)	(713)	(11)
Dividends paid	(162)	(169)	(170)
All other financing, net	(9)	23	0
Net cash provided by (used in) financing activities	(535)	(859)	(2,003)
Net increase in cash and cash equivalents of discontinued operations (Note 5)	0	0	130
Effect of exchange rate on cash and cash equivalents	0	(2)	4
Net increase (decrease) in cash and cash equivalents	(604)	903	(1,925)
Cash and cash equivalents	858	1,462	563
Cash and cash equivalents included in current assets held for sale	$ 0	$ (4)	$ 0

Consolidated Statements of Stoc

Consolidated Statements of Stockholders Equity - USD ($) shares in Millions, $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares				90
Beginning Balance at Dec. 31, 2016	$ 17,541	$ 0	$ 937	$ (3,431)	$ 7,446	$ 12,672	$ (83)
Shares Beginning Balance at Dec. 31, 2016			937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued - stock based compensation	67			117	(50)
Shares repurchased	(11)			$ (11)
Stock-based compensation	(17)				(17)
Net loss	5,723					5,723
Other Comprehensive Income (Loss), Net of Tax, Incl Disc Ops	21						21
Dividends paid	(170)					(170)
Shares issued - stock based compensation				(3)
Ending Balance at Dec. 31, 2017	11,708	0	$ 937	$ (3,325)	7,379	6,779	(62)
Shares Ending Balance at Dec. 31, 2017			937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares				87
Shares issued - stock based compensation	112			$ 221	(109)
Shares repurchased	(712)			$ (712)
Stock-based compensation	(32)				(32)
Net loss	(1,096)					(1,096)
Other Comprehensive Income (Loss), Net of Tax, Incl Disc Ops	125						125
Dividends paid	(169)					(169)
Shares issued - stock based compensation				(6)
Shares repurchased				37
Ending Balance at Dec. 31, 2018	$ 12,128	0	$ 937	$ (3,816)	7,238	7,706	63
Shares Ending Balance at Dec. 31, 2018			937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares	118			118
Cumulative Effect on Retained Earnings, Net of Tax	$ (31)					(31)
Shares issued - stock based compensation	63			$ 89	(26)
Shares repurchased	(362)			$ (362)
Stock-based compensation	(5)				(5)
Net loss	(480)
Other Comprehensive Income (Loss), Net of Tax, Incl Disc Ops	42						42
Dividends paid	$ (162)					(162)
Shares issued - stock based compensation				(2)
Shares repurchased	0			25
Ending Balance at Dec. 31, 2019	$ 12,153	$ 0	$ 937	$ (4,089)	$ 7,207	$ 7,993	$ 105
Shares Ending Balance at Dec. 31, 2019			937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares	141			141

Accounting Standards

Accounting Standards	12 Months Ended
	Dec. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Standards	Accounting Standards Not Yet Adopted Financial instruments – credit losses In June 2016, the FASB issued a new accounting standards update that changes the impairment model for trade receivables, net investments in leases, debt securities, loans and certain other instruments. The standard requires the use of a forward-looking “expected loss” model as opposed to the current “incurred loss” model. This standard is effective for us in the first quarter of 2020 and will be adopted on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the adoption period. The adoption of this standard did not result in a material impact on our consolidated results of operations, financial position and cash flows.
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Accounting Standards Not Yet Adopted Financial instruments – credit losses In June 2016, the FASB issued a new accounting standards update that changes the impairment model for trade receivables, net investments in leases, debt securities, loans and certain other instruments. The standard requires the use of a forward-looking “expected loss” model as opposed to the current “incurred loss” model. This standard is effective for us in the first quarter of 2020 and will be adopted on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the adoption period. The adoption of this standard did not result in a material impact on our consolidated results of operations, financial position and cash flows. Recently Adopted Lease accounting standard In February 2016, the FASB issued a new leasing accounting standard, which modified the definition of a lease and established comprehensive accounting and financial reporting requirements for leasing arrangements. It requires lessees to recognize a lease liability and a right-of-use (“ROU”) asset for all leases, including operating leases, with a term of greater than 12 months on the balance sheet. On January 1, 2019, we adopted the new lease accounting standard using the modified retrospective method and applied to all leases that existed as of that date. It does not apply to leases to explore for or use minerals, oil, natural gas and similar non-regenerative resources, including the intangible right to explore for those natural resources and rights to use the land in which those natural resources are contained. As a result of the adoption, we recorded a cumulative-effect adjustment to stockholders’ equity of $31 million . We continue presenting all prior comparative periods without any restatements. See Note 13 for further information. Hedge accounting standard In August 2017, the FASB issued a new accounting standards update that amends the hedge accounting model to enable entities to hedge certain financial and nonfinancial risk attributes previously not allowed. The amendment also reduces the overall complexity of documenting, assessing and measuring hedge effectiveness. This standard was effective for us in the first quarter of 2019. Adoption of this standard did not have a significant impact on our consolidated results of operations, financial position or cash flows.

Summary of Principal Accounting

Summary of Principal Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Principal Accounting Policies	Summary of Principal Accounting Policies We are an independent exploration and production company engaged in exploration, production and marketing of crude oil and condensate, NGLs and natural gas; as well as production and marketing of products manufactured from natural gas, such as LNG and methanol, in E.G. Basis of presentation and principles applied in consolidation – These consolidated financial statements, including notes have been prepared in accordance with U.S. GAAP. These consolidated financial statements include the accounts of our controlled subsidiaries. Investments in unincorporated joint ventures and undivided interests in certain operating assets are consolidated on a pro rata basis. Equity method investments – Investments in entities over which we have significant influence, but not control, are accounted for using the equity method of accounting. This includes entities in which we hold majority ownership but the minority stockholders have substantive participating rights in the investee. Income from equity method investments represents our proportionate share of net income generated by the equity method investees and is reflected in revenues and other income in our consolidated statements of income. Equity method investments are included as noncurrent assets on the consolidated balance sheet. Equity method investments are assessed for impairment whenever changes in the facts and circumstances indicate a loss in value may have occurred. When a loss is deemed to have occurred and is other than temporary, the carrying value of the equity method investment is written down to fair value, and the amount of the write-down is included in income. Discontinued operations – As a result of the sale of our Canadian business in 2017, we reflected this business as discontinued operations in all historical periods presented. Disclosures in this report related to results of operations and cash flows are presented on the basis of continuing operations unless otherwise stated. See Note 5 for discussion of the divestiture in further detail. Use of estimates – The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods. Estimated quantities of crude oil and condensate, NGLs and natural gas reserves is a significant estimate that requires judgment. All of the reserve data included in this Form 10-K are estimates. Reservoir engineering is a subjective process of estimating underground accumulations of crude oil and condensate, NGLs and natural gas. There are numerous uncertainties inherent in estimating quantities of proved crude oil and condensate, NGLs and natural gas reserves. The accuracy of any reserves estimate is a function of the quality of available data and of engineering and geological interpretation and judgment. As a result, reserve estimates may be different from the quantities of crude oil and condensate, NGLs and natural gas that are ultimately recovered. See unaudited Supplementary Data - Supplementary Information on Oil and Gas Producing Activities for further detail. Other items subject to estimates and assumptions include the carrying amounts of property, plant and equipment, asset retirement obligations, goodwill, valuation of derivative instruments and valuation allowances for deferred income tax assets, among others. Although we believe these estimates are reasonable, actual results could differ from these estimates. Foreign currency transactions – The U.S. dollar is the functional currency of our foreign operating subsidiaries. Foreign currency transaction gains and losses are included in net income. Revenue recognition – Revenues associated with the sales of crude oil and condensate, NGLs and natural gas are recognized when our performance obligation is satisfied, which typically occurs at the point where control transfers to the customer based on contract terms. Revenue is measured as the amount the company expects to receive in exchange for transferring commodities to the customer. Our hydrocarbon sales are typically based on prevailing market-based prices and may include quality or location differential adjustments. Payment is generally due within 30 days of delivery. We typically incur shipping and handling costs prior to control transferring to the customer and account for these activities as fulfillment costs. These costs are reflected in shipping, handling and other operating expense line in our consolidated statement of income. Our U.S. production of crude oil and condensate, NGLs and natural gas is generally sold immediately and transported to market. In our international segment, liquid hydrocarbon production may be stored as inventory and sold at a later time. Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid debt instruments with original maturities of three months or less. Accounts receivable – The majority of our receivables are from purchasers of commodities or joint interest owners in properties we operate, both of which are recorded at estimated or invoiced amounts and do not bear interest. We often have the ability to withhold future revenue disbursements to recover any non-payment of joint interest billings. We conduct credit reviews of commodity purchasers prior to making commodity sales to new customers or increasing credit for existing customers. Based on these reviews, we may require a standby letter of credit or a financial guarantee. We routinely assess the collectability of receivable balances to determine if the amount of the reserve in allowance for doubtful accounts is sufficient. Inventories – Crude oil and natural gas are recorded at weighted average cost and carried at the lower of cost or net realizable value. Supplies and other items consist principally of tubular goods and equipment which are valued at weighted average cost and reviewed periodically for obsol escence or impairment when market conditions indicate . We may enter into a contract to sell a particular quantity and quality of crude oil at a specified location and date to a particular counterparty, and simultaneously agree to buy a particular quantity and quality of the same commodity at a specified location on the same or another specified date from the same counterparty. We account for such matching buy/sell arrangements as exchanges of inventory. Derivative instruments – We may use derivatives to manage a portion of our exposure to commodity price risk, commodity locational risk and interest rate risk. All derivative instruments are recorded at fair value. Commodity derivatives and interest rate swaps are reflected on our consolidated balance sheet on a net basis by counterparty, as they are governed by master netting agreements. Cash flows related to derivatives used to manage commodity price risk, and interest rate risk are classified in operating activities. Our derivative instruments contain no significant contingent credit features. Fair value hedges – We may use interest rate swaps to manage our exposure to interest rate risk associated with fixed interest rate debt in our portfolio. Changes in the fair values of both the hedged item and the related derivative are recognized immediately in net income with an offsetting effect included in the basis of the hedged item. The net effect is to report in net income the extent to which the hedge is not effective in achieving offsetting changes in fair value. Cash flow hedges – We may use interest rate derivative instruments to manage the risk of interest rate changes during the period prior to anticipated borrowings as well as to stabilize future lease payments on our future Houston office, and designate them as cash flow hedges. Derivative instruments designated as cash flow hedges are linked to specific assets and liabilities or to specific firm commitments or forecasted transactions. The changes in the fair value of a qualifying cash flow hedge are recorded in other comprehensive income until the hedged transaction affects earnings and are then reclassified into net income. Beginning in 2019, ineffective portions of a cash flow hedge are no longer measured or disclosed separately. However, if it is determined that the likelihood of the original forecasted transaction occurring is no longer probable or the cash flow hedge is no longer expected to be highly effective, subsequent changes in fair value of the derivatives instrument are recorded in net income. Derivatives not designated as hedges – Derivatives that are not designated as hedges may include commodity derivatives used primarily to manage price and locational risks on the forecasted sale of crude oil, NGLs, and natural gas that we produce. Changes in the fair value of derivatives not designated as hedges are recognized immediately in net income. Concentrations of credit risk – All of our financial instruments, including derivatives, involve elements of credit and market risk. The most significant portion of our credit risk relates to nonperformance by counterparties. The counterparties to our financial instruments consist primarily of major financial institutions and companies within the energy industry. To manage counterparty risk associated with financial instruments, we select and monitor counterparties based on our assessment of their financial strength and on credit ratings, if available. Additionally, we limit the level of exposure with any single counterparty. Fair value transfer – We recognize transfers between levels of the fair value hierarchy as of the end of the reporting period. Property, plant and equipment – We use the successful efforts method of accounting for oil and gas producing activities. Property acquisition costs – Costs to acquire mineral interests in oil and natural gas properties, to drill exploratory wells in progress and those that find proved reserves, and to drill development wells are capitalized. Costs to drill exploratory wells that do not find proved reserves, geological and geophysical costs and costs of carrying and retaining unproved properties are expensed. Costs incurred for exploratory wells that find reserves but cannot yet be classified as proved are capitalized if (1) the well has found a sufficient quantity of reserves to justify its completion as a producing well and (2) we are making sufficient progress assessing the reserves and the economic and operating viability of the project. The status of suspended exploratory well costs is monitored continuously and reviewed at least quarterly. Depreciation, depletion and amortization – Capitalized costs to acquire oil and natural gas properties are depreciated and depleted on a units-of-production basis based on estimated proved reserves. Capitalized costs of exploratory wells and development costs are depreciated and depleted on a units-of-production basis based on estimated proved developed reserves. Support equipment and other property, plant and equipment related to oil and gas producing activities, as well as property, plant and equipment unrelated to oil and gas producing activities, are recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets as summarized below. Type of Asset Range of Useful Lives Office furniture, equipment and computer hardware 4 to 15 years Pipelines 5 to 40 years Plants, facilities and infrastructure 3 to 40 years Impairments – We evaluate our oil and gas producing properties, including capitalized costs of exploratory wells and development costs, for impairment of value whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the expected undiscounted future cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset. Oil and gas producing properties are reviewed for impairment on a field-by-field basis or, in certain instances, by logical grouping of assets if there is significant shared infrastructure or contractual terms that cause economic interdependency amongst separate, discrete fields. Oil and gas producing properties deemed to be impaired are written down to their fair value, as determined by discounted future net cash flows or, if available, comparable market value. We evaluate our unproved property investment and record impairment based on time or geologic factors. Information such as drilling results, reservoir performance, seismic interpretation or future plans to develop acreage is also considered. When unproved property investments are deemed to be impaired, this amount is reported in exploration expenses in our consolidated statements of income. Dispositions – When property, plant and equipment depreciated on an individual basis is sold or otherwise disposed of, any gains or losses are reflected in net gain (loss) on disposal of assets in our consolidated statements of income. Gains on the disposal of property, plant and equipment are recognized when earned, which is generally at the time of closing. If a loss on disposal is expected, such losses are recognized either when the assets are classified as held for sale, or are measured using a probability weighted income approach based on both the anticipated sales price and a held-for-use model depending on timing of the sale. Proceeds from the disposal of property, plant and equipment depreciated on a group basis are credited to accumulated depreciation, depletion and amortization with no immediate effect on net income until net book value is reduced to zero. Goodwill – Goodwill represents the excess of the purchase price over the estimated fair value of the net assets acquired in the acquisition of a business. Such goodwill is not amortized, but rather is tested for impairment annually and when events or changes in circumstances indicate that the fair value of a reporting unit with goodwill has been reduced below carrying value. The impairment test requires allocating goodwill and other assets and liabilities to a reporting unit. The fair value of a reporting unit is determined and compared to the book value of the reporting unit. If the fair value of the reporting unit is less than the book value, including goodwill, then the recorded goodwill is impaired to its implied fair value with a charge to impairments. Environmental costs – We provide for remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of a feasibility study or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed or reliably determinable. Environmental expenditures are capitalized only if the costs mitigate or prevent future contamination or if the costs improve the environmental safety or efficiency of the existing assets. Asset retirement obligations – The fair value of asset retirement obligations is recognized in the period in which the obligations are incurred if a reasonable estimate of fair value can be made. Our asset retirement obligations primarily relate to the abandonment of oil and gas producing facilities. Asset retirement obligations for such facilities include costs to dismantle and relocate or dispose of production platforms, gathering systems, wells and related structures and restoration costs of land, including those leased. Estimates of these costs are developed for each property based on the type of production facilities and equipment, reservoir characteristics, depth of the reservoir, market demand for equipment, currently available procedures and consultations with construction and engineering professionals. Inflation rates and credit-adjusted-risk-free interest rates are used to estimate the fair value of asset retirement obligations. Depreciation of capitalized asset retirement costs and accretion of asset retirement obligations are recorded over time. Depreciation is generally determined on a units-of-production basis based on estimated proved developed reserves for oil and gas production facilities, while accretion of the liability occurs over the useful lives of the assets. Deferred income taxes – Deferred tax assets and liabilities, measured at enacted tax rates, are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their tax bases as reported in our filings with the respective taxing authorities. We routinely assess the realizability of our deferred tax assets based on several interrelated factors and reduce such assets by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized. These factors include whether we are in a cumulative loss position in recent years, our reversal of temporary differences, and our expectation to generate sufficient future taxable income. We use the liability method in determining our provision and liabilities for our income taxes, under which current and deferred tax liabilities and assets are recorded in accordance with enacted tax laws and rates. Stock-based compensation arrangements – The fair value of stock options is estimated on the date of grant using the Black-Scholes option pricing model. The model employs various assumptions, based on management’s best estimates at the time of grant, which impact the calculation of fair value and ultimately, the amount of expense that is recognized over the life of the stock option award. Of the required assumptions, the expected volatility of our stock price and the stock price in relation to the strike price have the most significant impact on the fair value calculation. We have utilized historical data and analyzed current information which reasonably support these assumptions. The fair value of our restricted stock awards, restricted stock units and Director restricted stock units is determined based on the market value of our common stock on the date of grant. Restricted Stock Awards, restricted stock units, and Director restricted stock units are removed from Treasury Stock at grant, vesting, and distribution, respectively. The fair value of our cash-settled stock-based performance units is estimated using the Monte Carlo simulation method. Since these awards are settled in cash at the end of a defined performance period, they are classified as a liability and are re-measured quarterly until settlement. The fair value of our stock-settled stock-based performance units is estimated using the Monte Carlo simulation method at grant date only. Since these awards are settled in stock, they are classified as equity.

Income per Common Share

Income per Common Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Income per Common Share	and Dividends per Common Share Basic income (loss) per share is based on the weighted average number of common shares outstanding. Diluted income (loss) per share assumes exercise of stock options in all periods, provided the effect is not antidilutive. The per share calculations below exclude $6 million , $6 million and 11 million stock options in 2019 , 2018 and 2017 that were antidilutive. Year Ended December 31, (In millions, except per share data) 2019 2018 2017 Income (loss) from continuing operations $ 480 $ 1,096 $ (830 ) Loss from discontinued operations — — (4,893 ) Net income (loss) $ 480 $ 1,096 $ (5,723 ) Weighted average common shares outstanding 810 846 850 Effect of dilutive securities — 1 — Weighted average common shares, diluted 810 847 850 Per basic share: Income (loss) from continuing operations $ 0.59 $ 1.30 $ (0.97 ) Loss from discontinued operations $ — $ — $ (5.76 ) Net income (loss) $ 0.59 $ 1.30 $ (6.73 ) Per diluted share: Income (loss) from continuing operations $ 0.59 $ 1.29 $ (0.97 ) Loss from discontinued operations $ — $ — $ (5.76 ) Net income (loss) $ 0.59 $ 1.29 $ (6.73 ) Dividends per share $ 0.20 $ 0.20 $ 0.20

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	4 . Acquisitions 2019 – United States Segment In the fourth quarter of 2019, we acquired approximately 40,000 net acres in a Texas Delaware oil play in West Texas from multiple sellers for $106 million . We accounted for these transactions as an asset acquisition, allocating the purchase price to unproved property within property, plant and equipment. During the fourth quarter of 2019, we acquired a 100% working interest in approximately 18,000 net acres in the Eagle Ford from Rocky Creek Resources, LLC and RCR Midstream, LLC for $191 million in cash, subject to post-closing adjustments. We accounted for this transaction as a business combination, with the entire purchase price allocated between proved property, unproved property, and other assets, all within property, plant and equipment. The fair values of the assets acquired were measured using the market approach, specifically the market comparable technique. The fair values were based on market-corroborated inputs, which were derived from observable market data; such inputs represent Level 2 inputs. As the acquisition date was December 31, 2019, there is not a pro forma effect of this transaction on our consolidated statement of income. 2017 – United States Segment In the fourth quarter of 2017, we closed on our acquisition of additional acreage in the Northern Delaware basin of New Mexico from a private seller for $63 million in cash and accounted for this transaction as an asset acquisition, allocating the purchase price to unproved property within property, plant and equipment. In the second quarter of 2017, we closed on two acquisitions which included approximately 91,000 net acres in the Permian basin of New Mexico. The first acquisition with BC Operating, Inc. and other entities closed for approximately $1.1 billion in cash and the second acquisition with Black Mountain Oil & Gas and other private sellers closed for approximately $700 million

Dispositions

Dispositions	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Dispositions	Dispositions United States Segment In the third quarter of 2018, we closed on the sale of non-core, non-operated conventional properties, primarily in the Gulf of Mexico, for combined net proceeds of $16 million , before closing adjustments. A pre-tax gain of $32 million was recognized in the third quarter of 2018. International Segment On July 1, 2019, we closed on the sale of our U.K. business (Marathon Oil U.K. LLC and Marathon Oil West of Shetlands Limited), for proceeds of $95 million which reflects the assumption by RockRose Energy PLC (“RockRose”) of the U.K. business’ working capital and cash equivalent balances of approximately $345 million on December 31, 2018 . During the third quarter of 2019, we recorded a $6 million liability and corresponding expense related to the estimated fair value of our exposure to surety bonds we continued to hold that guaranteed decommissioning liabilities of Marathon Oil U.K. LLC. In November 2019, RockRose posted replacement security and accordingly, we reversed the aforementioned $6 million (see Note 25 for further detail). Income before taxes relating to our U.K. business for the year ended December 31, 2019 and 2018, was $33 million and $261 million , respectively. See Note 12 and Note 19 for additional details on U.K. ARO and the defined benefit pension plan as it relates to this disposition. In the second quarter of 2019, we closed on the sale of our 15% non-operated interest in the Atrush block in Kurdistan for proceeds of $63 million , before closing adjustments. This property was classified as held for sale in the consolidated balance sheet at December 31, 2018 , with total assets of $58 million and total liabilities of $17 million . In the first quarter of 2018, we closed on the sale of our subsidiary, Marathon Oil Libya Limited, which held our 16.33% non-operated interest in the Waha concessions in Libya, to a subsidiary of Total S.A. (Elf Aquitaine SAS) for proceeds of approximately $450 million , excluding closing adjustments, and recognized a pre-tax gain of $255 million . Canadian Business – Discontinued Operations On May 31, 2017 we closed on the sale of our Canadian business, which included our 20% non-operated interest in the AOSP to Shell and Canadian Natural Resources Limited for $2.5 billion , excluding closing adjustments. Under the terms of the agreement, $1.8 billion was paid to us upon closing. At closing we received two notes receivable for a combined $750 million for the remaining proceeds, which was received in the first quarter of 2018. In the first quarter of 2017, we recorded a non-cash impairment charge of $6.6 billion (after-tax of $4.96 billion ) primarily related to the property, plant and equipment of our Canadian business. This impairment was recorded for excess net book value over anticipated sales proceeds less costs to sell. Fair values of assets held for sale were determined based upon the anticipated sales proceeds less costs to sell, which resulted in a level 2 classification. As the effective date of the transaction was January 1, 2017, we recorded a loss on sale of $43 million during the second quarter of 2017 due to results of operations from our Canadian business that were transferred to the buyer upon closing. Our Canadian business is reflected as discontinued operations in the consolidated statements of income and the consolidated statements of cash flows for all periods presented. The following table contains select amounts reported in our historical consolidated statements of income and consolidated statements of cash flows as discontinued operations: Year Ended December 31, (In millions) 2017 Total revenue and other income $ 431 Net loss on disposal of assets (43 ) Total revenues and other income 388 Costs and expenses: Production 254 Depreciation, depletion and amortization 40 Impairments 6,636 Other 25 Total costs and expenses 6,955 Pretax loss from discontinued operations (6,567 ) Benefit for income taxes (1,674 ) Loss from discontinued operations $ (4,893 ) Year Ended December 31, (In millions) 2017 Cash flow from discontinued operations: Operating activities $ 141 Investing activities (13 ) Changes in cash included in current assets held for sale 2 Net increase in cash and cash equivalents of discontinued operations $ 130

Revenues

Revenues	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenues	evenues The majority of our revenues are derived from the sale of crude oil and condensate, NGLs and natural gas under spot and term agreements with our customers in the United States and various international locations. The following tables present our revenues from contracts with customers disaggregated by product type and geographic areas. United States Year Ended December 31, 2019 (In millions) Eagle Ford Bakken Oklahoma Northern Delaware Other U.S. Total Crude oil and condensate $ 1,358 $ 1,686 $ 425 $ 316 $ 102 $ 3,887 Natural gas liquids 114 46 116 26 5 307 Natural gas 121 39 156 16 17 349 Other 7 — — — 52 59 Revenues from contracts with customers $ 1,600 $ 1,771 $ 697 $ 358 $ 176 $ 4,602 Year Ended December 31, 2018 (In millions) Eagle Ford Bakken Oklahoma Northern Delaware Other U.S. Total Crude oil and condensate $ 1,554 $ 1,568 $ 426 $ 235 $ 164 $ 3,947 Natural gas liquids 205 62 181 38 9 495 Natural gas 145 38 184 20 26 413 Other 8 — — — 23 31 Revenues from contracts with customers $ 1,912 $ 1,668 $ 791 $ 293 $ 222 $ 4,886 International Year Ended December 31, 2019 (In millions) E.G. U.K. Other International Total Crude oil and condensate $ 271 $ 107 $ 20 $ 398 Natural gas liquids 4 1 — 5 Natural gas 32 12 — 44 Other — 14 — 14 Revenues from contracts with customers $ 307 $ 134 $ 20 $ 461 Year Ended December 31, 2018 (In millions) E.G. U.K. Libya Other International Total Crude oil and condensate $ 342 $ 282 $ 187 $ 77 $ 888 Natural gas liquids 4 5 — — 9 Natural gas 37 40 9 — 86 Other 1 32 — — 33 Revenues from contracts with customers $ 384 $ 359 $ 196 $ 77 $ 1,016 In 2019 , sales to Marathon Petroleum Corporation, Flint Hills Resources, Valero Marketing and Supply, and Shell Trading and each of their respective affiliates, accounted for approximately 13% , 13% , 11% , and 10% , respectively, of our total revenues . In 2018 , sales to Valero Marketing and Supply and Flint Hills Resources and their respective affiliates, each accounted for approximately 11% of our total revenues. In 2017 , sales to Vitol and their respective affiliates accounted for approximately 10% of our total revenues. The pricing in our hydrocarbon sales agreements are variable, determined using various published benchmarks which are adjusted for negotiated quality and location differentials. As a result, revenue collected under our agreements with customers is highly dependent on the market conditions and may fluctuate considerably as the hydrocarbon market prices rise or fall. Typically, our customers pay us monthly, within a short period of time after we deliver the hydrocarbon products. As such, we do not have any financing element associated with our contracts. We do not have any issues related to returns or refunds, as product specifications are standardized for the industry and are typically measured when transferred to a common carrier or midstream entity, and other contractual mechanisms (e.g., price adjustments) are used when products do not meet those specifications. In limited cases, we may also collect advance payments from customers as stipulated in our agreements; payments in excess of recognized revenue are recorded as contract liabilities on our consolidated balance sheet. Under our hydrocarbon sales agreements, the entire consideration amount is variable either due to pricing and/or volumes. We recognize revenue in the amount of variable consideration allocated to distinct units of hydrocarbons transferred to a customer. Such allocation reflects the amount of total consideration we expect to collect for completed deliveries of hydrocarbons and the terms of variable payment relate specifically to our efforts to satisfy the performance obligations under these contracts. Our performance obligations under our hydrocarbon sales agreements are to deliver either the entire production from the dedicated wells or specified contractual volumes of hydrocarbons. We often serve as the operator for jointly owned oil and gas properties. As part of this role, we perform activities to explore, develop and produce oil and gas properties in accordance with the joint operating arrangements. Other working interest owners reimburse us for costs incurred based on our agreements. We determined that these activities are not performed as part of customer relationships and such reimbursements will continue to not be recorded as revenues within the scope of the revenue accounting standard. In addition, we commonly market the share of production belonging to other working interest owners as the operator of jointly owned oil and gas properties. We concluded that those marketing activities are carried out as part of the collaborative arrangement. Therefore, we act as a principal only in regards to the sale of our share of production and recognize revenue for the volumes associated with our net production. Crude oil and condensate For the crude sales agreements, we satisfy our performance obligations and recognize revenue once customers take control of the crude at the designated delivery points, which include pipelines, trucks or vessels. Natural gas and NGLs When selling natural gas and NGLs, we engage midstream entities to process our production stream by separating natural gas from the NGLs. Frequently, these midstream entities also purchase our natural gas and NGLs under the same agreements. In these situations, we determined the performance obligation is complete and satisfied at the tailgate of the processing plant when the natural gas and NGLs become identifiable and measurable products. We determined the plant tailgate is the point in time where control is transferred to midstream entities and they are entitled to significant risks and rewards of ownership of the natural gas and NGLs. The amounts due to midstream entities for gathering and processing services are recognized as shipping and handling cost, since we make those payments in exchange for distinct services. Under some of our natural gas processing agreements, we have an option to take the processed natural gas and NGLs in-kind and sell to customers other than the processing company. In those circumstances, our performance obligations are complete after delivering the processed hydrocarbons to the customer at the designated delivery points, which may be the tailgate of the processing plant or an alternative delivery point requested by the customer. We have “percentage-of-proceeds” arrangements with some midstream entities where they retain a percentage of the proceeds collected for selling our processed natural gas and NGLs as compensation for their processing and marketing services. We recognize revenue for the gross sales volumes and recognize the proceeds retained by midstream companies as shipping and handling cost. Contract receivables and liabilities The following table provides information about receivables and contract assets (liabilities) from contracts with customers. December 31, (In millions) 2019 2018 Receivables from contracts with customers, included in receivables, less reserves $ 837 $ 714 Contract asset (liability) $ — $ (1 ) The contract liability balance on January 1, 2019 relates to the advance consideration received from customers for crude oil sales and processing services in the U.K. Subsequent to the sale of our U.K. business, we no longer hold this contract liability. Changes in the contract asset (liability) balance during the period are as follows. (In millions) Year Ended December 31, 2019 Contract asset (liability) balance as of January 1, 2019 $ (1 ) Revenue recognized as performance obligations are satisfied 74 Amounts invoiced to customers (52 ) Contract asset (liability) transferred to buyer (a) (21 ) Contract asset (liability) balance as of December 31, 2019 $ — (a) Refer to Note 5 for further information on the sale of our U.K. business.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information We have two reportable operating segments. Both of these segments are organized and managed based upon geographic location and the nature of the products and services offered. • United States (“U.S.”) – explores for, produces and markets crude oil and condensate, NGLs and natural gas in the United States • International (“Int’l”) – explores for, produces and markets crude oil and condensate, NGLs and natural gas outside of the United States as well as produces and markets products manufactured from natural gas, such as LNG and methanol, in E.G. Segment income represents income which excludes certain items not allocated to our operating segments, net of income taxes. A portion of our corporate and operations general and administrative support costs are not allocated to the operating segments. These unallocated costs primarily consist of employment costs (including pension effects), professional services, facilities and other costs associated with corporate and operations support activities. Additionally, items which affect comparability such as: gains or losses on dispositions, certain property impairments, certain exploration expenses relating to a strategic decision to exit conventional exploration, unrealized gains or losses on commodity derivative instruments, pension settlement losses or other items (as determined by the CODM) are not allocated to operating segments. As discussed in Note 5 , the sale of our Canadian business in 2017 is reflected as discontinued operations and is excluded from segment information in all periods presented. Year Ended December 31, 2019 (In millions) U.S. Int’l Not Allocated to Segments Total Revenues from contracts with customers $ 4,602 $ 461 $ — $ 5,063 Net gain (loss) on commodity derivatives 52 — (124 ) (b) (72 ) Income from equity method investments — 87 — 87 Net gain on disposal of assets — — 50 (c) 50 Other income 13 9 40 62 Less costs and expenses: Production 588 126 (2 ) 712 Shipping, handling and other operating 561 26 18 605 Exploration 149 — — 149 Depreciation, depletion and amortization 2,250 121 26 2,397 Impairments — — 24 (d) 24 Taxes other than income 311 — — 311 General and administrative 127 25 204 356 Net interest and other — — 244 244 Other net periodic benefit costs — (3 ) — (e) (3 ) Loss on early extinguishment of debt — — 3 3 Income tax provision (benefit) 6 29 (123 ) (88 ) Segment income (loss) $ 675 $ 233 $ (428 ) $ 480 Total assets $ 17,781 $ 1,530 $ 934 $ 20,245 Capital expenditures (a) $ 2,550 $ 16 $ 25 $ 2,591 (a) Includes accruals and excludes acquisitions. (b) Unrealized loss on commodity derivative instruments (see Note 15 ). (c) Primarily related to the sale of our working interest in the Droshky field (Gulf of Mexico) and the sale of our U.K. business (see Note 5 ). (d) Primarily a result of anticipated sales of non-core proved properties in our International and United States segments (see Note 11 ). (e) Includes pension settlement loss of $12 million (see Note 19 ). Year Ended December 31, 2018 (In millions) U.S. Int’l Not Allocated to Segments Total Revenues from contracts with customers $ 4,886 $ 1,016 $ — $ 5,902 Net gain (loss) on commodity derivatives (281 ) — 267 (b) (14 ) Income from equity method investments — 225 — 225 Net gain on disposal of assets — — 319 (c) 319 Other income 16 12 122 (d) 150 Less costs and expenses: Production 625 215 2 842 Shipping, handling and other operating 499 70 6 575 Exploration 246 3 40 (e) 289 Depreciation, depletion and amortization 2,217 197 27 2,441 Impairments — — 75 (f) 75 Taxes other than income 301 — (2 ) 299 General and administrative 146 32 216 394 Net interest and other — — 226 226 Other net periodic benefit costs — (9 ) 23 (g) 14 Income tax provision (benefit) (21 ) 272 80 331 Segment income $ 608 $ 473 $ 15 $ 1,096 Total assets $ 17,321 $ 2,083 $ 1,917 $ 21,321 Capital expenditures (a) $ 2,620 $ 39 $ 26 $ 2,685 (a) Includes accruals and excludes acquisitions. (b) Unrealized gain on commodity derivative instruments (see Note 15 ). (c) Primarily related to the gain on sale of our Libya subsidiary (see Note 5 ). (d) Primarily a reduction of asset retirement obligations in our International segment (see Note 12 ). (e) Primarily related to dry well expense and unproved property impairments associated with the Rodo well in Alba Block Sub Area B, offshore E.G. (see Note 10 ). (f) Due to the anticipated sales of certain non-core proved properties in our International and United States segments (see Note 11 ). (g) Includes pension settlement loss of $21 million (see Note 19 ). Year Ended December 31, 2017 (In millions) U.S. Int’l Not Allocated to Segments Total Revenues from contracts with customers $ 3,093 $ 1,154 $ — $ 4,247 Net gain (loss) on commodity derivatives 45 — (81 ) (b) (36 ) Marketing revenues 29 133 — 162 Income from equity method investments — 256 — 256 Net gain on disposal of assets 1 — 57 (c) 58 Other income 12 6 60 78 Less costs and expenses: Production 476 239 1 716 Marketing costs 36 132 — 168 Shipping, handling and other operating 354 77 — 431 Exploration 154 5 250 (d) 409 Depreciation, depletion and amortization 2,011 328 33 2,372 Impairments 4 — 225 (e) 229 Taxes other than income 173 — 10 183 General and administrative 119 30 222 371 Net interest and other — — 270 (f) 270 Other net periodic benefit costs — (8 ) 27 (g) 19 Loss on early extinguishment of debt — — 51 (h) 51 Income tax provision 1 372 3 376 Segment income (loss) $ (148 ) $ 374 $ (1,056 ) $ (830 ) Total assets $ 16,863 $ 4,201 $ 948 $ 22,012 Capital expenditures (a) $ 2,081 $ 42 $ 27 $ 2,150 (a) Includes accruals and excludes acquisitions. (b) Unrealized loss on commodity derivative instruments (see Note 15 ). (c) Primarily related to the sale of certain conventional assets in Oklahoma and Colorado (see Note 5 ). (d) Primarily related to unproved property impairments associated with certain non-core properties within our International segment (see Note 11 ). (e) Primarily related to proved property impairments associated with certain non-core properties within our International segment (see Note 11 ). (f) Includes a gain of $46 million resulting from the termination of our forward starting interest rate swaps (see Note 15 ). (g) Includes pension settlement loss of $32 million (see Note 19 ). (h) Primarily related to the make-whole call provisions paid upon redemption of our senior unsecured notes (see Note 17 ). The following summarizes property, plant and equipment and equity method investments. December 31, (In millions) 2019 2018 United States $ 16,507 $ 16,094 Equatorial Guinea 1,156 1,333 Other international (a) — 122 Total long-lived assets $ 17,663 $ 17,549 (a) The decrease in 2019 is due to the sale of our non-operated interest in the Atrush block in Kurdistan and the sale of our U.K. business (see Note 5 ).

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income (loss) from continuing operations before income taxes were: Year Ended December 31, (In millions) 2019 2018 2017 United States $ 43 $ 642 $ (783 ) Foreign 349 785 329 Total $ 392 $ 1,427 $ (454 ) Income tax provisions (benefits) for continuing operations were: Year Ended December 31, 2019 2018 2017 (In millions) Current Deferred Total Current Deferred Total Current Deferred Total Federal $ (116 ) $ (3 ) $ (119 ) $ 6 $ — $ 6 $ (32 ) $ 41 $ 9 State and local 4 3 7 (1 ) (23 ) (24 ) (14 ) 2 (12 ) Foreign 58 (34 ) 24 274 75 349 483 (104 ) 379 Total $ (54 ) $ (34 ) $ (88 ) $ 279 $ 52 $ 331 $ 437 $ (61 ) $ 376 A reconciliation of the federal statutory income tax rate applied to income (loss) from continuing operations before income taxes to the provision (benefit) for income taxes follows: Year Ended December 31, (In millions) 2019 2018 2017 Total pre-tax income (loss) from continuing operations $ 392 $ 1,427 $ (454 ) Total income tax expense (benefit) $ (88 ) $ 331 $ 376 Effective income tax rate (benefit) on continuing operations (22 )% 23 % 83 % Income taxes at the statutory tax rate (a)(b) $ 83 $ 300 $ (159 ) Effects of foreign operations (29 ) 214 140 Adjustments to valuation allowances (28 ) (177 ) 446 State income taxes 11 (17 ) (19 ) Tax law change — — (35 ) Other federal tax effects (125 ) 11 3 Income tax expense (benefit) on continuing operations $ (88 ) $ 331 $ 376 (a) Includes income tax benefits primarily related to our U.S. federal income taxes where we have maintained a full valuation allowance since December 2016. (b) As a result of the Tax Reform Legislation (see below), the U.S. corporate income tax rate was reduced to 21% in 2018. The U.S. corporate income tax rate was 35% in 2017. The effective income tax rate is influenced by a variety of factors including the geographic and functional sources of income and the relative magnitude of these sources of income. The difference between the total provision and the sum of the amounts allocated to segments is reported in the “Not Allocated to Segments” column of the tables in Note 7 . Effects of foreign operations – The effects of foreign operations decreased our tax expense in 2019 due to tax benefits related to our U.K. operations and pre-tax income in jurisdictions with effective tax rates lower than the U.S. The effects of foreign operations increased our tax expense in 2018 and 2017 due to the mix of pre-tax income between high and low tax jurisdictions, including Libya where the tax rate was 93.5% . Excluding Libya, the effective tax rates on continuing operations would be an expense of 14% in 2018 and 5% in 2017 . As a result of the sale of our Libya subsidiary in the first quarter of 2018, we do not expect to incur further tax expense related to Libya. Change in tax law – On December 22, 2017, the U.S. enacted the Tax Cuts and Jobs Act (the “Tax Reform Legislation”). Tax Reform Legislation, which is also commonly referred to as “U.S. tax reform”, significantly changing U.S. corporate income tax laws by, among other things, reducing the U.S. corporate income tax rate to 21% starting in 2018, and repeal of the corporate alternative minimum tax (“AMT”), and a one-time deemed repatriation of accumulated foreign earnings. In the fourth quarter of 2017, we remeasured our deferred taxes at 21%, in accordance with U.S. GAAP. The impact of the remeasurement on our federal deferred tax assets and liabilities was equally offset by an adjustment to our valuation allowance with no material impact to current year earnings. In accordance with Staff Accounting Bulletin No. 118 (“SAB 118”) we finalized our tax position in the fourth quarter of 2018 with no material changes made to positions considered provisional as of December 31, 2017. Other federal tax effects – The decrease in other federal tax effects is primarily related to the settlement of the 2010-2011 U.S. Federal Tax Audit (“IRS Audit”) in the first quarter of 2019. The release of the accrued tax positions resulted in a $126 million tax benefit, primarily related to AMT credits, see Note 25 for further detail. Deferred tax assets and liabilities resulted from the following: Year Ended December 31, (In millions) 2019 2018 Deferred tax assets: Employee benefits $ 90 $ 75 Operating loss carryforwards 1,685 1,304 Capital loss carryforwards 1 2 Foreign tax credits 611 611 Other 27 4 Subtotal 2,414 1,996 Valuation allowance (699 ) (721 ) Total deferred tax assets 1,715 1,275 Deferred tax liabilities: Property, plant and equipment 1,861 1,018 Accrued revenue 40 60 Other — 3 Total deferred tax liabilities 1,901 1,081 Net deferred tax liabilities $ 186 $ — Net deferred tax assets $ — $ 194 Operating loss carryforwards – At December 31, 2019 , our operating loss carryforwards, relating to tax years beginning prior to January 1, 2018, before valuation allowance, include $655 million from the U.S. that expire in 2035 - 2037 . Our operating loss carryforwards in the U.S. for tax years beginning after December 31, 2017, before our valuation allowance, include $829 million which can be carried forward indefinitely. Foreign operating loss carryforwards include $20 million that begin to expire in 2020. State operating loss carryforwards of $181 million expire in 2020 through 2038. Foreign tax credits – At December 31, 2019, we reflect foreign tax credits of $611 million , which will expire in years 2022 through 2026. Valuation allowances – At December 31, 2019 , we reflect a valuation allowance in our consolidated balance sheet of $699 million against our net deferred tax assets in various jurisdictions in which we operate. The decrease in valuation allowance primarily relates to current year activity. Property, plant and equipment – At December 31, 2019 , we reflected a deferred tax liability of $1.9 billion . The increase primarily relates to the sale of our U.K. business and corresponding reduction in the asset retirement obligations and current year activity in the U.S. Net deferred tax assets and liabilities were classified in the consolidated balance sheets as follows: December 31, (In millions) 2019 2018 Assets: Other noncurrent assets $ — $ 393 Liabilities: Noncurrent deferred tax liabilities 186 199 Net deferred tax liabilities $ 186 $ — Net deferred tax assets $ — $ 194 We are routinely undergoing examinations in the jurisdictions in which we operate. As of December 31, 2019 , our income tax returns remain subject to examination in the following major tax jurisdictions for the tax years indicated: United States (a) 2008-2018 Equatorial Guinea 2007-2018 (a) Includes federal and state jurisdictions. The following table summarizes the activity in unrecognized tax benefits: (In millions) 2019 2018 2017 Beginning balance $ 263 $ 126 $ 66 Additions for tax positions of prior years 13 152 83 Reductions for tax positions of prior years (152 ) (15 ) (3 ) Settlements (111 ) — (20 ) Ending balance $ 13 $ 263 $ 126 If the unrecognized tax benefits as of December 31, 2019 were recognized, $13 million would affect our effective income tax rate. As of December 31, 2019 , there are $5 million uncertain tax positions for which it is reasonably possible that the amount could significantly change during the next twelve months. During the first quarter of 2019, we withdrew our appeal related to the Brae area decommissioning costs in the U.K., thus the uncertain tax positions previously established are now considered effectively settled with no tax expense or benefit impact. Also, in the first quarter of 2019, we settled the 2010-2011 IRS Audit, resulting in a tax benefit of $126 million . See Note 25 for further detail. Pursuant to the Tax Sharing Agreement we entered into with Marathon Petroleum Corporation (“MPC”) in connection with the 2011 spin-off transaction, MPC agreed to indemnify us for certain liabilities. In addition to the benefit from the settlement of the IRS Audit in the first quarter of 2019, we recorded a current receivable and other income of $42 million for indemnity payments due from MPC for tax expense and interest we had previously recognized. The indemnity relates to tax and interest allocable to MPC as a result of the IRS Audit. During the second quarter of 2019, we paid the IRS and were subsequently reimbursed by MPC for settlement of their indemnity obligation. Interest and penalties are recorded as part of the tax provision and were $6 million , $2 million and $27 million related to unrecognized tax benefits in 2019 , 2018 and 2017 . As of December 31, 2019 and 2018 , $3 million and $27 million of interest and penalties were accrued related to income taxes.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories Crude oil and natural gas are recorded at weighted average cost and carried at the lower of cost or net realizable value. Supplies and other items consist principally of tubular goods and equipment which are valued at weighted average cost and reviewed periodically for obsol escence or impairment when market conditions indicate. December 31, (In millions) 2019 2018 Crude oil and natural gas $ 10 $ 11 Supplies and other items 62 85 Inventories $ 72 $ 96

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment December 31, (In millions) 2019 2018 United States $ 16,427 $ 16,011 International (a) 493 710 Not allocated to segments 80 83 Net property, plant and equipment $ 17,000 $ 16,804 (a) The International decrease is due to dispositions of our non-operated interest in the Atrush block in Kurdistan and our U.K. business during 2019 (see Note 5 ). At December 31, 2019 , 2018 and 2017 we had total deferred exploratory well costs as follows: December 31, (In millions) 2019 2018 2017 Amounts capitalized less than one year after completion of drilling $ 278 $ 297 $ 263 Amounts capitalized greater than one year after completion of drilling — — 32 Total deferred exploratory well costs $ 278 $ 297 $ 295 Number of projects with costs capitalized greater than one year after completion of drilling — — 1 (In millions) 2019 2018 2017 Beginning balance $ 297 $ 295 $ 249 Additions 218 262 212 Charges to expense (a) (5 ) (35 ) (64 ) Transfers to development (230 ) (197 ) (102 ) Dispositions (b) (2 ) (28 ) — Ending balance $ 278 $ 297 $ 295 (a) 2018 includes $32 million related to the Rodo well in Alba Block Sub Area B, offshore E.G. 2017 includes $64 million as a result of our agreement to sell Diaba License G4-223 in the Republic of Gabon (see Note 11 for further detail). (b) 2018 includes the sale of our Libya subsidiary. We had no exploratory well costs capitalized greater than one year as of December 31, 2019 and December 31, 2018

Impairment

Impairment	12 Months Ended
	Dec. 31, 2019
Impairments and Exploration Expenses [Abstract]
Impairment	Impairments The following table summarizes impairment charges of proved properties from continuing operations. Additionally, it presents the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition. 2019 2018 2017 (In millions) Fair Value Impairment Fair Value Impairment Fair Value Impairment Long-lived assets held for use $ 56 $ 24 $ 113 $ 75 $ 179 $ 229 • 2019 – Impairments of $24 million , to an aggregate fair value of $56 million , were primarily a result of proved property impairments primarily as a result of anticipated sales for certain non-core proved properties in our United States segment and the sale of our non-operated interest in the Atrush block (Kurdistan) in our International segment. The related fair value was measured using the market approach, based upon anticipated sales proceeds less costs to sell which resulted in a Level 2 classification. • 2018 – Impairments in our International and United States segments of $75 million , to a fair value of $113 million , were largely the result of anticipated sales for certain non-core proved properties. The related fair value measurement utilized the market approach, based upon anticipated sales proceeds less costs to sell which resulted in a Level 2 classification. • 2017 – Impairments in our International segment were primarily a result of lower forecasted long-term commodity prices and the anticipated sales of certain non-core proved properties of $136 million , to an aggregate fair value of $103 million . These fair values were measured using the market approach, based upon either anticipated sales proceeds less costs to sell or a market comparable sales price per boe which resulted in a Level 2 classification. Impairments in our United States segment were $89 million , to an aggregate fair value of $76 million , and related to Gulf of Mexico and certain conventional Oklahoma assets primarily as a result of lower forecasted long-term commodity prices. The fair values were measured using an income approach based upon internal estimates of future production levels, prices and discount rate. Inputs to the fair value measurement include reserve and production estimates made by our reservoir engineers, estimated future commodity prices adjusted for quality and location differentials and forecasted operating expenses for the remaining estimated life of the reservoir which resulted in a Level 3 classification. See Note 5 for discussion of the divestitures in further detail and Note 7 for relevant detail regarding segment presentation.

Asset Retirement Obligations (N

Asset Retirement Obligations (Notes)	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations Asset retirement obligations primarily consist of estimated costs to remove, dismantle and restore land at the end of oil and gas production operations. Changes in asset retirement obligations for the periods ended December 31 were as follows: (In millions) 2019 2018 Beginning balance $ 1,145 $ 1,483 Incurred liabilities, including acquisitions 34 21 Settled liabilities, including dispositions (1,110 ) (117 ) Accretion expense (included in depreciation, depletion and amortization) 31 70 Revisions of estimates 46 (204 ) Held for sale (a) 108 (108 ) Ending balance (b) $ 254 $ 1,145 (a) In the fourth quarter 2018, we entered into an agreement to sell our working interest in the Droshky field (Gulf of Mexico), including our $98 million asset retirement obligation; this transaction closed during the first quarter of 2019. (b) $944 million of the 2018 ending balance relates to our asset retirement obligations in the U.K., the sale of which closed in 2019. 2019 • Settled liabilities primarily relates to the sale of our U.K. business, which closed during the third quarter of 2019, and the sale of the Droshky field (Gulf of Mexico). • Held for sale reflects a transfer to settled liabilities during 2019. This transfer was primarily related to the Droshky field (Gulf of Mexico) which was considered held for sale at year-end 2018 and closed in the first quarter of 2019. • Ending balance includes $11 million classified as short-term at December 31, 2019 . 2018 • Settled liabilities include dispositions, primarily related to the sale of non-core, non-operated conventional properties in the Gulf of Mexico as well as retirements in the U.K. • Revisions of estimates were primarily due to the acceleration of U.K. abandonment activities to capture favorable market conditions and lower estimated abandonment costs. • Held for sale primarily related to the Droshky field, which was considered held for sale at year-end 2018. • Ending balance primarily relates to the U.K. and includes $64 million classified as short-term at December 31, 2018 .

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases Supplemental balance sheet information related to leases was as follows: (In millions) December 31, 2019 Operating Leases: Balance Sheet Location: ROU asset Other noncurrent assets $ 199 Current portion of long-term lease liability Other current liabilities $ 101 Long-term lease liability Deferred credits and other liabilities $ 107 In determining our ROU assets and long-term lease liabilities, the new lease standard requires certain accounting policy decisions, while also providing a number of optional practical expedients for transition accounting. Our accounting policies and the practical expedients utilized are summarized below: • Implemented an accounting policy to not recognize any right-of-use assets and lease liabilities related to short-term leases on the balance sheet. • Implemented an accounting policy to not separate the lease and nonlease components for all asset classes, except for vessels. • Elected the package of practical expedients which allows us to not reassess our prior conclusions regarding the lease identification and lease classification for contracts that commenced or expired prior to the effective date. • Elected the practical expedient pertaining to land easements which allows us to continue accounting for existing agreements under the previous accounting policies as nonlease transactions. Any modifications of existing contracts or new agreements will be assessed under the new lease accounting guidance and may become leases in the future. We enter into various lease agreements to support our operations including drilling rigs, well fracturing equipment, compressors, buildings, aircraft, vessels, vehicles and miscellaneous field equipment. We primarily act as a lessee in these transactions and all of our existing leases are classified as either short-term or long-term operating leases. The majority of the drilling rig agreements and all of fracturing equipment agreements are classified as short-term leases based on the noncancellable period for which we have the right to use the equipment and assessment of options present in each agreement. We also incur variable lease costs under these agreements primarily related to chemicals and sand used in fracturing operations or various additional on-demand equipment and labor. The lease costs associated with the drilling rigs and fracturing equipment are primarily capitalized as part of the well costs. Our long-term leases are comprised of compressors, buildings, drilling rigs, aircraft, vessels, vehicles and miscellaneous field equipment. Our lease agreements may require both fixed and variable payments; none of the variable payments are rate or index-based, therefore only fixed payments were considered for recognizing lease liabilities and ROU assets related to long-term leases. Also, based on our election not to separate the lease and nonlease components, fixed payments related to equipment, crew and other nonlease components are included in the initial measurement of lease liabilities and ROU assets for all asset classes, except for vessels. For vessels, the contractual consideration was allocated between lease and nonlease components based on estimates provided by service providers. Our leased assets may be used in joint oil and gas operations with other working interest owners. We recognize lease liabilities and ROU assets only when we are the signatory to a contract as an operator of joint properties. Such lease liabilities and ROU assets are determined based on gross contractual obligations. As we use the leased assets for joint operations, we have the contractual right to recover the other working interest owners’ share of lease costs. As a result, our lease costs are presented on a net basis, reduced for any costs recoverable from other working interest owners. The table below presents our net lease costs as of December 31, 2019 with the majority of operating lease costs expensed as incurred, while the majority of the short-term and variable lease costs are capitalized into property, plant and equipment. (In millions) Year Ended December 31, 2019 Lease costs: Operating lease costs (a) $ 84 Short-term lease costs (b) 321 Variable lease costs (c) 107 Total lease costs $ 512 Other information: Cash paid for amounts included in the measurement of operating lease liabilities $ 100 ROU assets obtained in exchange for new operating lease liabilities (d) $ 293 (a) Represents our net share of the ROU asset amortization and the interest expense. (b) Represents our net share of lease costs arising from leases of less than one year but longer than one month that were not included in the lease liability. (c) Represents our net share of variable lease payments that were not included in the lease liability. (d) Represents the cumulative value of ROU assets recognized at lease inception during the year of 2019 . This amount is then amortized as we utilize the ROU asset, the net effect of which is the ending ROU asset of $199 million (first table above). We use our periodic incremental borrowing rate to discount future contractual payments to their present values. The weighted average lease term and the discount rate relevant to long-term leases were two years and 4% as of December 31, 2019 . The remaining annual undiscounted cash flows associated with long-term leases and the reconciliation of these cash flows to the lease liabilities recognized on the consolidated balance sheet is summarized below. (In millions) Operating Lease Obligations 2020 $ 114 2021 63 2022 35 2023 5 2024 1 Thereafter — Total undiscounted lease payments $ 218 Less: amount representing interest 10 Total operating lease liabilities $ 208 Less: current portion of long-term lease liability as of December 31, 2019 101 Long-term lease liability as of December 31, 2019 $ 107 At December 31, 2018 , future minimum commitments under the previous accounting standard, ASC 840, for operating lease obligations having noncancellable lease terms in excess of one year were as follows: (In millions) Operating Lease Obligations 2019 $ 62 2020 54 2021 35 2022 12 2023 5 Thereafter 49 Sublease rentals — Total minimum lease payments $ 217 * Future minimum commitments for capital lease obligations were nil as of December 31, 2018 . Our wholly-owned subsidiary, Marathon E.G. Production Limited, is a lessor for residential housing in Equatorial Guinea, which is occupied by EGHoldings, a related party equity method investee – see Note 23 . The lease was classified as an operating lease and expires in 2024, with a lessee option to extend through 2034. Lease payments are fixed for the entire duration of the agreement at approximately $6 million per year. Our lease income is reported in other income in our consolidated statements of income for all periods presented. The undiscounted cash flows to be received under this lease agreement are summarized below. (In millions) Operating Lease Future Cash Receipts 2020 $ 6 2021 6 2022 6 2023 6 2024 6 Thereafter 60 Total undiscounted cash flows $ 90 In 2018, we signed an agreement with an owner/lessor to construct and lease a new build-to-suit office building in Houston, Texas. The new Houston office location is expected to be completed in 2021. The lessor and other participants are providing financing for up to $380 million , to fund the estimated project costs. As of December 31, 2019 , project costs incurred totaled approximately $58 million , primarily for land acquisition and initial design costs. The initial lease term is five years and will commence once construction is substantially complete and the new Houston office is ready for occupancy. At the end of the initial lease term, we can negotiate to extend the lease term for an additional five years , subject to the approval of the participants; purchase the property subject to certain terms and conditions; or remarket the property to an unrelated third party. The lease contains a residual value guarantee of approximately 89%
Leases	13 . Leases Supplemental balance sheet information related to leases was as follows: (In millions) December 31, 2019 Operating Leases: Balance Sheet Location: ROU asset Other noncurrent assets $ 199 Current portion of long-term lease liability Other current liabilities $ 101 Long-term lease liability Deferred credits and other liabilities $ 107 In determining our ROU assets and long-term lease liabilities, the new lease standard requires certain accounting policy decisions, while also providing a number of optional practical expedients for transition accounting. Our accounting policies and the practical expedients utilized are summarized below: • Implemented an accounting policy to not recognize any right-of-use assets and lease liabilities related to short-term leases on the balance sheet. • Implemented an accounting policy to not separate the lease and nonlease components for all asset classes, except for vessels. • Elected the package of practical expedients which allows us to not reassess our prior conclusions regarding the lease identification and lease classification for contracts that commenced or expired prior to the effective date. • Elected the practical expedient pertaining to land easements which allows us to continue accounting for existing agreements under the previous accounting policies as nonlease transactions. Any modifications of existing contracts or new agreements will be assessed under the new lease accounting guidance and may become leases in the future. We enter into various lease agreements to support our operations including drilling rigs, well fracturing equipment, compressors, buildings, aircraft, vessels, vehicles and miscellaneous field equipment. We primarily act as a lessee in these transactions and all of our existing leases are classified as either short-term or long-term operating leases. The majority of the drilling rig agreements and all of fracturing equipment agreements are classified as short-term leases based on the noncancellable period for which we have the right to use the equipment and assessment of options present in each agreement. We also incur variable lease costs under these agreements primarily related to chemicals and sand used in fracturing operations or various additional on-demand equipment and labor. The lease costs associated with the drilling rigs and fracturing equipment are primarily capitalized as part of the well costs. Our long-term leases are comprised of compressors, buildings, drilling rigs, aircraft, vessels, vehicles and miscellaneous field equipment. Our lease agreements may require both fixed and variable payments; none of the variable payments are rate or index-based, therefore only fixed payments were considered for recognizing lease liabilities and ROU assets related to long-term leases. Also, based on our election not to separate the lease and nonlease components, fixed payments related to equipment, crew and other nonlease components are included in the initial measurement of lease liabilities and ROU assets for all asset classes, except for vessels. For vessels, the contractual consideration was allocated between lease and nonlease components based on estimates provided by service providers. Our leased assets may be used in joint oil and gas operations with other working interest owners. We recognize lease liabilities and ROU assets only when we are the signatory to a contract as an operator of joint properties. Such lease liabilities and ROU assets are determined based on gross contractual obligations. As we use the leased assets for joint operations, we have the contractual right to recover the other working interest owners’ share of lease costs. As a result, our lease costs are presented on a net basis, reduced for any costs recoverable from other working interest owners. The table below presents our net lease costs as of December 31, 2019 with the majority of operating lease costs expensed as incurred, while the majority of the short-term and variable lease costs are capitalized into property, plant and equipment. (In millions) Year Ended December 31, 2019 Lease costs: Operating lease costs (a) $ 84 Short-term lease costs (b) 321 Variable lease costs (c) 107 Total lease costs $ 512 Other information: Cash paid for amounts included in the measurement of operating lease liabilities $ 100 ROU assets obtained in exchange for new operating lease liabilities (d) $ 293 (a) Represents our net share of the ROU asset amortization and the interest expense. (b) Represents our net share of lease costs arising from leases of less than one year but longer than one month that were not included in the lease liability. (c) Represents our net share of variable lease payments that were not included in the lease liability. (d) Represents the cumulative value of ROU assets recognized at lease inception during the year of 2019 . This amount is then amortized as we utilize the ROU asset, the net effect of which is the ending ROU asset of $199 million (first table above). We use our periodic incremental borrowing rate to discount future contractual payments to their present values. The weighted average lease term and the discount rate relevant to long-term leases were two years and 4% as of December 31, 2019 . The remaining annual undiscounted cash flows associated with long-term leases and the reconciliation of these cash flows to the lease liabilities recognized on the consolidated balance sheet is summarized below. (In millions) Operating Lease Obligations 2020 $ 114 2021 63 2022 35 2023 5 2024 1 Thereafter — Total undiscounted lease payments $ 218 Less: amount representing interest 10 Total operating lease liabilities $ 208 Less: current portion of long-term lease liability as of December 31, 2019 101 Long-term lease liability as of December 31, 2019 $ 107 At December 31, 2018 , future minimum commitments under the previous accounting standard, ASC 840, for operating lease obligations having noncancellable lease terms in excess of one year were as follows: (In millions) Operating Lease Obligations 2019 $ 62 2020 54 2021 35 2022 12 2023 5 Thereafter 49 Sublease rentals — Total minimum lease payments $ 217 * Future minimum commitments for capital lease obligations were nil as of December 31, 2018 . Our wholly-owned subsidiary, Marathon E.G. Production Limited, is a lessor for residential housing in Equatorial Guinea, which is occupied by EGHoldings, a related party equity method investee – see Note 23 . The lease was classified as an operating lease and expires in 2024, with a lessee option to extend through 2034. Lease payments are fixed for the entire duration of the agreement at approximately $6 million per year. Our lease income is reported in other income in our consolidated statements of income for all periods presented. The undiscounted cash flows to be received under this lease agreement are summarized below. (In millions) Operating Lease Future Cash Receipts 2020 $ 6 2021 6 2022 6 2023 6 2024 6 Thereafter 60 Total undiscounted cash flows $ 90 In 2018, we signed an agreement with an owner/lessor to construct and lease a new build-to-suit office building in Houston, Texas. The new Houston office location is expected to be completed in 2021. The lessor and other participants are providing financing for up to $380 million , to fund the estimated project costs. As of December 31, 2019 , project costs incurred totaled approximately $58 million , primarily for land acquisition and initial design costs. The initial lease term is five years and will commence once construction is substantially complete and the new Houston office is ready for occupancy. At the end of the initial lease term, we can negotiate to extend the lease term for an additional five years , subject to the approval of the participants; purchase the property subject to certain terms and conditions; or remarket the property to an unrelated third party. The lease contains a residual value guarantee of approximately 89%

Goodwill (Notes)

Goodwill (Notes)	12 Months Ended
	Dec. 31, 2019
Goodwill Disclosure [Abstract]
Goodwill	Goodwill As of December 31, 2019 , our consolidated balance sheet included goodwill of $95 million . Goodwill is tested for impairment on an annual basis, or between annual tests when events or changes in circumstances indicate the fair value may have been reduced below its carrying value. Goodwill is tested for impairment at the reporting unit level. Our reporting units are the same as our reporting segments, of which only International includes goodwill. We first assess the qualitative factors in order to determine whether the fair value of our International reporting unit is more likely than not less than its carrying amount. Certain qualitative factors used in our evaluation include, among other things, the results of the most recent quantitative assessment of the goodwill impairment test, macroeconomic conditions; industry and market conditions (including commodity prices and cost factors); overall financial performance; and other relevant entity-specific events. If, after considering these events and circumstances we determined that it is more likely than not that the fair value of the International reporting unit is less than its carrying amount, a quantitative goodwill test is performed. The quantitative goodwill test is performed using a combination of market and income approaches. The market approach references observable inputs specific to us and our industry, such as the price of our common equity, our enterprise value, and valuation multiples of us and our peers from the investor analyst community. The income approach utilizes discounted cash flows, which are based on forecasted assumptions. Key assumptions to the income approach include future liquid hydrocarbon and natural gas pricing, estimated quantities of liquid hydrocarbons and natural gas proved and probable reserves, estimated timing of production, discount rates, future capital requirements, operating expenses and tax rates. The assumptions used in the income approach are consistent with those that management uses to make business decisions. This quantitative goodwill test would represent Level 3 fair value measurements. During the second quarter of 2019 , we performed our annual impairment test of goodwill using the qualitative assessment. Our qualitative assessment considered the significant excess fair value over carrying value in our most recent step 1 test (second quarter 2017) and noted a general improvement in the qualitative factors above. After assessing the totality of the qualitative factors which could have a positive or negative impact on goodwill, our assessment did not indicate that it is more likely than not that the fair value is less than its carrying value. As a result, we concluded that no impairment to goodwill was required for our International reporting unit. As of December 31, 2019 and 2018 our International segment is the only reporting segment which includes goodwill. The table below displays the allocated beginning goodwill balance of our International segment along with changes in the carrying amount of goodwill for 2019 and 2018 : (In millions) International 2018 Beginning balance, gross $ 115 Less: accumulated impairments — Beginning balance, net 115 Dispositions (a) (18 ) Impairment — Ending balance, net $ 97 2019 Beginning balance, gross $ 97 Less: accumulated impairments — Beginning balance, net 97 Dispositions (2 ) Impairment — Ending balance, net $ 95 (a) Primarily related to the sale of our Libya subsidiary (see Note 5 ).

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives See Note 16 for further information regarding the fair value measurement of derivative instruments. See Note 1 for discussion of the types of derivatives we may use and the reasons for them. All of our commodity derivatives and interest rate derivatives are/were subject to enforceable master netting arrangements or similar agreements under which we report net amounts. The following tables present the gross fair values of derivative instruments and the reported net amounts along with where they appear on the consolidated balance sheets. December 31, 2019 (In millions) Asset Liability Net Asset (Liability) Balance Sheet Location Not Designated as Hedges Commodity $ 9 $ 1 $ 8 Other current assets Commodity 1 — 1 Other noncurrent assets Commodity — 5 (5 ) Other current liabilities Total Not Designated as Hedges $ 10 $ 6 $ 4 Cash Flow Hedges Interest Rate $ 2 $ — $ 2 Other noncurrent assets Total Designated Hedges $ 2 $ — $ 2 Total $ 12 $ 6 $ 6 December 31, 2018 (In millions) Asset Liability Net Asset (Liability) Balance Sheet Location Not Designated as Hedges Commodity $ 131 $ — $ 131 Other current assets Commodity — 4 (4 ) Deferred credits and other liabilities Total Not Designated as Hedges $ 131 $ 4 $ 127 Derivatives Not Designated as Hedges Terminated Interest Rate Swaps During the second quarter of 2017, we de-designated forward starting interest rate swaps used to hedge the variations in cash flows related to fluctuations in long term interest rates from debt that was refinanced in the third quarter of 2017. In the third quarter of 2017, we terminated our forward starting interest rate swaps for proceeds of $54 million and recognized a gain of $46 million in net interest. See Note 17 for further detail. The following table sets forth the net impact of the terminated forward starting interest rate swap derivatives de-designated as cash flow hedges on other comprehensive income (loss). Year Ended December 31, (In millions) 2017 Interest Rate Swaps Beginning balance $ 60 Change in fair value recognized in other comprehensive income (13 ) Reclassification from other comprehensive income (47 ) Ending balance $ — Commodity Derivatives We have entered into multiple crude oil and natural gas derivatives indexed to NYMEX WTI and Henry Hub related to a portion of our forecasted United States sales through 2021. These commodity derivatives consist of three-way collars and basis swaps. Three-way collars consist of a sold call (ceiling), a purchased put (floor) and a sold put. The ceiling price is the maximum we will receive for the contract volumes; the floor is the minimum price we will receive, unless the market price falls below the sold put strike price. In this case, we receive the NYMEX WTI price plus the difference between the floor and the sold put price. These crude oil derivatives were not designated as hedges. The following table sets forth outstanding derivative contracts as of December 31, 2019 and the weighted average prices for those contracts: 2020 2021 Crude Oil First Quarter Second Quarter Third Quarter Fourth Quarter Full Year NYMEX WTI Three-Way Collars Volume (Bbls/day) 60,000 60,000 60,000 60,000 — Weighted average price per Bbl: Ceiling $ 66.04 $ 66.04 $ 63.74 $ 63.74 $ — Floor $ 55.00 $ 55.00 $ 55.00 $ 55.00 $ — Sold put $ 47.67 $ 47.67 $ 48.00 $ 48.00 $ — Basis Swaps - Argus WTI Midland (a) Volume (Bbls/day) 15,000 15,000 15,000 15,000 — Weighted average price per Bbl $ (0.94 ) $ (0.94 ) $ (0.94 ) $ (0.94 ) $ — Basis Swaps - NYMEX WTI / ICE Brent (b) Volume (Bbls/day) 5,000 5,000 5,000 5,000 808 Weighted average price per Bbl $ (7.24 ) $ (7.24 ) $ (7.24 ) $ (7.24 ) $ (7.24 ) Natural Gas Three-Way Collars Volume (MMBtu/day) 100,000 — — — — Weighted average price per MMBtu: Ceiling $ 3.32 $ — $ — $ — $ — Floor $ 2.75 $ — $ — $ — $ — Sold put $ 2.25 $ — $ — $ — $ — (a) The basis differential price is indexed against Argus WTI Midland. (b) The basis differential price is indexed against Intercontinental Exchange (“ICE”) Brent and NYMEX WTI. Between January 1, 2020 and February 10, 2020 , we entered into 20,000 bbls/day of three-way collars for 2020 with a ceiling price of $66.37 , a floor price of $55.00 and a sold put price of $48.00 . The mark-to-market impact and settlement of these commodity derivative instruments appears in the table below and is reflected in net gain (loss) on commodity derivatives in the consolidated statements of income. Year Ended December 31, (In millions) 2019 2018 2017 Mark-to-market gain (loss) $ (124 ) $ 267 $ (81 ) Net settlements of commodity derivative instruments $ 52 $ (281 ) $ 45 Derivatives Designated as Cash Flow Hedges During 2019, we entered into forward starting interest rate swaps with a total notional amount of $320 million to hedge variations in cash flows related to the 1-month London Interbank Offered Rate (“LIBOR”) component of future lease payments of our future Houston office. These swaps will settle monthly on the same day the lease payment is made with the first swap settlement occurring in January 2022. We expect the first lease payment to commence sometime in the period from December 2021 to May 2022. The last swap will mature on September 9, 2026. See Note 13 for further details regarding the lease of the new Houston office. The following table presents information about our interest rate swap agreements, including the weighted average LIBOR-based, fixed rate. December 31, 2019 December 31, 2018 (In millions, except fixed rates) Aggregate Notional Amount Weighted Average, LIBOR Aggregate Notional Amount Weighted Average, LIBOR Interest rate swaps $ 320 1.514 % $ — — % At December 31, 2019 , accumulated other comprehensive income included deferred gains of $2 million related to forward starting interest rate swaps. No amounts related to these swaps are expected to impact the consolidated statements of income in the next 12 months.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	air Value Measurements Fair Values – Recurring The following tables’ present assets and liabilities accounted for at fair value on a recurring basis as of December 31, 2019 and 2018 by hierarchy level. December 31, 2019 (In millions) Level 1 Level 2 Level 3 Total Derivative instruments, assets Commodity (a) $ — $ 7 $ — $ 7 Interest rate — 2 — 2 Derivative instruments, assets $ — $ 9 $ — $ 9 Derivative instruments, liabilities Commodity (a) $ (3 ) $ — $ — $ (3 ) Derivative instruments, liabilities $ (3 ) $ — $ — $ (3 ) Total $ (3 ) $ 9 $ — $ 6 December 31, 2018 (In millions) Level 1 Level 2 Level 3 Total Derivative instruments, assets Commodity (a) $ 21 $ 106 $ — $ 127 Derivative instruments, assets $ 21 $ 106 $ — $ 127 Derivative instruments, liabilities Derivative instruments, liabilities $ — $ — $ — $ — Total $ 21 $ 106 $ — $ 127 (a) Derivative instruments are recorded on a net basis in our consolidated balance sheet (see Note 15 ). Commodity derivatives include three-way collars and basis swaps. These instruments are measured at fair value using either a Black-Scholes or a modified Black-Scholes Model. For basis swaps, inputs to the models include only commodity prices and interest rates and are categorized as Level 1 because all assumptions and inputs are observable in active markets throughout the term of the instruments. For three-way collars, inputs to the models include commodity prices, and implied volatility and are categorized as Level 2 because predominantly all assumptions and inputs are observable in active markets throughout the term of the instruments. The forward starting interest rate swaps are measured at fair value with a market approach using actionable broker quotes, which are Level 2 inputs. See Note 15 for details on the forward starting interest swaps. Fair Values – Goodwill See Note 14 for detail information relating to goodwill. Fair Values – Nonrecurring See Note 5 and Note 11 for detail on our fair values for nonrecurring items, such as impairments. Fair Values – Financial Instruments Our current assets and liabilities include financial instruments, the most significant of which are receivables, the current portion of our long-term debt and payables. We believe the carrying values of our receivables and payables approximate fair value. Our fair value assessment incorporates a variety of considerations, including (1) the short-term duration of the instruments, (2) our credit rating and (3) our historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk. The following table summarizes financial instruments, excluding receivables, payables and derivative financial instruments, and their reported fair values by individual balance sheet line item at December 31, 2019 and 2018 . December 31, 2019 2018 (In millions) Fair Value Carrying Amount Fair Value Carrying Amount Financial assets Current assets $ 4 $ 4 $ 3 $ 3 Other noncurrent assets 26 38 76 81 Total financial assets $ 30 $ 42 $ 79 $ 84 Financial liabilities Other current liabilities $ 62 $ 90 $ 37 $ 58 Long-term debt, including current portion (a) 6,174 5,529 5,469 5,528 Deferred credits and other liabilities 99 86 93 88 Total financial liabilities $ 6,335 $ 5,705 $ 5,599 $ 5,674 (a) Excludes debt issuance costs. Fair values of our notes receivable and our financial assets included in other noncurrent assets, and of our financial liabilities included in other current liabilities and deferred credits and other liabilities, are measured using an income approach and most inputs are internally generated, which results in a Level 3 classification. Estimated future cash flows are discounted using a rate deemed appropriate to obtain the fair value.

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt Revolving Credit Facility In September 2019, we entered into a fourth amendment to our unsecured revolving credit facility (the “Credit Facility”) to reduce the maximum borrowing from $3.4 billion to $3.0 billion and extended the maturity date by one year to May 28, 2023. As of December 31, 2019 , we had no borrowings against our $3.0 billion Credit Facility or under our U.S. commercial paper program that is backed by the Credit Facility. The Credit Facility includes a covenant requiring that our ratio of total debt to total capitalization not exceed 65% as of the last day of each fiscal quarter. If an event of default occurs, the lenders holding more than half of the commitments may terminate the commitments under the Credit Facility and require the immediate repayment of all outstanding borrowings and the cash collateralization of all outstanding letters of credit under the Credit Facility. As of December 31, 2019 , we were in compliance with this covenant with a debt-to-capitalization ratio of 31% . Long-term debt The following table details our long-term debt: December 31, (In millions) 2019 2018 Senior unsecured notes: 2.700% notes due 2020 (a) $ — $ 600 2.800% notes due 2022 (a) 1,000 1,000 9.375% notes due 2022 (b) 32 32 Series A notes due 2022 (b) 3 3 8.500% notes due 2023 (b) 70 70 8.125% notes due 2023 (b) 131 131 3.850% notes due 2025 (a) 900 900 4.400% notes due 2027 (a) 1,000 1,000 6.800% notes due 2032 (a) 550 550 6.600% notes due 2037 (a) 750 750 5.200% notes due 2045 (a) 500 500 Bonds: (c) 2.00% bonds due 2037 200 — 2.10% bonds due 2037 200 — 2.20% bonds due 2037 200 — Total (b) 5,536 5,536 Unamortized discount (7 ) (8 ) Unamortized debt issuance cost (28 ) (29 ) Total long-term debt $ 5,501 $ 5,499 (a) These notes contain a make-whole provision allowing us to repay the debt at a premium to market price. (b) In the event of a change in control, as defined in the related agreements, debt obligations totaling $236 million at December 31, 2019 may be declared immediately due and payable. (c) Mandatory purchase dates for these bonds: April 1, 2023 for the 2.00% bonds; July 1, 2024 for the 2.10% bonds; and July 1, 2026 for the 2.20% bonds. Subsequent to the various mandatory purchase dates, we will also have the right to convert and remarket these any time up to the 2037 maturity date. On October 3, 2019, we redeemed our $600 million 2.7% senior unsecured notes due June 2020. The following table shows future debt payments: (In millions) 2020 $ — 2021 — 2022 1,035 2023 401 2024 200 Thereafter 3,900 Total long-term debt, including current portion $ 5,536 Debt Issuance On October 1, 2019, we closed a $600 million remarketing to investors of sub-series A bonds which are part of the $1.0 billion St. John the Baptist, State of Louisiana revenue refunding bonds originally issued and purchased in December 2017. The $600 million in proceeds from the conversion and remarketing were used to pay the purchase price of our converted 2017 bonds on the closing date. We continue to own the remaining $400 million

Incentive Based Compensation Pl

Incentive Based Compensation Plans	12 Months Ended
	Dec. 31, 2019
Incentive Based Compensation Plans [Abstract]
Incentive Based Compensation	Incentive Based Compensation Description of stock-based compensation plans – The Marathon Oil Corporation 2019 Incentive Compensation Plan (the “2019 Plan”) was approved by our stockholders in May 2019 and authorizes the Compensation Committee of the Board of Directors to grant stock options, stock appreciation rights (“SARs”), stock awards (including restricted stock and restricted stock unit awards), performance unit awards and cash awards to employees. The 2019 Plan also allows us to provide equity compensation to our non-employee directors. No more than 27.9 million shares of our common stock may be issued under the 2019 Plan. In connection with the granting of an award under the 2019 Plan, the number of shares available for issuance under the 2019 Plan will be reduced by one share for each share of our common stock in respect of which the award is granted, except that awards that by their terms do not permit settlement in shares of our common stock will not reduce the number of shares of common stock available for issuance under the 2019 Plan. Shares subject to awards under the 2019 Plan that are forfeited, terminated or expire unexercised become available for future grants. In addition, the number of shares of our common stock reserved for issuance under the 2019 Plan will not be increased by shares tendered to satisfy the purchase price of an award, exchanged for other awards or withheld to satisfy tax withholding obligations. Shares issued as a result of awards granted under the 2019 Plan are generally funded out of common stock held in treasury, except to the extent there are insufficient treasury shares, in which case new common shares are issued. After approval of the 2019 Plan, no new grants were or will be made from any prior plans. Any awards previously granted under any prior plans shall continue to be exercisable in accordance with their original terms and conditions. Stock-based awards under the plans Stock options – We grant stock options under the 2019 Plan. Our stock options represent the right to purchase shares of our common stock at its fair market value on the date of grant. In general, our stock options vest ratably over a three -year period and have a maximum term of ten years from the date they are granted. SARs – At December 31, 2019 , there are no SARs outstanding. Restricted stock – We grant restricted stock under the 2019 Plan. The restricted stock awards granted to officers generally vest three years from the date of grant, contingent on the recipient’s continued employment. We also grant restricted stock to certain non-officer employees based on their performance within certain guidelines and for retention purposes. The restricted stock awards to non-officers generally vest ratably over a three -year period, contingent on the recipient’s continued employment. Prior to vesting, all restricted stock recipients have the right to vote such stock and receive dividends thereon. The non-vested shares of restricted stock are not transferable and are held by our transfer agent. Stock-based performance units – We grant stock-based performance units to officers under the 2019 Plan. At the grant date, each unit represents the value of one share of our common stock. These units are settled in shares, and the number of shares of our common stock to be paid is based on the vesting percentage, which can be from zero to 200% based on performance achieved over a three-year performance period, and as determined by the Compensation Committee of the Board of Directors. The performance goals are tied to our total shareholder return (“TSR”) as compared to TSR for a group of peer companies determined by the Compensation Committee of our Board of Directors. Dividend equivalents may accrue during the performance period and would be paid in cash at the end of the performance period based on the amount of dividends credited generally over the performance period on shares of our common stock that represent the value of the units granted multiplied by the vesting percentage. Restricted stock units – We maintain an equity compensation program for our non-employee directors. All non-employee directors receive annual grants of common stock units. Any units granted prior to 2012 must be held until completion of board service, at which time the non-employee director will receive common shares. For units granted between 2012 and 2016, common shares will generally vest following completion of board service or three years from the date of grant, whichever is earlier. For awards issued in 2017 and later, directors may elect to defer settlement of their common stock units until after they cease serving on the Board. Absent such an election to defer, common shares will vest upon the earlier of three years from the date of grant or completion of board service. Under the 2019 Plan, we also grant restricted stock units to officers, which generally vest three years from the date of the grant and restricted stock units to certain non-officer employees, which generally vest ratably over a three -year period. Both awards are contingent on the recipient’s continued employment. Grants of restricted stock units to these non-officer employees are generally based on their performance and for retention purposes. Common shares will be issued for these restricted stock units after vesting. Prior to vesting, recipients of restricted stock units typically receive dividend equivalent payments, but they may not vote. Total stock-based compensation expense – Total employee stock-based compensation expense was $60 million , $53 million and $50 million in 2019 , 2018 and 2017 . Due to the full valuation allowance on our net federal deferred tax assets, we recognized no tax benefit during these years. Cash received upon exercise of stock option awards was $1 million and $26 million for 2019 and 2018. There was no cash received upon exercise of stock option awards 2017. There were no tax benefits realized for deductions for stock awards settled during 2019 , 2018 and 2017 . Stock option awards – During 2019 , 2018 and 2017 we granted stock option awards to officer employees. The weighted average grant date fair value of these awards was based on the following weighted average Black-Scholes assumptions: 2019 2018 2017 Exercise price per share $ 16.79 $ 14.52 $ 15.80 Expected annual dividend yield 1.2 % 1.4 % 1.3 % Expected life in years 5.82 6.45 6.4 Expected volatility 43 % 43 % 42 % Risk-free interest rate 2.5 % 2.8 % 2.1 % Weighted average grant date fair value of stock option awards granted $ 6.62 $ 5.83 $ 6.07 The following is a summary of stock option award activity in 2019 . Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (in millions) Outstanding at beginning of year 6,180,007 $ 24.39 Granted 648,526 $ 16.79 Exercised (84,804) $ 8.17 Canceled (1,083,998) $ 25.45 Outstanding at end of year 5,659,731 $ 23.55 5 years $ 3 Exercisable at end of year 4,323,312 $ 25.96 4 years $ 3 Expected to vest 1,319,850 $ 15.76 8 years $ — The intrinsic value of stock option awards exercised during 2018 was $13 million while it was immaterial during 2019 and 2017 . As of December 31, 2019 , unrecognized compensation cost related to stock option awards was $5 million , which is expected to be recognized over a weighted average period of 1 year. Restricted stock awards and restricted stock units – The following is a summary of restricted stock and restricted stock unit award activity in 2019 . Awards Weighted Average Grant Date Fair Value Unvested at beginning of year 8,504,946 $ 14.04 Granted 4,113,190 $ 16.65 Vested and Exercised (3,813,221 ) $ 12.64 Canceled (1,630,529 ) $ 15.78 Unvested at end of year 7,174,386 $ 15.88 The vesting date fair value of restricted stock awards which vested during 2019 , 2018 and 2017 was $48 million , $48 million and $39 million . The weighted average grant date fair value of restricted stock awards was $15.88 , $14.04 and $14.24 for awards unvested at December 31, 2019 , 2018 and 2017 . As of December 31, 2019 there was $65 million of unrecognized compensation cost related to restricted stock awards which is expected to be recognized over a weighted average period of 1 year. Stock-based performance unit awards – During 2019 , 2018 and 2017 we granted 656,636 , 754,140 and 563,631 stock-based performance unit awards to officers. At December 31, 2019 , there were 1,282,296 units outstanding. Total stock-based performance unit awards expense was $7 million in 2019 , $13 million in 2018 and $8 million in 2017 . The key assumptions used in the Monte Carlo simulation to determine the fair value of stock-based performance units granted in 2019 , 2018 and 2017 were: 2019 (a) 2018 2017 (b) Valuation date stock price $ 16.79 $ 13.69 $ 13.58 Expected annual dividend yield 1.2 % 1.5 % N/A Expected volatility 43 % 41 % N/A Risk-free interest rate 2.5 % 1.5 % N/A Fair value of stock-based performance units outstanding $ 20.66 $ 17.29 $ 14.18 (a) Represents key assumptions at grant date, as 2019 performance unit awards are settled in stock. (b)

Defined Benefit Postretirement

Defined Benefit Postretirement Plans and Defined Contribution Plan (Notes)	12 Months Ended
	Dec. 31, 2019
Defined Benefit Plan [Abstract]
Defined Benefit Postretirement Plans and Defined Contribution Plan	Defined Benefit Postretirement Plans and Defined Contribution Plan We have noncontributory defined benefit pension plans covering substantially all domestic employees. Benefits under these plans are based on plan provisions specific to each plan. We also had a noncontributory defined benefit pension plan covering eligible U.K. employees that was transferred to the buyer in connection with the sale of our U.K. business during 2019. See Note 5 for further information on this disposition. During the year ended December 31, 2019 , we reclassified $20 million from accumulated other comprehensive income to pension assets upon remeasurement of the plan. We also have plans for other postretirement benefits covering our U.S. employees. Health care benefits are provided up to age 65 through comprehensive hospital, surgical and major medical benefit provisions subject to various cost-sharing features. Post-age 65 health care benefits are provided to certain U.S. employees on a defined contribution basis. Life insurance benefits are provided to certain retiree beneficiaries. These other postretirement benefits are not funded in advance. Employees hired after 2016 are not eligible for any postretirement health care or life insurance benefits. Obligations and funded status – The following summarizes the obligations and funded status for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits 2019 2018 2019 2018 (In millions) U.S. Int’l U.S. Int’l U.S. U.S. Accumulated benefit obligation $ 343 $ — $ 320 $ 511 $ 89 $ 96 Change in pension benefit obligations: Beginning balance $ 326 $ 511 $ 384 $ 599 $ 96 $ 221 Service cost 19 — 18 — 1 2 Interest cost 12 8 12 14 3 7 Plan amendment — — — 3 — (99 ) Divestiture (a) — (549 ) — — — — Actuarial loss (gain) 48 36 (20 ) (38 ) 9 (15 ) Foreign currency exchange rate changes — 6 — (29 ) — — Settlements paid (45 ) — (62 ) (23 ) — — Benefits paid (6 ) (12 ) (6 ) (15 ) (20 ) (20 ) Ending balance $ 354 $ — $ 326 $ 511 $ 89 $ 96 Change in fair value of plan assets: Beginning balance $ 203 $ 594 $ 216 $ 670 $ — $ — Actual return on plan assets 44 68 (6 ) (21 ) — — Employer contributions 40 8 61 17 20 20 Foreign currency exchange rate changes — 8 — (34 ) — — Divestiture (a) — (666 ) — — — — Settlements paid (45 ) — (62 ) (23 ) — — Benefits paid (6 ) (12 ) (6 ) (15 ) (20 ) (20 ) Ending balance $ 236 $ — $ 203 $ 594 $ — $ — Funded status of plans at December 31 $ (118 ) $ — $ (123 ) $ 83 $ (89 ) $ (96 ) Amounts recognized in the consolidated balance sheets: Noncurrent assets $ — $ — $ — $ 83 $ — $ — Current liabilities (6 ) — (5 ) — (18 ) (19 ) Noncurrent liabilities (112 ) — (118 ) — (71 ) (77 ) Accrued benefit cost $ (118 ) $ — $ (123 ) $ 83 $ (89 ) $ (96 ) Pretax amounts in accumulated other comprehensive loss: Net loss $ 85 $ — $ 90 $ 59 $ 23 $ 14 Prior service cost (29 ) — (36 ) 5 (129 ) (147 ) (a) Refer to Note 5 for further information on the sale of our U.K. business. Components of net periodic benefit cost from continuing operations and other comprehensive (income) loss – The following summarizes the net periodic benefit costs and the amounts recognized as other comprehensive (income) loss for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits Year Ended December 31, Year Ended December 31, 2019 2018 2017 2019 2018 2017 (In millions) U.S. Int’l U.S. Int’l U.S. Int’l U.S. U.S. U.S. Components of net periodic benefit cost: Service cost $ 19 $ — $ 18 $ — $ 22 $ — $ 1 $ 2 $ 2 Interest cost 12 8 12 14 13 17 3 7 8 Expected return on plan assets (10 ) (11 ) (11 ) (24 ) (13 ) (30 ) — — — Amortization: - prior service credit (7 ) — (10 ) — (10 ) — (19 ) (8 ) (7 ) - actuarial loss 7 — 11 — 8 1 1 1 — Net settlement loss (a) 12 — 18 3 28 4 — — — Net periodic benefit cost (b) $ 33 $ (3 ) $ 38 $ (7 ) $ 48 $ (8 ) $ (14 ) $ 2 $ 3 Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss (pretax): Actuarial loss (gain) $ 14 $ (21 ) $ (4 ) $ 8 $ 28 $ (26 ) $ 9 $ (15 ) $ 5 Amortization of actuarial gain (loss) (19 ) (41 ) (29 ) (3 ) (36 ) (4 ) (1 ) (1 ) — Prior service cost (credit) — — — 3 — — — (99 ) — Amortization of prior service credit (cost) 7 (6 ) 10 — 10 — 19 8 7 Total recognized in other comprehensive (income) loss $ 2 $ (68 ) $ (23 ) $ 8 $ 2 $ (30 ) $ 27 $ (107 ) $ 12 Total recognized in net periodic benefit cost and other comprehensive (income) loss $ 35 $ (71 ) $ 15 $ 1 $ 50 $ (38 ) $ 13 $ (105 ) $ 15 (a) Settlements are recognized as they occur, once it is probable that lump sum payments from a plan for a given year will exceed the plan’s total service and interest costs for that year. (b) Net periodic benefit cost reflects a calculated market-related value of plan assets which recognizes changes in fair value over three years. The estimated net loss and prior service credit for our defined benefit pension plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost in 2020 are $9 million and $7 million . The estimated net loss and prior service credit for our other defined benefit postretirement plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost in 2020 are $2 million and $18 million . Plan assumptions – The following summarizes the assumptions used to determine the benefit obligations at December 31, and net periodic benefit cost for the defined benefit pension and other postretirement plans for 2019 , 2018 and 2017 . Pension Benefits Other Benefits 2019 2018 2017 2019 2018 2017 (In millions) U.S. U.S. Int’l U.S. Int’l U.S. U.S. U.S. Weighted average assumptions used to determine benefit obligation: Discount rate 3.13 % 4.26 % 2.90 % 3.55 % 2.50 % 2.91 % 4.09 % 3.54 % Rate of compensation increase 4.50 % 4.00 % — % 4.00 % — % 4.50 % 4.00 % 4.00 % Weighted average assumptions used to determine net periodic benefit cost: Discount rate 3.70 % 3.88 % 2.50 % 3.86 % 2.70 % 4.09 % 3.54 % 3.98 % Expected long-term return on plan assets 6.25 % 6.50 % 3.70 % 6.50 % 4.50 % — % — % — % Rate of compensation increase 4.00 % 4.00 % — % 4.00 % — % 4.00 % 4.00 % 4.00 % Expected long-term return on plan assets – The expected long-term return on plan assets assumption for our U.S. funded plan is determined based on an asset rate-of-return modeling tool developed by a third-party investment group which utilizes underlying assumptions based on actual returns by asset category and inflation and takes into account our U.S. pension plan’s asset allocation. To determine the expected long-term return on plan assets assumption for our international plans, we consider the current level of expected returns on risk-free investments (primarily government bonds), the historical levels of the risk premiums associated with the other applicable asset categories and the expectations for future returns of each asset class. The expected return for each asset category is then weighted based on the actual asset allocation to develop the overall expected long-term return on plan assets assumption. Assumed weighted average health care cost trend rates Employer provided subsidies for post-65 retiree health care coverage were frozen effective January 1, 2017 at January 1, 2016 established amount levels. Company contributions are funded to a Health Reimbursement Account on the retiree’s behalf to subsidize the retiree’s cost of obtaining health care benefits through a private exchange (the “post-65 retiree health benefits”). Therefore, a 1% change in health care cost trend rates would not have a material impact on either the service and interest cost components and the postretirement benefit obligations. In the fourth quarter of 2018, we terminated the post-65 retiree health benefits effective as of December 31, 2020. The post-65 retiree health benefits will no longer be provided after that date. In addition, the pre-65 retiree medical coverage subsidy has been frozen as of January 1, 2019, and the ability for retirees to opt in and out of this coverage, as well as pre-65 retiree dental and vision coverage, has also been eliminated. Retirees must enroll in connection with retirement for such coverage, or they lose eligibility. These plan changes reduced our retiree medical benefit obligation by approximately $99 million at December 31, 2018. Plan investment policies and strategies – The investment policies for our U.S. and international pension plan assets reflect the funded status of the plans and expectations regarding our future ability to make further contributions. Long-term investment goals are to: (1) manage the assets in accordance with applicable legal requirements; (2) produce investment returns which meet or exceed the rates of return achievable in the capital markets while maintaining the risk parameters set by the plan’s investment committees and protecting the assets from any erosion of purchasing power; and (3) position the portfolios with a long-term risk/return orientation. Investment performance and risk is measured and monitored on an ongoing basis through quarterly investment meetings and periodic asset and liability studies. U.S. plan – The plan’s current targeted asset allocation is comprised of 55% equity securities and 45% other fixed income securities. Over time, as the plan’s funded ratio (as defined by the investment policy) improves, in order to reduce volatility in returns and to better match the plan’s liabilities, the allocation to equity securities will decrease while the amount allocated to fixed income securities will increase. The plan’s assets are managed by a third-party investment manager. International plan – As mentioned above, the plan covering eligible U.K. employees that was transferred to the buyer in connection with the sale of our U.K. business during 2019. Fair value measurements – Plan assets are measured at fair value. The following provides a description of the valuation techniques employed for each major plan asset class at December 31, 2019 and 2018 . Cash and cash equivalents – Cash and cash equivalents are valued using a market approach and are considered Level 1. Equity securities – Investments in common stock are valued using a market approach at the closing price reported in an active market and are therefore considered Level 1. Private equity investments include interests in limited partnerships which are valued based on the sum of the estimated fair values of the investments held by each partnership, determined using a combination of market, income and cost approaches, plus working capital, adjusted for liabilities, currency translation and estimated performance incentives. These private equity investments are considered Level 3. Investments in pooled funds are valued using a market approach, these various funds consist of equity with underlying investments held in U.S. and non-U.S. securities. The pooled funds are benchmarked against a relative public index and are considered Level 2. Fixed income securities – Fixed income securities are valued using a market approach. U.S. treasury notes and exchange traded funds (“ETFs”) are valued at the closing price reported in an active market and are considered Level 1. Corporate bonds, private placements, and GNMA/FNMA/FHLMC pools are valued using calculated yield curves created by models that incorporate various market factors. Primarily investments are held in U.S. and non-U.S. corporate bonds in diverse industries and are considered Level 2. Forward contracts included under government securities are traded in the over-the-counter market and occur between two parties only with no intermediary. The details of each contract such as trade size, price and maturity are tailored to each security and negotiated between the two parties, as such, these investments are considered Level 3. Other fixed income investments include zero coupon and interest rate swaps. Investments in pooled funds are valued using a market approach, and primarily have investments held in U.S. and non-U.S. publicly traded investment grade government and corporate bonds and are considered Level 2. Other – Other investments are comprised of an unallocated annuity contract, two limited liability companies, and real estate. All are considered Level 3, as significant inputs to determine fair value are unobservable. Commingled funds – The investment in the commingled funds are valued using the net asset value of units held as a practical expedient. The commingled funds consist of equity and fixed income portfolios with underlying investments held in U.S. and non-U.S. securities. The following tables present the fair values of our defined benefit pension plan’s assets, by level within the fair value hierarchy, as of December 31, 2019 and 2018 . December 31, 2019 (In millions) Level 1 Level 2 Level 3 Total Cash and cash equivalents (a) $ (7 ) $ — $ — $ (7 ) Equity securities: Common stock 75 — — 75 Private equity — — 10 10 Pooled funds — — — — Fixed income securities: Corporate — 2 — 2 Exchange traded funds 3 — — 3 Government 31 11 5 47 Pooled funds — — — — Other — — 18 18 Total investments, at fair value 102 13 33 148 Commingled funds (b) — — — 88 Total investments $ 102 $ 13 $ 33 $ 236 December 31, 2018 (In millions) Level 1 Level 2 Level 3 Total U.S. Int’l U.S. Int’l U.S. Int’l U.S. Int’l Cash and cash equivalents (a) $ (1 ) $ 5 $ — $ — $ — $ — $ (1 ) $ 5 Equity securities: Common stock 75 — — — — — 75 — Private equity — — — — 14 — 14 — Pooled funds — — — 191 — — — 191 Fixed income securities: Corporate — — 4 — — — 4 — Government 22 — 9 — 3 — 34 — Pooled funds — — — 398 — — — 398 Other — — — — 17 — 17 — Total investments, at fair value 96 5 13 589 34 — 143 594 Commingled funds (b) — — — — — — 60 — Total investments $ 96 $ 5 $ 13 $ 589 $ 34 $ — $ 203 $ 594 (a) The negative cash balance was due to the timing of when investment trades occur and when they settle. (b) After the adoption of the FASB update for the fair value hierarchy, we separately report the investments for which fair value was measured using the net asset value per share as a practical expedient. Amounts presented in this table are intended to reconcile the fair value hierarchy to the pension plan assets. The activity during the year ended December 31, 2019 and 2018 , for the assets using Level 3 fair value measurements was immaterial. Cash flows Estimated future benefit payments – The following gross benefit payments, which were estimated based on actuarial assumptions applied at December 31, 2019 and reflect expected future services, as appropriate, are to be paid in the years indicated. (In millions) Pension Benefits Other Benefits 2020 $ 39 $ 18 2021 35 10 2022 31 9 2023 29 8 2024 27 7 2025 through 2029 116 25 Contributions to defined benefit plans – We expect to make contributions to the funded pension plan of up to $28 million in 2020 . Cash contributions to be paid from our general assets for the unfunded pension and postretirement plans are expected to be approximately $6 million and $18 million in 2020 . Contributions to defined contribution plans – We contribute to several defined contribution plans for eligible employees. Contributions to these plans totaled $18 million , $22 million and $20 million in 2019 , 2018 and 2017 .

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income (Notes)	12 Months Ended
	Dec. 31, 2019
Reclassifications out of AccumulatedOtherComprehensiveIncome [Abstract]
Reclassification out of AOCI [Text Block]	Reclassifications Out of Accumulated Other Comprehensive Income (Loss) The following table presents a summary of amounts reclassified from accumulated other comprehensive income (loss): Year Ended December 31, (In millions) 2019 2018 Income Statement Line Postretirement and postemployment plans Amortization of prior service credit $ 26 $ 18 Other net periodic benefit costs Amortization of actuarial loss (8 ) (12 ) Other net periodic benefit costs Net settlement loss, net of tax (12 ) (20 ) Other net periodic benefit costs 6 (14 ) Other U.K pension plan transferred to buyer (a)(b) 83 — Foreign currency translation adjustment related to sale of U.K. business (b) 30 — Income taxes related to sale of U.K. business (b) (45 ) — 68 — Net gain on disposal of assets Other insignificant items, net of tax 1 — Net interest and other Total reclassifications to expense, net of tax $ 75 $ (14 ) Net income (loss) (a) See Note 19 for detail on the U.K. pension plan. (b) See Note 5 for detail on the U.K. disposition.
Comprehensive Income (Loss) Note [Text Block]	Reclassifications Out of Accumulated Other Comprehensive Income (Loss) The following table presents a summary of amounts reclassified from accumulated other comprehensive income (loss): Year Ended December 31, (In millions) 2019 2018 Income Statement Line Postretirement and postemployment plans Amortization of prior service credit $ 26 $ 18 Other net periodic benefit costs Amortization of actuarial loss (8 ) (12 ) Other net periodic benefit costs Net settlement loss, net of tax (12 ) (20 ) Other net periodic benefit costs 6 (14 ) Other U.K pension plan transferred to buyer (a)(b) 83 — Foreign currency translation adjustment related to sale of U.K. business (b) 30 — Income taxes related to sale of U.K. business (b) (45 ) — 68 — Net gain on disposal of assets Other insignificant items, net of tax 1 — Net interest and other Total reclassifications to expense, net of tax $ 75 $ (14 ) Net income (loss) (a) See Note 19 for detail on the U.K. pension plan. (b) See Note 5 for detail on the U.K. disposition.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Year Ended December 31, (In millions) 2019 2018 2017 Included in operating activities: Interest paid, net of amounts capitalized $ 269 $ 270 $ 379 Income taxes paid to taxing authorities, net of refunds received (a) 73 287 391 Noncash investing activities, related to continuing operations: Increase (decrease) in asset retirement costs $ 80 $ (183 ) $ (202 ) Asset retirement obligations assumed by buyer (b) 1,082 82 14 Notes receivable for disposition of assets — — 748 (a) 2019 , 2018 and 2017 includes $90 million , $37 million and $1 million , related to tax refunds. 2017 included a payment of $108 million made to the U.K. tax authorities to preserve our appeal rights, see Note 25 for additional discussion. (b) In 2019, our dispositions include the sale of the Droshky field (Gulf of Mexico), the sale of our non-operated interest in the Atrush block in Kurdistan and the sale of our U.K. business. See Note 5 for further detail on dispositions. Other noncash investing activities include accrued capital expenditures as of December 31, 2019 , 2018 and 2017 of $288 million , $250 million and $329 million .

Other Items

Other Items	12 Months Ended
	Dec. 31, 2019
Interest and Other Income [Abstract]
Interest and Other Income [Text Block]	Other Items Net interest and other Year Ended December 31, (In millions) 2019 2018 2017 Interest: Interest income $ 25 $ 32 $ 34 Interest expense (280 ) (280 ) (380 ) Income on interest rate swaps — — 53 Interest capitalized — — 3 Total interest (255 ) (248 ) (290 ) Other: Net foreign currency gain (loss) 4 9 8 Other 7 13 12 Total other 11 22 20 Net interest and other $ (244 ) $ (226 ) $ (270 ) Foreign currency – Aggregate foreign currency gains (losses) were included in the consolidated statements of income as follows: Year Ended December 31, (In millions) 2019 2018 2017 Net interest and other $ 4 $ 9 $ 8 Provision for income taxes 2 10 57 Aggregate foreign currency gains $ 6 $ 19 $ 65

Equity Method Investments and R

Equity Method Investments and Related Party Transactions (Notes)	12 Months Ended
	Dec. 31, 2019
Equity Method Investments Disclosure [Abstract]
Equity Method Investments and Related Party Transactions	Equity Method Investments During 2019 , 2018 and 2017 our equity method investees were considered related parties and included: • EGHoldings, in which we have a 60% noncontrolling interest. EGHoldings is engaged in LNG production activity. • Alba Plant LLC, in which we have a 52% noncontrolling interest. Alba Plant LLC processes LPG. • AMPCO, in which we have a 45% noncontrolling interest. AMPCO is engaged in methanol production activity. Our equity method investments are summarized in the following table: Ownership as of December 31, (In millions) December 31, 2019 2019 2018 EGHoldings 60% $ 310 $ 402 Alba Plant LLC 52% 163 167 AMPCO 45% 190 176 Total $ 663 $ 745 Dividends and partnership distributions received from equity method investees (excluding distributions that represented a return of capital previously contributed) were $105 million in 2019 , $270 million in 2018 and $276 million in 2017 . Summarized financial information for equity method investees is as follows: (In millions) 2019 2018 2017 Income data – year: Revenues and other income $ 832 $ 1,269 $ 1,294 Income from operations 250 588 631 Net income 187 459 508 Balance sheet data – December 31: Current assets $ 455 $ 559 Noncurrent assets 1,049 931 Current liabilities 284 253 Noncurrent liabilities 183 87 Revenues from related parties were $42 million , $48 million and $60 million in 2019 , 2018 and 2017 , respectively, with the majority related to EGHoldings in all years. We had no purchases from related parties during both 2019 and 2018 , and $132 million in 2017 , with the majority related to Alba Plant LLC. Current receivables from related parties at December 31, 2019 and 2018 were $28 million and $25 million , with the majority related to EGHoldings and Alba Plant LLC for 2019 and EGHoldings in 2018. Payables to related parties were $11 million and $15 million at December 31, 2019 and 2018 , respectively, with the majority related to Alba Plant LLC.

Stockholders Equity (Notes)

Stockholders Equity (Notes)	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders’ Equity	Stockholders’ Equity On July 31, 2019, the Board of Directors authorized an extension of the share repurchase program, which increased the remaining share repurchase authorization to $1.5 billion . During 2019 , we acquired approximately 24 million of common shares at a cost of $345 million , which were held as treasury stock. During 2018 , we acquired 36 million of common shares at a cost of $700 million under the same program. As of December 31, 2019 the total remaining share repurchase authorization was $1.4 billion

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Following the sale of our U.K. business to RockRose, we continued to hold outstanding surety bonds which guaranteed our decommissioning liabilities related to the Marathon Oil U.K. LLC assets. We issued these surety bonds in November 2018 with a notional value of approximately £92 million and an expiration date of December 31, 2019. RockRose was contractually required to post a replacement security to cover 2020 by no later than December 1, 2019. During the third quarter of 2019, we recorded a $6 million liability and corresponding expense related to the estimated fair value of our exposure to surety bonds. In November 2019, RockRose posted replacement security and accordingly, we reversed the aforementioned $6 million . See Note 5 for discussion of the U.K. sale in further detail. In the second quarter of 2019, Marathon E.G. Production Limited (“MEGPL”), a consolidated and wholly-owned subsidiary, signed a series of agreements to process third-party Alen Unit gas through existing infrastructure located in Punta Europa, E.G. MEGPL is a signatory to the agreements related to our equity method investee, Alba Plant LLC. These agreements contain clauses that cause MEGPL to indemnify the owners of the Alen Unit against actions or inaction by Alba Plant LLC. Pursuant to these agreements, MEGPL agreed to indemnify third party property or events, including environmental assessments, injury to Alba Plant LLC’s personnel, and damage to or loss of Alba Plant LLC’s automobiles. At this time, we cannot reasonably estimate this obligation as we do not have any history of prior indemnification claims, as completion of the plant modifications is not expected to finish until 2021, and as such, we do not have any history of environmental discharge or contamination. Therefore, we have not recorded a liability with respect to these indemnification clauses since the amount of potential future payments under such guarantees is not determinable. We are routinely undergoing examination of our U.S. federal income tax returns by the IRS. With the closure of the 2010-2011 IRS Audit referenced in Note 8 , these audits have been completed through the 2016 tax year with the exception of the following item. During the third quarter of 2017, we received a partnership adjustment notification related to the 2010 and 2011 tax years, for which we filed a Tax Court Petition in the fourth quarter of 2017. During the third quarter of 2019, we received the court decision which ruled in our favor for all material items. At December 31, 2019 , all issues have been effectively settled related to the partnership audit. Various groups, including the State of North Dakota and three Indian tribes represented by the Bureau of Indian Affairs, have been involved in a dispute regarding the ownership of certain lands underlying the Missouri River and Little Missouri River. As a result, as of December 31, 2019 , we have recorded a $93 million liability in suspended royalty and working interest revenue, including interest, and have recorded a long-term receivable of $20 million for capital and expenses. We are a defendant in a number of legal and administrative proceedings arising in the ordinary course of business including, but not limited to, royalty claims, contract claims, tax disputes and environmental claims. While the ultimate outcome and impact to us cannot be predicted with certainty, we believe the resolution of these proceedings will not have a material adverse effect on our consolidated financial position, results of operations or cash flows. Certain of these matters are discussed below. Environmental matters – We have incurred and will continue to incur capital, operating and maintenance, and remediation expenditures as a result of environmental laws and regulations. If these expenditures, as with all costs, are not ultimately offset by the prices we receive for our products and services, our operating results will be adversely affected. We believe that substantially all of our competitors must comply with similar environmental laws and regulations. However, the specific impact on each competitor may vary depending on a number of factors, including the age and location of its operating facilities, marketing areas and production processes. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites. Penalties may be imposed for noncompliance. At December 31, 2019 and 2018 , accrued liabilities for remediation were not material. It is not presently possible to estimate the ultimate amount of all remediation costs that might be incurred or the penalties that may be imposed. Guarantees – Over the years, we have sold various assets in the normal course of our business. Certain of the related agreements contain performance and general guarantees, including guarantees regarding inaccuracies in representations, warranties, covenants and agreements, and environmental and general indemnifications that require us to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications are part of the normal course of selling assets. We are typically not able to calculate the maximum potential amount of future payments that could be made under such contractual provisions because of the variability inherent in the guarantees and indemnities. Most often, the nature of the guarantees and indemnities is such that there is no appropriate method for quantifying the exposure because the underlying triggering event has little or no past experience upon which a reasonable prediction of the outcome can be based. Contract commitments – At December 31, 2019 and 2018 , contractual commitments to acquire property, plant and equipment totaled $41 million and $57 million . In connection with the sale of our operated producing properties in the greater Ewing Bank area and non-operated producing interests in the Petronius and Neptune fields in the Gulf of Mexico, we retained an overriding royalty interest in the properties. As part of the sale agreement, proceeds associated with the production of our override were $46 million as of December 31, 2019 , and are dedicated solely to the satisfaction of the corresponding future abandonment obligations of the properties. The term of our override ends once sales proceeds equal $70 million .

Summary of Principal Accounti_2

Summary of Principal Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Principles applied in consolidation	Basis of presentation and principles applied in consolidation – These consolidated financial statements, including notes have been prepared in accordance with U.S. GAAP. These consolidated financial statements include the accounts of our controlled subsidiaries. Investments in unincorporated joint ventures and undivided interests in certain operating assets are consolidated on a pro rata basis. Equity method investments – Investments in entities over which we have significant influence, but not control, are accounted for using the equity method of accounting. This includes entities in which we hold majority ownership but the minority stockholders have substantive participating rights in the investee. Income from equity method investments represents our proportionate share of net income generated by the equity method investees and is reflected in revenues and other income in our consolidated statements of income. Equity method investments are included as noncurrent assets on the consolidated balance sheet. Equity method investments are assessed for impairment whenever changes in the facts and circumstances indicate a loss in value may have occurred. When a loss is deemed to have occurred and is other than temporary, the carrying value of the equity method investment is written down to fair value, and the amount of the write-down is included in income. Discontinued operations – As a result of the sale of our Canadian business in 2017, we reflected this business as discontinued operations in all historical periods presented. Disclosures in this report related to results of operations and cash flows are presented on the basis of continuing operations unless otherwise stated. See Note 5 for discussion of the divestiture in further detail.
Use of estimates	Use of estimates – The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods. Estimated quantities of crude oil and condensate, NGLs and natural gas reserves is a significant estimate that requires judgment. All of the reserve data included in this Form 10-K are estimates. Reservoir engineering is a subjective process of estimating underground accumulations of crude oil and condensate, NGLs and natural gas. There are numerous uncertainties inherent in estimating quantities of proved crude oil and condensate, NGLs and natural gas reserves. The accuracy of any reserves estimate is a function of the quality of available data and of engineering and geological interpretation and judgment. As a result, reserve estimates may be different from the quantities of crude oil and condensate, NGLs and natural gas that are ultimately recovered. See unaudited Supplementary Data - Supplementary Information on Oil and Gas Producing Activities for further detail. Other items subject to estimates and assumptions include the carrying amounts of property, plant and equipment, asset retirement obligations, goodwill, valuation of derivative instruments and valuation allowances for deferred income tax assets, among others. Although we believe these estimates are reasonable, actual results could differ from these estimates.
Foreign currency transactions	Foreign currency transactions – The U.S. dollar is the functional currency of our foreign operating subsidiaries. Foreign currency transaction gains and losses are included in net income.
Revenue recognition	Revenue recognition – Revenues associated with the sales of crude oil and condensate, NGLs and natural gas are recognized when our performance obligation is satisfied, which typically occurs at the point where control transfers to the customer based on contract terms. Revenue is measured as the amount the company expects to receive in exchange for transferring commodities to the customer. Our hydrocarbon sales are typically based on prevailing market-based prices and may include quality or location differential adjustments. Payment is generally due within 30 days of delivery. We typically incur shipping and handling costs prior to control transferring to the customer and account for these activities as fulfillment costs. These costs are reflected in shipping, handling and other operating expense line in our consolidated statement of income. Our U.S. production of crude oil and condensate, NGLs and natural gas is generally sold immediately and transported to market. In our international segment, liquid hydrocarbon production may be stored as inventory and sold at a later time.
Cash and cash equivalents	Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid debt instruments with original maturities of three months or less.
Investment, Policy [Policy Text Block]	.
Accounts receivable	Accounts receivable – The majority of our receivables are from purchasers of commodities or joint interest owners in properties we operate, both of which are recorded at estimated or invoiced amounts and do not bear interest. We often have the ability to withhold future revenue disbursements to recover any non-payment of joint interest billings. We conduct credit reviews of commodity purchasers prior to making commodity sales to new customers or increasing credit for existing customers. Based on these reviews, we may require a standby letter of credit or a financial guarantee. We routinely assess the collectability of receivable balances to determine if the amount of the reserve in allowance for doubtful accounts is sufficient.
Inventories	Inventories – Crude oil and natural gas are recorded at weighted average cost and carried at the lower of cost or net realizable value. Supplies and other items consist principally of tubular goods and equipment which are valued at weighted average cost and reviewed periodically for obsol escence or impairment when market conditions indicate . We may enter into a contract to sell a particular quantity and quality of crude oil at a specified location and date to a particular counterparty, and simultaneously agree to buy a particular quantity and quality of the same commodity at a specified location on the same or another specified date from the same counterparty. We account for such matching buy/sell arrangements as exchanges of inventory.
Derivative instruments	Derivative instruments – We may use derivatives to manage a portion of our exposure to commodity price risk, commodity locational risk and interest rate risk. All derivative instruments are recorded at fair value. Commodity derivatives and interest rate swaps are reflected on our consolidated balance sheet on a net basis by counterparty, as they are governed by master netting agreements. Cash flows related to derivatives used to manage commodity price risk, and interest rate risk are classified in operating activities. Our derivative instruments contain no significant contingent credit features.
Hedges	Fair value hedges – We may use interest rate swaps to manage our exposure to interest rate risk associated with fixed interest rate debt in our portfolio. Changes in the fair values of both the hedged item and the related derivative are recognized immediately in net income with an offsetting effect included in the basis of the hedged item. The net effect is to report in net income the extent to which the hedge is not effective in achieving offsetting changes in fair value. Cash flow hedges – We may use interest rate derivative instruments to manage the risk of interest rate changes during the period prior to anticipated borrowings as well as to stabilize future lease payments on our future Houston office, and designate them as cash flow hedges. Derivative instruments designated as cash flow hedges are linked to specific assets and liabilities or to specific firm commitments or forecasted transactions. The changes in the fair value of a qualifying cash flow hedge are recorded in other comprehensive income until the hedged transaction affects earnings and are then reclassified into net income. Beginning in 2019, ineffective portions of a cash flow hedge are no longer measured or disclosed separately. However, if it is determined that the likelihood of the original forecasted transaction occurring is no longer probable or the cash flow hedge is no longer expected to be highly effective, subsequent changes in fair value of the derivatives instrument are recorded in net income.
Derivatives not designated as hedges	Derivatives not designated as hedges
Concentrations of credit risk	Concentrations of credit risk – All of our financial instruments, including derivatives, involve elements of credit and market risk. The most significant portion of our credit risk relates to nonperformance by counterparties. The counterparties to our financial instruments consist primarily of major financial institutions and companies within the energy industry. To manage counterparty risk associated with financial instruments, we select and monitor counterparties based on our assessment of their financial strength and on credit ratings, if available. Additionally, we limit the level of exposure with any single counterparty.
Fair value transfer	Fair value transfer – We recognize transfers between levels of the fair value hierarchy as of the end of the reporting period.
Property, plant and equipment	Property, plant and equipment – We use the successful efforts method of accounting for oil and gas producing activities.
Property acquisition costs	Property acquisition costs – Costs to acquire mineral interests in oil and natural gas properties, to drill exploratory wells in progress and those that find proved reserves, and to drill development wells are capitalized. Costs to drill exploratory wells that do not find proved reserves, geological and geophysical costs and costs of carrying and retaining unproved properties are expensed. Costs incurred for exploratory wells that find reserves but cannot yet be classified as proved are capitalized if (1) the well has found a sufficient quantity of reserves to justify its completion as a producing well and (2) we are making sufficient progress assessing the reserves and the economic and operating viability of the project. The status of suspended exploratory well costs is monitored continuously and reviewed at least quarterly.
Depreciation, depletion and amortization	Depreciation, depletion and amortization – Capitalized costs to acquire oil and natural gas properties are depreciated and depleted on a units-of-production basis based on estimated proved reserves. Capitalized costs of exploratory wells and development costs are depreciated and depleted on a units-of-production basis based on estimated proved developed reserves. Support equipment and other property, plant and equipment related to oil and gas producing activities, as well as property, plant and equipment unrelated to oil and gas producing activities, are recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets as summarized below. Type of Asset Range of Useful Lives Office furniture, equipment and computer hardware 4 to 15 years Pipelines 5 to 40 years Plants, facilities and infrastructure 3 to 40 years
Impairments	Impairments – We evaluate our oil and gas producing properties, including capitalized costs of exploratory wells and development costs, for impairment of value whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the expected undiscounted future cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset. Oil and gas producing properties are reviewed for impairment on a field-by-field basis or, in certain instances, by logical grouping of assets if there is significant shared infrastructure or contractual terms that cause economic interdependency amongst separate, discrete fields. Oil and gas producing properties deemed to be impaired are written down to their fair value, as determined by discounted future net cash flows or, if available, comparable market value. We evaluate our unproved property investment and record impairment based on time or geologic factors. Information such as drilling results, reservoir performance, seismic interpretation or future plans to develop acreage is also considered. When unproved property investments are deemed to be impaired, this amount is reported in exploration expenses in our consolidated statements of income.
Dispositions	Dispositions – When property, plant and equipment depreciated on an individual basis is sold or otherwise disposed of, any gains or losses are reflected in net gain (loss) on disposal of assets in our consolidated statements of income. Gains on the disposal of property, plant and equipment are recognized when earned, which is generally at the time of closing. If a loss on disposal is expected, such losses are recognized either when the assets are classified as held for sale, or are measured using a probability weighted income approach based on both the anticipated sales price and a held-for-use model depending on timing of the sale. Proceeds from the disposal of property, plant and equipment depreciated on a group basis are credited to accumulated depreciation, depletion and amortization with no immediate effect on net income until net book value is reduced to zero.
Goodwill	Goodwill
Environmental costs	Environmental costs – We provide for remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of a feasibility study or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed or reliably determinable. Environmental expenditures are capitalized only if the costs mitigate or prevent future contamination or if the costs improve the environmental safety or efficiency of the existing assets.
Asset retirement obligations	Asset retirement obligations – The fair value of asset retirement obligations is recognized in the period in which the obligations are incurred if a reasonable estimate of fair value can be made. Our asset retirement obligations primarily relate to the abandonment of oil and gas producing facilities. Asset retirement obligations for such facilities include costs to dismantle and relocate or dispose of production platforms, gathering systems, wells and related structures and restoration costs of land, including those leased. Estimates of these costs are developed for each property based on the type of production facilities and equipment, reservoir characteristics, depth of the reservoir, market demand for equipment, currently available procedures and consultations with construction and engineering professionals.
Deferred income taxes	Deferred income taxes – Deferred tax assets and liabilities, measured at enacted tax rates, are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their tax bases as reported in our filings with the respective taxing authorities. We routinely assess the realizability of our deferred tax assets based on several interrelated factors and reduce such assets by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized. These factors include whether we are in a cumulative loss position in recent years, our reversal of temporary differences, and our expectation to generate sufficient future taxable income. We use the liability method in determining our provision and liabilities for our income taxes, under which current and deferred tax liabilities and assets are recorded in accordance with enacted tax laws and rates.
Stock based compensation arrangements	Stock-based compensation arrangements – The fair value of stock options is estimated on the date of grant using the Black-Scholes option pricing model. The model employs various assumptions, based on management’s best estimates at the time of grant, which impact the calculation of fair value and ultimately, the amount of expense that is recognized over the life of the stock option award. Of the required assumptions, the expected volatility of our stock price and the stock price in relation to the strike price have the most significant impact on the fair value calculation. We have utilized historical data and analyzed current information which reasonably support these assumptions. The fair value of our restricted stock awards, restricted stock units and Director restricted stock units is determined based on the market value of our common stock on the date of grant. Restricted Stock Awards, restricted stock units, and Director restricted stock units are removed from Treasury Stock at grant, vesting, and distribution, respectively. The fair value of our cash-settled stock-based performance units is estimated using the Monte Carlo simulation method. Since these awards are settled in cash at the end of a defined performance period, they are classified as a liability and are re-measured quarterly until settlement. The fair value of our stock-settled stock-based performance units is estimated using the Monte Carlo simulation method at grant date only. Since these awards are settled in stock, they are classified as equity.

Income per Common Share (Tables

Income per Common Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The per share calculations below exclude $6 million , $6 million and 11 million stock options in 2019 , 2018 and 2017 that were antidilutive. Year Ended December 31, (In millions, except per share data) 2019 2018 2017 Income (loss) from continuing operations $ 480 $ 1,096 $ (830 ) Loss from discontinued operations — — (4,893 ) Net income (loss) $ 480 $ 1,096 $ (5,723 ) Weighted average common shares outstanding 810 846 850 Effect of dilutive securities — 1 — Weighted average common shares, diluted 810 847 850 Per basic share: Income (loss) from continuing operations $ 0.59 $ 1.30 $ (0.97 ) Loss from discontinued operations $ — $ — $ (5.76 ) Net income (loss) $ 0.59 $ 1.30 $ (6.73 ) Per diluted share: Income (loss) from continuing operations $ 0.59 $ 1.29 $ (0.97 ) Loss from discontinued operations $ — $ — $ (5.76 ) Net income (loss) $ 0.59 $ 1.29 $ (6.73 ) Dividends per share $ 0.20 $ 0.20 $ 0.20

Dispositions (Tables)

Dispositions (Tables)	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures	The following table contains select amounts reported in our historical consolidated statements of income and consolidated statements of cash flows as discontinued operations: Year Ended December 31, (In millions) 2017 Total revenue and other income $ 431 Net loss on disposal of assets (43 ) Total revenues and other income 388 Costs and expenses: Production 254 Depreciation, depletion and amortization 40 Impairments 6,636 Other 25 Total costs and expenses 6,955 Pretax loss from discontinued operations (6,567 ) Benefit for income taxes (1,674 ) Loss from discontinued operations $ (4,893 ) Year Ended December 31, (In millions) 2017 Cash flow from discontinued operations: Operating activities $ 141 Investing activities (13 ) Changes in cash included in current assets held for sale 2 Net increase in cash and cash equivalents of discontinued operations $ 130

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables present our revenues from contracts with customers disaggregated by product type and geographic areas. United States Year Ended December 31, 2019 (In millions) Eagle Ford Bakken Oklahoma Northern Delaware Other U.S. Total Crude oil and condensate $ 1,358 $ 1,686 $ 425 $ 316 $ 102 $ 3,887 Natural gas liquids 114 46 116 26 5 307 Natural gas 121 39 156 16 17 349 Other 7 — — — 52 59 Revenues from contracts with customers $ 1,600 $ 1,771 $ 697 $ 358 $ 176 $ 4,602 Year Ended December 31, 2018 (In millions) Eagle Ford Bakken Oklahoma Northern Delaware Other U.S. Total Crude oil and condensate $ 1,554 $ 1,568 $ 426 $ 235 $ 164 $ 3,947 Natural gas liquids 205 62 181 38 9 495 Natural gas 145 38 184 20 26 413 Other 8 — — — 23 31 Revenues from contracts with customers $ 1,912 $ 1,668 $ 791 $ 293 $ 222 $ 4,886 International Year Ended December 31, 2019 (In millions) E.G. U.K. Other International Total Crude oil and condensate $ 271 $ 107 $ 20 $ 398 Natural gas liquids 4 1 — 5 Natural gas 32 12 — 44 Other — 14 — 14 Revenues from contracts with customers $ 307 $ 134 $ 20 $ 461 Year Ended December 31, 2018 (In millions) E.G. U.K. Libya Other International Total Crude oil and condensate $ 342 $ 282 $ 187 $ 77 $ 888 Natural gas liquids 4 5 — — 9 Natural gas 37 40 9 — 86 Other 1 32 — — 33 Revenues from contracts with customers $ 384 $ 359 $ 196 $ 77 $ 1,016
Contract with Customer, Asset and Liability	Changes in the contract asset (liability) balance during the period are as follows. (In millions) Year Ended December 31, 2019 Contract asset (liability) balance as of January 1, 2019 $ (1 ) Revenue recognized as performance obligations are satisfied 74 Amounts invoiced to customers (52 ) Contract asset (liability) transferred to buyer (a) (21 ) Contract asset (liability) balance as of December 31, 2019 $ — (a) Refer to Note 5 for further information on the sale of our U.K. business. The following table provides information about receivables and contract assets (liabilities) from contracts with customers. December 31, (In millions) 2019 2018 Receivables from contracts with customers, included in receivables, less reserves $ 837 $ 714 Contract asset (liability) $ — $ (1 )

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Year Ended December 31, 2019 (In millions) U.S. Int’l Not Allocated to Segments Total Revenues from contracts with customers $ 4,602 $ 461 $ — $ 5,063 Net gain (loss) on commodity derivatives 52 — (124 ) (b) (72 ) Income from equity method investments — 87 — 87 Net gain on disposal of assets — — 50 (c) 50 Other income 13 9 40 62 Less costs and expenses: Production 588 126 (2 ) 712 Shipping, handling and other operating 561 26 18 605 Exploration 149 — — 149 Depreciation, depletion and amortization 2,250 121 26 2,397 Impairments — — 24 (d) 24 Taxes other than income 311 — — 311 General and administrative 127 25 204 356 Net interest and other — — 244 244 Other net periodic benefit costs — (3 ) — (e) (3 ) Loss on early extinguishment of debt — — 3 3 Income tax provision (benefit) 6 29 (123 ) (88 ) Segment income (loss) $ 675 $ 233 $ (428 ) $ 480 Total assets $ 17,781 $ 1,530 $ 934 $ 20,245 Capital expenditures (a) $ 2,550 $ 16 $ 25 $ 2,591 (a) Includes accruals and excludes acquisitions. (b) Unrealized loss on commodity derivative instruments (see Note 15 ). (c) Primarily related to the sale of our working interest in the Droshky field (Gulf of Mexico) and the sale of our U.K. business (see Note 5 ). (d) Primarily a result of anticipated sales of non-core proved properties in our International and United States segments (see Note 11 ). (e) Includes pension settlement loss of $12 million (see Note 19 ). Year Ended December 31, 2018 (In millions) U.S. Int’l Not Allocated to Segments Total Revenues from contracts with customers $ 4,886 $ 1,016 $ — $ 5,902 Net gain (loss) on commodity derivatives (281 ) — 267 (b) (14 ) Income from equity method investments — 225 — 225 Net gain on disposal of assets — — 319 (c) 319 Other income 16 12 122 (d) 150 Less costs and expenses: Production 625 215 2 842 Shipping, handling and other operating 499 70 6 575 Exploration 246 3 40 (e) 289 Depreciation, depletion and amortization 2,217 197 27 2,441 Impairments — — 75 (f) 75 Taxes other than income 301 — (2 ) 299 General and administrative 146 32 216 394 Net interest and other — — 226 226 Other net periodic benefit costs — (9 ) 23 (g) 14 Income tax provision (benefit) (21 ) 272 80 331 Segment income $ 608 $ 473 $ 15 $ 1,096 Total assets $ 17,321 $ 2,083 $ 1,917 $ 21,321 Capital expenditures (a) $ 2,620 $ 39 $ 26 $ 2,685 (a) Includes accruals and excludes acquisitions. (b) Unrealized gain on commodity derivative instruments (see Note 15 ). (c) Primarily related to the gain on sale of our Libya subsidiary (see Note 5 ). (d) Primarily a reduction of asset retirement obligations in our International segment (see Note 12 ). (e) Primarily related to dry well expense and unproved property impairments associated with the Rodo well in Alba Block Sub Area B, offshore E.G. (see Note 10 ). (f) Due to the anticipated sales of certain non-core proved properties in our International and United States segments (see Note 11 ). (g) Includes pension settlement loss of $21 million (see Note 19 ). Year Ended December 31, 2017 (In millions) U.S. Int’l Not Allocated to Segments Total Revenues from contracts with customers $ 3,093 $ 1,154 $ — $ 4,247 Net gain (loss) on commodity derivatives 45 — (81 ) (b) (36 ) Marketing revenues 29 133 — 162 Income from equity method investments — 256 — 256 Net gain on disposal of assets 1 — 57 (c) 58 Other income 12 6 60 78 Less costs and expenses: Production 476 239 1 716 Marketing costs 36 132 — 168 Shipping, handling and other operating 354 77 — 431 Exploration 154 5 250 (d) 409 Depreciation, depletion and amortization 2,011 328 33 2,372 Impairments 4 — 225 (e) 229 Taxes other than income 173 — 10 183 General and administrative 119 30 222 371 Net interest and other — — 270 (f) 270 Other net periodic benefit costs — (8 ) 27 (g) 19 Loss on early extinguishment of debt — — 51 (h) 51 Income tax provision 1 372 3 376 Segment income (loss) $ (148 ) $ 374 $ (1,056 ) $ (830 ) Total assets $ 16,863 $ 4,201 $ 948 $ 22,012 Capital expenditures (a) $ 2,081 $ 42 $ 27 $ 2,150 (a) Includes accruals and excludes acquisitions. (b) Unrealized loss on commodity derivative instruments (see Note 15 ). (c) Primarily related to the sale of certain conventional assets in Oklahoma and Colorado (see Note 5 ). (d) Primarily related to unproved property impairments associated with certain non-core properties within our International segment (see Note 11 ). (e) Primarily related to proved property impairments associated with certain non-core properties within our International segment (see Note 11 ). (f) Includes a gain of $46 million resulting from the termination of our forward starting interest rate swaps (see Note 15 ). (g) Includes pension settlement loss of $32 million (see Note 19 ). (h) Primarily related to the make-whole call provisions paid upon redemption of our senior unsecured notes (see Note 17 ).
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country	The following summarizes property, plant and equipment and equity method investments. December 31, (In millions) 2019 2018 United States $ 16,507 $ 16,094 Equatorial Guinea 1,156 1,333 Other international (a) — 122 Total long-lived assets $ 17,663 $ 17,549

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	Income (loss) from continuing operations before income taxes were: Year Ended December 31, (In millions) 2019 2018 2017 United States $ 43 $ 642 $ (783 ) Foreign 349 785 329 Total $ 392 $ 1,427 $ (454 )
Schedule of Components of Income Tax Expense (Benefit)	Income tax provisions (benefits) for continuing operations were: Year Ended December 31, 2019 2018 2017 (In millions) Current Deferred Total Current Deferred Total Current Deferred Total Federal $ (116 ) $ (3 ) $ (119 ) $ 6 $ — $ 6 $ (32 ) $ 41 $ 9 State and local 4 3 7 (1 ) (23 ) (24 ) (14 ) 2 (12 ) Foreign 58 (34 ) 24 274 75 349 483 (104 ) 379 Total $ (54 ) $ (34 ) $ (88 ) $ 279 $ 52 $ 331 $ 437 $ (61 ) $ 376
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the federal statutory income tax rate applied to income (loss) from continuing operations before income taxes to the provision (benefit) for income taxes follows: Year Ended December 31, (In millions) 2019 2018 2017 Total pre-tax income (loss) from continuing operations $ 392 $ 1,427 $ (454 ) Total income tax expense (benefit) $ (88 ) $ 331 $ 376 Effective income tax rate (benefit) on continuing operations (22 )% 23 % 83 % Income taxes at the statutory tax rate (a)(b) $ 83 $ 300 $ (159 ) Effects of foreign operations (29 ) 214 140 Adjustments to valuation allowances (28 ) (177 ) 446 State income taxes 11 (17 ) (19 ) Tax law change — — (35 ) Other federal tax effects (125 ) 11 3 Income tax expense (benefit) on continuing operations $ (88 ) $ 331 $ 376
Schedule of Deferred Tax Assets and Liabilities	Deferred tax assets and liabilities resulted from the following: Year Ended December 31, (In millions) 2019 2018 Deferred tax assets: Employee benefits $ 90 $ 75 Operating loss carryforwards 1,685 1,304 Capital loss carryforwards 1 2 Foreign tax credits 611 611 Other 27 4 Subtotal 2,414 1,996 Valuation allowance (699 ) (721 ) Total deferred tax assets 1,715 1,275 Deferred tax liabilities: Property, plant and equipment 1,861 1,018 Accrued revenue 40 60 Other — 3 Total deferred tax liabilities 1,901 1,081 Net deferred tax liabilities $ 186 $ — Net deferred tax assets $ — $ 194
Net Deferred Tax Assets Liabilities Table	Net deferred tax assets and liabilities were classified in the consolidated balance sheets as follows: December 31, (In millions) 2019 2018 Assets: Other noncurrent assets $ — $ 393 Liabilities: Noncurrent deferred tax liabilities 186 199 Net deferred tax liabilities $ 186 $ — Net deferred tax assets $ — $ 194
Income Tax Returns Remaining Subject To Examination Table	As of December 31, 2019 , our income tax returns remain subject to examination in the following major tax jurisdictions for the tax years indicated: United States (a) 2008-2018 Equatorial Guinea 2007-2018 (a) Includes federal and state jurisdictions.
Summary Of Activity In Unrecognized Tax Benefits Table	The following table summarizes the activity in unrecognized tax benefits: (In millions) 2019 2018 2017 Beginning balance $ 263 $ 126 $ 66 Additions for tax positions of prior years 13 152 83 Reductions for tax positions of prior years (152 ) (15 ) (3 ) Settlements (111 ) — (20 ) Ending balance $ 13 $ 263 $ 126

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	December 31, (In millions) 2019 2018 Crude oil and natural gas $ 10 $ 11 Supplies and other items 62 85 Inventories $ 72 $ 96

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule Of Property Plant And Equipment	Property, Plant and Equipment December 31, (In millions) 2019 2018 United States $ 16,427 $ 16,011 International (a) 493 710 Not allocated to segments 80 83 Net property, plant and equipment $ 17,000 $ 16,804
Schedule of Projects with Exploratory Well Costs Capitalized for More than One Year	At December 31, 2019 , 2018 and 2017 we had total deferred exploratory well costs as follows: December 31, (In millions) 2019 2018 2017 Amounts capitalized less than one year after completion of drilling $ 278 $ 297 $ 263 Amounts capitalized greater than one year after completion of drilling — — 32 Total deferred exploratory well costs $ 278 $ 297 $ 295 Number of projects with costs capitalized greater than one year after completion of drilling — — 1 (In millions) 2019 2018 2017 Beginning balance $ 297 $ 295 $ 249 Additions 218 262 212 Charges to expense (a) (5 ) (35 ) (64 ) Transfers to development (230 ) (197 ) (102 ) Dispositions (b) (2 ) (28 ) — Ending balance $ 278 $ 297 $ 295 (a) 2018 includes $32 million related to the Rodo well in Alba Block Sub Area B, offshore E.G. 2017 includes $64 million as a result of our agreement to sell Diaba License G4-223 in the Republic of Gabon (see Note 11 for further detail). (b) 2018 includes the sale of our Libya subsidiary.

Impairment (Tables)

Impairment (Tables)	12 Months Ended
	Dec. 31, 2019
Impairments and Exploration Expenses [Abstract]
Fair Value Measurements, Nonrecurring [Table Text Block]	The following table summarizes impairment charges of proved properties from continuing operations. Additionally, it presents the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition. 2019 2018 2017 (In millions) Fair Value Impairment Fair Value Impairment Fair Value Impairment Long-lived assets held for use $ 56 $ 24 $ 113 $ 75 $ 179 $ 229

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Change in Asset Retirement Obligation	Asset retirement obligations primarily consist of estimated costs to remove, dismantle and restore land at the end of oil and gas production operations. Changes in asset retirement obligations for the periods ended December 31 were as follows: (In millions) 2019 2018 Beginning balance $ 1,145 $ 1,483 Incurred liabilities, including acquisitions 34 21 Settled liabilities, including dispositions (1,110 ) (117 ) Accretion expense (included in depreciation, depletion and amortization) 31 70 Revisions of estimates 46 (204 ) Held for sale (a) 108 (108 ) Ending balance (b) $ 254 $ 1,145

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Supplemental Balance Sheet Information	Supplemental balance sheet information related to leases was as follows: (In millions) December 31, 2019 Operating Leases: Balance Sheet Location: ROU asset Other noncurrent assets $ 199 Current portion of long-term lease liability Other current liabilities $ 101 Long-term lease liability Deferred credits and other liabilities $ 107
Lease Costs	The table below presents our net lease costs as of December 31, 2019 with the majority of operating lease costs expensed as incurred, while the majority of the short-term and variable lease costs are capitalized into property, plant and equipment. (In millions) Year Ended December 31, 2019 Lease costs: Operating lease costs (a) $ 84 Short-term lease costs (b) 321 Variable lease costs (c) 107 Total lease costs $ 512 Other information: Cash paid for amounts included in the measurement of operating lease liabilities $ 100 ROU assets obtained in exchange for new operating lease liabilities (d) $ 293 (a) Represents our net share of the ROU asset amortization and the interest expense. (b) Represents our net share of lease costs arising from leases of less than one year but longer than one month that were not included in the lease liability. (c) Represents our net share of variable lease payments that were not included in the lease liability. (d) Represents the cumulative value of ROU assets recognized at lease inception during the year of 2019 . This amount is then amortized as we utilize the ROU asset, the net effect of which is the ending ROU asset of $199 million (first table above).
Operating Lease, Maturity	The remaining annual undiscounted cash flows associated with long-term leases and the reconciliation of these cash flows to the lease liabilities recognized on the consolidated balance sheet is summarized below. (In millions) Operating Lease Obligations 2020 $ 114 2021 63 2022 35 2023 5 2024 1 Thereafter — Total undiscounted lease payments $ 218 Less: amount representing interest 10 Total operating lease liabilities $ 208 Less: current portion of long-term lease liability as of December 31, 2019 101 Long-term lease liability as of December 31, 2019 $ 107
Operating Lease, Maturity	At December 31, 2018 , future minimum commitments under the previous accounting standard, ASC 840, for operating lease obligations having noncancellable lease terms in excess of one year were as follows: (In millions) Operating Lease Obligations 2019 $ 62 2020 54 2021 35 2022 12 2023 5 Thereafter 49 Sublease rentals — Total minimum lease payments $ 217 * Future minimum commitments for capital lease obligations were nil as of December 31, 2018 .
Operating Lease, Undiscounted Cash Flows to be Received	The undiscounted cash flows to be received under this lease agreement are summarized below. (In millions) Operating Lease Future Cash Receipts 2020 $ 6 2021 6 2022 6 2023 6 2024 6 Thereafter 60 Total undiscounted cash flows $ 90

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill Disclosure [Abstract]
Schedule of Goodwill [Table Text Block]	The table below displays the allocated beginning goodwill balance of our International segment along with changes in the carrying amount of goodwill for 2019 and 2018 : (In millions) International 2018 Beginning balance, gross $ 115 Less: accumulated impairments — Beginning balance, net 115 Dispositions (a) (18 ) Impairment — Ending balance, net $ 97 2019 Beginning balance, gross $ 97 Less: accumulated impairments — Beginning balance, net 97 Dispositions (2 ) Impairment — Ending balance, net $ 95

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions	The following table sets forth outstanding derivative contracts as of December 31, 2019 and the weighted average prices for those contracts: 2020 2021 Crude Oil First Quarter Second Quarter Third Quarter Fourth Quarter Full Year NYMEX WTI Three-Way Collars Volume (Bbls/day) 60,000 60,000 60,000 60,000 — Weighted average price per Bbl: Ceiling $ 66.04 $ 66.04 $ 63.74 $ 63.74 $ — Floor $ 55.00 $ 55.00 $ 55.00 $ 55.00 $ — Sold put $ 47.67 $ 47.67 $ 48.00 $ 48.00 $ — Basis Swaps - Argus WTI Midland (a) Volume (Bbls/day) 15,000 15,000 15,000 15,000 — Weighted average price per Bbl $ (0.94 ) $ (0.94 ) $ (0.94 ) $ (0.94 ) $ — Basis Swaps - NYMEX WTI / ICE Brent (b) Volume (Bbls/day) 5,000 5,000 5,000 5,000 808 Weighted average price per Bbl $ (7.24 ) $ (7.24 ) $ (7.24 ) $ (7.24 ) $ (7.24 ) Natural Gas Three-Way Collars Volume (MMBtu/day) 100,000 — — — — Weighted average price per MMBtu: Ceiling $ 3.32 $ — $ — $ — $ — Floor $ 2.75 $ — $ — $ — $ — Sold put $ 2.25 $ — $ — $ — $ — (a) The basis differential price is indexed against Argus WTI Midland. (b) The basis differential price is indexed against Intercontinental Exchange (“ICE”) Brent and NYMEX WTI. Between January 1, 2020 and February 10, 2020 , we entered into 20,000 bbls/day of three-way collars for 2020 with a ceiling price of $66.37 , a floor price of $55.00 and a sold put price of $48.00 . The mark-to-market impact and settlement of these commodity derivative instruments appears in the table below and is reflected in net gain (loss) on commodity derivatives in the consolidated statements of income. Year Ended December 31, (In millions) 2019 2018 2017 Mark-to-market gain (loss) $ (124 ) $ 267 $ (81 ) Net settlements of commodity derivative instruments $ 52 $ (281 ) $ 45 Derivatives Designated as Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives as they appear on the Balance Sheet	sent the gross fair values of derivative instruments and the reported net amounts along with where they appear on the consolidated balance sheets. December 31, 2019 (In millions) Asset Liability Net Asset (Liability) Balance Sheet Location Not Designated as Hedges Commodity $ 9 $ 1 $ 8 Other current assets Commodity 1 — 1 Other noncurrent assets Commodity — 5 (5 ) Other current liabilities Total Not Designated as Hedges $ 10 $ 6 $ 4 Cash Flow Hedges Interest Rate $ 2 $ — $ 2 Other noncurrent assets Total Designated Hedges $ 2 $ — $ 2 Total $ 12 $ 6 $ 6 December 31, 2018 (In millions) Asset Liability Net Asset (Liability) Balance Sheet Location Not Designated as Hedges Commodity $ 131 $ — $ 131 Other current assets Commodity — 4 (4 ) Deferred credits and other liabilities Total Not Designated as Hedges $ 131 $ 4 $ 127
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table sets forth the net impact of the terminated forward starting interest rate swap derivatives de-designated as cash flow hedges on other comprehensive income (loss). Year Ended December 31, (In millions) 2017 Interest Rate Swaps Beginning balance $ 60 Change in fair value recognized in other comprehensive income (13 ) Reclassification from other comprehensive income (47 ) Ending balance $ —

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables’ present assets and liabilities accounted for at fair value on a recurring basis as of December 31, 2019 and 2018 by hierarchy level. December 31, 2019 (In millions) Level 1 Level 2 Level 3 Total Derivative instruments, assets Commodity (a) $ — $ 7 $ — $ 7 Interest rate — 2 — 2 Derivative instruments, assets $ — $ 9 $ — $ 9 Derivative instruments, liabilities Commodity (a) $ (3 ) $ — $ — $ (3 ) Derivative instruments, liabilities $ (3 ) $ — $ — $ (3 ) Total $ (3 ) $ 9 $ — $ 6 December 31, 2018 (In millions) Level 1 Level 2 Level 3 Total Derivative instruments, assets Commodity (a) $ 21 $ 106 $ — $ 127 Derivative instruments, assets $ 21 $ 106 $ — $ 127 Derivative instruments, liabilities Derivative instruments, liabilities $ — $ — $ — $ — Total $ 21 $ 106 $ — $ 127 (a) Derivative instruments are recorded on a net basis in our consolidated balance sheet (see Note 15
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis	The following table summarizes impairment charges of proved properties from continuing operations. Additionally, it presents the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition. 2019 2018 2017 (In millions) Fair Value Impairment Fair Value Impairment Fair Value Impairment Long-lived assets held for use $ 56 $ 24 $ 113 $ 75 $ 179 $ 229
Fair Value, by Balance Sheet Grouping	The following table summarizes financial instruments, excluding receivables, payables and derivative financial instruments, and their reported fair values by individual balance sheet line item at December 31, 2019 and 2018 . December 31, 2019 2018 (In millions) Fair Value Carrying Amount Fair Value Carrying Amount Financial assets Current assets $ 4 $ 4 $ 3 $ 3 Other noncurrent assets 26 38 76 81 Total financial assets $ 30 $ 42 $ 79 $ 84 Financial liabilities Other current liabilities $ 62 $ 90 $ 37 $ 58 Long-term debt, including current portion (a) 6,174 5,529 5,469 5,528 Deferred credits and other liabilities 99 86 93 88 Total financial liabilities $ 6,335 $ 5,705 $ 5,599 $ 5,674 (a) Excludes debt issuance costs.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt Instrument Table	The following table details our long-term debt: December 31, (In millions) 2019 2018 Senior unsecured notes: 2.700% notes due 2020 (a) $ — $ 600 2.800% notes due 2022 (a) 1,000 1,000 9.375% notes due 2022 (b) 32 32 Series A notes due 2022 (b) 3 3 8.500% notes due 2023 (b) 70 70 8.125% notes due 2023 (b) 131 131 3.850% notes due 2025 (a) 900 900 4.400% notes due 2027 (a) 1,000 1,000 6.800% notes due 2032 (a) 550 550 6.600% notes due 2037 (a) 750 750 5.200% notes due 2045 (a) 500 500 Bonds: (c) 2.00% bonds due 2037 200 — 2.10% bonds due 2037 200 — 2.20% bonds due 2037 200 — Total (b) 5,536 5,536 Unamortized discount (7 ) (8 ) Unamortized debt issuance cost (28 ) (29 ) Total long-term debt $ 5,501 $ 5,499 (a) These notes contain a make-whole provision allowing us to repay the debt at a premium to market price. (b) In the event of a change in control, as defined in the related agreements, debt obligations totaling $236 million at December 31, 2019 may be declared immediately due and payable.
Five Year Schedule Of Debt Payments Table	The following table shows future debt payments: (In millions) 2020 $ — 2021 — 2022 1,035 2023 401 2024 200 Thereafter 3,900 Total long-term debt, including current portion $ 5,536

Incentive Based Compensation _2

Incentive Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Incentive Based Compensation Plans [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	The weighted average grant date fair value of these awards was based on the following weighted average Black-Scholes assumptions: 2019 2018 2017 Exercise price per share $ 16.79 $ 14.52 $ 15.80 Expected annual dividend yield 1.2 % 1.4 % 1.3 % Expected life in years 5.82 6.45 6.4 Expected volatility 43 % 43 % 42 % Risk-free interest rate 2.5 % 2.8 % 2.1 % Weighted average grant date fair value of stock option awards granted $ 6.62 $ 5.83 $ 6.07
Schedule of Share-based Compensation, Stock Options, Activity	The following is a summary of stock option award activity in 2019 . Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (in millions) Outstanding at beginning of year 6,180,007 $ 24.39 Granted 648,526 $ 16.79 Exercised (84,804) $ 8.17 Canceled (1,083,998) $ 25.45 Outstanding at end of year 5,659,731 $ 23.55 5 years $ 3 Exercisable at end of year 4,323,312 $ 25.96 4 years $ 3 Expected to vest 1,319,850 $ 15.76 8 years $ —
Schedule of Nonvested Restricted Stock Units Activity	The following is a summary of restricted stock and restricted stock unit award activity in 2019 . Awards Weighted Average Grant Date Fair Value Unvested at beginning of year 8,504,946 $ 14.04 Granted 4,113,190 $ 16.65 Vested and Exercised (3,813,221 ) $ 12.64 Canceled (1,630,529 ) $ 15.78 Unvested at end of year 7,174,386 $ 15.88
Schedule of Performance Units, Valuation [Table Text Block]	The key assumptions used in the Monte Carlo simulation to determine the fair value of stock-based performance units granted in 2019 , 2018 and 2017 were: 2019 (a) 2018 2017 (b) Valuation date stock price $ 16.79 $ 13.69 $ 13.58 Expected annual dividend yield 1.2 % 1.5 % N/A Expected volatility 43 % 41 % N/A Risk-free interest rate 2.5 % 1.5 % N/A Fair value of stock-based performance units outstanding $ 20.66 $ 17.29 $ 14.18 (a) Represents key assumptions at grant date, as 2019 performance unit awards are settled in stock. (b)

Defined Benefit Postretiremen_2

Defined Benefit Postretirement Plans and Defined Contribution Plan (Tables)	12 Months Ended
	Dec. 31, 2019
Defined Benefit Plan [Abstract]
Summary Of Defined Benefit Pension Plans With Accumulated Benefit Obligations	Obligations and funded status – The following summarizes the obligations and funded status for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits 2019 2018 2019 2018 (In millions) U.S. Int’l U.S. Int’l U.S. U.S. Accumulated benefit obligation $ 343 $ — $ 320 $ 511 $ 89 $ 96 Change in pension benefit obligations: Beginning balance $ 326 $ 511 $ 384 $ 599 $ 96 $ 221 Service cost 19 — 18 — 1 2 Interest cost 12 8 12 14 3 7 Plan amendment — — — 3 — (99 ) Divestiture (a) — (549 ) — — — — Actuarial loss (gain) 48 36 (20 ) (38 ) 9 (15 ) Foreign currency exchange rate changes — 6 — (29 ) — — Settlements paid (45 ) — (62 ) (23 ) — — Benefits paid (6 ) (12 ) (6 ) (15 ) (20 ) (20 ) Ending balance $ 354 $ — $ 326 $ 511 $ 89 $ 96 Change in fair value of plan assets: Beginning balance $ 203 $ 594 $ 216 $ 670 $ — $ — Actual return on plan assets 44 68 (6 ) (21 ) — — Employer contributions 40 8 61 17 20 20 Foreign currency exchange rate changes — 8 — (34 ) — — Divestiture (a) — (666 ) — — — — Settlements paid (45 ) — (62 ) (23 ) — — Benefits paid (6 ) (12 ) (6 ) (15 ) (20 ) (20 ) Ending balance $ 236 $ — $ 203 $ 594 $ — $ — Funded status of plans at December 31 $ (118 ) $ — $ (123 ) $ 83 $ (89 ) $ (96 ) Amounts recognized in the consolidated balance sheets: Noncurrent assets $ — $ — $ — $ 83 $ — $ — Current liabilities (6 ) — (5 ) — (18 ) (19 ) Noncurrent liabilities (112 ) — (118 ) — (71 ) (77 ) Accrued benefit cost $ (118 ) $ — $ (123 ) $ 83 $ (89 ) $ (96 ) Pretax amounts in accumulated other comprehensive loss: Net loss $ 85 $ — $ 90 $ 59 $ 23 $ 14 Prior service cost (29 ) — (36 ) 5 (129 ) (147 ) (a) Refer to Note 5 for further information on the sale of our U.K. business.
Schedule Of Net Periodic Benefit Cost And Other Comprehensive Income	Components of net periodic benefit cost from continuing operations and other comprehensive (income) loss – The following summarizes the net periodic benefit costs and the amounts recognized as other comprehensive (income) loss for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits Year Ended December 31, Year Ended December 31, 2019 2018 2017 2019 2018 2017 (In millions) U.S. Int’l U.S. Int’l U.S. Int’l U.S. U.S. U.S. Components of net periodic benefit cost: Service cost $ 19 $ — $ 18 $ — $ 22 $ — $ 1 $ 2 $ 2 Interest cost 12 8 12 14 13 17 3 7 8 Expected return on plan assets (10 ) (11 ) (11 ) (24 ) (13 ) (30 ) — — — Amortization: - prior service credit (7 ) — (10 ) — (10 ) — (19 ) (8 ) (7 ) - actuarial loss 7 — 11 — 8 1 1 1 — Net settlement loss (a) 12 — 18 3 28 4 — — — Net periodic benefit cost (b) $ 33 $ (3 ) $ 38 $ (7 ) $ 48 $ (8 ) $ (14 ) $ 2 $ 3 Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss (pretax): Actuarial loss (gain) $ 14 $ (21 ) $ (4 ) $ 8 $ 28 $ (26 ) $ 9 $ (15 ) $ 5 Amortization of actuarial gain (loss) (19 ) (41 ) (29 ) (3 ) (36 ) (4 ) (1 ) (1 ) — Prior service cost (credit) — — — 3 — — — (99 ) — Amortization of prior service credit (cost) 7 (6 ) 10 — 10 — 19 8 7 Total recognized in other comprehensive (income) loss $ 2 $ (68 ) $ (23 ) $ 8 $ 2 $ (30 ) $ 27 $ (107 ) $ 12 Total recognized in net periodic benefit cost and other comprehensive (income) loss $ 35 $ (71 ) $ 15 $ 1 $ 50 $ (38 ) $ 13 $ (105 ) $ 15 (a) Settlements are recognized as they occur, once it is probable that lump sum payments from a plan for a given year will exceed the plan’s total service and interest costs for that year. (b) Net periodic benefit cost reflects a calculated market-related value of plan assets which recognizes changes in fair value over three years.
Schedule of Assumptions Used	Plan assumptions – The following summarizes the assumptions used to determine the benefit obligations at December 31, and net periodic benefit cost for the defined benefit pension and other postretirement plans for 2019 , 2018 and 2017 . Pension Benefits Other Benefits 2019 2018 2017 2019 2018 2017 (In millions) U.S. U.S. Int’l U.S. Int’l U.S. U.S. U.S. Weighted average assumptions used to determine benefit obligation: Discount rate 3.13 % 4.26 % 2.90 % 3.55 % 2.50 % 2.91 % 4.09 % 3.54 % Rate of compensation increase 4.50 % 4.00 % — % 4.00 % — % 4.50 % 4.00 % 4.00 % Weighted average assumptions used to determine net periodic benefit cost: Discount rate 3.70 % 3.88 % 2.50 % 3.86 % 2.70 % 4.09 % 3.54 % 3.98 % Expected long-term return on plan assets 6.25 % 6.50 % 3.70 % 6.50 % 4.50 % — % — % — % Rate of compensation increase 4.00 % 4.00 % — % 4.00 % — % 4.00 % 4.00 % 4.00 % Expected long-term return on plan assets
Schedule of Health Care Cost Trend Rates	Assumed weighted average health care cost trend rates
Fair Value of Defined Benefit Pension Plans Assets	The following tables present the fair values of our defined benefit pension plan’s assets, by level within the fair value hierarchy, as of December 31, 2019 and 2018 . December 31, 2019 (In millions) Level 1 Level 2 Level 3 Total Cash and cash equivalents (a) $ (7 ) $ — $ — $ (7 ) Equity securities: Common stock 75 — — 75 Private equity — — 10 10 Pooled funds — — — — Fixed income securities: Corporate — 2 — 2 Exchange traded funds 3 — — 3 Government 31 11 5 47 Pooled funds — — — — Other — — 18 18 Total investments, at fair value 102 13 33 148 Commingled funds (b) — — — 88 Total investments $ 102 $ 13 $ 33 $ 236 December 31, 2018 (In millions) Level 1 Level 2 Level 3 Total U.S. Int’l U.S. Int’l U.S. Int’l U.S. Int’l Cash and cash equivalents (a) $ (1 ) $ 5 $ — $ — $ — $ — $ (1 ) $ 5 Equity securities: Common stock 75 — — — — — 75 — Private equity — — — — 14 — 14 — Pooled funds — — — 191 — — — 191 Fixed income securities: Corporate — — 4 — — — 4 — Government 22 — 9 — 3 — 34 — Pooled funds — — — 398 — — — 398 Other — — — — 17 — 17 — Total investments, at fair value 96 5 13 589 34 — 143 594 Commingled funds (b) — — — — — — 60 — Total investments $ 96 $ 5 $ 13 $ 589 $ 34 $ — $ 203 $ 594 (a) The negative cash balance was due to the timing of when investment trades occur and when they settle. (b) After the adoption of the FASB update for the fair value hierarchy, we separately report the investments for which fair value was measured using the net asset value per share as a practical expedient. Amounts presented in this table are intended to reconcile the fair value hierarchy to the pension plan assets. The activity during the year ended December 31, 2019 and 2018 , for the assets using Level 3 fair value measurements was immaterial. Cash flows Estimated future benefit payments – The following gross benefit payments, which were estimated based on actuarial assumptions applied at December 31, 2019 and reflect expected future services, as appropriate, are to be paid in the years indicated. (In millions) Pension Benefits Other Benefits 2020 $ 39 $ 18 2021 35 10 2022 31 9 2023 29 8 2024 27 7 2025 through 2029 116 25 Contributions to defined benefit plans – We expect to make contributions to the funded pension plan of up to $28 million
Schedule of Expected Benefit Payments	Estimated future benefit payments – The following gross benefit payments, which were estimated based on actuarial assumptions applied at December 31, 2019 and reflect expected future services, as appropriate, are to be paid in the years indicated. (In millions) Pension Benefits Other Benefits 2020 $ 39 $ 18 2021 35 10 2022 31 9 2023 29 8 2024 27 7 2025 through 2029 116 25

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Year Ended December 31, (In millions) 2019 2018 2017 Included in operating activities: Interest paid, net of amounts capitalized $ 269 $ 270 $ 379 Income taxes paid to taxing authorities, net of refunds received (a) 73 287 391 Noncash investing activities, related to continuing operations: Increase (decrease) in asset retirement costs $ 80 $ (183 ) $ (202 ) Asset retirement obligations assumed by buyer (b) 1,082 82 14 Notes receivable for disposition of assets — — 748 (a) 2019 , 2018 and 2017 includes $90 million , $37 million and $1 million , related to tax refunds. 2017 included a payment of $108 million made to the U.K. tax authorities to preserve our appeal rights, see Note 25 for additional discussion. (b) In 2019, our dispositions include the sale of the Droshky field (Gulf of Mexico), the sale of our non-operated interest in the Atrush block in Kurdistan and the sale of our U.K. business. See Note 5 for further detail on dispositions. Other noncash investing activities include accrued capital expenditures as of December 31, 2019 , 2018 and 2017 of $288 million , $250 million and $329 million .

Other Items (Tables)

Other Items (Tables)	12 Months Ended
	Dec. 31, 2019
Interest and Other Income [Abstract]
Schedule Of Net Interest And Other Financing Table	Net interest and other Year Ended December 31, (In millions) 2019 2018 2017 Interest: Interest income $ 25 $ 32 $ 34 Interest expense (280 ) (280 ) (380 ) Income on interest rate swaps — — 53 Interest capitalized — — 3 Total interest (255 ) (248 ) (290 ) Other: Net foreign currency gain (loss) 4 9 8 Other 7 13 12 Total other 11 22 20 Net interest and other $ (244 ) $ (226 ) $ (270 )
Schedule Of Foreign Currency Transactions Table	Foreign currency – Aggregate foreign currency gains (losses) were included in the consolidated statements of income as follows: Year Ended December 31, (In millions) 2019 2018 2017 Net interest and other $ 4 $ 9 $ 8 Provision for income taxes 2 10 57 Aggregate foreign currency gains $ 6 $ 19 $ 65

Equity Method Investments and_2

Equity Method Investments and Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2019
Equity Method Investments Disclosure [Abstract]
Schedule of Equity Method Investments	Our equity method investments are summarized in the following table: Ownership as of December 31, (In millions) December 31, 2019 2019 2018 EGHoldings 60% $ 310 $ 402 Alba Plant LLC 52% 163 167 AMPCO 45% 190 176 Total $ 663 $ 745
Income And Balance Sheet Information of Equity Investees Table	Summarized financial information for equity method investees is as follows: (In millions) 2019 2018 2017 Income data – year: Revenues and other income $ 832 $ 1,269 $ 1,294 Income from operations 250 588 631 Net income 187 459 508 Balance sheet data – December 31: Current assets $ 455 $ 559 Noncurrent assets 1,049 931 Current liabilities 284 253 Noncurrent liabilities 183 87

Accounting Standards Lease acco

Accounting Standards Lease accounting standard (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ (31)
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ (31)

Summary of Principal Accounti_3

Summary of Principal Accounting Policies DDA (Details)	12 Months Ended
	Dec. 31, 2019
Office furniture, equipment and computer hardwareWells and Related Equipment and Facilities [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	4 years
Office furniture, equipment and computer hardwareWells and Related Equipment and Facilities [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Pipelines [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Pipelines [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Plants, facilities, mine equipment and infrastructure [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Plants, facilities, mine equipment and infrastructure [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years

Income per Common Share (Detail

Income per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 480	$ 1,096	$ (830)
Loss from discontinued operations	0	0	(4,893)
Net income (loss)	$ 480	$ 1,096	$ (5,723)
Weighted average common shares outstanding, basic	810	846	850
Weighted Average Number Diluted Shares Outstanding Adjustment	0	1	0
Weighted average common shares outstanding, diluted	810	847	850
Basic:
Income from continuing operations (in dollars per basic share)	$ 0.59	$ 1.30	$ (0.97)
Discontinued operations (in dollars per basic share)	0	0	(5.76)
Net income (in dollars per basic share)	0.59	1.30	(6.73)
Diluted:
Income from continuing operations (in dollars per diluted share)	0.59	1.29	(0.97)
Discontinued operations (in dollars per diluted share)	0	0	(5.76)
Net income (in dollars per diluted share)	$ 0.59	$ 1.29	$ (6.73)
Antidilutive securities excluded from computation of earnings per share	6	6	11
Common Stock, Dividends, Per Share, Cash Paid	$ 0.20	$ 0.20	$ 0.20

Acquisitions Acquisitions Asset

Acquisitions Acquisitions Asset (Details) a in Thousands, $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2019USD ($)a	Dec. 31, 2017USD ($)	Jun. 30, 2017USD ($)aacquisition	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				$ 293	$ 25	$ 1,891
Number Of Acquisitions Closed | acquisition			2
Texas Delaware [Member]
Business Acquisition [Line Items]
OilandGasAcresUndevelopedandDevelopedNet | a	40
Payments to Acquire Businesses, Net of Cash Acquired	$ 106
Eagle Ford
Business Acquisition [Line Items]
OilandGasAcresUndevelopedandDevelopedNet | a	18
Payments to Acquire Businesses, Net of Cash Acquired	$ 191
Ownership Percentage				100.00%
Permian Basin [Member]
Business Acquisition [Line Items]
Gas and Oil Acres, Undeveloped and Developed, Net | a			91
Payments to Acquire Businesses, Net of Cash Acquired		$ 63
Permian Basin [Member] | BC Operating Transaction [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired			$ 1,100
Permian Basin [Member] | Black Mountain Oil and Gas Transaction [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired			$ 700

Dispositions - United States E&

Dispositions - United States E&P Segment (Details) - United States Exploration and Production [Member] - Gulf of Mexico Assets [Member] - Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] $ in Millions	3 Months Ended
	Sep. 30, 2018USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal of assets, net of cash transferred to the buyer	$ 16
Gain (loss) on disposal	$ 32

Dispositions - International E&

Dispositions - International E&P Segment (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			12 Months Ended
	Jul. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Surety Bond Exposure, Liability		$ 6			$ 6
Document Period End Date					Dec. 31, 2019
Income (loss) from continuing operations before income taxes					$ 392	$ 1,427	$ (454)
International | U.K. Business [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal of assets, net of cash transferred to the buyer	$ 95
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents						345
Income (loss) from continuing operations before income taxes					$ 33	261
International | Atrush Block in Kurdistan [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets						58
Liabilities						$ 17
International | Atrush Block in Kurdistan [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage interest in property		15.00%
Disposal of assets, net of cash transferred to the buyer			$ 63
International | Marathon Oil Libya Limited [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage interest in property				16.33%
Disposal of assets, net of cash transferred to the buyer				$ 450
Gain (loss) on disposal				$ 255

Dispositions - Canadian Busines

Dispositions - Canadian Business - Discontinued Operations (Details) - USD ($) $ in Millions	May 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairments				$ 24	$ 75	$ 229
Net gain on disposal of assets				$ 50	$ 319	58
Canadian Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairments			$ 6,600
Impairments, after-tax			$ 4,960
Canadian Business [Member] | Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 2,500
Disposal of assets, net of cash transferred to the buyer	$ 1,800
Impairments						$ 6,636
Net gain on disposal of assets		$ (43)
Variable Interest Entity, Not Primary Beneficiary [Member] | Canadian Business [Member] | Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest in business	20.00%
Notes Receivable [Member] | Canadian Business [Member] | Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Notes receivables received	$ 750

Discontinued Operations - Repor

Discontinued Operations - Reported in Consolidated Statements of Income and Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Income
Impairments		$ 24	$ 75	$ 229
Cash Flow from Discontinued Operations
Net increase in cash and cash equivalents of discontinued operations		$ 0	$ 0	130
Canadian Business [Member]
Consolidated Statements of Income
Impairments	$ 6,600
Canadian Business [Member] | Discontinued Operations, Disposed of by Sale [Member]
Consolidated Statements of Income
Total revenue and other income				431
Net loss on disposal of assets				(43)
Total revenues and other income				388
Production				254
Depreciation, depletion and amortization				40
Impairments				6,636
Other				25
Total costs and expenses				6,955
Pretax loss from discontinued operations				(6,567)
Benefit for income taxes				(1,674)
Loss from discontinued operations				(4,893)
Cash Flow from Discontinued Operations
Operating activities				141
Investing activities				(13)
Changes in cash included in current assets held for sale				2
Net increase in cash and cash equivalents of discontinued operations				$ 130

Revenues Revenues from Contract

Revenues Revenues from Contracts with Customers by Product Type and Geographic Areas (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 5,063	$ 5,902	$ 4,247
United States E&P
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,602	4,886
United States E&P | Eagle Ford
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,600	1,912
United States E&P | Bakken
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,771	1,668
United States E&P | Oklahoma
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	697	791
United States E&P | Northern Delaware
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	358	293
United States E&P | Other U.S.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	176	222
United States E&P | Crude oil and condensate
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,887	3,947
United States E&P | Crude oil and condensate | Eagle Ford
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,358	1,554
United States E&P | Crude oil and condensate | Bakken
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,686	1,568
United States E&P | Crude oil and condensate | Oklahoma
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	425	426
United States E&P | Crude oil and condensate | Northern Delaware
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	316	235
United States E&P | Crude oil and condensate | Other U.S.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	102	164
United States E&P | Natural gas liquids
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	307	495
United States E&P | Natural gas liquids | Eagle Ford
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	114	205
United States E&P | Natural gas liquids | Bakken
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46	62
United States E&P | Natural gas liquids | Oklahoma
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	116	181
United States E&P | Natural gas liquids | Northern Delaware
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	26	38
United States E&P | Natural gas liquids | Other U.S.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5	9
United States E&P | Natural gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	349	413
United States E&P | Natural gas | Eagle Ford
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	121	145
United States E&P | Natural gas | Bakken
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	39	38
United States E&P | Natural gas | Oklahoma
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	156	184
United States E&P | Natural gas | Northern Delaware
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	16	20
United States E&P | Natural gas | Other U.S.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	17	26
United States E&P | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	59	31
United States E&P | Other | Eagle Ford
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	7	8
United States E&P | Other | Bakken
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
United States E&P | Other | Oklahoma
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
United States E&P | Other | Northern Delaware
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
United States E&P | Other | Other U.S.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	52	23
International
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	461	1,016
International | E.G.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	307	384
International | U.K.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	134	359
International | Libya
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		196
International | Other International
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	20	77
International | Crude oil and condensate
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	398	888
International | Crude oil and condensate | E.G.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	271	342
International | Crude oil and condensate | U.K.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	107	282
International | Crude oil and condensate | Libya
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		187
International | Crude oil and condensate | Other International
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	20	77
International | Natural gas liquids
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5	9
International | Natural gas liquids | E.G.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4	4
International | Natural gas liquids | U.K.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1	5
International | Natural gas liquids | Libya
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0
International | Natural gas liquids | Other International
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
International | Natural gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	44	86
International | Natural gas | E.G.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	32	37
International | Natural gas | U.K.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	12	40
International | Natural gas | Libya
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		9
International | Natural gas | Other International
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
International | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	14	33
International | Other | E.G.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	1
International | Other | U.K.
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	14	32
International | Other | Libya
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers		0
International | Other | Other International
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 0	$ 0

Revenues Contract Receivables a

Revenues Contract Receivables and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Receivables from contracts with customers, included in receivables, less reserves	$ 837	$ 714
Contract with Customer, Asset, Net, Current	0
Contract asset (liability)	0	$ (1)
Revenue recognized as performance obligations are satisfied	74
Contract with Customer, Asset, Reclassified to Receivable	52
Contract With Customer, Liability, Increase (Decrease) For Contract Sold In Disposition	$ 21

Revenues - Significant Changes

Revenues - Significant Changes in the Contract Liability Balance (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	$ (1)
Revenue recognized as performance obligations are satisfied	74
Amounts invoiced to customers	(52)
Ending balance	$ 0

Revenues Revenues - Concentrati

Revenues Revenues - Concentration of Credit Risk (Details) - Revenue Benchmark [Member]	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Marathon Petroleum Corporation [Member]
Revenue, Major Customer [Line Items]
Concentration Risk, Percentage	13.00%
Shell Trading [Member]
Revenue, Major Customer [Line Items]
Concentration Risk, Percentage	10.00%
Vitol [Member]
Revenue, Major Customer [Line Items]
Concentration Risk, Percentage			10.00%
Valero Marketing and Supply [Member]
Revenue, Major Customer [Line Items]
Concentration Risk, Percentage	11.00%	11.00%
Flint Hills Resources [Member]
Revenue, Major Customer [Line Items]
Concentration Risk, Percentage	13.00%	11.00%

Segment Information (Details)

Segment Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment	2
Revenues from contracts with customers	$ 5,063	$ 5,902	$ 4,247
Net loss on commodity derivatives	(72)	(14)	(36)
Income from equity method investments	87	225	256
Net gain (loss) on disposal of assets and other income			58
Net gain on disposal of assets	50	319	58
Other income	62	150	78
Production	712	842	716
Results of Operations, Transportation Costs	605	575	431
Exploration	149	289	409
Depreciation, depletion and amortization	2,397	2,441	2,372
Impairment of Oil and Gas Properties	24	75	229
Taxes other than income	311	299	183
General and Administrative Expense	356	394	371
Net interest and other	244	226	270
Net settlement loss	3	(14)	(19)
Loss on early extinguishment of debt	3	0	51
Provision (benefit) for income taxes	(88)	331	376
Income (loss) from continuing operations	480	1,096	(830)
Net Income (Loss) Attributable to Parent	480	1,096	(5,723)
Assets	20,245	21,321	22,012
Property, Plant and Equipment, Additions	2,591	2,685	2,150
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	0	0	47
United States Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers	4,602	4,886
International Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers	461	1,016
United States
Segment Reporting Information [Line Items]
Net settlement loss	(12)	(18)	(28)
Pension Plan [Member]
Segment Reporting Information [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment			32
Interest Rate Swap [Member]
Segment Reporting Information [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax			46
Operating Segments [Member] | United States Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers	4,602	4,886	3,093
Net loss on commodity derivatives	52	(281)	45
Income from equity method investments	0	0	0
Net gain (loss) on disposal of assets and other income			1
Net gain on disposal of assets	0	0
Other income	13	16	12
Production	588	625	476
Results of Operations, Transportation Costs	561	499
Other Cost and Expense, Operating			354
Exploration	149	246	154
Depreciation, depletion and amortization	2,250	2,217	2,011
Impairment of Oil and Gas Properties	0	0	4
Taxes other than income	311	301	173
General and Administrative Expense	127	146	119
Net interest and other	0	0	0
Net settlement loss	0	0	0
Provision (benefit) for income taxes	6	(21)	1
Income (loss) from continuing operations		608	(148)
Net Income (Loss) Attributable to Parent	675
Assets	17,781	17,321	16,863
Property, Plant and Equipment, Additions	2,550	2,620	2,081
Operating Segments [Member] | International Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers	461	1,016	1,154
Net loss on commodity derivatives	0	0	0
Income from equity method investments	87	225	256
Net gain (loss) on disposal of assets and other income			0
Net gain on disposal of assets	0	0
Other income	9	12	6
Production	126	215	239
Results of Operations, Transportation Costs	26	70
Other Cost and Expense, Operating			77
Exploration	0	3	5
Depreciation, depletion and amortization	121	197	328
Impairment of Oil and Gas Properties	0	0	0
Taxes other than income	0	0	0
General and Administrative Expense	25	32	30
Net interest and other	0	0	0
Net settlement loss	3	9	8
Provision (benefit) for income taxes	29	272	372
Income (loss) from continuing operations		473	374
Net Income (Loss) Attributable to Parent	233
Assets	1,530	2,083	4,201
Property, Plant and Equipment, Additions	16	39	42
Not Allocated to Segments [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers	0	0	0
Net loss on commodity derivatives	(124)	267	(81)
Income from equity method investments	0	0	0
Net gain (loss) on disposal of assets and other income			57
Net gain on disposal of assets	50	319
Other income	40	122	60
Production	(2)	2	1
Results of Operations, Transportation Costs	18	6
Other Cost and Expense, Operating			0
Exploration	0	40	250
Depreciation, depletion and amortization	26	27	33
Impairment of Oil and Gas Properties	24	75	225
Taxes other than income	0	(2)	10
General and Administrative Expense	204	216	222
Net interest and other	244	226	(270)
Net settlement loss	0	(23)	(27)
Loss on early extinguishment of debt	3		51
Provision (benefit) for income taxes	(123)	80	3
Income (loss) from continuing operations		15	(1,056)
Net Income (Loss) Attributable to Parent	(428)
Assets	934	1,917	948
Property, Plant and Equipment, Additions	25	26	27
Reclassification out of Accumulated Other Comprehensive Income [Member]
Segment Reporting Information [Line Items]
Net gain on disposal of assets	68	0
Net interest and other	(1)	0
Net settlement loss	6	(14)
Net Income (Loss) Attributable to Parent	75	(14)
Net settlement loss, net of tax | Reclassification out of Accumulated Other Comprehensive Income [Member]
Segment Reporting Information [Line Items]
Net settlement loss	(12)	(21)
Marketing revenues
Segment Reporting Information [Line Items]
Revenues from contracts with customers	0	0	162
Marketing, including purchases from related parties	$ 0	$ 0	168
Marketing revenues | Operating Segments [Member] | United States Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers			29
Marketing, including purchases from related parties			36
Marketing revenues | Operating Segments [Member] | International Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers			133
Marketing, including purchases from related parties			132
Marketing revenues | Not Allocated to Segments [Member]
Segment Reporting Information [Line Items]
Revenues from contracts with customers			0
Marketing, including purchases from related parties			$ 0

Segment Information - Geographi

Segment Information - Geographical (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 17,663	$ 17,549
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	16,507	16,094
EQUATORIAL GUINEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	1,156	1,333
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	$ 0	$ 122

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income (Loss) Before Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ 43	$ 642	$ (783)
Foreign	349	785	329
Income (loss) from continuing operations before income taxes	$ 392	$ 1,427	$ (454)

Income Taxes (Income Tax Expen

Income Taxes (Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal
Current	$ (116)	$ 6	$ (32)
Deferred	(3)	0	41
Total	(119)	6	9
State and local
Current	4	(1)	(14)
Deferred	3	(23)	2
Total	7	(24)	(12)
Foreign
Current	58	274	483
Deferred	(34)	75	(104)
Total	24	349	379
Total
Current	(54)	279	437
Deferred	(34)	52	(61)
Total income tax expense (benefit)	$ (88)	$ 331	$ 376

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Total pre-tax income (loss) from continuing operations	$ 392	$ 1,427	$ (454)
Total income tax expense (benefit)	$ (88)	$ 331	$ 376
Effective income tax rate (benefit) on continuing operations	(22.00%)	23.00%	83.00%
Income taxes at the statutory tax rate	$ 83	$ 300	$ (159)
Effects of foreign operations	(29)	214	140
Adjustments to valuation allowances	(28)	(177)	446
State income taxes	11	(17)	(19)
Tax law change	0	0	(35)
Other federal tax effects	$ (125)	$ 11	$ 3

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Libya statutory income tax rate		93.50%
Effective income tax rate excluding Libya		14.00%	5.00%
Change in valuation allowance	$ (28)	$ (177)	$ 446
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Tax Settlement, Foreign, Amount	(126)
Operating loss carryforwards	1,685	1,304
Foreign tax credits	611	611
Deferred tax liability, property, plant and equipment	1,861	1,018
Income tax receivable, current	42
Interest and penalties recorded	6	2	$ 27
Interest and penalties accrued	3	$ 27
United States
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, subject to expiration	655
Operating loss carryforwards, not subject to expiration	829
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	181
Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 20

Income Taxes (Schedule of Net

Income Taxes (Schedule of Net Deferred Tax Asset/Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Employee benefits	$ 90	$ 75
Operating loss carryforwards	1,685	1,304
Capital loss carryforwards	1	2
Foreign tax credits	611	611
Other	27	4
Subtotal	2,414	1,996
Valuation allowance	(699)	(721)
Total deferred tax assets	1,715	1,275
Deferred tax liabilities:
Property, plant and equipment	1,861	1,018
Accrued revenue	40	60
Other	0	3
Total deferred tax liabilities	1,901	1,081
Net deferred tax liabilities	186	0
Net deferred tax assets	$ 0	$ 194

Income Taxes (Balance Sheet Cla

Income Taxes (Balance Sheet Classification) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Assets
Other noncurrent assets	$ 0	$ 393
Liabilities
Noncurrent deferred tax liabilities	186	199
Net deferred tax assets	0	194
Net deferred tax liabilities	$ 186	$ 0

Income Taxes (Unrecognized Tax

Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 13
Increase in Unrecognized Tax Benefits is Reasonably Possible	5
Unrecognized Tax Benefit Rollforward [Abstract]
Unrecognized Tax Benefits, Beginning Balance	263	$ 126	$ 66
Additions for tax positions of prior years	13	152	83
Reductions for tax positions of prior years	(152)	(15)	(3)
Settlements	(111)	0	(20)
Unrecognized Tax Benefits, Ending Balance	$ 13	$ 263	$ 126

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Crude oil and natural gas	$ 10	$ 11
Supplies and sundry items	62	85
Inventories at cost	$ 72	$ 96

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 17,000	$ 16,804
Not Allocated to Segments [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	80	83
International Exploration and Production [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	493	710
United States Exploration and Production [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 16,427	$ 16,011

Property, Plant and Equipment_3

Property, Plant and Equipment (Details 2) $ in Millions	Dec. 31, 2019USD ($)project	Dec. 31, 2018USD ($)project	Dec. 31, 2017USD ($)project	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Abstract]
Amounts capitalized less than one year after completion of drilling	$ 278	$ 297	$ 263
Amounts capitalized greater than one year after completion of drilling	0	0	32
Total deferred exploratory well costs	$ 278	$ 297	$ 295	$ 249
Projects that have Exploratory Well Costs that have been Capitalized for Period Greater than One Year, Number of Projects | project	0	0	1

Property, Plant and Equipment P

Property, Plant and Equipment Property, Plant and Equipment (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Beginning balance	$ 297	$ 295	$ 249
Additions	218	262	212
Charges to expense	(5)	(35)	(64)
Transfers to development	(230)	(197)	(102)
Dispositions	(2)	(28)	0
Ending balance	278	297	295
Amounts capitalized greater than one year after completion of drilling	$ 0	0	32
Rodo
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Charges to expense		$ (32)
Diaba
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Charges to expense			$ (64)

Impairments (Details)

Impairments (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Impaired Long-Lived Assets Held and Used [Line Items]
Fair Value	$ 56	$ 113	$ 179
Impairment	$ 24	$ 75	$ 229

Impairment (Narrative) (Details

Impairment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Impaired Long-Lived Assets Held and Used [Line Items]
Impairments	$ 24	$ 75	$ 229
Fair Value, Measurements, Nonrecurring
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment	24	75	229
Fair Value	$ 56	$ 113	179
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring | International
Impaired Long-Lived Assets Held and Used [Line Items]
Fair Value			103
Impairments			136
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring | Gulf of Mexico Assets
Impaired Long-Lived Assets Held and Used [Line Items]
Fair Value			76
Impairments			$ 89

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation Beginning Balance	$ 1,145	$ 1,483
Incurred, including acquisitions	34	21
Settled, including dispositions	(1,110)	(117)
Accretion expense (included in depreciation, depletion and amortization)	31	70
Revisions to previous estimates	46	(204)
Held for sale	108	(108)
Asset Retirement Obligation Ending Balance	254	1,145
Asset Retirement Obligation, Current	11	64
Droshky Field
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Held for sale		98
U.K.
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset Retirement Obligation Beginning Balance	$ 944
Asset Retirement Obligation Ending Balance		$ 944

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) $ in Millions	Dec. 31, 2019USD ($)
Leases [Abstract]
ROU asset	$ 199
Current portion of long-term lease liability	101
Long-term lease liability	$ 107

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease costs	$ 84
Short-term lease costs	321
Variable lease costs	107
Total lease costs	512
Cash paid for amounts included in the measurement of operating lease liabilities	100
ROU assets obtained in exchange for new operating lease liabilities(d)	293
ROU asset	$ 199

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Weighted average lease term	2 years
Discount rate	4.00%
Annual payments to be received	$ 6
Maximum financing available		$ 380
Total costs incurred under lease	$ 58
Term of contract	5 years
Finance lease extension term	5 years
Residual value guarantee	89.00%

Leases - Lease Maturity (Detai

Leases - Lease Maturity (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	$ 114,000,000
2021	63,000,000
2022	35,000,000
2023	5,000,000
2024	1,000,000
Thereafter	0
Total undiscounted lease payments	218,000,000
Less: amount representing interest	10,000,000
Total operating lease liabilities	208,000,000
Less: current portion of long-term lease liability as of December 31, 2019	101,000,000
Long-term lease liability as of December 31, 2019	107,000,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019	62,000,000
2020	54,000,000
2021	35,000,000
2022	12,000,000
2023	5,000,000
Thereafter	49,000,000
Sublease rentals	0
Total minimum lease payments	$ 217,000,000
Future minimum commitments for capital lease obligations		$ 0

Leases - Lease Payments to be

Leases - Lease Payments to be Received (Details) $ in Millions	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 6
2021	6
2022	6
2023	6
2024	6
Thereafter	60
Total undiscounted cash flows	$ 90

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Beginning balance, net	$ 97
Ending balance, net	95	$ 97
International Exploration and Production [Member]
Goodwill [Line Items]
Goodwill, gross		97	$ 115
Less: accumulated impairment		0	$ 0
Goodwill [Roll Forward]
Beginning balance, net	97	115
Dispositions	(2)	(18)
Impairment	0	0
Ending balance, net	$ 95	$ 97

Derivatives (Balance Sheet) (De

Derivatives (Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 12
Derivative Liability, Fair Value, Gross Liability	6
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	6
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	10	$ 131
Derivative Liability, Fair Value, Gross Liability	6	4
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		(127)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	4
Other Current Assets [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	9	131
Derivative Liability, Fair Value, Gross Liability	1
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	8	131
Other Noncurrent Assets [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	1
Other Current Liabilities [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0
Derivative Liability, Fair Value, Gross Liability	5	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(5)
Other Noncurrent Liabilities [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability		4
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		$ (4)
Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2
Derivative Liability, Fair Value, Gross Liability	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	2
Cash Flow Hedging [Member] | Other Noncurrent Assets [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2
Derivative Liability, Fair Value, Gross Liability	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 2

Derivatives Derivatives (Schedu

Derivatives Derivatives (Schedule of Cash Flow Hedges Rollforward) (Details) - Interest Rate Swap [Member] - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Cash Flow Hedges Derivative Instruments at Fair Value, Net	$ 0	$ 60
Change in fair value recognized in other comprehensive income	(13)
Reclassification from other comprehensive income	$ (47)

Derivatives (Non Hedges Commodi

Derivatives (Non Hedges Commodity) (Details) - Not Designated as Hedging Instrument [Member]	12 Months Ended
	Dec. 31, 2019USD ($)MMBTU_per_dayBbls_per_day$ / MMBTU$ / bbl	Jun. 30, 2019Bbls_per_day
Three-Way Collars - Crude Oil 2020 Q1 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	60,000
Three-Way Collars - Crude Oil 2020 Q2 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	60,000
Three-Way Collars - Crude Oil 2020 Q3 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	60,000
Three-Way Collars - Crude Oil 2020 Q4 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	60,000
Three-Way Collars - Crude Oil 2021 [Member]
Derivative [Line Items]
Volume | Bbls_per_day		0
Three-Way Collars - Crude Oil 2020 Q1, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	66.04
Three-Way Collars - Crude Oil 2020 Q2, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	66.04
Three-Way Collars - Crude Oil 2020 Q3, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	63.74
Three-Way Collars - Crude Oil 2020 Q4, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	63.74
Three-Way Collars - Crude Oil 2021, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	0
Three-Way Collars - Crude Oil 2020 Q1, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	55
Three-Way Collars - Crude Oil 2020 Q2, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	55
Three-Way Collars - Crude Oil 2020 Q3, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	55
Three-Way Collars - Crude Oil 2020 Q4, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	55
Three-Way Collars - Crude Oil 2021, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	0
Three-Way Collars - Crude Oil 2020 Q1, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	47.67
Three-Way Collars - Crude Oil 2020 Q2, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	47.67
Three-Way Collars - Crude Oil 2020 Q3, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	48
Three-Way Collars - Crude Oil 2020 Q4, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	48
Three-Way Collars - Crude Oil 2021, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / bbl	0
Midland Basis Swaps - Crude Oil 2020 Q1 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	15,000
Weighted Average Commodity Price | $	$ (0.94)
Midland Basis Swaps - Crude Oil 2020 Q2 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	15,000
Weighted Average Commodity Price | $	$ (0.94)
Midland Basis Swaps - Crude Oil 2020 Q3 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	15,000
Weighted Average Commodity Price | $	$ (0.94)
Midland Basis Swaps - Crude Oil 2020 Q4 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	15,000
Weighted Average Commodity Price | $	$ (0.94)
Midland Basis Swaps - Crude Oil 2021 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	0
Weighted Average Commodity Price | $	$ 0
Brent Basis Swaps - Crude Oil 2020 Q1 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	5,000
Weighted Average Commodity Price | $	$ (7.24)
Brent Basis Swaps - Crude Oil 2020 Q2 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	5,000
Weighted Average Commodity Price | $	$ (7.24)
Brent Basis Swaps - Crude Oil 2020 Q3 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	5,000
Weighted Average Commodity Price | $	$ (7.24)
Brent Basis Swaps - Crude Oil 2020 Q4 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	5,000
Weighted Average Commodity Price | $	$ (7.24)
Brent Basis Swaps - Crude Oil 2021 [Member]
Derivative [Line Items]
Volume | Bbls_per_day	808
Weighted Average Commodity Price | $	$ (7.24)
Three-Way Collars - Natural Gas 2020 Q1 [Member]
Derivative [Line Items]
Volume | MMBTU_per_day	100,000
Three-Way Collars - Natural Gas 2020 Q2 [Member]
Derivative [Line Items]
Volume | MMBTU_per_day	0
Three-Way Collars - Natural Gas 2020 Q3 [Member]
Derivative [Line Items]
Volume | MMBTU_per_day	0
Three-Way Collars - Natural Gas 2020 Q4 [Member]
Derivative [Line Items]
Volume | MMBTU_per_day	0
Three-Way Collars - Natural Gas 2021 [Member]
Derivative [Line Items]
Volume | MMBTU_per_day	0
Three-Way Collars - Natural Gas 2020 Q1, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	3.32
Three-Way Collars - Natural Gas 2020 Q2, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q3, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q4, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2021, Ceiling [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q1, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	2.75
Three-Way Collars - Natural Gas 2020 Q2, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q3, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q4, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2021, Floor [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q1, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	2.25
Three-Way Collars - Natural Gas 2020 Q2, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q3, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2020 Q4, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0
Three-Way Collars - Natural Gas 2021, Sold Put [Member]
Derivative [Line Items]
Weighted average price | $ / MMBTU	0

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	Feb. 10, 2020Bbls_per_day$ / bbl	Sep. 30, 2017USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax			$ 0	$ 0	$ 47
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax					$ 46
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash Proceeds Received from Derivatives		$ 54
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount				$ 0
Unrealized Gain (Loss) on Cash Flow Hedging Instruments			(2)
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount			$ 320
Subsequent Event [Member] | Three-Way Collars - Natural Gas Q1 2020 [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Volume | Bbls_per_day	20,000
Subsequent Event [Member] | Three-Way Collars - Natural Gas Q1 2020, Ceiling [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Weighted average price | $ / bbl	66.37
Subsequent Event [Member] | Three-Way Collars - Natural Gas Q1 2020, Floor [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Weighted average price | $ / bbl	55
Subsequent Event [Member] | Three-Way Collars - Natural Gas Q1 2020, Sold Put [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Weighted average price | $ / bbl	48

Derivatives Derivatives - Sched

Derivatives Derivatives - Schedule of mark-to-market impact and commodity derivative settlements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net loss on commodity derivatives	$ (72)	$ (14)	$ (36)
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net loss on commodity derivatives	(124)	267	(81)
Derivative Instrument Not Designated As Hedging Instruments, Gain (Loss) On Settlements, Net	$ 52	$ (281)	$ 45

Derivatives Derivatives - Sch_2

Derivatives Derivatives - Schedule of Interest Rate Swap Agreements (Details) - Interest Rate Contract [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative, Notional Amount		$ 0
Derivative, Average Variable Interest Rate	1.514%	0.00%
Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 320

Fair Value Measurements (Detail

Fair Value Measurements (Details-Recurring) - Fair Value, Recurring [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	$ 9	$ 127
Derivative Liability	3	0
Derivative Assets (Liabilities), at Fair Value, Net	6	(127)
Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	7	127
Derivative Liability	(3)
Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	2
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	0	21
Derivative Liability	3	0
Derivative Assets (Liabilities), at Fair Value, Net	3	(21)
Fair Value, Inputs, Level 1 [Member] | Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	0	21
Derivative Liability	(3)
Fair Value, Inputs, Level 1 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	9	106
Derivative Liability	0	0
Derivative Assets (Liabilities), at Fair Value, Net	(9)	(106)
Fair Value, Inputs, Level 2 [Member] | Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	7	106
Derivative Liability	0
Fair Value, Inputs, Level 2 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	2
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	0	0
Derivative Liability	0	0
Derivative Assets (Liabilities), at Fair Value, Net	0	0
Fair Value, Inputs, Level 3 [Member] | Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	0	$ 0
Derivative Liability	0
Fair Value, Inputs, Level 3 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement [Line Items]
Derivative Assets	$ 0

Fair Value Measurements (Deta_2

Fair Value Measurements (Details 2-Nonrecurring) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement [Line Items]
Impairments	$ 24	$ 75	$ 229
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	56	113	179
Assets, Fair Value Adjustment	$ 24	$ 75	229
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | International Exploration and Production [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure			103
Impairments			136
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Gulf of Mexico Assets [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure			76
Impairments			$ 89

Fair Value Measurements (Deta_3

Fair Value Measurements (Details 3-Reported) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Estimate of Fair Value Measurement [Member]
Financial assets
Current assets	$ 4	$ 3
Other noncurrent assets	26	76
Total financial assets	30	79
Financial liabilities
Other current liabilities	62	37
Long-term debt, including current portion(a)	6,174	5,469
Deferred credits and other liabilities	99	93
Total financial liabilities	6,335	5,599
Reported Value Measurement [Member]
Financial assets
Current assets	4	3
Other noncurrent assets	38	81
Total financial assets	42	84
Financial liabilities
Other current liabilities	90	58
Long-term debt, including current portion(a)	5,529	5,528
Deferred credits and other liabilities	86	88
Total financial liabilities	$ 5,705	$ 5,674

Debt Revolver (Details)

Debt Revolver (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)	Aug. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Other Long-term Debt, Noncurrent	$ 5,536		$ 5,536
Line of Credit Facility, Expiration Date	May 28, 2023
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,000	$ 3,400
Line of Credit Facility, Maximum Borrowing Capacity	$ 0
Maximum [Member]
Debt Instrument [Line Items]
Ratio of Indebtedness to Net Capital	0.65
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 0
Ratio of Indebtedness to Net Capital	0.31

Debt (Details)

Debt (Details) - USD ($)	Oct. 01, 2019	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 03, 2019
Debt Instrument [Line Items]
Loss on early extinguishment of debt			$ (3,000,000)	$ 0	$ (51,000,000)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax			0	0	47,000,000
Repayments of Long-term Debt			600,000,000	0	2,764,000,000
Other Long-term Debt, Noncurrent			5,536,000,000	5,536,000,000
Unamortized Discount			(7,000,000)	(8,000,000)
Unamortized Debt Issuance Expense			(28,000,000)	(29,000,000)
Total long-term debt due after one year			5,501,000,000	5,499,000,000
Debt Immediately Due If Change In Control			236,000,000
Proceeds from Issuance of Debt	$ 600,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Year 1			0
Year 2			0
Year 3			1,035,000,000
Year 4			401,000,000
Year 5			200,000,000
Thereafter			3,900,000,000
Other Long-term Debt, Noncurrent			$ 5,536,000,000	5,536,000,000
Senior Unsecured Notes Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.70%
Other Long-term Debt, Noncurrent			$ 0	600,000,000		$ 600,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 0	600,000,000		$ 600,000,000
Senior Unsecured Notes Due 2022 [A] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.80%
Other Long-term Debt, Noncurrent				1,000,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent				1,000,000,000
Senior Unsecured Notes Due 2022 [B] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			9.375%
Other Long-term Debt, Noncurrent			$ 32,000,000	32,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			32,000,000	32,000,000
Series Medium Term Notes Due 2022 [Member]
Debt Instrument [Line Items]
Other Long-term Debt, Noncurrent			3,000,000	3,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 3,000,000	3,000,000
Senior Unsecured Notes Due 2023 [A] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			8.50%
Other Long-term Debt, Noncurrent			$ 70,000,000	70,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 70,000,000	70,000,000
Senior Unsecured Notes Due 2023 [B] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			8.125%
Other Long-term Debt, Noncurrent			$ 131,000,000	131,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 131,000,000	131,000,000
Senior Unsecured Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.85%
Other Long-term Debt, Noncurrent			$ 900,000,000	900,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 900,000,000	900,000,000
Senior Unsecured Notes Due 2032 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			6.80%
Other Long-term Debt, Noncurrent			$ 550,000,000	550,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 550,000,000	550,000,000
Notes Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.40%
Other Long-term Debt, Noncurrent			$ 1,000,000,000	1,000,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 1,000,000,000	1,000,000,000
Senior Unsecured Notes Due 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			6.60%
Other Long-term Debt, Noncurrent			$ 750,000,000	750,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			$ 750,000,000	750,000,000
Senior Unsecured Notes Due 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.20%
Other Long-term Debt, Noncurrent			$ 500,000,000	500,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
Other Long-term Debt, Noncurrent			500,000,000	500,000,000
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax					$ 46,000,000
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Debt Instrument [Line Items]
Cash Proceeds Received from Derivatives		$ 54,000,000
Senior Unsecured Note Due 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt due after one year			1,000,000,000
Sub-series A-1 Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 200,000,000
Debt Instrument, Interest Rate, Stated Percentage			2.00%
Sub-series A-2 Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 200,000,000
Debt Instrument, Interest Rate, Stated Percentage			2.10%
St. John the Baptist Parish, State of Louisiana Revenue Bonds Due 2037 [Member]
Debt Instrument [Line Items]
Revenue Refunding Bond			$ 400,000,000	$ 1,000,000,000
Sub-series A-3 Bonds [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 200,000,000
Debt Instrument, Interest Rate, Stated Percentage			2.20%
Senior Unsecured Notes Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						2.70%

Incentive Based Compensation _3

Incentive Based Compensation Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	27,900,000
Granted, stock option awards (in shares)	648,526
Allocated stock-based compensation expense	$ 60,000,000	$ 53,000,000	$ 50,000,000
Proceeds from stock options exercised	1,000,000	$ 26,000,000
Tax benefit realized from exercise of stock options	$ 0
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award contractual period	10 years
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, stock option awards (in shares)	0
Restricted Stock [Member] | Granted Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Restricted Stock [Member] | Non Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Share-based Payment Arrangement [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	0.00%
Share-based Payment Arrangement [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	200.00%
Restricted Stock Units (RSUs) [Member] | Non Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Share-based Compensation Plans Prior to the 2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, stock option awards (in shares)	0

Incentive Based Compensation _4

Incentive Based Compensation Plans - Stock Option Award Assumptions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Incentive Based Compensation Plans [Abstract]
Share-based Payment Arrangement, Exercise of Option, Tax Benefit	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Exercise price per share (in dollars per share)	$ 16.79	$ 14.52	$ 15.80
Expected annual dividend yield	1.20%	1.40%	1.30%
Expected life in years	5 years 9 months 25 days	6 years 5 months 12 days	6 years 4 months 24 days
Expected volatility	43.00%	43.00%	42.00%
Risk-free interest rate	2.50%	2.80%	2.10%
Weighted average grant date fair value of stock option awards granted (in dollars per share)	$ 6.62	$ 5.83	$ 6.07

Incentive Based Compensation _5

Incentive Based Compensation Plans - Stock Option Award Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Beginning of year, stock option awards (in shares)	6,180,007
Granted, stock option awards (in shares)	648,526
Exercised, stock option awards (in shares)	(84,804)
Canceled, stock option awards (in shares)	(1,083,998)
End of year, stock option awards (in shares)	5,659,731	6,180,007
Exercisable at end of year, stock option awards (in shares)	4,323,312
Expected to vest, stock option awards (in shares)	1,319,850
Weighted Average Exercise Price
Beginning of year, weighted average exercise price (in dollars per share)	$ 24.39
Granted, weighted average exercise price (in dollars per share)	16.79	$ 14.52	$ 15.80
Exercises, weighted average exercise price (in dollars per share)	8.17
Canceled, weighted average exercise price (in dollars per share)	25.45
End of year, weighted average exercise price (in dollars per share)	23.55	$ 24.39
Exercisable at end of year, weighted average exercise price (in dollars per share)	25.96
Expected to vest, weighted average exercise price (in dollars per share)	$ 15.76
Share-based Payment Arrangement [Abstract]
Outstanding at end of year, Weighted Average Remaining Contractual Term	5 years
Exercisable at end of year, Weighted Average Remaining Contractual Term	4 years
Expected to vest, Weighted Average Remaining Contractual Term	8 years
Outstanding at end of year, Average Intrinsic Value	$ 3
Exercisable at end of year, Average Intrinsic Value	3
Expected to vest, Average Intrinsic Value	0
Stock option awards, intrinsic value		$ 13
Unrecognized compensation costs	$ 5
Unrecognized compensation costs, period for recognition	1 year

Incentive Based Compensation _6

Incentive Based Compensation Plans - Restricted Stock Awards and RSUs (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Grant Date Fair Value
Unrecognized compensation costs	$ 5
Unrecognized compensation costs, period for recognition	1 year
Restricted Stock [Member]
Awards
Unvested at beginning of year (in shares)	8,504,946
Granted (in shares)	4,113,190
Vested & Exercised (in shares)	(3,813,221)
Canceled (in shares)	(1,630,529)
Unvested at end of year (in shares)	7,174,386	8,504,946
Weighted Average Grant Date Fair Value
Unvested at beginning of year (in dollars per share)	$ 14.04	$ 14.24
Granted (in dollars per share)	16.65
Vested & Exercised (in dollars per share)	12.64
Canceled (in dollars per share)	15.78
Unvested at end of year (in dollars per share)	$ 15.88	$ 14.04	$ 14.24
Vested in period, total fair value	$ 48	$ 48	$ 39
Unrecognized compensation costs	$ 65
Unrecognized compensation costs, period for recognition	1 year

Incentive Based Compensation _7

Incentive Based Compensation Plans - Performance Unit Awards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Exercise of Option, Tax Benefit	$ 0
Allocated stock-based compensation expense	$ 60,000,000	$ 53,000,000	$ 50,000,000
Expected annual dividend yield	1.20%	1.40%	1.30%
Expected volatility	43.00%	43.00%	42.00%
Risk-free interest rate	2.50%	2.80%	2.10%
Performance Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested units (in shares)	1,282,296
Valuation date stock price (in dollars per share)	$ 16.79	$ 13.69	$ 13.58
Expected annual dividend yield	1.20%	1.50%
Expected volatility	43.00%	41.00%
Risk-free interest rate	2.50%	1.50%
Fair value of stock-based performance units outstanding	$ 20.66	$ 17.29	$ 14.18
Granted Officer [Member] | Performance Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	656,636	754,140	563,631
Allocated stock-based compensation expense	$ 7,000,000	$ 13,000,000	$ 8,000,000

Defined Benefit Postretiremen_3

Defined Benefit Postretirement Plans and Defined Contribution Plan - Obligations and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Divestiture	$ 0	$ 0
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	343	320
Change in benefit obligations:
Benefit obligations at January 1	326	384
Service cost	19	18
Interest cost	12	12
Plan amendment	0	0
Actuarial loss	48	(20)
Foreign currency exchange rate changes	0	0
Settlements paid	(45)	(62)
Benefits paid	(6)	(6)
Benefit obligations at December 31	354	326
Change in fair value of plan assets:
Fair value of plan assets at January 1	203	216
Actual return on plan assets	44	(6)
Employer contributions	40	61
Foreign currency exchange rate changes	0	0
Settlements paid	(45)	(62)
Benefits paid	(6)	(6)
Fair value of plan assets at December 31	236	203
Funded status of plans at December 31
Funded status of plans at December 31	(118)	(123)
Amounts recognized in the consolidated balance sheets:
Noncurrent assets	0	0
Current liabilities	(6)	(5)
Noncurrent liabilities	(112)	(118)
Accrued benefit cost	(118)	(123)
Pretax amounts in accumulated other comprehensive loss:
Net loss	85	90
Prior service cost	(29)	(36)
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Divestiture	666	0
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	0	511
Change in benefit obligations:
Benefit obligations at January 1	511	599
Service cost	0	0
Interest cost	8	14
Plan amendment	0	3
Defined Benefit Plan, Benefit Obligation, Divestiture	(549)
Actuarial loss	36	38
Foreign currency exchange rate changes	6	(29)
Settlements paid	0	23
Benefits paid	(12)	(15)
Benefit obligations at December 31	0	511
Change in fair value of plan assets:
Fair value of plan assets at January 1	594	670
Actual return on plan assets	68	(21)
Employer contributions	8	17
Foreign currency exchange rate changes	8	(34)
Settlements paid	0	(23)
Benefits paid	(12)	(15)
Fair value of plan assets at December 31	0	594
Funded status of plans at December 31
Funded status of plans at December 31	0	83
Amounts recognized in the consolidated balance sheets:
Noncurrent assets	0	83
Current liabilities	0	0
Noncurrent liabilities	0	0
Accrued benefit cost	0	83
Pretax amounts in accumulated other comprehensive loss:
Net loss	0	(59)
Prior service cost	0	5
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Divestiture		0
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	89	96
Change in benefit obligations:
Benefit obligations at January 1	96	221
Service cost	1	2
Interest cost	3	7
Plan amendment	0	(99)
Actuarial loss	9	(15)
Foreign currency exchange rate changes	0	0
Settlements paid	0	0
Benefits paid	(20)	(20)
Benefit obligations at December 31	89	96
Change in fair value of plan assets:
Fair value of plan assets at January 1	0	0
Actual return on plan assets	0	0
Employer contributions	20	20
Foreign currency exchange rate changes	0	0
Settlements paid	0	0
Benefits paid	(20)	(20)
Fair value of plan assets at December 31	0	0
Funded status of plans at December 31
Funded status of plans at December 31	(89)	(96)
Amounts recognized in the consolidated balance sheets:
Noncurrent assets	0	0
Current liabilities	(18)	(19)
Noncurrent liabilities	(71)	(77)
Accrued benefit cost	(89)	(96)
Pretax amounts in accumulated other comprehensive loss:
Net loss	23	14
Prior service cost	$ (129)	$ (147)

Defined Benefit Postretiremen_4

Defined Benefit Postretirement Plans and Defined Contribution Plan - Schedule of Net Periodic Benefit Cost and OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2020
Depreciation, Depletion and Amortization [Abstract]
Net settlement loss	$ 3	$ (14)	$ (19)
Foreign Plan [Member]
Components of net periodic benefit cost:
Service cost	0	0	0
Interest cost	8	14	17
Expected return on plan assets	(11)	(24)	(30)
Depreciation, Depletion and Amortization [Abstract]
- prior service cost (credit)	0	0	0
- actuarial loss	0	0	1
Net settlement loss	0	(3)	(4)
Net periodic benefit cost	(3)	(7)	(8)
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss (pretax):
Actuarial loss (gain)	(21)	8	(26)
Amortization of actuarial (loss) gain	(41)	(3)	(4)
Prior service cost	0	3	0
Amortization of prior service credit (cost)	(6)	0	0
Total recognized in other comprehensive (income) loss	(68)	8	(30)
Total recognized in net periodic benefit cost and other comprehensive (income) loss	(71)	1	(38)
UNITED STATES
Components of net periodic benefit cost:
Service cost	19	18	22
Interest cost	12	12	13
Expected return on plan assets	(10)	(11)	(13)
Depreciation, Depletion and Amortization [Abstract]
- prior service cost (credit)	(7)	(10)	(10)
- actuarial loss	7	11	8
Net settlement loss	(12)	(18)	(28)
Net periodic benefit cost	33	38	48
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss (pretax):
Actuarial loss (gain)	14	(4)	28
Amortization of actuarial (loss) gain	(19)	(29)	(36)
Prior service cost	0	0	0
Amortization of prior service credit (cost)	7	10	10
Total recognized in other comprehensive (income) loss	2	(23)	2
Total recognized in net periodic benefit cost and other comprehensive (income) loss	35	15	50
Other Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic benefit cost:
Service cost	1	2	2
Interest cost	3	7	8
Expected return on plan assets	0	0	0
Depreciation, Depletion and Amortization [Abstract]
- prior service cost (credit)	(19)	(8)	(7)
- actuarial loss	1	1	0
Net settlement loss	0	0	0
Net periodic benefit cost	(14)	2	3
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss (pretax):
Actuarial loss (gain)	9	(15)	5
Amortization of actuarial (loss) gain	(1)	(1)	0
Prior service cost	0	(99)	0
Amortization of prior service credit (cost)	19	8	7
Total recognized in other comprehensive (income) loss	27	(107)	12
Total recognized in net periodic benefit cost and other comprehensive (income) loss	$ 13	$ (105)	$ 15
Forecast [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Defined Benefit Plan, Amortization of Net Gains (Losses)				$ 9
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)				7
Forecast [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Defined Benefit Plan, Amortization of Net Gains (Losses)				2
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)				$ 18

Defined Benefit Postretiremen_5

Defined Benefit Postretirement Plans and Defined Contribution Plan - Plan Assumptions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Assumptions Used In Calculations [Line Items]
Increase (Decrease) in Obligation, Other Postretirement Benefits	$ 99
UNITED STATES
Weighted average assumptions used to determine benefit obligation:
Discount rate	3.13%	4.26%	3.55%
Rate of compensation increase	4.50%	4.00%	4.00%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate	3.70%	3.88%	3.86%
Expected long-term return on plan assets	6.25%	6.50%	6.50%
Rate of compensation increase	4.00%	4.00%	4.00%
Foreign Plan [Member]
Weighted average assumptions used to determine benefit obligation:
Discount rate		2.90%	2.50%
Rate of compensation increase		0.00%	0.00%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate		2.50%	2.70%
Expected long-term return on plan assets		3.70%	4.50%
Rate of compensation increase		0.00%	0.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]
Weighted average assumptions used to determine benefit obligation:
Discount rate	2.91%	4.09%	3.54%
Rate of compensation increase	4.50%	4.00%	4.00%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate	4.09%	3.54%	3.98%
Expected long-term return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	4.00%	4.00%	4.00%

Defined Benefit Postretiremen_6

Defined Benefit Postretirement Plans and Defined Contribution Plan - Health Care Cost Trends Table and Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Pension Plan [Member]
Defined Benefit Plan Assumed Health Care Cost Trend Rates [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 20
Equity Securities [Member]
Defined Benefit Plan Assumed Health Care Cost Trend Rates [Line Items]
Target allocation percentage	55.00%
Fixed Income Securities [Member]
Defined Benefit Plan Assumed Health Care Cost Trend Rates [Line Items]
Target allocation percentage	45.00%

Defined Benefit Postretiremen_7

Defined Benefit Postretirement Plans and Defined Contribution Plan - Fair Value of Defined Benefit Pension Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 236	$ 203	$ 216
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds	148	143
UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	(7)	(1)
UNITED STATES | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	75	75
UNITED STATES | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	10	14
UNITED STATES | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
UNITED STATES | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2	4
UNITED STATES | Exchange Traded Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	3
UNITED STATES | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	47	34
UNITED STATES | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
UNITED STATES | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	18	17
UNITED STATES | Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	88	60
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0	0
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	594	$ 670
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds		594
Foreign Plan [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		5
Foreign Plan [Member] | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Foreign Plan [Member] | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Foreign Plan [Member] | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		191
Foreign Plan [Member] | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Foreign Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Foreign Plan [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		398
Foreign Plan [Member] | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	102	96
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds	102	96
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	(7)	(1)
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	75	75
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Exchange Traded Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	3
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	31	22
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | UNITED STATES | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		5
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds		5
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		5
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 1 [Member] | Foreign Plan [Member] | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	13	13
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds	13	13
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2	4
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Exchange Traded Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	11	9
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | UNITED STATES | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		589
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds		589
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		191
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		398
Fair Value, Inputs, Level 2 [Member] | Foreign Plan [Member] | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	33	34
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds	33	34
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	10	14
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Exchange Traded Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	5	3
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value, Inputs, Level 3 [Member] | UNITED STATES | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 18	17
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Defined Benefit Plan, Fair Value of Plan Assets, Before Commingled Funds		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Common And Preferred Stock [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Private Equity And Reit [Member] [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Mutual And Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | Pooled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		0
Fair Value, Inputs, Level 3 [Member] | Foreign Plan [Member] | MRO Other investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 0

Defined Benefit Postretiremen_8

Defined Benefit Postretirement Plans and Defined Contribution Plan - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2020
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
Employer discretionary contribution amount	$ 18	$ 22	$ 20
Forecast [Member]
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
Estimated future employer contributions in Year 1				$ 28
UNITED STATES
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
Year 1	39
Year 2	35
Year 3	31
Year 4	29
Year 5	27
2025 through 2029	116
Unfunded Plans [Member] | Forecast [Member]
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
Estimated future employer contributions in Year 1				6
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
Year 1	18
Year 2	10
Year 3	9
Year 4	8
Year 5	7
2025 through 2029	$ 25
Other Postretirement Benefit Plans, Defined Benefit [Member] | Forecast [Member]
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
Estimated future employer contributions in Year 1				$ 18

Reclassifications Out of Accu_2

Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	$ (3)	$ 14	$ 19
Foreign currency translation adjustment related to sale of U.K. business	(30)	0	0
Income taxes related to sale of U.K. business (b)	(7)	0	(4)
Net gain on disposal of assets	50	319	58
Net interest and other	(244)	(226)	(270)
Net income (loss)	480	1,096	$ (5,723)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	(6)	14
U.K. pension plan transferred to buyer	83	0
Foreign currency translation adjustment related to sale of U.K. business	(30)	0
Net gain on disposal of assets	68	0
Net interest and other	1	0
Net income (loss)	75	(14)
Amortization of prior service credit | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	(26)	(18)
Amortization of actuarial loss | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	8	12
Net settlement loss, net of tax | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	12	21
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	(12)	(20)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income taxes related to sale of U.K. business (b)	$ (45)	$ 0

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Interest paid (net of amounts capitalized)	$ 269	$ 270	$ 379
Income taxes paid to taxing authorities	73	287	391
Asset Retirement Obligation, Period Increase (Decrease)	80	(183)	(202)
Noncash investing and financing activities:
Asset Retirement Obligation, Liabilities Transferred	1,082	82	14
Notes receivable	0	0
Receivable Related To Disposal Of Assets			748
Increase in capital expenditure accrual	288	250	329
Income Tax Examination [Line Items]
Proceeds from Income Tax Refunds	$ 90	$ 37	1
Foreign Tax Authority [Member] | UK Government [Member]
Income Tax Examination [Line Items]
Income Tax Examination, Penalties and Interest Expense			$ 108

Other Items (Details)

Other Items (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Interest and Other Financing [Abstract]
Interest income	$ 25	$ 32	$ 34
Interest expense(a)	(280)	(280)	(380)
Income on interest rate swaps	0	0	53
Interest capitalized	0	0	3
Total interest	(255)	(248)	(290)
Net foreign currency gains (losses)	4	9	8
Other	7	13	12
Total other	11	22	20
Net interest and other	(244)	(226)	(270)
Aggregate foreign currency gains losses [Abstract]
Net interest and other	4	9	8
Provision for income taxes	2	10	57
Aggregate foreign currency gains (losses)	$ 6	$ 19	$ 65

Equity Method Investments and_3

Equity Method Investments and Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Method Investments Disclosure [Abstract]
Proceeds from Equity Method Investment, Distribution	$ 105	$ 270	$ 276
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	663	745
Equity Method Investment, Summarized Financial Information [Abstract]
Revenues and other income	832	1,269	1,294
Income from operations	250	588	631
Net income	187	459	508
Current assets	455	559
Noncurrent assets	1,049	931
Current liabilities	284	253
Noncurrent liabilities	183	87
Related Party Transactions [Abstract]
Revenue from Related Parties	42	48	60
Related Party Transaction, Purchases from Related Party		0	$ 132
Accounts Receivable, Related Parties, Current	28	25
Accounts Payable, Related Parties, Current	$ 11	15
EG Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	60.00%
Equity Method Investments	$ 310	402
Alba Plant LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	52.00%
Equity Method Investments	$ 163	167
AMPCO [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	45.00%
Equity Method Investments	$ 190	$ 176

Stockholders Equity (Details)

Stockholders Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 31, 2019
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method	$ 362	$ 712	$ 11
Treasury Stock, Shares, Acquired	0
Common stock, par value per share	$ 1	$ 1
Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 1,400			$ 1,500
Treasury Stock, Value, Acquired, Cost Method	$ 345	$ 700
Treasury Stock, Shares, Acquired	24	36

Commitments and Contingencies (

Commitments and Contingencies (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)	Nov. 30, 2018GBP (£)
Guarantor Obligations [Line Items]
Surety Bond, Notional Amount | £				£ 92
Surety Bond Exposure, Liability	$ 6	$ 6
Contingent Royalty Liability	93
Contingent Capital And Expense Receivable, Noncurrent	20
Commitments to acquire property, plant and equipment	41		$ 57
Override Royalty, Amount Earned Directed To Corresponding Asset Retirement Obligations	46
Override Royalty - GOM Future Abandonment	$ 70