CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Feb. 29, 2012	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenues		$ 4,377	$ 3,877	$ 3,334	$ 3,242	$ 3,516	$ 3,382	$ 3,938	$ 3,771	$ 14,830	$ 14,607	$ 20,001
Cost of sales:
Production and delivery										10,697	10,693	11,116
Depreciation, depletion and amortization										2,530	3,240	3,635
Impairment of Oil and Gas Properties			239	291	3,800	3,700	3,700	2,700	3,100	4,317	13,144	3,737
Metals inventory adjustments		9	20	2	5	184	91	59	4	36	338	6
Total cost of sales										17,580	27,415	18,494
Selling, general and administrative expenses										607	558	580
Mining exploration and research expenses										64	107	106
Environmental obligations and shutdown costs										20	78	119
Goodwill impairment										0	0	1,717
Net gain on sales of assets		113		(13)	(749)				(39)	(649)	(39)	(717)
Total costs and expenses										17,622	28,119	20,299
Operating loss		703	359	18	(3,872)	(4,097)	(3,964)	(2,421)	(3,030)	(2,792)	(13,512)	(298)
Interest expense, net										(755)	(617)	(606)
Net gain on exchanges and early extinguishment of debt										26	0	73
Other income, net										49	1	31
Loss from continuing operations before income taxes and equity in affiliated companies' net earnings (losses)										(3,472)	(14,128)	(800)
(Provision for) benefit from income taxes										(371)	1,951	(225)
Equity in affiliated companies’ net earnings (losses)										11	(3)	3
Net loss from continuing operations		202	292	(229)	(4,097)	(4,090)	(3,815)	(1,828)	(2,447)	(3,832)	(12,180)	(1,022)
Net (loss) income from discontinued operations		(2)	(6)	(181)	(4)	(4)	25	29	41	(193)	91	277
Net loss		200	286	(410)	(4,101)	(4,094)	(3,790)	(1,799)	(2,406)	(4,025)	(12,089)	(745)
Net income attributable to noncontrolling interests: Continuing Operations										(227)	(27)	(358)
Net income attributable to noncontrolling interests: Discontinued Operations		(19)	(22)	(12)	(10)	(11)	(16)	(26)	(26)	(63)	(79)	(165)
Gain on redemption and preferred dividends attributable to redeemable noncontrolling interest										161	(41)	(40)
Net loss attributable to common stockholders		$ 292	$ 217	$ (479)	$ (4,184)	$ (4,081)	$ (3,830)	$ (1,851)	$ (2,474)	$ (4,154)	$ (12,236)	$ (1,308)
Basic and diluted net (loss) income per share attributable to common stockholders:
Continuing operations (in dollars per share)		$ 0.22	$ 0.18	$ (0.23)	$ (3.34)	$ (3.46)	$ (3.59)	$ (1.78)	$ (2.40)	$ (2.96)	$ (11.32)	$ (1.37)
Discontinued operations (in dollars per share)		(0.01)	(0.02)	(0.15)	(0.01)	(0.01)	0.01	0.00	0.02	(0.20)	0.01	0.11
Earnings per share, basic and diluted (in dollars per share)		$ 0.21	$ 0.16	$ (0.38)	$ (3.35)	$ (3.47)	$ (3.58)	$ (1.78)	(2.38)	$ (3.16)	$ (11.31)	$ (1.26)
Basic and diluted weighted-average shares of common stock outstanding (in shares)										1,318	1,082	1,039
Dividends declared per share of common stock (in dollars per share)	$ 1.25								$ 0.20	$ 0	$ 0.2605	$ 1.25