Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
REVENUES
Oil and natural gas sales	$ 312	$ 541	$ 987	$ 1,720
Net derivative gain (loss) from commodity contracts	0	37	75	(31)
Revenue not from contract with customer	97	103	196	335
Total revenues	409	681	1,258	2,024
COSTS
Production costs	141	221	460	684
General and administrative expenses	64	66	193	228
Depreciation, depletion and amortization	89	118	296	357
Asset impairments	0	0	1,736	0
Taxes other than on income	42	42	121	119
Exploration expense	2	5	9	25
Other expenses, net	22	8	75	33
Total costs	422	533	3,035	1,697
OPERATING (LOSS) INCOME	(13)	148	(1,777)	327
NON-OPERATING (LOSS) INCOME
Reorganization items, net	66	0	66	0
Interest and debt expense, net	(28)	(95)	(200)	(293)
Net gain on early extinguishment of debt	0	82	5	108
Other non-operating expenses	(32)	(8)	(93)	(18)
(LOSS) INCOME BEFORE INCOME TAXES	(7)	127	(1,999)	124
Income tax	0	0	0	0
NET (LOSS) INCOME	(7)	127	(1,999)	124
NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTERESTS
Mezzanine equity	(25)	(30)	(85)	(87)
Equity	3	(3)	(12)	2
Net income attributable to noncontrolling interests	(22)	(33)	(97)	(85)
NET (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCK	$ (29)	$ 94	$ (2,096)	$ 39
Net (loss) income attributable to common stock per share
Basic (includes return from noncontrolling interest) (in dollars per share)	$ 2.20	$ 1.89	$ (39.64)	$ 0.78
Diluted (includes return from noncontrolling interest) (in dollars per share)	$ 2.20	$ 1.89	$ (39.64)	$ 0.77
Marketing and trading
REVENUES
Revenue not from contract with customer	$ 50	$ 62	$ 109	$ 230
COSTS
Costs of sales	35	45	67	170
Electricity sales
REVENUES
Revenue not from contract with customer	43	38	75	88
Other revenue
REVENUES
Revenue not from contract with customer	4	3	12	17
Electricity cost of sales
COSTS
Costs of sales	17	18	47	51
Transportation costs
COSTS
Costs of sales	$ 10	$ 10	$ 31	$ 30