CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues and Other
Oil and condensate sales	$ 5,420	$ 9,748	$ 9,178
Natural-gas sales	2,007	3,849	3,388
Natural-gas liquids sales	833	1,572	1,262
Gathering, processing, and marketing sales	1,226	1,206	1,039
Gains (losses) on divestitures and other, net	(788)	2,095	(286)
Total	8,698	18,470	14,581
Costs and Expenses
Oil and gas operating	1,014	1,171	1,092
Oil and gas transportation	1,117	1,116	981
Exploration	2,644	1,639	1,329
Gathering, processing, and marketing	1,054	1,030	869
General and administrative	1,176	1,316	1,090
Depreciation, depletion, and amortization	4,603	4,550	3,927
Other taxes	553	1,244	1,077
Impairments	5,075	836	794
Other operating expense	271	165	89
Total	17,507	13,067	11,248
Operating Income (Loss)	(8,809)	5,403	3,333
Other (Income) Expense
Interest expense	825	772	686
(Gains) losses on derivatives, net	(100)	207	(392)
Other (income) expense, net	149	20	89
Total	880	5,349	1,227
Income (Loss) Before Income Taxes	(9,689)	54	2,106
Income tax expense (benefit)	(2,877)	1,617	1,165
Net Income (Loss)	(6,812)	(1,563)	941
Net income (loss) attributable to noncontrolling interests	(120)	187	140
Net Income (Loss) Attributable to Common Stockholders	$ (6,692)	$ (1,750)	$ 801
Per Common Share
Net income (loss) attributable to common stockholders—basic	$ (13.18)	$ (3.47)	$ 1.58
Net income (loss) attributable to common stockholders—diluted	$ (13.18)	$ (3.47)	$ 1.58
Average Number of Common Shares Outstanding—Basic	508	506	502
Average Number of Common Shares Outstanding—Diluted	508	506	505
Dividends (per Common Share)	$ 1.08	$ 0.99	$ 0.54
Judicial Ruling [Member] | Tronox Litigation [Member]
Other (Income) Expense
Litigation-related contingent loss	$ 5	$ 4,360	$ 850
Commodity Contract and Interest-Rate Swap [Member]
Other (Income) Expense
(Gains) losses on derivatives, net	$ (99)	$ 197	$ (398)