Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating revenues:
Oil sales	$ 498	$ 348	$ 1,461	$ 929
Natural gas sales	129	82	345	181
Total operating revenues	627	430	1,806	1,110
Operating costs and expenses:
Oil and natural gas production	106	71	293	240
Production and ad valorem taxes	48	33	140	89
Exploration and abandonments	7	10	42	54
Depreciation, depletion and amortization	284	299	848	890
Accretion of discount on asset retirement obligations	2	2	6	5
Impairments of long-lived assets	0	0	0	1,525
General and administrative (including non-cash stock-based compensation of $17 and $15 for the three months ended September 30, 2017 and 2016, respectively, and $43 for each of the nine months ended September 30, 2017 and 2016)	64	53	180	160
(Gain) loss on derivatives	206	(41)	(289)	176
(Gain) loss on disposition of assets, net	(13)	1	(667)	(109)
Total operating costs and expenses	704	428	553	3,030
Income (loss) from operations	(77)	2	1,253	(1,920)
Other income (expense):
Interest expense	(39)	(53)	(118)	(162)
Loss on extinguishment of debt	(65)	(28)	(66)	(28)
Other, net	2	(2)	18	(9)
Total other expense	(102)	(83)	(166)	(199)
Income (loss) before income taxes	(179)	(81)	1,087	(2,119)
Income tax (expense) benefit	66	30	(398)	782
Net income (loss)	$ (113)	$ (51)	$ 689	$ (1,337)
Earnings per share:
Basic net income (loss)	$ (0.77)	$ (0.38)	$ 4.64	$ (10.18)
Diluted net income (loss)	$ (0.77)	$ (0.38)	$ 4.63	$ (10.18)