Anadarko Petroleum 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document And Entity Information [Abstract]
Trading Symbol	APC
Entity Registrant Name	ANADARKO PETROLEUM CORP
Entity Central Index Key	0000773910
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		502,118,789

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues and Other
Sales revenues	$ 3,338	$ 3,236
Gains (losses) on divestitures and other, net	92	19
Total	3,218	3,045
Costs and Expenses
Oil and gas operating	289	276
Oil and gas transportation	222	196
Exploration	49	168
General and administrative	267	278
Depreciation, depletion, and amortization	1,081	990
Production, property, and other taxes	199	190
Impairments	0	19
Other operating expense	21	140
Total	2,384	2,494
Operating Income (Loss)	834	551
Other (Income) Expense
Interest expense	253	228
(Gains) losses on derivatives, net	315	36
Other (income) expense, net	6	(12)
Total	572	251
Income (Loss) Before Income Taxes	262	300
Income tax expense (benefit)	166	126
Net Income (Loss)	96	174
Net income (loss) attributable to noncontrolling interests	111	53
Net Income (Loss) Attributable to Common Stockholders	$ (15)	$ 121
Per Common Share
Net income (loss) attributable to common stockholders—basic (in usd per share)	$ (0.03)	$ 0.23
Net income (loss) attributable to common stockholders—diluted (in usd per share)	$ (0.03)	$ 0.22
Average Number of Common Shares Outstanding—Basic (in shares)	490	518
Average Number of Common Shares Outstanding—Diluted (in shares)	490	519
Commodity Contract and Interest Rate Swap [Member]
Other (Income) Expense
(Gains) losses on derivatives, net	$ 313	$ 35
Oil sales [Member]
Revenues and Other
Sales revenues	2,096	2,127
Natural gas sales [Member]
Revenues and Other
Sales revenues	320	247
Natural-gas liquids sales [Member]
Revenues and Other
Sales revenues	240	292
Gathering, processing, and marketing sales [Member]
Revenues and Other
Sales revenues	470	360
Costs and Expenses
Gathering, processing, and marketing	$ 256	$ 237

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 96	$ 174
Adjustments for derivative instruments
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net	1	1
Total adjustments for derivative instruments, net of taxes	1	1
Adjustments for pension and other postretirement plans
Amortization of net actuarial (gain) loss to other (income) expense, net	8	7
Income taxes on amortization of net actuarial (gain) loss	(2)	(2)
Amortization of net prior service (credit) cost to other (income) expense, net	(1)	(6)
Income taxes on amortization of net prior service (credit) cost	0	1
Total adjustments for pension and other postretirement plans, net of taxes	5	0
Total	6	1
Comprehensive Income (Loss)	102	175
Comprehensive income (loss) attributable to noncontrolling interests	111	53
Comprehensive Income (Loss) Attributable to Common Stockholders	$ (9)	$ 122

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents ($100 and $92 related to VIEs)		$ 2,026	$ 1,295
Accounts receivable (net of allowance of $11 and $13)
Customers ($138 and $138 related to VIEs)		1,553	1,491
Others		512	535
Other current assets		338	474
Total		4,429	3,795
Net Properties and Equipment (net of accumulated depreciation, depletion, and amortization of $38,903 and $37,905) ($8,630 and $6,612 related to VIEs)		28,936	28,615
Other Assets ($1,246 and $868 related to VIEs)		3,006	2,336
Goodwill and Other Intangible Assets ($1,279 and $1,163 related to VIEs)		5,622	5,630
Total Assets		41,993	40,376
Accounts payable
Trade ($196 and $263 related to VIEs)		1,946	2,003
Other ($6 and $15 related to VIEs)		165	161
Short-term debt		2,021	947
Current asset retirement obligations ($23 and $26 related to VIEs)		277	252
Other current liabilities ($107 and $54 related to VIEs)		1,340	1,295
Total		5,749	4,658
Long-term Debt		15,903	15,470
Other Long-term Liabilities
Deferred income taxes		2,624	2,437
Asset retirement obligations ($312 and $260 related to VIEs)		2,876	2,847
Other		4,308	4,021
Total		9,808	9,305
Stockholders’ equity
Common stock, par value $0.10 per share (1.0 billion shares authorized, 577.8 million and 576.6 million shares issued)		57	57
Paid-in capital		13,057	12,393
Retained earnings		1,024	1,245
Treasury stock (87.5 million and 87.2 million shares)		(4,881)	(4,864)
Accumulated other comprehensive income (loss)		(329)	(335)
Total Stockholders’ Equity		8,928	8,496
Noncontrolling interests		1,605	2,447
Total Equity		10,533	10,943
Total Liabilities and Equity		41,993	40,376
Anadarko [Member]
Accounts payable
Short-term debt	[1]	21	919
Long-term Debt	[1]	10,695	10,683
WES [Member]
Accounts payable
Short-term debt		2,000	28
Long-term Debt		$ 5,208	$ 4,787
[1]	Excludes WES.

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 2,026	$ 1,295
Accounts receivable
Allowance for uncollectible accounts	11	13
Customers	1,553	1,491
Others	512	535
Property, Plant and Equipment, Net [Abstract]
Net properties and equipment related to VIEs	28,936	28,615
Accumulated depreciation, depletion and amortization	38,903	37,905
Other Assets	3,006	2,336
Goodwill and Other Intangible Assets	5,622	5,630
Accounts payable
Trade	1,946	2,003
Other	165	161
Current asset retirement obligations	277	252
Other current liabilities	1,340	1,295
Other Long-term Liabilities
Asset retirement obligations	$ 2,876	$ 2,847
Stockholders’ equity
Common stock, par value per share (in usd per share)	$ 0.1	$ 0.10
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	577,800,000	576,600,000
Treasury stock (in shares)	87,500,000	87,200,000
Variable Interest Entity, Primary Beneficiary [Member]
Current Assets
Cash and cash equivalents	$ 100	$ 92
Accounts receivable
Customers	138	138
Others	11	16
Property, Plant and Equipment, Net [Abstract]
Net properties and equipment related to VIEs	8,630	6,612
Other Assets	1,246	868
Goodwill and Other Intangible Assets	1,279	1,163
Accounts payable
Trade	196	263
Other	6	15
Current asset retirement obligations	23	26
Other current liabilities	107	54
Other Long-term Liabilities
Asset retirement obligations	$ 312	$ 260

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Subsidiary Equity Transactions [Member]	Common Stock [Member]	Paid-in Capital [Member]	Paid-in Capital [Member]Subsidiary Equity Transactions [Member]	Retained Earnings [Member]	Retained Earnings [Member]Subsidiary Equity Transactions [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member]Subsidiary Equity Transactions [Member]
Balance at Dec. 31, 2017	$ 13,790		$ 57	$ 12,000		$ 1,109		$ (2,132)	$ (338)	$ 3,094
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	174					121				53
Share-based compensation expense	39			39
Dividends—common stock	(127)					(127)
Repurchases of common stock	(1,959)			(332)				(1,627)
Subsidiary equity transactions		$ 3			$ (6)						$ 9
Distributions to noncontrolling interest owners	(118)									(118)
Adjustments for pension and other postretirement plans	0
Other	1								1
Balance at Mar. 31, 2018	11,756		57	11,701		1,152		(3,759)	(410)	3,015
Balance at Dec. 31, 2018	10,943		57	12,393		1,245		(4,864)	(335)	2,447
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	96					(15)				111
Share-based compensation expense	38			38
Dividends—common stock	(150)					(150)
Repurchases of common stock	(17)							(17)
Subsidiary equity transactions		$ (198)			$ 626		$ (1)				$ (823)
Distributions to noncontrolling interest owners	(130)									(130)
Adjustments for pension and other postretirement plans	5								5
Other	1								1
Balance at Mar. 31, 2019	$ 10,533		$ 57	$ 13,057		$ 1,024		$ (4,881)	$ (329)	$ 1,605

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash Flows from Operating Activities
Net income (loss)	$ 96	$ 174
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Depreciation, depletion, and amortization	1,081	990
Deferred income taxes	1	42
Dry hole expense and impairments of unproved properties	0	106
Impairments	0	19
(Gains) losses on divestitures, net	5	24
Total (gains) losses on derivatives, net	315	36
Operating portion of net cash received (paid) in settlement of derivative instruments	1	(63)
Other	42	74
Changes in assets and liabilities
(Increase) decrease in accounts receivable	(39)	23
Increase (decrease) in accounts payable and other current liabilities	(294)	45
Other items, net	(79)	(40)
Net cash provided by (used in) operating activities	1,129	1,430
Cash Flows from Investing Activities
Additions to properties and equipment	(1,389)	(1,547)
Divestitures of properties and equipment and other assets	7	371
Other, net	(146)	63
Net cash provided by (used in) investing activities	(1,528)	(1,113)
Cash Flows from Financing Activities
Borrowings, net of issuance costs	2,420	1,333
Repayments of debt	(935)	(639)
Financing portion of net cash received (paid) for derivative instruments	(98)	54
Increase (decrease) in outstanding checks	68	(26)
Dividends paid	(150)	(127)
Repurchases of common stock	(17)	(1,959)
Distributions to noncontrolling interest owners	(130)	(118)
Payments of future hard-minerals royalty revenues conveyed	(24)	(25)
Other	(5)	0
Net cash provided by (used in) financing activities	1,129	(1,507)
Effect of exchange rate changes on cash, cash equivalents, restricted cash, and restricted cash equivalents	1	0
Net Increase (Decrease) in Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents	731	(1,190)
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents at Beginning of Period	1,429	4,674
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents at End of Period	$ 2,160	$ 3,484

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	The consolidated financial statements include the accounts of Anadarko and subsidiaries in which Anadarko holds, directly or indirectly, more than 50% of the voting rights and VIEs for which Anadarko is the primary beneficiary. The Company has determined that WES is a VIE. Anadarko is considered the primary beneficiary and consolidates WES. WES functions with a capital structure that is separate from Anadarko, consisting of its own debt instruments and publicly traded common units. All intercompany transactions have been eliminated. Undivided interests in oil and natural-gas exploration and production joint ventures are consolidated on a proportionate basis. Investments in noncontrolled entities that Anadarko has the ability to exercise significant influence over operating and financial policies and VIEs for which Anadarko is not the primary beneficiary are accounted for using the equity method. In applying the equity method of accounting, the investments are initially recognized at cost and subsequently adjusted for the Company’s proportionate share of earnings, losses, and distributions. Investments are included in other assets on the Company’s Consolidated Balance Sheets.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	2. Revenue from Contracts with Customers Disaggregation of Revenue from Contracts with Customers The following table disaggregates revenue by significant product type and segment: millions Exploration WES Midstream Other and Total Three Months Ended March 31, 2019 Oil sales $ 2,096 $ — $ — $ 2,096 Natural-gas sales 320 — — 320 Natural-gas liquids sales 240 — — 240 Gathering, processing, and marketing sales (1) 1 672 (25 ) 648 Other, net 9 — 25 34 Total Revenue from Customers $ 2,666 $ 672 $ — $ 3,338 Gathering, processing, and marketing sales (2) — — (178 ) (178 ) Gains (losses) on divestitures, net — — (5 ) (5 ) Other, net (1 ) 57 7 63 Total Revenue from Other than Customers $ (1 ) $ 57 $ (176 ) $ (120 ) Total Revenue and Other $ 2,665 $ 729 $ (176 ) $ 3,218 Three Months Ended March 31, 2018 Oil sales $ 2,127 $ — $ — $ 2,127 Natural-gas sales 247 — — 247 Natural-gas liquids sales 292 — — 292 Gathering, processing, and marketing sales (1) — 502 46 548 Other, net 3 — 19 22 Total Revenue from Customers $ 2,669 $ 502 $ 65 $ 3,236 Gathering, processing, and marketing sales (2) — (1 ) (187 ) (188 ) Gains (losses) on divestitures, net (33 ) — 9 (24 ) Other, net (12 ) 44 (11 ) 21 Total Revenue from Other than Customers $ (45 ) $ 43 $ (189 ) $ (191 ) Total Revenue and Other $ 2,624 $ 545 $ (124 ) $ 3,045 (1) The amount in Other and Intersegment Eliminations primarily represents sales of third-party natural gas and NGLs of $209 million and intersegment eliminations of $(223) million for the three months ended March 31, 2019 , and sales of third-party natural gas and NGLs of $224 million and intersegment eliminations of $(163) million for the three months ended March 31, 2018 . (2) The amount in Other and Intersegment Eliminations represents purchases of third-party natural gas and NGLs. Although these purchases are reported net in gathering, processing, and marketing sales in the Company’s Consolidated Statements of Income, they are shown separately on this table as the purchases are not considered revenue from customers. 2. Revenue from Contracts with Customers (Continued) Contract Liabilities Contract liabilities primarily relate to midstream fees and capital reimbursements that are charged to customers for only a portion of the contract term and must be recognized as revenues over the expected period of benefit, fixed and variable fees that are received from customers but revenue recognition is deferred under midstream cost of service contracts, and hard-minerals bonus payments received from customers that must be recognized as revenue over the expected period of benefit. The following table summarizes the current period activity related to contract liabilities from contracts with customers: millions Balance at December 31, 2018 $ 150 Increase due to cash received, excluding revenues recognized in the period 21 Decrease due to revenue recognized (18 ) Balance at March 31, 2019 $ 153 Contract liabilities at March 31, 2019 Other current liabilities $ 23 Other long-term liabilities - other 130 Total contract liabilities from contracts with customers $ 153 Transaction Price Allocated to Remaining Performance Obligations Revenue expected to be recognized from certain performance obligations that are unsatisfied as of March 31, 2019 , is reflected in the table below. The Company applies the optional exemptions in Topic 606 and does not disclose consideration for remaining performance obligations with an original expected duration of one year or less or for variable consideration related to unsatisfied performance obligations. Therefore, the following table represents only a small portion of Anadarko’s expected future consolidated revenues as future revenue from the sale of most products and services is dependent on future production or variable customer volume and variable commodity prices for that volume. millions Exploration & Production WES Midstream Other and Intersegment Eliminations Total Remainder of 2019 $ 80 $ 533 $ (352 ) $ 261 2020 103 862 (622 ) 343 2021 103 912 (698 ) 317 2022 7 976 (770 ) 213 2023 7 933 (770 ) 170 Thereafter 58 4,500 (4,009 ) 549 Total $ 358 $ 8,716 $ (7,221 ) $ 1,853

Commodity Inventories

Commodity Inventories	3 Months Ended
	Mar. 31, 2019
Energy Related Inventory [Abstract]
Commodity Inventories	3. Commodity Inventories The following summarizes the major classes of commodity inventories included in other current assets: millions March 31, 2019 December 31, 2018 Oil $ 169 $ 139 Natural gas 1 18 NGLs 84 78 Total commodity inventories $ 254 $ 235

Divestitures

Divestitures	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Divestitures	4. Divestitures The following summarizes the proceeds received and gains (losses) recognized on divestitures: Three Months Ended March 31, millions 2019 2018 Proceeds received, net of closing adjustments $ 7 $ 371 Gains (losses) on divestitures, net (5 ) (24 ) 2018 During the three months ended March 31, 2018, the Company divested of its Alaska nonoperated assets, included in the Exploration and Production reporting segment, for net proceeds of $383 million and net losses of $30 million in 2018 and $154 million in the fourth quarter of 2017.

Suspended Exploratory Well Cost

Suspended Exploratory Well Costs	3 Months Ended
	Mar. 31, 2019
Capitalized Exploratory Well Costs [Abstract]
Suspended Exploratory Well Costs	5. Suspended Exploratory Well Costs The Company’s suspended exploratory well costs were $460 million at March 31, 2019, and $444 million at December 31, 2018 . For exploratory wells, drilling costs are capitalized, or “suspended,” on the balance sheet when the well has found a sufficient quantity of reserves to justify its completion as a producing well and sufficient progress is being made in assessing the reserves and the economic and operating viability of the project. If additional information becomes available that raises substantial doubt as to the economic or operational viability of any of these projects, the associated costs will be expensed at that time. During the three months ended March 31, 2019, there was no exploration expense recorded for suspended exploratory well costs previously capitalized for greater than one year at December 31, 2018 .

Current Liabilities

Current Liabilities	3 Months Ended
	Mar. 31, 2019
Payables and Accruals [Abstract]
Current Liabilities	6. Current Liabilities Accounts Payable Accounts payable, trade included liabilities of $248 million at March 31, 2019 , and $180 million at December 31, 2018 , representing the amount by which checks issued but not presented to the Company’s banks for collection exceeded balances in applicable bank accounts. Changes in these liabilities are classified as cash flows from financing activities. Other Current Liabilities The following summarizes the Company’s other current liabilities: millions March 31, 2019 December 31, 2018 Accrued income taxes $ 211 $ 167 Interest payable 159 267 Production, property, and other taxes payable 314 309 Accrued employee benefits 153 319 Derivatives 121 89 Operating lease liabilities 245 — Other 137 144 Total other current liabilities $ 1,340 $ 1,295

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	7. Derivative Instruments Objective and Strategy The Company uses derivative instruments to manage its exposure to cash-flow variability from commodity-price and interest-rate risks. Futures, swaps, and options are used to manage exposure to commodity-price risk inherent in the Company’s oil and natural-gas production and natural-gas processing operations (Oil and Natural-Gas Production/Processing Derivative Activities). Futures contracts and commodity-price swap agreements are used to fix the price of expected future oil and natural-gas sales at major industry trading locations, such as Cushing, Oklahoma or Sullom Voe, Scotland for oil and Henry Hub, Louisiana for natural gas. Basis swaps are periodically used to fix or float the price differential between product prices at one market location versus another. Options are used to establish a floor price, a ceiling price, or a floor and a ceiling price (collar) for expected future oil and natural-gas sales. Derivative instruments are also used to manage commodity-price risk inherent in customer price requirements and to fix margins on the future sale of natural gas and NGLs from the Company’s leased storage facilities. Interest-rate swaps are used to fix or float interest rates on existing or anticipated indebtedness. The purpose of these instruments is to manage the Company’s existing or anticipated exposure to interest-rate changes. The fair value of the Company’s current interest-rate swap portfolio is subject to changes in interest rates. The Company does not apply hedge accounting to any of its currently outstanding derivative instruments. As a result, gains and losses associated with derivative instruments are recognized currently in earnings. Net derivative losses attributable to derivatives previously subject to hedge accounting reside in accumulated other comprehensive income (loss) and are reclassified to earnings as the transactions to which the derivatives relate are recognized in earnings. Oil and Natural-Gas Production/Processing Derivative Activities The oil prices listed below are a combination of NYMEX WTI and Intercontinental Exchange, Inc. (ICE) Brent Blend prices. The Company had no natural-gas production/processing derivatives at March 31, 2019 . The following is a summary of the Company’s oil derivative instruments at March 31, 2019 : 2019 Settlement Oil Three-Way Collars (MBbls/d) 87 Average price per barrel Ceiling sold price (call) $ 72.98 Floor purchased price (put) $ 56.72 Floor sold price (put) $ 46.72 A three-way collar is a combination of three options: a sold call, a purchased put, and a sold put. The sold call establishes the maximum price that the Company will receive for the contracted commodity volume. The purchased put establishes the minimum price that the Company will receive for the contracted volume unless the market price for the commodity falls below the sold put strike price, at which point the minimum price equals the reference price (e.g., NYMEX) plus the excess of the purchased put strike price over the sold put strike price. 7. Derivative Instruments (Continued) Anadarko Interest-Rate Derivatives (Excluding WES) Anadarko has outstanding interest-rate swap contracts to manage interest-rate risk associated with anticipated debt issuances. The Company has locked in a fixed interest rate in exchange for a floating interest rate indexed to the three-month LIBOR. At March 31, 2019 , the Company had outstanding interest-rate swaps with a notional amount of $1.6 billion due prior to or in September 2023 that manage interest-rate risk associated with potential future debt issuances. Depending on market conditions, liability-management actions, or other factors, the Company may enter into offsetting interest-rate swap positions or settle or amend certain or all of the currently outstanding interest-rate swaps. The Company had the following outstanding interest-rate swaps at March 31, 2019 : millions except percentages Mandatory Weighted-Average Notional Principal Amount Reference Period Termination Date Interest Rate $ 550 September 2016 - 2046 September 2020 6.418 % $ 250 September 2016 - 2046 September 2022 6.809 % $ 100 September 2017 - 2047 September 2020 6.891 % $ 250 September 2017 - 2047 September 2021 6.570 % $ 450 September 2017 - 2047 September 2023 6.445 % Derivative settlements and collateralization are classified as cash flows from operating activities unless the derivatives contain an other-than-insignificant financing element, in which case the settlements and collateralization are classified as cash flows from financing activities. As a result of prior extensions of reference-period start dates without settlement of the related interest-rate derivative obligations, the interest-rate derivatives in Anadarko’s portfolio contain an other-than-insignificant financing element, and therefore, any settlements, collateralization, or cash payments for amendments related to these extended interest-rate derivatives are classified as cash flows from financing activities. Net cash payments related to settlements and amendments of interest-rate swap agreements were $41 million during the three months ended March 31, 2019, and $46 million during the three months ended March 31, 2018 . WES Interest-Rate Derivatives WES entered into interest-rate swap agreements with an aggregate notional amount of $750 million in December 2018 and $375 million in March 2019 to manage interest-rate risk associated with anticipated 2019 debt issuances. WES exchanged a floating interest rate indexed to the three-month LIBOR for a fixed interest rate. Depending on market conditions, liability management actions, or other factors, WES may settle or amend certain or all of the currently outstanding interest-rate swaps. The following interest-rate swaps were outstanding at March 31, 2019 : millions except percentages Mandatory Weighted-Average Notional Principal Amount Reference Period Termination Date Interest Rate $ 375 December 2019 - 2024 December 2019 2.662 % $ 375 December 2019 - 2029 December 2019 2.802 % $ 375 December 2019 - 2049 December 2019 2.885 % 7. Derivative Instruments (Continued) Effect of Derivative Instruments — Balance Sheet The following summarizes the fair value of the Company’s derivative instruments: Gross Derivative Assets Gross Derivative Liabilities millions March 31, December 31, March 31, December 31, Balance Sheet Classification 2019 2018 2019 2018 Commodity derivatives - Anadarko Other current assets $ 45 $ 300 $ (27 ) $ (126 ) Other current liabilities — 1 (2 ) (6 ) 45 301 (29 ) (132 ) Interest-rate derivatives - Anadarko (1) Other current assets 21 22 — — Other assets 30 34 — — Other current liabilities — — (83 ) (82 ) Other liabilities — — (1,237 ) (1,156 ) 51 56 (1,320 ) (1,238 ) Interest-rate derivatives - WES Other current liabilities — — (44 ) (8 ) Total derivatives $ 96 $ 357 $ (1,393 ) $ (1,378 ) (1) Excludes amounts related to WES interest-rate swap agreements. Effect of Derivative Instruments — Statement of Income The following summarizes gains and losses related to derivative instruments: Three Months Ended millions March 31, Classification of (Gain) Loss Recognized 2019 2018 Commodity derivatives - Anadarko Gathering, processing, and marketing sales $ 2 $ 1 (Gains) losses on derivatives, net 149 162 Interest-rate derivatives - Anadarko (1) (Gains) losses on derivatives, net 128 (127 ) Interest-rate derivatives - WES (Gains) losses on derivatives, net 36 — Total (gains) losses on derivatives, net $ 315 $ 36 (1) Excludes amounts related to WES interest-rate swap agreements. 7. Derivative Instruments (Continued) Credit-Risk Considerations The financial integrity of exchange-traded contracts, which are subject to nominal credit risk, is assured by NYMEX or ICE through systems of financial safeguards and transaction guarantees. Over-the-counter traded swaps, options, and futures contracts expose the Company to counterparty credit risk. The Company monitors the creditworthiness of its counterparties, establishes credit limits according to the Company’s credit policies and guidelines, and assesses the impact on the fair value of its counterparties’ creditworthiness. The Company has the ability to require cash collateral or letters of credit to mitigate its credit-risk exposure. The Company has netting agreements with financial institutions that permit net settlement of gross commodity derivative assets against gross commodity derivative liabilities and routinely exercises its contractual right to offset gains and losses when settling with derivative counterparties. In addition, the Company has setoff agreements with certain financial institutions that may be exercised in the event of default and provide for contract termination and net settlement across derivative types. The Company’s derivative instruments are subject to individually negotiated credit provisions that may require collateral of cash or letters of credit depending on the derivative’s portfolio valuation versus negotiated credit thresholds. These credit thresholds generally require full or partial collateralization of the Company’s obligations depending on certain credit-risk-related provisions, such as the Company’s credit rating from S&P and Moody’s. As of March 31, 2019 , the Company’s long-term debt was rated investment grade (BBB) by both S&P and Fitch and below investment grade (Ba1) by Moody’s. In January 2019, Moody’s changed its outlook with respect to its rating from stable to positive. The Company may be required to post additional collateral with respect to its derivative instruments if its credit ratings decline below current levels or if the liability associated with any such derivative instrument increases above the credit threshold. The aggregate fair value of derivative instruments with credit-risk-related contingent features for which a net liability position existed was $1.2 billion (net of $123 million of collateral) at March 31, 2019 , and $1.1 billion (net of $66 million of collateral) at December 31, 2018 . 7. Derivative Instruments (Continued) Fair Value Fair value of futures contracts is based on unadjusted quoted prices in active markets for identical assets or liabilities, which represent Level 1 inputs. Valuations of physical-delivery purchase and sale agreements, over-the-counter financial swaps, and commodity option collars are based on similar transactions observable in active markets and industry-standard models that primarily rely on market-observable inputs. Inputs used to estimate fair value in industry-standard models are categorized as Level 2 inputs because substantially all assumptions and inputs are observable in active markets throughout the full term of the instruments. Inputs used to estimate the fair value of swaps and options include market-price curves; contract terms and prices; credit-risk adjustments; and, for Black-Scholes option valuations, discount factors and implied market volatility. The following summarizes the fair value of the Company’s derivative assets and liabilities by input level within the fair-value hierarchy: millions Level 1 Level 2 Level 3 Netting (1) Collateral Total March 31, 2019 Assets Anadarko (2) Commodity derivatives $ — $ 45 $ — $ (27 ) $ — $ 18 Interest-rate derivatives — 51 — — — 51 Total derivative assets $ — $ 96 $ — $ (27 ) $ — $ 69 Liabilities Anadarko (2) Commodity derivatives $ — $ (29 ) $ — $ 27 $ — $ (2 ) Interest-rate derivatives — (1,320 ) — — 123 (1,197 ) WES Interest-rate derivatives — (44 ) — — — (44 ) Total derivative liabilities $ — $ (1,393 ) $ — $ 27 $ 123 $ (1,243 ) December 31, 2018 Assets Anadarko (2) Commodity derivatives $ 1 $ 300 $ — $ (127 ) $ — $ 174 Interest-rate derivatives — 56 — — — 56 Total derivative assets $ 1 $ 356 $ — $ (127 ) $ — $ 230 Liabilities Anadarko (2) Commodity derivatives $ (2 ) $ (130 ) $ — $ 127 $ 2 $ (3 ) Interest-rate derivatives — (1,238 ) — — 66 (1,172 ) WES Interest-rate derivatives — (8 ) — — — (8 ) Total derivative liabilities $ (2 ) $ (1,376 ) $ — $ 127 $ 68 $ (1,183 ) (1) Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle. (2) Excludes amounts related to WES interest-rate swap agreements.

Debt

Debt	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	8. Debt Debt Activity The following summarizes the Company’s borrowing activity, after eliminating the effect of intercompany transactions, during the three months ended March 31, 2019 : Carrying Value millions Anadarko (1) WES Anadarko Consolidated Description Balance at December 31, 2018 $ 11,354 $ 4,815 $ 16,169 Borrowings — 2,000 2,000 WES 364-Day Facility — 420 420 WES RCF Repayments (600 ) — (600 ) 8.700 % Senior Notes due 2019 (300 ) — (300 ) 6.950 % Senior Notes due 2019 — (28 ) (28 ) WGP RCF Other, net 12 1 13 Amortization of discounts, premiums, and debt issuance costs Balance at March 31, 2019 $ 10,466 $ 7,208 $ 17,674 (1) Excludes WES. Debt The following summarizes the Company’s outstanding debt, including finance lease liabilities, after eliminating the effect of intercompany transactions: millions Anadarko (1) WES Anadarko Consolidated March 31, 2019 Total borrowings at face value $ 11,893 $ 7,260 $ 19,153 Net unamortized discounts, premiums, and debt issuance costs (2) (1,427 ) (52 ) (1,479 ) Total borrowings (3) 10,466 7,208 17,674 Finance lease liabilities 250 — 250 Less short-term debt 21 2,000 2,021 Total long-term debt $ 10,695 $ 5,208 $ 15,903 December 31, 2018 Total borrowings at face value $ 12,793 $ 4,868 $ 17,661 Net unamortized discounts, premiums, and debt issuance costs (2) (1,439 ) (53 ) (1,492 ) Total borrowings (3) 11,354 4,815 16,169 Finance lease liabilities 248 — 248 Less short-term debt 919 28 947 Total long-term debt $ 10,683 $ 4,787 $ 15,470 (1) Excludes WES. (2) Unamortized discounts, premiums, and debt issuance costs are amortized over the term of the related debt. Debt issuance costs related to RCFs are included in other current assets and other assets on the Company’s Consolidated Balance Sheets. (3) The Company’s outstanding borrowings, except for borrowings under the WGP RCF, are senior unsecured. 8. Debt (Continued) Fair Value The Company uses a market approach to determine the fair value of its fixed-rate debt using observable market data, which results in a Level 2 fair-value measurement. The carrying amount of floating-rate debt approximates fair value as the interest rates are variable and reflective of market rates. The estimated fair value of the Company’s total borrowings was $19.3 billion at March 31, 2019, and $16.8 billion at December 31, 2018 . Anadarko Debt (Excluding WES) In January 2019 , the $2.0 billion 364 -day senior unsecured RCF ( 364 -Day Facility) expired. At March 31, 2019, the Company had a $3.0 billion senior unsecured RCF maturing in January 2023 (APC RCF). At March 31, 2019, Anadarko had no outstanding borrowings under the APC RCF and was in compliance with all covenants. In March 2019, Anadarko repaid $600 million of 8.700% Senior Notes at maturity and redeemed its $300 million of 6.950% Senior Notes due June 2019. Anadarko’s Zero Coupons can be put to the Company in October of each year, in whole or in part, for the then-accreted value of the outstanding Zero Coupons, which, if put in whole, would be $942 million at the next put date in October 2019 . Anadarko’s Zero Coupons were classified as long-term debt on the Company’s Consolidated Balance Sheet at March 31, 2019, as the Company has the ability and intent to refinance these obligations using long-term debt, should a put be exercised. The Company also has notes payable related to its ownership of certain noncontrolling mandatorily redeemable interests that are not included in the Company’s reported debt balance and do not affect consolidated interest expense. See Note 9—Equity-Method Investments in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. WES and WGP Debt Effective on February 15, 2019, WES amended the maturity date of its senior unsecured RCF from February 2023 to February 2024 , and upon completion of the WES Merger, expanded the borrowing capacity from $1.5 billion to $2.0 billion (WES RCF). During the three months ended March 31, 2019, WES borrowed $420 million under its RCF, which was used for general partnership purposes. At March 31, 2019, WES had outstanding borrowings under its RCF of $640 million at an interest rate of 3.79% , outstanding letters of credit of $5 million , available borrowing capacity of $1.4 billion , and was in compliance with all covenants. In February 2019, WES borrowed $2.0 billion under its 364 -day senior unsecured credit facility (WES 364 -Day Facility) to fund substantially all of the cash portion of the consideration under the WES midstream asset contribution and sale and the payment of related transaction costs. The WES 364 -Day Facility will mature on February 27, 2020, the day prior to the one-year anniversary of the completion of the WES Merger. Net cash proceeds received from future asset sales and debt or equity offerings by WES must be used to repay amounts outstanding under the WES 364 -Day Facility. At March 31, 2019, WES had outstanding borrowings under its WES 364 -Day Facility of $2.0 billion at an interest rate of 3.87% and was in compliance with all covenants. WES intends to refinance the obligations under the 364 -Day Facility prior to its maturity in February 2020. In March 2019, the $35 million senior secured RCF (WGP RCF) matured following the completion of the WES Merger. During the three months ended March 31, 2019, WES made repayments of $28 million for the WGP RCF. See Note 1—Summary of Significant Accounting Policies for additional information related to the WES Merger.

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	9. Leases Operating Leases At March 31, 2019 , total lease liabilities related to operating leases were $551 million and primarily related to offshore and onshore drilling rigs and real estate. The operating lease liabilities included $216 million for three offshore drilling vessels and certain contracts for onshore drilling rigs expiring at various dates through 2021. Lease payments commonly vary based on activities being performed by the rig. To the extent that lease payments vary from amounts recognized on the Company’s balance sheet, the amount is included in variable lease cost. Additionally, the Company has $193 million of operating lease liabilities for real estate, primarily related to the Company’s Denver corporate office lease expiring in 2033, with options to terminate the lease early. Finance Leases At March 31, 2019 , total lease liabilities related to finance leases were $250 million and primarily related to an FPSO for the Company’s TEN field in Ghana. The initial FPSO lease term ends in 2026 with annual renewal periods for an additional 10 years, annual purchase options that decrease over time, and no residual value guarantees. The following table summarizes information related to the Company’s leases at March 31, 2019 : millions except lease term and discount rate Operating Leases Finance Leases Assets Other assets $ 534 $ — Net properties and equipment — 186 Total lease assets (1) $ 534 $ 186 Liabilities Current liabilities Other current liabilities $ 245 $ — Short-term debt - Anadarko — 21 Long-term liabilities Other 306 — Long-term debt - Anadarko — 229 Total lease liabilities (1) $ 551 $ 250 Weighted-average remaining lease term (years) 5 16 Weighted-average discount rate (2) 4.3 % 15.4 % (1) Includes additions to ROU assets and lease liabilities of $60 million related to operating leases and $6 million related to finance leases for the three months ended March 31, 2019 . (2) The FPSO finance lease commenced prior to the adoption of ASU 2016-02, Leases (Topic 842). In accordance with previous accounting guidance, the implied rate is based on the fair value of the underlying asset. 9. Leases (Continued) The following table summarizes the Company’s lease cost before amounts recovered from partners: Three Months Ended millions March 31, 2019 Operating lease cost $ 78 Short-term lease cost 19 Variable lease cost 39 Finance lease cost Amortization of ROU assets 10 Interest on lease liabilities 9 Total lease cost $ 155 The following table summarizes cash paid for amounts included in the measurement of lease liabilities: Three Months Ended March 31, 2019 millions Operating Leases Finance Leases Operating cash flows $ 78 $ 9 Investing cash flows 24 — Financing cash flows — 4 The following table reconciles the undiscounted cash flows to the operating and finance lease liabilities recorded on the Company’s Consolidated Balance Sheet at March 31, 2019 : millions Operating Leases (1) Finance Leases Remainder of 2019 $ 185 $ 46 2020 166 51 2021 60 50 2022 43 46 2023 30 43 Thereafter 142 324 Total lease payments $ 626 $ 560 Less portion representing imputed interest 75 310 Total lease liabilities $ 551 $ 250 (1) For leases commencing prior to 2019, lease payments exclude payments to lessors for drilling rig services and real estate services, taxes, and common area maintenance. 9. Leases (Continued) The following table summarizes future minimum lease payments related to the Company’s operating and finance leases as of December 31, 2018 : millions Operating Leases Finance Leases 2019 $ 264 $ 58 2020 139 50 2021 57 48 2022 35 45 2023 24 43 Thereafter 135 323 Total lease payments $ 654 $ 567 Less portion representing imputed interest * 319 Total lease liabilities * $ 248 * Prior to the adoption of ASU 2016-02, Leases (Topic 842) on January 1, 2019, operating lease liabilities were not recognized on the Company’s Consolidated Balance Sheet. Refer to Note 1—Summary of Significant Accounting Policies for additional information.
Leases	9. Leases Operating Leases At March 31, 2019 , total lease liabilities related to operating leases were $551 million and primarily related to offshore and onshore drilling rigs and real estate. The operating lease liabilities included $216 million for three offshore drilling vessels and certain contracts for onshore drilling rigs expiring at various dates through 2021. Lease payments commonly vary based on activities being performed by the rig. To the extent that lease payments vary from amounts recognized on the Company’s balance sheet, the amount is included in variable lease cost. Additionally, the Company has $193 million of operating lease liabilities for real estate, primarily related to the Company’s Denver corporate office lease expiring in 2033, with options to terminate the lease early. Finance Leases At March 31, 2019 , total lease liabilities related to finance leases were $250 million and primarily related to an FPSO for the Company’s TEN field in Ghana. The initial FPSO lease term ends in 2026 with annual renewal periods for an additional 10 years, annual purchase options that decrease over time, and no residual value guarantees. The following table summarizes information related to the Company’s leases at March 31, 2019 : millions except lease term and discount rate Operating Leases Finance Leases Assets Other assets $ 534 $ — Net properties and equipment — 186 Total lease assets (1) $ 534 $ 186 Liabilities Current liabilities Other current liabilities $ 245 $ — Short-term debt - Anadarko — 21 Long-term liabilities Other 306 — Long-term debt - Anadarko — 229 Total lease liabilities (1) $ 551 $ 250 Weighted-average remaining lease term (years) 5 16 Weighted-average discount rate (2) 4.3 % 15.4 % (1) Includes additions to ROU assets and lease liabilities of $60 million related to operating leases and $6 million related to finance leases for the three months ended March 31, 2019 . (2) The FPSO finance lease commenced prior to the adoption of ASU 2016-02, Leases (Topic 842). In accordance with previous accounting guidance, the implied rate is based on the fair value of the underlying asset. 9. Leases (Continued) The following table summarizes the Company’s lease cost before amounts recovered from partners: Three Months Ended millions March 31, 2019 Operating lease cost $ 78 Short-term lease cost 19 Variable lease cost 39 Finance lease cost Amortization of ROU assets 10 Interest on lease liabilities 9 Total lease cost $ 155 The following table summarizes cash paid for amounts included in the measurement of lease liabilities: Three Months Ended March 31, 2019 millions Operating Leases Finance Leases Operating cash flows $ 78 $ 9 Investing cash flows 24 — Financing cash flows — 4 The following table reconciles the undiscounted cash flows to the operating and finance lease liabilities recorded on the Company’s Consolidated Balance Sheet at March 31, 2019 : millions Operating Leases (1) Finance Leases Remainder of 2019 $ 185 $ 46 2020 166 51 2021 60 50 2022 43 46 2023 30 43 Thereafter 142 324 Total lease payments $ 626 $ 560 Less portion representing imputed interest 75 310 Total lease liabilities $ 551 $ 250 (1) For leases commencing prior to 2019, lease payments exclude payments to lessors for drilling rig services and real estate services, taxes, and common area maintenance. 9. Leases (Continued) The following table summarizes future minimum lease payments related to the Company’s operating and finance leases as of December 31, 2018 : millions Operating Leases Finance Leases 2019 $ 264 $ 58 2020 139 50 2021 57 48 2022 35 45 2023 24 43 Thereafter 135 323 Total lease payments $ 654 $ 567 Less portion representing imputed interest * 319 Total lease liabilities * $ 248 * Prior to the adoption of ASU 2016-02, Leases (Topic 842) on January 1, 2019, operating lease liabilities were not recognized on the Company’s Consolidated Balance Sheet. Refer to Note 1—Summary of Significant Accounting Policies for additional information.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The following summarizes income tax expense (benefit) and effective tax rates: Three Months Ended March 31, millions except percentages 2019 2018 Current income tax expense (benefit) $ 168 $ 90 Deferred income tax expense (benefit) (2 ) 36 Total income tax expense (benefit) $ 166 $ 126 Income (loss) before income taxes 262 300 Effective tax rate 63 % 42 % The Company’s tax provision for interim periods is determined using an estimate of its annual current and deferred effective tax rates, adjusted for discrete items. Each quarter, the Company updates these rates and records a cumulative adjustment to current and deferred tax expense by applying the rates to the year-to-date pre-tax income excluding discrete items. The Company’s quarterly estimate of its annual current and deferred effective tax rates can vary significantly based on various forecasted items, including future commodity prices, capital expenditures, expenses for which tax benefits are not recognized, and the geographic mix of pre-tax income and losses. The variance from the U.S. federal statutory rate of 21% for the three months ended March 31, 2019, was primarily attributable to the following items: – tax impact from foreign operations – non-deductible Algerian exceptional profits tax for Algerian income tax purposes – income attributable to noncontrolling interests The variance from the U.S. federal statutory rate of 21% for the three months ended March 31, 2018 , was primarily attributable to the following items: – state taxes, net of federal benefits – tax impact from foreign operations – non-deductible Algerian exceptional profits tax for Algerian income tax purposes – net changes in uncertain tax positions – income attributable to noncontrolling interests. The Company recognized a tax benefit of $346 million as of March 31, 2019 and December 31, 2018 , related to the deduction of its 2015 settlement payment for the Tronox Adversary Proceeding. This benefit is net of uncertain tax positions of $1.2 billion as of March 31, 2019 and December 31, 2018 , due to uncertainty related to the deductibility of the settlement payment. Due to the deduction of the settlement payment on the Company’s 2015 tax return, the Company had a net operating loss carryback, which resulted in a tentative tax refund of $881 million in 2016. The IRS has audited this position and, in April 2018, issued a final notice of proposed adjustment denying the deductibility of the settlement payment. In September 2018, the Company received a statutory notice of deficiency from the IRS disallowing the net operating loss carryback and rejecting the Company’s refund claim. As a result, the Company filed a petition with the U.S. Tax Court to dispute the disallowances in November 2018 and, pursuant to standard U.S. Tax Court procedures, the Company is not required to repay the $881 million refund to dispute the IRS’s position. Accordingly, the Company has not revised its estimate of the benefit that will ultimately be realized. After the case is tried and briefed in the Tax Court, the court will issue an opinion and then enter a decision. If the Company does not prevail on the issue, the earliest date the Company might be required to repay the refund received, plus interest, would be 91 days after entry of the decision. At such time, the Company would reverse the portion of the $346 million net benefit previously recognized in its consolidated financial statements to the extent necessary to reflect the result of the Tax Court decision. It is reasonably possible the amount of uncertain tax position and/or tax benefit could materially change as the Company asserts its position in the Tax Court proceedings. Although management cannot predict the timing of a final resolution of the Tax Court proceedings, the Company does not currently anticipate a decision to be entered before 2022.

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Contingencies	11. Contingencies Litigation There are no material developments in previously reported contingencies nor are there any other material matters that have arisen since the filing of the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.

Pension Plans and Other Postret

Pension Plans and Other Postretirement Benefits	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
Pension Plans and Other Postretirement Benefits	12. Pension Plans and Other Postretirement Benefits The Company has contributory and non-contributory defined-benefit pension plans, which include both qualified and supplemental plans. The Company also provides certain health care and life insurance benefits for certain retired employees. Retiree health care benefits are funded by contributions from the retiree and, in certain circumstances, contributions from the Company. The Company’s retiree life insurance plan is noncontributory. The following summarizes the Company’s pension and other postretirement benefit cost: Pension Benefits Other Benefits millions 2019 2018 2019 2018 Three Months Ended March 31 Service cost $ 22 $ 23 $ — $ — Interest cost 20 19 3 3 Expected (return) loss on plan assets (21 ) (21 ) — — Amortization of net actuarial loss (gain) 4 7 — — Amortization of net prior service cost (credit) — — (1 ) (6 ) Settlement expense 4 — — — Net periodic benefit cost (1) $ 29 $ 28 $ 2 $ (3 ) (1) The service cost component of net periodic benefit cost is included in G&A; oil and gas operating expense; gathering, processing, and marketing expense; and exploration expense, and all other components of net periodic benefit cost are included in other (income) expense on the Company’s Consolidated Statements of Income. The Company contributed $65 million to funded pension plans and $21 million to unfunded pension plans during the three months ended March 31, 2019 . The Company expects to contribute an additional $26 million to funded pension plans and $26 million to unfunded pension plans during 2019.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
Stockholders' Equity	13. Stockholders’ Equity Earnings Per Share The Company’s basic earnings per share (EPS) is computed based on the average number of shares of common stock outstanding for the period and includes the effect of any participating securities and TEUs as appropriate. Diluted EPS includes the effect of the Company’s outstanding stock options, restricted stock awards, restricted stock units, and TEUs, if the inclusion of these items is dilutive. All outstanding TEUs were settled in June 2018. The following provides a reconciliation between basic and diluted EPS attributable to common stockholders: Three Months Ended March 31, millions except per-share amounts 2019 2018 Net income (loss) Net income (loss) attributable to common stockholders $ (15 ) $ 121 Income (loss) effect of TEUs — (3 ) Less distributions on participating securities 2 1 Basic $ (17 ) $ 117 Income (loss) effect of TEUs — (1 ) Diluted $ (17 ) $ 116 Shares Average number of common shares outstanding—basic 490 518 Dilutive effect of stock options — 1 Average number of common shares outstanding—diluted 490 519 Excluded due to anti-dilutive effect 12 10 Net income (loss) per common share Basic $ (0.03 ) $ 0.23 Diluted $ (0.03 ) $ 0.22 Dividends per common share $ 0.30 $ 0.25 Common Stock The Share-Repurchase Program authorizes the repurchase of the Company’s common stock in the open market or through private transactions. During 2018, the Share-Repurchase Program was expanded to $5.0 billion and extended through mid-year 2020. As of December 31, 2018 , the Company had completed $3.75 billion of the Share-Repurchase Program through ASR Agreements and open-market repurchases. These transactions were accounted for as equity transactions, with all of the repurchased shares classified as treasury stock. Additionally, the receipt of these shares reduced the average number of shares of common stock outstanding used to compute both basic and diluted EPS. There were no additional repurchases of common stock under the Share-Repurchase Program for the three months ended March 31, 2019 . No additional share repurchases under the Share-Repurchase Program are anticipated pursuant to the terms of the Chevron Merger Agreement. See Note 1—Summary of Significant Accounting Policies for additional information on the Chevron Merger Agreement.

Noncontrolling Interests

Noncontrolling Interests	3 Months Ended
	Mar. 31, 2019
Noncontrolling Interest Items [Abstract]
Noncontrolling Interests	14. Noncontrolling Interests WES is a limited partnership formed by Anadarko in September 2012 and owns a 98% limited partner interest in WES Operating, a Delaware limited partnership formed by Anadarko in 2007 to acquire, own, develop and operate midstream assets, and all of the outstanding equity interests of WES Operating’s general partner, which holds the entire non-economic general partner interest in WES Operating. WES Operating Class C units issued to Anadarko converted into WES Operating common units in a unit-for-unit, tax-free exchange immediately prior to the closing of the WES Merger on February 28, 2019. Prior to the closing of the WES Merger, the Class C units received quarterly distributions in the form of additional Class C units. WES distributed 309 thousand Class C units to Anadarko during the three months ended March 31, 2019, and 1.1 million Class C units to Anadarko during 2018 . See Note 1—Summary of Significant Accounting Policies for additional information on the WES Merger. At March 31, 2019, Anadarko’s ownership interest in WES consisted of a 55.5% limited partner interest and the entire non-economic general partner interest. The remaining 44.5% limited partner interest in WES was owned by the public. At March 31, 2019, Anadarko’s ownership interest in WES Operating consisted of a 2% limited partner interest.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2019
Variable Interest Entities [Abstract]
Variable Interest Entities	15. Variable Interest Entities Consolidated VIEs The Company determined that the partners in WES with equity at risk lack the power, through voting rights or similar rights, to direct the activities that most significantly impact WES’s economic performance; therefore, WES is considered a VIE. Anadarko, through its ownership of the general partner interest in WES, has the power to direct the activities that most significantly affect economic performance and the obligation to absorb losses or the right to receive benefits that could be potentially significant to WES; therefore, Anadarko is considered the primary beneficiary and consolidates WES and all of its consolidated subsidiaries. For additional information on WES, see Note 14—Noncontrolling Interests . Assets and Liabilities of VIEs The assets of WES and its subsidiaries cannot be used by Anadarko for general corporate purposes and are included in and disclosed parenthetically on the Company’s Consolidated Balance Sheets. The carrying amounts of liabilities related to WES and its subsidiaries for which the creditors do not have recourse to other Anadarko assets are included in and disclosed parenthetically on the Company’s Consolidated Balance Sheets. All outstanding debt for WES at March 31, 2019 , and December 31, 2018 , including any borrowings under the WES RCF and WES 364-Day Facility, is recourse to WES Operating’s general partner, which in turn has been indemnified in certain circumstances by certain wholly owned subsidiaries of the Company for such liabilities. See Note 8—Debt for additional information on WES short-term and long-term debt balances. VIE Financing WES’s sources of liquidity include cash and cash equivalents, cash flows generated from operations, interest income from a note receivable from Anadarko as discussed below, borrowings under the WES RCF, the issuance of additional partnership units, and debt offerings. See Note 8—Debt and Note 14—Noncontrolling Interests for additional information on WES financing activity. VIE Distributions The following table presents WES distributions: Three Months Ended March 31, millions 2019 2018 WES distributions to Anadarko (1) $ 105 $ 100 WES distributions to third parties 130 118 (1) WES distributions to Anadarko are eliminated upon consolidation. Financial Support Provided to VIEs Concurrent with the closing of its May 2008 IPO, WES Operating loaned the Company $260 million in exchange for a 30 -year note bearing interest at a fixed annual rate of 6.50% , payable quarterly. The related interest income for WES Operating was $4 million for the three months ended March 31, 2019 and 2018 . The note receivable and related interest income are eliminated in consolidation. To reduce WES’s exposure to a majority of the commodity-price risk inherent in certain of its contracts, Anadarko had commodity price swap agreements in place with WES Operating that expired without renewal on December 31, 2018 and final settlement occurred in the first quarter of 2019. WES recorded a capital contribution from Anadarko in its Consolidated Statement of Equity and Partners’ Capital for an amount equal to (i) the amount by which the swap price for product sales exceeds the applicable market price, minus (ii) the amount by which the swap price for product purchases exceeds the market price. WES recorded a capital contribution from Anadarko of $7 million for the three months ended March 31, 2019 , and $14 million for the three months ended March 31, 2018 .

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	16. Supplemental Cash Flow Information Additions to properties and equipment as presented within Anadarko’s cash flows from investing activities include cash payments for cost of properties, equipment, and facilities. The cost of properties includes the initial capitalization of drilling costs associated with all exploratory wells whether or not they were deemed to have a commercially sufficient quantity of proved reserves. The following summarizes cash paid (received) for interest and income taxes, as well as non-cash investing and financing activities: Three Months Ended March 31, millions 2019 2018 Cash paid (received) Interest, net of amounts capitalized $ 371 $ 326 Income taxes, net of refunds 18 12 Non-cash investing activities Fair value of properties and equipment acquired $ — $ 2 Asset retirement cost additions 71 63 Accruals of property, plant, and equipment 781 965 Net liabilities assumed (divested) in acquisitions and divestitures — (25 ) Non-cash investing and financing activities Finance leases $ 6 $ — The following table provides a reconciliation of Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents as reported in the Consolidated Statement of Cash Flows to the line items within the Consolidated Balance Sheets: millions March 31, 2019 December 31, 2018 Cash and cash equivalents $ 2,026 $ 1,295 Restricted cash and restricted cash equivalents included in Other Assets 134 134 Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents $ 2,160 $ 1,429 Included in cash and cash equivalents is restricted cash and restricted cash equivalents of $100 million at March 31, 2019, and $139 million at December 31, 2018 . Total restricted cash and restricted cash equivalents are primarily associated with certain international joint venture operations, payments of future hard-minerals royalty revenues conveyed, like-kind exchanges of property, and a judicially-controlled account related to a Brazilian tax dispute. See Note 18—Contingencies in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Information	Anadarko’s business segments are separately managed due to distinct operational differences. On February 28, 2019, Anadarko completed the previously announced contribution and sale of substantially all of its remaining midstream assets to WES. Due to this contribution and sale, the Company will no longer report an Other Midstream segment and will now have two reporting segments: Exploration and Production and WES Midstream, which include their respective marketing results. Prior period amounts have been reclassified to conform to the current period’s presentation. The Exploration and Production reporting segment is engaged in the exploration, development, production, and sale of oil, natural gas, and NGLs and in advancing its Mozambique LNG project toward FID. The WES Midstream reporting segment is engaged in gathering, compressing, treating, processing, and transporting of natural gas; gathering, stabilizing, and transporting of oil and NGLs; and gathering and disposing of produced water. To assess the performance of Anadarko’s operating segments, the chief operating decision maker analyzes Adjusted EBITDAX. The Company defines Adjusted EBITDAX as income (loss) before income taxes; interest expense; DD&A; exploration expense; gains (losses) on divestitures, net; impairments; total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives; certain items not related to the Company’s normal operations; and less net income (loss) attributable to noncontrolling interests. The Company’s definition of Adjusted EBITDAX excludes gains (losses) on divestitures, net and exploration expense as they are not indicators of operating efficiency for a given reporting period. DD&A and impairments are excluded from Adjusted EBITDAX as a measure of segment operating performance because capital expenditures are evaluated at the time capital costs are incurred. Adjusted EBITDAX also excludes interest expense to allow for assessment of segment operating results without regard to Anadarko’s financing methods or capital structure. Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives are excluded from Adjusted EBITDAX because these (gains) losses are not considered a measure of asset operating performance. Finally, net income (loss) attributable to noncontrolling interests is excluded from the Company’s measure of Adjusted EBITDAX because it represents earnings that are not attributable to the Company’s common stockholders. Management believes Adjusted EBITDAX provides information useful in assessing the Company’s operating and financial performance across periods. Adjusted EBITDAX as defined by Anadarko may not be comparable to similarly titled measures used by other companies and should be considered in conjunction with net income (loss) attributable to common stockholders and other performance measures, such as operating income. Below is a reconciliation of consolidated Adjusted EBITDAX to income (loss) before income taxes: Three Months Ended March 31, millions 2019 2018 Income (loss) before income taxes $ 262 $ 300 Interest expense 253 228 DD&A 1,081 990 Exploration expense 49 168 (Gains) losses on divestitures, net 5 24 Impairments — 19 Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives 316 (27 ) Reorganization-related charges 18 — Less net income (loss) attributable to noncontrolling interests 111 53 Consolidated Adjusted EBITDAX $ 1,873 $ 1,649 17. Segment Information (Continued) Information presented below as “Other and Intersegment Eliminations” includes corporate costs, margin on sales of third-party commodity purchases, deficiency fee expenses, results from hard-minerals royalties, net cash from settlement of commodity derivatives, and net income (loss) attributable to noncontrolling interests. The following summarizes selected financial information for Anadarko’s reporting segments: millions Exploration WES Midstream Other and Total Three Months Ended March 31, 2019 Sales revenues $ 2,606 $ 499 $ 21 $ 3,126 Intersegment revenues 51 172 (223 ) — Other 8 58 31 97 Total revenues and other (1) 2,665 729 (171 ) 3,223 Operating costs and expenses (2) 992 337 (89 ) 1,240 Net cash from settlement of commodity derivatives — — (6 ) (6 ) Other (income) expense, net (3) — (36 ) 38 2 Net income (loss) attributable to noncontrolling interests — — 111 111 Total expenses and other 992 301 54 1,347 Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement — — (3 ) (3 ) Adjusted EBITDAX $ 1,673 $ 428 $ (228 ) $ 1,873 Three Months Ended March 31, 2018 Sales revenues $ 2,656 $ 355 $ 15 $ 3,026 Intersegment revenues 10 153 (163 ) — Other (9 ) 37 15 43 Total revenues and other (1) 2,657 545 (133 ) 3,069 Operating costs and expenses (2) 870 233 214 1,317 Net cash from settlement of commodity derivatives — — 68 68 Other (income) expense, net — — (12 ) (12 ) Net income (loss) attributable to noncontrolling interests — — 53 53 Total expenses and other 870 233 323 1,426 Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement — — 6 6 Adjusted EBITDAX $ 1,787 $ 312 $ (450 ) $ 1,649 (1) Total revenues and other excludes gains (losses) on divestitures, net since these gains and losses are excluded from Adjusted EBITDAX. (2) Operating costs and expenses excludes exploration expense, DD&A, impairments, reorganization-related charges, and certain other operating expenses since these expenses are excluded from Adjusted EBITDAX. (3) Other (income) expense, net excludes reorganization-related charges since these expenses are excluded from Adjusted EBITDAX. 17. Segment Information (Continued) The following summarizes selected financial information for Anadarko’s reporting segments: millions Exploration WES Midstream Other and Total March 31, 2019 Net properties and equipment $ 18,342 $ 8,630 $ 1,964 $ 28,936 Capital expenditures (1) $ 922 $ 315 $ 59 $ 1,296 Goodwill $ 4,343 $ 446 $ — $ 4,789 December 31, 2018 Net properties and equipment $ 18,267 $ 8,410 $ 1,938 $ 28,615 Capital expenditures (1) $ 4,103 $ 1,912 $ 170 $ 6,185 Goodwill $ 4,343 $ 446 $ — $ 4,789 (1) WES Midstream includes $49 million at March 31, 2019, and $734 million at December 31, 2018, of capitalized costs incurred prior to the contribution and sale of midstream assets to WES.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Consolidation	The consolidated financial statements include the accounts of Anadarko and subsidiaries in which Anadarko holds, directly or indirectly, more than 50% of the voting rights and VIEs for which Anadarko is the primary beneficiary. The Company has determined that WES is a VIE. Anadarko is considered the primary beneficiary and consolidates WES. WES functions with a capital structure that is separate from Anadarko, consisting of its own debt instruments and publicly traded common units. All intercompany transactions have been eliminated. Undivided interests in oil and natural-gas exploration and production joint ventures are consolidated on a proportionate basis. Investments in noncontrolled entities that Anadarko has the ability to exercise significant influence over operating and financial policies and VIEs for which Anadarko is not the primary beneficiary are accounted for using the equity method. In applying the equity method of accounting, the investments are initially recognized at cost and subsequently adjusted for the Company’s proportionate share of earnings, losses, and distributions. Investments are included in other assets on the Company’s Consolidated Balance Sheets.
Recently Issued Accounting Standards	Recently Adopted Accounting Standards ASU 2016-02, Leases (Topic 842) This ASU requires lessees to recognize a lease liability and an ROU asset on the balance sheet for all leases, including operating leases. This ASU modifies the definition of a lease and outlines the recognition, measurement, presentation, and disclosure of leasing arrangements by both lessees and lessors. The Company adopted Topic 842 on January 1, 2019, using the modified retrospective method applied to all leases that existed on January 1, 2019, and prior-period financial statements were not adjusted. Anadarko elected not to reassess contracts that commenced prior to adoption, to continue applying its current accounting policy for existing or expired land easements, and not to recognize ROU assets or lease liabilities for short-term leases. Upon adoption, the Company recognized approximately $600 million of ROU assets and lease liabilities related to leases existing at January 1, 2019. The difference between ROU assets and operating lease liabilities, net of the deferred tax impact, was recognized as a $55 million reduction in the opening balance of retained earnings as a cumulative effect adjustment. See Note 9—Leases for additional information. Accounting Policy Leases Anadarko determines if an arrangement is a lease based on rights and obligations conveyed at inception of a contract. At the commencement date, a lease is classified as either operating or finance, and an ROU asset and lease liability is recognized based on the present value of future lease payments over the lease term. As the rate implicit in Anadarko’s leases generally is not readily determinable, the Company discounts lease liabilities using the Company’s incremental borrowing rate at the commencement date. Non-lease components associated with leases that begin in 2019 or later are accounted for as part of the lease component, and prepaid lease payments are included in the ROU asset. Options to extend or terminate a lease are included in the lease term when it is reasonably certain that Anadarko will exercise that option. Leases of 12 months or less are not recognized on the Company’s Consolidated Balance Sheet. Lease cost is recognized over the lease term, unless the end of the useful life of the underlying asset in a finance lease is before the end of the lease term. Lease cost is recognized on a straight-line basis unless another method better represents the pattern that benefit is expected to be derived from the right to use the underlying asset. For finance leases, interest expense is recognized over the lease term using the effective interest method. Variable lease payments are recognized when the obligation for those payments is incurred. Generally, a contract in a joint arrangement is evaluated as a lease if Anadarko is the operator. Anadarko recognizes an ROU asset and lease liability for the full amount of each contract determined to be a lease, although a portion of lease payments is generally recovered from partners. Lease payments associated with the drilling of exploratory wells and development wells net of amounts billed to partners will initially be capitalized as a component of oil and gas properties and either depreciated, impaired, or written off as exploration expense in future periods.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table disaggregates revenue by significant product type and segment: millions Exploration WES Midstream Other and Total Three Months Ended March 31, 2019 Oil sales $ 2,096 $ — $ — $ 2,096 Natural-gas sales 320 — — 320 Natural-gas liquids sales 240 — — 240 Gathering, processing, and marketing sales (1) 1 672 (25 ) 648 Other, net 9 — 25 34 Total Revenue from Customers $ 2,666 $ 672 $ — $ 3,338 Gathering, processing, and marketing sales (2) — — (178 ) (178 ) Gains (losses) on divestitures, net — — (5 ) (5 ) Other, net (1 ) 57 7 63 Total Revenue from Other than Customers $ (1 ) $ 57 $ (176 ) $ (120 ) Total Revenue and Other $ 2,665 $ 729 $ (176 ) $ 3,218 Three Months Ended March 31, 2018 Oil sales $ 2,127 $ — $ — $ 2,127 Natural-gas sales 247 — — 247 Natural-gas liquids sales 292 — — 292 Gathering, processing, and marketing sales (1) — 502 46 548 Other, net 3 — 19 22 Total Revenue from Customers $ 2,669 $ 502 $ 65 $ 3,236 Gathering, processing, and marketing sales (2) — (1 ) (187 ) (188 ) Gains (losses) on divestitures, net (33 ) — 9 (24 ) Other, net (12 ) 44 (11 ) 21 Total Revenue from Other than Customers $ (45 ) $ 43 $ (189 ) $ (191 ) Total Revenue and Other $ 2,624 $ 545 $ (124 ) $ 3,045 (1) The amount in Other and Intersegment Eliminations primarily represents sales of third-party natural gas and NGLs of $209 million and intersegment eliminations of $(223) million for the three months ended March 31, 2019 , and sales of third-party natural gas and NGLs of $224 million and intersegment eliminations of $(163) million for the three months ended March 31, 2018 . (2) The amount in Other and Intersegment Eliminations represents purchases of third-party natural gas and NGLs. Although these purchases are reported net in gathering, processing, and marketing sales in the Company’s Consolidated Statements of Income, they are shown separately on this table as the purchases are not considered revenue from customers.
Schedule of Contract with Customer Liabilities Activity	The following table summarizes the current period activity related to contract liabilities from contracts with customers: millions Balance at December 31, 2018 $ 150 Increase due to cash received, excluding revenues recognized in the period 21 Decrease due to revenue recognized (18 ) Balance at March 31, 2019 $ 153 Contract liabilities at March 31, 2019 Other current liabilities $ 23 Other long-term liabilities - other 130 Total contract liabilities from contracts with customers $ 153
Schedule of Expected Revenue Recognition from Satisfaction of Performance Obligations	Therefore, the following table represents only a small portion of Anadarko’s expected future consolidated revenues as future revenue from the sale of most products and services is dependent on future production or variable customer volume and variable commodity prices for that volume. millions Exploration & Production WES Midstream Other and Intersegment Eliminations Total Remainder of 2019 $ 80 $ 533 $ (352 ) $ 261 2020 103 862 (622 ) 343 2021 103 912 (698 ) 317 2022 7 976 (770 ) 213 2023 7 933 (770 ) 170 Thereafter 58 4,500 (4,009 ) 549 Total $ 358 $ 8,716 $ (7,221 ) $ 1,853

Commodity Inventories (Tables)

Commodity Inventories (Tables)	3 Months Ended
	Mar. 31, 2019
Energy Related Inventory [Abstract]
Inventory Disclosure Table	The following summarizes the major classes of commodity inventories included in other current assets: millions March 31, 2019 December 31, 2018 Oil $ 169 $ 139 Natural gas 1 18 NGLs 84 78 Total commodity inventories $ 254 $ 235

Divestitures (Tables)

Divestitures (Tables)	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Proceeds Received and Gains (Losses) Recognized on Divestitures	The following summarizes the proceeds received and gains (losses) recognized on divestitures: Three Months Ended March 31, millions 2019 2018 Proceeds received, net of closing adjustments $ 7 $ 371 Gains (losses) on divestitures, net (5 ) (24 )

Current Liabilities (Tables)

Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Payables and Accruals [Abstract]
Schedule of Other Current Liabilities	The following summarizes the Company’s other current liabilities: millions March 31, 2019 December 31, 2018 Accrued income taxes $ 211 $ 167 Interest payable 159 267 Production, property, and other taxes payable 314 309 Accrued employee benefits 153 319 Derivatives 121 89 Operating lease liabilities 245 — Other 137 144 Total other current liabilities $ 1,340 $ 1,295

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following is a summary of the Company’s oil derivative instruments at March 31, 2019 : 2019 Settlement Oil Three-Way Collars (MBbls/d) 87 Average price per barrel Ceiling sold price (call) $ 72.98 Floor purchased price (put) $ 56.72 Floor sold price (put) $ 46.72 The Company had the following outstanding interest-rate swaps at March 31, 2019 : millions except percentages Mandatory Weighted-Average Notional Principal Amount Reference Period Termination Date Interest Rate $ 550 September 2016 - 2046 September 2020 6.418 % $ 250 September 2016 - 2046 September 2022 6.809 % $ 100 September 2017 - 2047 September 2020 6.891 % $ 250 September 2017 - 2047 September 2021 6.570 % $ 450 September 2017 - 2047 September 2023 6.445 % The following interest-rate swaps were outstanding at March 31, 2019 : millions except percentages Mandatory Weighted-Average Notional Principal Amount Reference Period Termination Date Interest Rate $ 375 December 2019 - 2024 December 2019 2.662 % $ 375 December 2019 - 2029 December 2019 2.802 % $ 375 December 2019 - 2049 December 2019 2.885 %
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following summarizes gains and losses related to derivative instruments: Three Months Ended millions March 31, Classification of (Gain) Loss Recognized 2019 2018 Commodity derivatives - Anadarko Gathering, processing, and marketing sales $ 2 $ 1 (Gains) losses on derivatives, net 149 162 Interest-rate derivatives - Anadarko (1) (Gains) losses on derivatives, net 128 (127 ) Interest-rate derivatives - WES (Gains) losses on derivatives, net 36 — Total (gains) losses on derivatives, net $ 315 $ 36 (1) Excludes amounts related to WES interest-rate swap agreements. The following summarizes the fair value of the Company’s derivative instruments: Gross Derivative Assets Gross Derivative Liabilities millions March 31, December 31, March 31, December 31, Balance Sheet Classification 2019 2018 2019 2018 Commodity derivatives - Anadarko Other current assets $ 45 $ 300 $ (27 ) $ (126 ) Other current liabilities — 1 (2 ) (6 ) 45 301 (29 ) (132 ) Interest-rate derivatives - Anadarko (1) Other current assets 21 22 — — Other assets 30 34 — — Other current liabilities — — (83 ) (82 ) Other liabilities — — (1,237 ) (1,156 ) 51 56 (1,320 ) (1,238 ) Interest-rate derivatives - WES Other current liabilities — — (44 ) (8 ) Total derivatives $ 96 $ 357 $ (1,393 ) $ (1,378 ) (1) Excludes amounts related to WES interest-rate swap agreements.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following summarizes the fair value of the Company’s derivative assets and liabilities by input level within the fair-value hierarchy: millions Level 1 Level 2 Level 3 Netting (1) Collateral Total March 31, 2019 Assets Anadarko (2) Commodity derivatives $ — $ 45 $ — $ (27 ) $ — $ 18 Interest-rate derivatives — 51 — — — 51 Total derivative assets $ — $ 96 $ — $ (27 ) $ — $ 69 Liabilities Anadarko (2) Commodity derivatives $ — $ (29 ) $ — $ 27 $ — $ (2 ) Interest-rate derivatives — (1,320 ) — — 123 (1,197 ) WES Interest-rate derivatives — (44 ) — — — (44 ) Total derivative liabilities $ — $ (1,393 ) $ — $ 27 $ 123 $ (1,243 ) December 31, 2018 Assets Anadarko (2) Commodity derivatives $ 1 $ 300 $ — $ (127 ) $ — $ 174 Interest-rate derivatives — 56 — — — 56 Total derivative assets $ 1 $ 356 $ — $ (127 ) $ — $ 230 Liabilities Anadarko (2) Commodity derivatives $ (2 ) $ (130 ) $ — $ 127 $ 2 $ (3 ) Interest-rate derivatives — (1,238 ) — — 66 (1,172 ) WES Interest-rate derivatives — (8 ) — — — (8 ) Total derivative liabilities $ (2 ) $ (1,376 ) $ — $ 127 $ 68 $ (1,183 ) (1) Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle. (2) Excludes amounts related to WES interest-rate swap agreements.

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Debt Outstanding	The following summarizes the Company’s borrowing activity, after eliminating the effect of intercompany transactions, during the three months ended March 31, 2019 : Carrying Value millions Anadarko (1) WES Anadarko Consolidated Description Balance at December 31, 2018 $ 11,354 $ 4,815 $ 16,169 Borrowings — 2,000 2,000 WES 364-Day Facility — 420 420 WES RCF Repayments (600 ) — (600 ) 8.700 % Senior Notes due 2019 (300 ) — (300 ) 6.950 % Senior Notes due 2019 — (28 ) (28 ) WGP RCF Other, net 12 1 13 Amortization of discounts, premiums, and debt issuance costs Balance at March 31, 2019 $ 10,466 $ 7,208 $ 17,674 (1) Excludes WES. Debt The following summarizes the Company’s outstanding debt, including finance lease liabilities, after eliminating the effect of intercompany transactions: millions Anadarko (1) WES Anadarko Consolidated March 31, 2019 Total borrowings at face value $ 11,893 $ 7,260 $ 19,153 Net unamortized discounts, premiums, and debt issuance costs (2) (1,427 ) (52 ) (1,479 ) Total borrowings (3) 10,466 7,208 17,674 Finance lease liabilities 250 — 250 Less short-term debt 21 2,000 2,021 Total long-term debt $ 10,695 $ 5,208 $ 15,903 December 31, 2018 Total borrowings at face value $ 12,793 $ 4,868 $ 17,661 Net unamortized discounts, premiums, and debt issuance costs (2) (1,439 ) (53 ) (1,492 ) Total borrowings (3) 11,354 4,815 16,169 Finance lease liabilities 248 — 248 Less short-term debt 919 28 947 Total long-term debt $ 10,683 $ 4,787 $ 15,470 (1) Excludes WES. (2) Unamortized discounts, premiums, and debt issuance costs are amortized over the term of the related debt. Debt issuance costs related to RCFs are included in other current assets and other assets on the Company’s Consolidated Balance Sheets. (3) The Company’s outstanding borrowings, except for borrowings under the WGP RCF, are senior unsecured.

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Summary of Leases	The following table summarizes information related to the Company’s leases at March 31, 2019 : millions except lease term and discount rate Operating Leases Finance Leases Assets Other assets $ 534 $ — Net properties and equipment — 186 Total lease assets (1) $ 534 $ 186 Liabilities Current liabilities Other current liabilities $ 245 $ — Short-term debt - Anadarko — 21 Long-term liabilities Other 306 — Long-term debt - Anadarko — 229 Total lease liabilities (1) $ 551 $ 250 Weighted-average remaining lease term (years) 5 16 Weighted-average discount rate (2) 4.3 % 15.4 % (1) Includes additions to ROU assets and lease liabilities of $60 million related to operating leases and $6 million related to finance leases for the three months ended March 31, 2019 . (2) The FPSO finance lease commenced prior to the adoption of ASU 2016-02, Leases (Topic 842). In accordance with previous accounting guidance, the implied rate is based on the fair value of the underlying asset.
Summary of Lease Cost	The following table summarizes the Company’s lease cost before amounts recovered from partners: Three Months Ended millions March 31, 2019 Operating lease cost $ 78 Short-term lease cost 19 Variable lease cost 39 Finance lease cost Amortization of ROU assets 10 Interest on lease liabilities 9 Total lease cost $ 155 The following table summarizes cash paid for amounts included in the measurement of lease liabilities: Three Months Ended March 31, 2019 millions Operating Leases Finance Leases Operating cash flows $ 78 $ 9 Investing cash flows 24 — Financing cash flows — 4
Operating Leases Maturity	The following table reconciles the undiscounted cash flows to the operating and finance lease liabilities recorded on the Company’s Consolidated Balance Sheet at March 31, 2019 : millions Operating Leases (1) Finance Leases Remainder of 2019 $ 185 $ 46 2020 166 51 2021 60 50 2022 43 46 2023 30 43 Thereafter 142 324 Total lease payments $ 626 $ 560 Less portion representing imputed interest 75 310 Total lease liabilities $ 551 $ 250 (1) For leases commencing prior to 2019, lease payments exclude payments to lessors for drilling rig services and real estate services, taxes, and common area maintenance.
Finance Leases Maturity	The following table reconciles the undiscounted cash flows to the operating and finance lease liabilities recorded on the Company’s Consolidated Balance Sheet at March 31, 2019 : millions Operating Leases (1) Finance Leases Remainder of 2019 $ 185 $ 46 2020 166 51 2021 60 50 2022 43 46 2023 30 43 Thereafter 142 324 Total lease payments $ 626 $ 560 Less portion representing imputed interest 75 310 Total lease liabilities $ 551 $ 250 (1) For leases commencing prior to 2019, lease payments exclude payments to lessors for drilling rig services and real estate services, taxes, and common area maintenance.
Future Minimum Lease Payments, Operating Leases	The following table summarizes future minimum lease payments related to the Company’s operating and finance leases as of December 31, 2018 : millions Operating Leases Finance Leases 2019 $ 264 $ 58 2020 139 50 2021 57 48 2022 35 45 2023 24 43 Thereafter 135 323 Total lease payments $ 654 $ 567 Less portion representing imputed interest * 319 Total lease liabilities * $ 248 * Prior to the adoption of ASU 2016-02, Leases (Topic 842) on January 1, 2019, operating lease liabilities were not recognized on the Company’s Consolidated Balance Sheet. Refer to Note 1—Summary of Significant Accounting Policies for additional information.
Future Minimum Lease Payments, Finance Leases	The following table summarizes future minimum lease payments related to the Company’s operating and finance leases as of December 31, 2018 : millions Operating Leases Finance Leases 2019 $ 264 $ 58 2020 139 50 2021 57 48 2022 35 45 2023 24 43 Thereafter 135 323 Total lease payments $ 654 $ 567 Less portion representing imputed interest * 319 Total lease liabilities * $ 248 * Prior to the adoption of ASU 2016-02, Leases (Topic 842) on January 1, 2019, operating lease liabilities were not recognized on the Company’s Consolidated Balance Sheet. Refer to Note 1—Summary of Significant Accounting Policies for additional information.

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income Taxes and Effective Tax Rate	The following summarizes income tax expense (benefit) and effective tax rates: Three Months Ended March 31, millions except percentages 2019 2018 Current income tax expense (benefit) $ 168 $ 90 Deferred income tax expense (benefit) (2 ) 36 Total income tax expense (benefit) $ 166 $ 126 Income (loss) before income taxes 262 300 Effective tax rate 63 % 42 %

Pension Plans and Other Postr_2

Pension Plans and Other Postretirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Cost Table	The following summarizes the Company’s pension and other postretirement benefit cost: Pension Benefits Other Benefits millions 2019 2018 2019 2018 Three Months Ended March 31 Service cost $ 22 $ 23 $ — $ — Interest cost 20 19 3 3 Expected (return) loss on plan assets (21 ) (21 ) — — Amortization of net actuarial loss (gain) 4 7 — — Amortization of net prior service cost (credit) — — (1 ) (6 ) Settlement expense 4 — — — Net periodic benefit cost (1) $ 29 $ 28 $ 2 $ (3 ) (1) The service cost component of net periodic benefit cost is included in G&A; oil and gas operating expense; gathering, processing, and marketing expense; and exploration expense, and all other components of net periodic benefit cost are included in other (income) expense on the Company’s Consolidated Statements of Income.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
Earnings Per Share Table	The following provides a reconciliation between basic and diluted EPS attributable to common stockholders: Three Months Ended March 31, millions except per-share amounts 2019 2018 Net income (loss) Net income (loss) attributable to common stockholders $ (15 ) $ 121 Income (loss) effect of TEUs — (3 ) Less distributions on participating securities 2 1 Basic $ (17 ) $ 117 Income (loss) effect of TEUs — (1 ) Diluted $ (17 ) $ 116 Shares Average number of common shares outstanding—basic 490 518 Dilutive effect of stock options — 1 Average number of common shares outstanding—diluted 490 519 Excluded due to anti-dilutive effect 12 10 Net income (loss) per common share Basic $ (0.03 ) $ 0.23 Diluted $ (0.03 ) $ 0.22 Dividends per common share $ 0.30 $ 0.25

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2019
Variable Interest Entities [Abstract]
Schedule of Financial Data of VIE	The following table presents WES distributions: Three Months Ended March 31, millions 2019 2018 WES distributions to Anadarko (1) $ 105 $ 100 WES distributions to third parties 130 118 (1) WES distributions to Anadarko are eliminated upon consolidation.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Table	The following summarizes cash paid (received) for interest and income taxes, as well as non-cash investing and financing activities: Three Months Ended March 31, millions 2019 2018 Cash paid (received) Interest, net of amounts capitalized $ 371 $ 326 Income taxes, net of refunds 18 12 Non-cash investing activities Fair value of properties and equipment acquired $ — $ 2 Asset retirement cost additions 71 63 Accruals of property, plant, and equipment 781 965 Net liabilities assumed (divested) in acquisitions and divestitures — (25 ) Non-cash investing and financing activities Finance leases $ 6 $ —
Schedule of Cash and Cash Equivalents Balance Sheet Locations	The following table provides a reconciliation of Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents as reported in the Consolidated Statement of Cash Flows to the line items within the Consolidated Balance Sheets: millions March 31, 2019 December 31, 2018 Cash and cash equivalents $ 2,026 $ 1,295 Restricted cash and restricted cash equivalents included in Other Assets 134 134 Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents $ 2,160 $ 1,429
Schedule of Restricted Cash and Cash Equivalents Balance Sheet Locations	The following table provides a reconciliation of Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents as reported in the Consolidated Statement of Cash Flows to the line items within the Consolidated Balance Sheets: millions March 31, 2019 December 31, 2018 Cash and cash equivalents $ 2,026 $ 1,295 Restricted cash and restricted cash equivalents included in Other Assets 134 134 Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents $ 2,160 $ 1,429

Segment Information Supplementa

Segment Information Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Reconciliation of Consolidated Adjusted EBITDAX to Income (Loss) Before Income Taxes	Below is a reconciliation of consolidated Adjusted EBITDAX to income (loss) before income taxes: Three Months Ended March 31, millions 2019 2018 Income (loss) before income taxes $ 262 $ 300 Interest expense 253 228 DD&A 1,081 990 Exploration expense 49 168 (Gains) losses on divestitures, net 5 24 Impairments — 19 Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives 316 (27 ) Reorganization-related charges 18 — Less net income (loss) attributable to noncontrolling interests 111 53 Consolidated Adjusted EBITDAX $ 1,873 $ 1,649
Schedule of Segment Reporting Information, by Segment	The following summarizes selected financial information for Anadarko’s reporting segments: millions Exploration WES Midstream Other and Total Three Months Ended March 31, 2019 Sales revenues $ 2,606 $ 499 $ 21 $ 3,126 Intersegment revenues 51 172 (223 ) — Other 8 58 31 97 Total revenues and other (1) 2,665 729 (171 ) 3,223 Operating costs and expenses (2) 992 337 (89 ) 1,240 Net cash from settlement of commodity derivatives — — (6 ) (6 ) Other (income) expense, net (3) — (36 ) 38 2 Net income (loss) attributable to noncontrolling interests — — 111 111 Total expenses and other 992 301 54 1,347 Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement — — (3 ) (3 ) Adjusted EBITDAX $ 1,673 $ 428 $ (228 ) $ 1,873 Three Months Ended March 31, 2018 Sales revenues $ 2,656 $ 355 $ 15 $ 3,026 Intersegment revenues 10 153 (163 ) — Other (9 ) 37 15 43 Total revenues and other (1) 2,657 545 (133 ) 3,069 Operating costs and expenses (2) 870 233 214 1,317 Net cash from settlement of commodity derivatives — — 68 68 Other (income) expense, net — — (12 ) (12 ) Net income (loss) attributable to noncontrolling interests — — 53 53 Total expenses and other 870 233 323 1,426 Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement — — 6 6 Adjusted EBITDAX $ 1,787 $ 312 $ (450 ) $ 1,649 (1) Total revenues and other excludes gains (losses) on divestitures, net since these gains and losses are excluded from Adjusted EBITDAX. (2) Operating costs and expenses excludes exploration expense, DD&A, impairments, reorganization-related charges, and certain other operating expenses since these expenses are excluded from Adjusted EBITDAX. (3) Other (income) expense, net excludes reorganization-related charges since these expenses are excluded from Adjusted EBITDAX. 17. Segment Information (Continued) The following summarizes selected financial information for Anadarko’s reporting segments: millions Exploration WES Midstream Other and Total March 31, 2019 Net properties and equipment $ 18,342 $ 8,630 $ 1,964 $ 28,936 Capital expenditures (1) $ 922 $ 315 $ 59 $ 1,296 Goodwill $ 4,343 $ 446 $ — $ 4,789 December 31, 2018 Net properties and equipment $ 18,267 $ 8,410 $ 1,938 $ 28,615 Capital expenditures (1) $ 4,103 $ 1,912 $ 170 $ 6,185 Goodwill $ 4,343 $ 446 $ — $ 4,789 (1) WES Midstream includes $49 million at March 31, 2019, and $734 million at December 31, 2018, of capitalized costs incurred prior to the contribution and sale of midstream assets to WES.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Millions	May 06, 2019$ / sharesshares	Apr. 11, 2019USD ($)$ / sharesshares	Feb. 28, 2019USD ($)	Mar. 31, 2019Segment	Jan. 01, 2019USD ($)		Jan. 01, 2018USD ($)	[2]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Sale of assets, consideration			$ 4,000
Cash proceeds from sale of assets			2,000
Number of reporting segments | Segment				2
Cumulative effect of accounting change					$ (55)	[1]	$ (47)
ASU 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ROU Assets					600
Lease liabilities					600
Cumulative effect of accounting change					$ 55
WES Operating [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common units received from sale of assets			$ 2,000
WES Operating [Member] | Limited Partner [Member] | WES [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Ownership interest in subsidiary			98.00%
WES Operating [Member] | Limited Partner [Member] | Anadarko Limited Partner Interest In WES [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Ownership interest in subsidiary			2.00%	2.00%
WES [Member] | Limited Partner [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Ownership interest in subsidiary			55.50%
WES [Member] | Limited Partner [Member] | Anadarko Limited Partner Interest In WES [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Ownership interest in subsidiary				55.50%
Subsequent Event [Member] | Anadarko, Chevron offer [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Merger, termination fee		$ 1,000
Subsequent Event [Member] | Anadarko, Chevron offer [Member] | Chevron [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Merger, consideration transferred		$ 33,000
Merger, share price (in usd per share) | $ / shares		$ 65
Merger, shares received (in shares) | shares		0.3869
Merger, cash received per share (in usd per share) | $ / shares		$ 16.25
Subsequent Event [Member] | Anadarko [Member] | Occidental [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Merger, shares received (in shares) | shares	0.2934
Merger, cash received per share (in usd per share) | $ / shares	$ 59
[1]	Beginning January 1, 2019, the Company adopted ASU 2016-02, Leases (Topic 842). See Note 1—Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements for further information.
[2]	Beginning January 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), and ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. See Note 1—Summary of Significant Accounting Policies in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Disaggregation of Revenue (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues from Customers	$ 3,338	$ 3,236
Revenue from Other than Customers	(120)	(191)
Total	3,218	3,045
Oil sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	2,096	2,127
Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	320	247
Natural-gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	240	292
Gathering, processing, and marketing sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	648	548
Revenue from Other than Customers	(178)	(188)
Gains (losses) on divestitures, net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Other than Customers	(5)	(24)
Other, net [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	34	22
Revenue from Other than Customers	63	21
Operating Segments [Member] | Exploration and Production [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	2,666	2,669
Revenue from Other than Customers	(1)	(45)
Total	2,665	2,624
Operating Segments [Member] | Exploration and Production [Member] | Oil sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	2,096	2,127
Operating Segments [Member] | Exploration and Production [Member] | Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	320	247
Operating Segments [Member] | Exploration and Production [Member] | Natural-gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	240	292
Operating Segments [Member] | Exploration and Production [Member] | Gathering, processing, and marketing sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	1	0
Revenue from Other than Customers	0	0
Operating Segments [Member] | Exploration and Production [Member] | Gains (losses) on divestitures, net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Other than Customers	0	(33)
Operating Segments [Member] | Exploration and Production [Member] | Other, net [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	9	3
Revenue from Other than Customers	(1)	(12)
Operating Segments [Member] | WES Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	672	502
Revenue from Other than Customers	57	43
Total	729	545
Operating Segments [Member] | WES Midstream [Member] | Oil sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Operating Segments [Member] | WES Midstream [Member] | Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Operating Segments [Member] | WES Midstream [Member] | Natural-gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Operating Segments [Member] | WES Midstream [Member] | Gathering, processing, and marketing sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	672	502
Revenue from Other than Customers	0	(1)
Operating Segments [Member] | WES Midstream [Member] | Gains (losses) on divestitures, net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Other than Customers	0	0
Operating Segments [Member] | WES Midstream [Member] | Other, net [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Revenue from Other than Customers	57	44
Other and Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	65
Revenue from Other than Customers	(176)	(189)
Total	(176)	(124)
Other and Intersegment Eliminations [Member] | Oil sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Other and Intersegment Eliminations [Member] | Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Other and Intersegment Eliminations [Member] | Natural-gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	0	0
Other and Intersegment Eliminations [Member] | Gathering, processing, and marketing sales [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	(25)	46
Revenue from Other than Customers	(178)	(187)
Third-party marketing revenue	209	224
Intercompany eliminations	(223)	(163)
Other and Intersegment Eliminations [Member] | Gains (losses) on divestitures, net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Other than Customers	(5)	9
Other and Intersegment Eliminations [Member] | Other, net [Member]
Disaggregation of Revenue [Line Items]
Revenues from Customers	25	19
Revenue from Other than Customers	$ 7	$ (11)

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2019
Change in Contract with Customer, Liability [Roll Forward]
Balance at December 31, 2018	$ 150
Increase due to cash received, excluding revenues recognized in the period	21
Decrease due to revenue recognized	(18)
Balance at March 31, 2019	153
Contract liabilities at March 31, 2019
Other current liabilities		$ 23
Other long-term liabilities - other		130
Total contract liabilities from contracts with customers	$ 150	$ 153

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Revenue Recognition Expected (Detail) $ in Millions	Mar. 31, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 261
Performance obligation expected to be satisfied, expected timing	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 343
Performance obligation expected to be satisfied, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 317
Performance obligation expected to be satisfied, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 213
Performance obligation expected to be satisfied, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 170
Performance obligation expected to be satisfied, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 549
Performance obligation expected to be satisfied, expected timing
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 1,853
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 80
Performance obligation expected to be satisfied, expected timing	9 months
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 103
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 103
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 7
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 7
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 58
Performance obligation expected to be satisfied, expected timing
Operating Segments [Member] | Exploration and Production [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 358
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 533
Performance obligation expected to be satisfied, expected timing	9 months
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 862
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 912
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 976
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 933
Performance obligation expected to be satisfied, expected timing	1 year
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 4,500
Performance obligation expected to be satisfied, expected timing
Operating Segments [Member] | WES Midstream [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ 8,716
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (352)
Performance obligation expected to be satisfied, expected timing	9 months
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (622)
Performance obligation expected to be satisfied, expected timing	1 year
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (698)
Performance obligation expected to be satisfied, expected timing	1 year
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (770)
Performance obligation expected to be satisfied, expected timing	1 year
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (770)
Performance obligation expected to be satisfied, expected timing	1 year
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (4,009)
Performance obligation expected to be satisfied, expected timing
Other and Intersegment Eliminations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation expected to be satisfied	$ (7,221)

Commodity Inventories - Summary

Commodity Inventories - Summary of the Major Classes of Commodity Inventories (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Energy Related Inventory [Abstract]
Oil	$ 169	$ 139
Natural gas	1	18
NGLs	84	78
Total commodity inventories	$ 254	$ 235

Divestitures - Summary of Proce

Divestitures - Summary of Proceeds Received and Gains (Losses) Recognized on Divestitures (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment [Abstract]
Proceeds received, net of closing adjustments	$ 7	$ 371
Gains (losses) on divestitures, net	$ (5)	$ (24)

Divestitures - Additional Infor

Divestitures - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds	$ 7	$ 371
Net losses	$ 5	$ 24
Certain Onshore Domestic Assets Alaska [Member] | Exploration and Production [Member] | Asset Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds				$ 383
Net losses			$ 154	$ 30

Suspended Exploratory Well Co_2

Suspended Exploratory Well Costs - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Capitalized Exploratory Well Costs [Abstract]
Suspended exploratory well costs	$ 460,000,000	$ 444,000,000
Suspended exploratory well costs previously capitalized for a period greater than one year since the completion of drilling at December 31, 2016, charged to exploration expense	$ 0

Current Liabilities - Summary o

Current Liabilities - Summary of Other Current Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Outstanding checks in excess of bank account balances	$ 248	$ 180
Other Current Liabilities
Accrued income taxes	211	167
Interest payable	159	267
Production, property, and other taxes payable	314	309
Accrued employee benefits	153	319
Derivatives	121	89
Operating lease liabilities	245
Other	137	144
Total other current liabilities	$ 1,340	$ 1,295

Derivative Instruments - Oil an

Derivative Instruments - Oil and Natural-Gas Production/Processing Derivative Activities Table (Detail) - Not Designated as Hedging Instrument [Member] - Three Way Collars Oil 2019 [Member] MBbls / d in Thousands	3 Months Ended
	Mar. 31, 2019MBbls / d$ / bbl
Derivative [Line Items]
Oil or NGL derivative nonmonetary notional amount per day | MBbls / d	87
Call Option [Member] | Short [Member]
Average price per barrel
Average ceiling price (in usd per barrel)	72.98
Put Option [Member] | Short [Member]
Average price per barrel
Average floor price (in usd per barrel)	46.72
Put Option [Member] | Long [Member]
Average price per barrel
Average floor price (in usd per barrel)	56.72

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Derivative [Line Items]
Amount of collateral posted related to derivative instruments with credit-risk-related contingent features	$ 123		$ 66
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Aggregate fair value of derivative instruments with credit-risk-related contingent features for which a net liability position existed (net of collateral)	1,200		1,100
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Cash payment for interest-rate swap agreements	41	$ 46
Interest Rate Swaps 1 Through 5 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	1,600
Interest Rate Swaps 6 Through 8 [Member] | Not Designated as Hedging Instrument [Member] | WES [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 375		$ 750

Derivative Instruments - Intere

Derivative Instruments - Interest-Rate Derivatives Table (Detail) - Not Designated as Hedging Instrument [Member] $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Interest-Rate Swap 1 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 550
Reference Period Start Date	Sep. 15, 2016
Reference Period End Date	Sep. 15, 2046
Derivative, Maturity Date	Sep. 1, 2020
Weighted-average interest rate for interest-rate swap	6.418%
Interest-Rate Swap 2 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 250
Reference Period Start Date	Sep. 15, 2016
Reference Period End Date	Sep. 15, 2046
Derivative, Maturity Date	Sep. 1, 2022
Weighted-average interest rate for interest-rate swap	6.809%
Interest-Rate Swap 3 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 100
Reference Period Start Date	Sep. 15, 2017
Reference Period End Date	Sep. 15, 2047
Derivative, Maturity Date	Sep. 1, 2020
Weighted-average interest rate for interest-rate swap	6.891%
Interest-Rate Swap 4 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 250
Reference Period Start Date	Sep. 15, 2017
Reference Period End Date	Sep. 15, 2047
Derivative, Maturity Date	Sep. 1, 2021
Weighted-average interest rate for interest-rate swap	6.57%
Interest-Rate Swap 5 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 450
Reference Period Start Date	Sep. 15, 2017
Reference Period End Date	Sep. 15, 2047
Derivative, Maturity Date	Sep. 1, 2023
Weighted-average interest rate for interest-rate swap	6.445%
WES [Member] | Interest-Rate Swap 6 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 375
Reference Period Start Date	Dec. 31, 2019
Reference Period End Date	Dec. 31, 2024
Derivative, Maturity Date	Dec. 31, 2019
Weighted-average interest rate for interest-rate swap	2.662%
WES [Member] | Interest Rate Swap 7 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 375
Reference Period Start Date	Dec. 31, 2019
Reference Period End Date	Dec. 31, 2029
Derivative, Maturity Date	Dec. 31, 2019
Weighted-average interest rate for interest-rate swap	2.802%
WES [Member] | Interest Rate Swap 8 [Member]
Derivative [Line Items]
Notional principal amount of interest-rate swap	$ 375
Reference Period Start Date	Dec. 31, 2019
Reference Period End Date	Dec. 31, 2049
Derivative, Maturity Date	Dec. 31, 2019
Weighted-average interest rate for interest-rate swap	2.885%

Derivative Instruments - Effect

Derivative Instruments - Effect of Derivative Instruments - Balance Sheet Table (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives Fair Value [Line Items]
Gross derivative assets	$ 96	$ 357
Gross derivative liabilities	(1,393)	(1,378)
Commodity derivatives [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	45	301
Gross derivative liabilities	(29)	(132)
Commodity derivatives [Member] | Other current assets [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	45	300
Gross derivative liabilities	(27)	(126)
Commodity derivatives [Member] | Other current liabilities [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	0	1
Gross derivative liabilities	(2)	(6)
Interest-rate derivatives [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	51	56
Gross derivative liabilities	(1,320)	(1,238)
Interest-rate derivatives [Member] | Other current assets [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	21	22
Gross derivative liabilities	0	0
Interest-rate derivatives [Member] | Other assets [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	30	34
Gross derivative liabilities	0	0
Interest-rate derivatives [Member] | Other current liabilities [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	(83)	(82)
Interest-rate derivatives [Member] | Other liabilities [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	(1,237)	(1,156)
WES [Member] | Interest-rate derivatives [Member] | Other current liabilities [Member]
Derivatives Fair Value [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	$ (44)	$ (8)

Derivative Instruments - Effe_2

Derivative Instruments - Effect of Derivative Instruments - Statement of Income Table (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative [Line Items]
Total (gains) losses on derivatives, net	$ 315	$ 36
Commodity derivatives [Member] | Gathering, processing, and marketing sales [Member]
Derivative [Line Items]
Total (gains) losses on derivatives, net	2	1
Commodity derivatives [Member] | (Gains) losses on derivatives, net [Member]
Derivative [Line Items]
Total (gains) losses on derivatives, net	149	162
Interest-rate derivatives [Member] | (Gains) losses on derivatives, net [Member]
Derivative [Line Items]
Total (gains) losses on derivatives, net	128	(127)
WES [Member] | Interest-rate derivatives [Member] | (Gains) losses on derivatives, net [Member]
Derivative [Line Items]
Total (gains) losses on derivatives, net	$ 36	$ 0

Derivative Instruments - Fair V

Derivative Instruments - Fair Value Table (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	$ 96	$ 357
Derivative assets Netting	(27)	(127)
Derivative assets, Collateral	0	0
Derivative assets	69	230
Gross derivative liabilities	(1,393)	(1,378)
Derivative liabilities Netting	27	127
Derivative liabilities, Collateral	123	68
Derivative liabilities	(1,243)	(1,183)
Commodity derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	45	301
Derivative assets Netting	(27)	(127)
Derivative assets, Collateral	0	0
Derivative assets	18	174
Gross derivative liabilities	(29)	(132)
Derivative liabilities Netting	27	127
Derivative liabilities, Collateral	0	2
Derivative liabilities	(2)	(3)
Interest-rate derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	51	56
Derivative assets Netting	0	0
Derivative assets, Collateral	0	0
Derivative assets	51	56
Gross derivative liabilities	(1,320)	(1,238)
Derivative liabilities Netting	0	0
Derivative liabilities, Collateral	123	66
Derivative liabilities	(1,197)	(1,172)
Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	0	1
Gross derivative liabilities	0	(2)
Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	96	356
Gross derivative liabilities	(1,393)	(1,376)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	0	0
Recurring [Member] | Commodity derivatives [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	0	1
Gross derivative liabilities	0	(2)
Recurring [Member] | Commodity derivatives [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	45	300
Gross derivative liabilities	(29)	(130)
Recurring [Member] | Commodity derivatives [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	0	0
Recurring [Member] | Interest-rate derivatives [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	0	0
Recurring [Member] | Interest-rate derivatives [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	51	56
Gross derivative liabilities	(1,320)	(1,238)
Recurring [Member] | Interest-rate derivatives [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative assets	0	0
Gross derivative liabilities	0	0
WES [Member] | Interest-rate derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities Netting	0	0
Derivative liabilities, Collateral	0	0
Derivative liabilities	(44)	(8)
WES [Member] | Recurring [Member] | Interest-rate derivatives [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative liabilities	0	0
WES [Member] | Recurring [Member] | Interest-rate derivatives [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative liabilities	(44)	(8)
WES [Member] | Recurring [Member] | Interest-rate derivatives [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross derivative liabilities	$ 0	$ 0

Debt - Debt Activity Table (Det

Debt - Debt Activity Table (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2019	Mar. 31, 2019
Changes in Debt Outstanding [Roll Forward]
Balance at December 31, 2018		$ 16,169
Other, net		13
Balance at March 31, 2019		17,674
Anadarko excluding WES [Member]
Changes in Debt Outstanding [Roll Forward]
Balance at December 31, 2018		11,354
Other, net		12
Balance at March 31, 2019		10,466
Western Midstream Partners, LP [Member]
Changes in Debt Outstanding [Roll Forward]
Balance at December 31, 2018		4,815
Other, net		1
Balance at March 31, 2019		7,208
WES 364-Day Facility [Member]
Changes in Debt Outstanding [Roll Forward]
Borrowings, credit facility		2,000
WES 364-Day Facility [Member] | Western Midstream Partners, LP [Member]
Changes in Debt Outstanding [Roll Forward]
Borrowings, credit facility	$ 2,000	2,000
WES RCF [Member]
Changes in Debt Outstanding [Roll Forward]
Borrowings, credit facility		420
WES RCF [Member] | Western Midstream Partners, LP [Member]
Changes in Debt Outstanding [Roll Forward]
Borrowings, credit facility		420
WGP RCF [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments, credit facility		(28)
WGP RCF [Member] | Western Midstream Partners, LP [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments, credit facility		(28)
8.700 % Senior Notes due 2019 [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments, senior notes		$ (600)
Debt instrument, stated interest rate		8.70%
8.700 % Senior Notes due 2019 [Member] | Anadarko excluding WES [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments, senior notes		$ (600)
6.950% Senior Notes due 2019 [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments, senior notes		$ (300)
Debt instrument, stated interest rate		6.95%
6.950% Senior Notes due 2019 [Member] | Anadarko excluding WES [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments, senior notes		$ (300)

Debt - Outstanding Debt Table (

Debt - Outstanding Debt Table (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total borrowings at face value	$ 19,153	$ 17,661
Net unamortized discounts, premiums, and debt issuance costs	(1,479)	(1,492)
Total borrowings	17,674	16,169
Finance lease liabilities	250	248
Less short-term debt	2,021	947
Total long-term debt	15,903	15,470
WES [Member]
Debt Instrument [Line Items]
Total borrowings at face value	7,260	4,868
Net unamortized discounts, premiums, and debt issuance costs	(52)	(53)
Total borrowings	7,208	4,815
Finance lease liabilities	0	0
Less short-term debt	2,000	28
Total long-term debt	5,208	4,787
Anadarko excluding WES [Member]
Debt Instrument [Line Items]
Total borrowings at face value	11,893	12,793
Net unamortized discounts, premiums, and debt issuance costs	(1,427)	(1,439)
Total borrowings	10,466	11,354
Finance lease liabilities	250	248
Less short-term debt	21	919
Total long-term debt	$ 10,695	$ 10,683

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended
	Feb. 28, 2019	Jan. 31, 2019	Mar. 31, 2019	Feb. 15, 2019	Feb. 14, 2019	Dec. 31, 2018	Jan. 31, 2018
Zero-Coupon Senior Notes [Member] | Accreted Value at Next Potential Put Date [Member]
Debt Instrument [Line Items]
Debt instrument, accreted value			$ 942,000,000
Anadarko excluding WES [Member] | 8.700 % Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Outstanding borrowings			$ 600,000,000
Line of credit, interest rate			8.70%
Anadarko excluding WES [Member] | 6.950% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Outstanding borrowings			$ 300,000,000
Line of credit, interest rate			6.95%
364-Day Credit Facility Due 2017 [Member]
Debt Instrument [Line Items]
Line of credit, outstanding borrowings			$ 0
364-Day Credit Facility Due 2017 [Member] | Anadarko excluding WES [Member]
Debt Instrument [Line Items]
Line of credit, maximum capacity							$ 2,000,000,000
Debt instrument, term		364 days
APC RCF [Member]
Debt Instrument [Line Items]
Line of credit, maximum capacity			3,000,000,000
Line of credit, outstanding borrowings			0
WES RCF [Member]
Debt Instrument [Line Items]
Borrowings, credit facility			420,000,000
WES RCF [Member] | WES [Member]
Debt Instrument [Line Items]
Line of credit, maximum capacity				$ 2,000,000,000	$ 1,500,000,000
Line of credit, outstanding borrowings			$ 640,000,000
Line of credit, interest rate			3.79%
Borrowings, credit facility			$ 420,000,000
Letters of credit, outstanding			5,000,000
Line of credit, available borrowing capacity			1,400,000,000
WES 364-Day Facility [Member]
Debt Instrument [Line Items]
Borrowings, credit facility			$ 2,000,000,000
WES 364-Day Facility [Member] | WES [Member]
Debt Instrument [Line Items]
Debt instrument, term			364 days
Line of credit, outstanding borrowings			$ 2,000,000,000
Line of credit, interest rate			3.87%
Borrowings, credit facility	$ 2,000,000,000		$ 2,000,000,000
WGP RCF [Member]
Debt Instrument [Line Items]
Repayments, credit facility			28,000,000
WGP RCF [Member] | WES [Member]
Debt Instrument [Line Items]
Repayments, credit facility			28,000,000
WGP RCF [Member] | Wgp Excluding Wes [Member]
Debt Instrument [Line Items]
Line of credit, maximum capacity			35,000,000
Repayments, credit facility			28,000,000
Fair Value, Inputs, Level 2 [Member] | Valuation, Market Approach [Member]
Debt Instrument [Line Items]
Estimated fair value of total borrowings			$ 19,300,000,000			$ 16,800,000,000

Leases - Additional Information

Leases - Additional Information (Details) $ in Millions	Mar. 31, 2019USD ($)drilling_vessel
Lessee, Lease, Description [Line Items]
Operating leases, total lease liabilities	$ 551
Number of offshore drilling vessels under operating leases | drilling_vessel	3
Finance leases, total lease liabilities	$ 250
Finance lease, FSPO, renewal term	10 years
Offshore Drilling Vessels and Onshore Drilling Rigs [Member]
Lessee, Lease, Description [Line Items]
Operating leases, total lease liabilities	$ 216
Real Estate [Member]
Lessee, Lease, Description [Line Items]
Operating leases, total lease liabilities	$ 193

Leases - Summary of Information

Leases - Summary of Information Related to Leases (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating leases, assets	$ 534
Finance leases, assets	186
Operating leases, current liabilities	245
Finance leases, current liabilities	21
Operating leases, long-term liabilities	306
Finance leases, long-term liabilities	229
Operating leases, total lease liabilities	551
Finance leases, total lease liabilities	$ 250
Weighted-average remaining lease term, operating leases	5 years
Weighted-average remaining lease term, finance leases	16 years
Weighted-average discount rate, operating leases	4.30%
Weighted-average discount rate, finance leases	15.40%
Operating leases, additions to ROU assets and lease liabilities	$ 60
Finance leases, additions to ROU assets and lease liabilities	$ 6

Leases - Summary of Lease Cost

Leases - Summary of Lease Cost (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 78
Short-term lease cost	19
Variable lease cost	39
Finance lease cost, amortization of ROU assets	10
Finance lease cost, interest on lease liabilities	9
Total lease cost	$ 155

Leases - Cash Flow Activity rel

Leases - Cash Flow Activity related to Leases (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Operating cash flows
Operating Leases	$ 78
Finance Leases	9
Investing cash flows
Operating Leases	24
Financing cash flows
Finance Leases	$ 4

Leases - Reconciliation of Oper

Leases - Reconciliation of Operating and Finance Lease Liabilities Recorded on the Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
Remainder of 2019	$ 185
2020	166
2021	60
2022	43
2023	30
Thereafter	142
Total lease payments	626
Less portion representing imputed interest	75
Total lease liabilities	551
Finance Leases
Remainder of 2019	46
2020	51
2021	50
2022	46
2023	43
Thereafter	324
Total lease payments	560
Less portion representing imputed interest	310
Total lease liabilities	250
Operating Leases
2019		$ 264
2020		139
2021		57
2022		35
2023		24
Thereafter		135
Total lease payments		654
Finance Leases
2019		58
2020		50
2021		48
2022		45
2023		43
Thereafter		323
Total lease payments		567
Capital Leases, Future Minimum Payments, Interest Included in Payments		319
Capital Lease Obligations	$ 250	$ 248

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense (Benefit) Table (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ 168	$ 90
Deferred income tax expense (benefit)	(2)	36
Total income tax expense (benefit)	166	126
Income (loss) before income taxes	$ 262	$ 300
Effective tax rate	63.00%	42.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Income tax benefit	$ (166)	$ (126)
Judicial Ruling [Member] | Tronox Litigation [Member]
Income Tax Disclosure [Line Items]
Income tax benefit	346		$ 346
Unrecognized tax benefits	$ 1,200		$ 1,200
Income tax refunds				$ 881

Pension Plans and Other Postr_3

Pension Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Cost Table (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Benefits [Member]
Components of net periodic benefit cost
Service cost	$ 22	$ 23
Interest cost	20	19
Expected (return) loss on plan assets	(21)	(21)
Amortization of net actuarial loss (gain)	4	7
Amortization of net prior service cost (credit)	0	0
Settlement expense	4	0
Net periodic benefit cost	29	28
Other Benefits [Member]
Components of net periodic benefit cost
Service cost	0	0
Interest cost	3	3
Expected (return) loss on plan assets	0	0
Amortization of net actuarial loss (gain)	0	0
Amortization of net prior service cost (credit)	(1)	(6)
Settlement expense	0	0
Net periodic benefit cost	$ 2	$ (3)

Pension Plans and Other Postr_4

Pension Plans and Other Postretirement Benefits - Additional Information (Detail) - Pension Benefits [Member] $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 65
Expected employer contributions in 2019	26
Unfunded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	21
Expected employer contributions in 2019	$ 26

Stockholders' Equity - Earnings

Stockholders' Equity - Earnings Per Share Reconciliation (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income (loss)
Net income (loss) attributable to common stockholders	$ (15)	$ 121
Income (loss) effect of TEUs	0	(3)
Less distributions on participating securities	2	1
Basic	(17)	117
Income (loss) effect of TEUs	0	(1)
Diluted	$ (17)	$ 116
Shares
Average number of common shares outstanding—basic (in shares)	490	518
Dilutive effect of stock options (in shares)	0	1
Average number of common shares outstanding—diluted (in shares)	490	519
Excluded due to anti-dilutive effect (in shares)	12	10
Net income (loss) per common share
Basic (in usd per share)	$ (0.03)	$ 0.23
Diluted (in usd per share)	(0.03)	0.22
Dividends per common share (in usd per share)	$ 0.30	$ 0.25

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Authorized share-repurchase program	$ 5,000,000,000
Amount of share repurchase program completed	$ 0	$ 3,750,000,000

Noncontrolling Interests - Addi

Noncontrolling Interests - Additional Information (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Feb. 28, 2019
WES [Member] | Class C Units [Member]
Noncontrolling Interest [Line Items]
Units issued in private placement (in shares)	309	1,100
WES [Member] | Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary			55.50%
Public ownership interest in subsidiary	44.50%
WES [Member] | WES Operating [Member] | Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary			98.00%
Anadarko Limited Partner Interest In WES [Member] | WES Operating [Member] | Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary	2.00%		2.00%
Anadarko Limited Partner Interest In WES [Member] | WES [Member] | Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary	55.50%

Variable Interest Entities - Fi

Variable Interest Entities - Financial Data of WGP (Detail) - WES [Member] - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Variable Interest Entity [Line Items]
WES distributions to Anadarko	$ 105	$ 100
WES distributions to third parties	$ 130	$ 118

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Detail) - WES [Member] - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	May 31, 2008	Mar. 31, 2019	Mar. 31, 2018
Variable Interest Entity [Line Items]
Note receivable for WES	$ 260
Debt instrument, term	30 years
Fixed annual rate	6.50%
Interest income for WES		$ 4	$ 4
Above-market component of swap extensions with Anadarko		$ 7	$ 14

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Summary of Cash Paid (Received) for Interest and Income Taxes and Non-cash Investing and Financing Activities (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash paid (received)
Interest, net of amounts capitalized	$ 371	$ 326
Income taxes, net of refunds	18	12
Non-cash investing activities
Fair value of properties and equipment acquired	0	2
Asset retirement cost additions	71	63
Accruals of property, plant, and equipment	781	965
Net liabilities assumed (divested) in acquisitions and divestitures	0	$ (25)
Non-cash investing and financing activities
Finance leases	$ 6

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information - Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Line Items]
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents	$ 2,160	$ 1,429	$ 3,484	$ 4,674
Cash and cash equivalents [Member]
Cash and Cash Equivalents [Line Items]
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents	2,026	1,295
Restricted cash and restricted cash equivalents	100	139
Restricted cash and restricted cash equivalents included in Other Assets [Member]
Cash and Cash Equivalents [Line Items]
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents	$ 134	$ 134

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019Segment
Segment Reporting [Abstract]
Number of reporting segments	2

Segment Information - Reconcili

Segment Information - Reconciliation of Consolidated Adjusted EBITDAX to Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting [Abstract]
Income (loss) before income taxes	$ 262	$ 300
Interest expense	253	228
DD&A	1,081	990
Exploration expense	49	168
(Gains) losses on divestitures, net	5	24
Impairments	0	19
Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives	316	(27)
Reorganization-related charges	18	0
Less net income (loss) attributable to noncontrolling interests	111	53
Consolidated Adjusted EBITDAX	$ 1,873	$ 1,649

Segment Information - Selected

Segment Information - Selected Financial Information for Anadarko's Reporting Segments Table (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Sales revenues	$ 3,338	$ 3,236
Other	97	43
Total revenues and other	3,218	3,045
Operating costs and expenses	2,384	2,494
Net cash from settlement of commodity derivatives	(1)	63
Other (income) expense, net	6	(12)
Net income (loss) attributable to noncontrolling interests	111	53
Total expenses and other	1,347	1,426
Consolidated Adjusted EBITDAX	1,873	1,649
Net properties and equipment	28,936		$ 28,615
Capital expenditures	1,296		6,185
Goodwill	4,789		4,789
(Gains) losses on derivatives, net [Member] | Commodity Contract [Member]
Segment Reporting Information [Line Items]
Net cash from settlement of commodity derivatives	(6)	68
Gathering, processing, and marketing sales [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement	(3)	6
Excluding Gains Losses On Divestitures Net [Member]
Segment Reporting Information [Line Items]
Total revenues and other	3,223	3,069
Excluding Certain Items [Member]
Segment Reporting Information [Line Items]
Operating costs and expenses	1,240	1,317
Excluding Certain Other Nonoperating Items [Member]
Segment Reporting Information [Line Items]
Other (income) expense, net	2	(12)
Operating Segments [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Sales revenues	2,666	2,669
Other	8	(9)
Total revenues and other	2,665	2,624
Net income (loss) attributable to noncontrolling interests	0	0
Total expenses and other	992	870
Consolidated Adjusted EBITDAX	1,673	1,787
Net properties and equipment	18,342		18,267
Capital expenditures	922		4,103
Goodwill	4,343		4,343
Operating Segments [Member] | Exploration and Production [Member] | (Gains) losses on derivatives, net [Member] | Commodity Contract [Member]
Segment Reporting Information [Line Items]
Net cash from settlement of commodity derivatives	0	0
Operating Segments [Member] | Exploration and Production [Member] | Gathering, processing, and marketing sales [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement	0	0
Operating Segments [Member] | Exploration and Production [Member] | Excluding Gains Losses On Divestitures Net [Member]
Segment Reporting Information [Line Items]
Total revenues and other	2,665	2,657
Operating Segments [Member] | Exploration and Production [Member] | Excluding Certain Items [Member]
Segment Reporting Information [Line Items]
Operating costs and expenses	992	870
Operating Segments [Member] | Exploration and Production [Member] | Excluding Certain Other Nonoperating Items [Member]
Segment Reporting Information [Line Items]
Other (income) expense, net	0	0
Operating Segments [Member] | WES Midstream [Member]
Segment Reporting Information [Line Items]
Sales revenues	672	502
Other	58	37
Total revenues and other	729	545
Net income (loss) attributable to noncontrolling interests	0	0
Total expenses and other	301	233
Consolidated Adjusted EBITDAX	428	312
Net properties and equipment	8,630		8,410
Capital expenditures	315		1,912
Goodwill	446		446
Operating Segments [Member] | WES Midstream [Member] | (Gains) losses on derivatives, net [Member] | Commodity Contract [Member]
Segment Reporting Information [Line Items]
Net cash from settlement of commodity derivatives	0	0
Operating Segments [Member] | WES Midstream [Member] | Gathering, processing, and marketing sales [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement	0	0
Operating Segments [Member] | WES Midstream [Member] | Excluding Gains Losses On Divestitures Net [Member]
Segment Reporting Information [Line Items]
Total revenues and other	729	545
Operating Segments [Member] | WES Midstream [Member] | Excluding Certain Items [Member]
Segment Reporting Information [Line Items]
Operating costs and expenses	337	233
Operating Segments [Member] | WES Midstream [Member] | Excluding Certain Other Nonoperating Items [Member]
Segment Reporting Information [Line Items]
Other (income) expense, net	(36)	0
Operating Segments [Member] | WES Midstream, Capitalized Cost incurred prior to sale of Midstream Assets [Member]
Segment Reporting Information [Line Items]
Capital expenditures	49		734
Other and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales revenues	0	65
Other	31	15
Total revenues and other	(176)	(124)
Net income (loss) attributable to noncontrolling interests	111	53
Total expenses and other	54	323
Consolidated Adjusted EBITDAX	(228)	(450)
Net properties and equipment	1,964		1,938
Capital expenditures	59		170
Goodwill	0		$ 0
Other and Intersegment Eliminations [Member] | (Gains) losses on derivatives, net [Member] | Commodity Contract [Member]
Segment Reporting Information [Line Items]
Net cash from settlement of commodity derivatives	(6)	68
Other and Intersegment Eliminations [Member] | Gathering, processing, and marketing sales [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement	(3)	6
Other and Intersegment Eliminations [Member] | Excluding Gains Losses On Divestitures Net [Member]
Segment Reporting Information [Line Items]
Total revenues and other	(171)	(133)
Other and Intersegment Eliminations [Member] | Excluding Certain Items [Member]
Segment Reporting Information [Line Items]
Operating costs and expenses	(89)	214
Other and Intersegment Eliminations [Member] | Excluding Certain Other Nonoperating Items [Member]
Segment Reporting Information [Line Items]
Other (income) expense, net	38	(12)
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Sales revenues	3,126	3,026
Oil and Gas [Member] | Operating Segments [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Sales revenues	2,606	2,656
Oil and Gas [Member] | Operating Segments [Member] | Exploration and Production [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Sales revenues	51	10
Oil and Gas [Member] | Operating Segments [Member] | WES Midstream [Member]
Segment Reporting Information [Line Items]
Sales revenues	499	355
Oil and Gas [Member] | Operating Segments [Member] | WES Midstream [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Sales revenues	172	153
Oil and Gas [Member] | Other and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales revenues	21	15
Oil and Gas [Member] | Other and Intersegment Eliminations [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Sales revenues	$ (223)	$ (163)

Uncategorized Items - apc-20190

Label	Element	Value
Noncontrolling Interest [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (23,000,000)	[1]
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	49,000,000	[1]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(55,000,000)	[2]
AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (73,000,000)	[1]
[1]	Beginning January 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), and ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. See Note 1—Summary of Significant Accounting Policies in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.
[2]	Beginning January 1, 2019, the Company adopted ASU 2016-02, Leases (Topic 842). See Note 1—Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements for further information.