Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues	$ 3,341	$ 3,242
Cost of sales:
Production and delivery	2,200	2,499
Depreciation, depletion and amortization	389	662
Impairment of oil and gas properties	0	3,787
Total cost of sales	2,589	6,948
Selling, general and administrative expenses	153	138
Mining exploration and research expenses	15	18
Environmental obligations and shutdown costs	27	10
Net gain on sales of assets	(23)	0
Total costs and expenses	2,761	7,114
Operating income (loss)	580	(3,872)
Interest expense, net	(167)	(191)
Other income, net	25	36
Income (loss) from continuing operations before income taxes and equity in affiliated companies’ net earnings	438	(4,027)
Provision for income taxes	(174)	(77)
Equity in affiliated companies’ net earnings	4	7
Net income (loss) from continuing operations	268	(4,097)
Net income (loss) from discontinued operations	38	(4)
Net income (loss)	306	(4,101)
Net income attributable to noncontrolling interests:
Continuing operations	(75)	(62)
Discontinued operations	(3)	(10)
Preferred dividends attributable to redeemable noncontrolling interest	0	11
Net income (loss) attributable to common stockholders	$ 228	$ (4,184)
Basic and diluted net income (loss) per share attributable to common stockholders:
Continuing operations	$ 0.13	$ (3.34)
Discontinued operations	0.03	(0.01)
Basic and diluted net income (loss) per share attributable to common stockholders:	$ 0.16	$ (3.35)
Basic	1,446	1,251
Diluted	1,454	1,251