CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Revenues and Other
Revenues from Customers	$ 3,851			$ 10,501
Gains (losses) on divestitures and other, net	90		$ (114)	232		$ 1,052
Total	3,697		2,496	10,033		8,979
Costs and Expenses
Oil and gas operating	294		253	845		738
Oil and gas transportation	228		220	633		698
Exploration	118	[1]	750	380	[1]	2,366
General and administrative	248		261	814		768
Depreciation, depletion, and amortization	1,130		1,083	3,123		3,235
Production, property, and other taxes	246		159	637		449
Impairments	172		0	319		383
Other operating expense	26		123	188		157
Total	2,718		3,245	7,684		9,895
Operating Income (Loss)	979		(749)	2,349		(916)
Other (Income) Expense
Interest expense	240		230	705		682
(Gains) losses on derivatives, net	33		82	506		(33)
Other (income) expense, net	24		5	16		51
Total	296		317	1,224		700
Income (Loss) Before Income Taxes	683		(1,066)	1,125		(1,616)
Income tax expense (benefit)	256		(425)	507		(366)
Net Income (Loss)	427		(641)	618		(1,250)
Net income (loss) attributable to noncontrolling interests	64		58	105		182
Net Income (Loss) Attributable to Common Stockholders	$ 363		$ (699)	$ 513		$ (1,432)
Per Common Share
Net income (loss) attributable to common stockholders—basic (in usd per share)	$ 0.72		$ (1.27)	$ 0.99		$ (2.60)
Net income (loss) attributable to common stockholders—diluted (in usd per share)	$ 0.72		$ (1.27)	$ 0.99		$ (2.61)
Average Number of Common Shares Outstanding—Basic	499		553	507		552
Average Number of Common Shares Outstanding—Diluted	500		553	508		552
Dividends (in usd per share)	$ 0.25		$ 0.05	$ 0.75		$ 0.15
Commodity Contract and Interest Rate Swap [Member]
Other (Income) Expense
(Gains) losses on derivatives, net	$ 32		$ 82	$ 503		$ (33)
Oil sales [Member]
Revenues and Other
Revenues from Customers	2,572		1,567	6,964		4,652
Natural gas sales [Member]
Revenues and Other
Revenues from Customers	232		269	682		1,090
Natural-gas liquids sales [Member]
Revenues and Other
Revenues from Customers	382		265	992		768
Gathering, processing, and marketing [Member]
Revenues and Other
Revenues from Customers	421		509	1,163		1,417
Costs and Expenses
Gathering, processing, and marketing	$ 256		$ 396	$ 745		$ 1,101

[1] Includes restructuring charges of $20 million for the three and nine months ended September 30, 2018.