CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME (LOSS)	$ (9,750)	$ (308)	$ 228
ADJUSTMENTS TO RECONCILE NET INCOME (LOSS) TO CASH PROVIDED BY OPERATING ACTIVITIES:
Depreciation, depletion and amortization	1,097	2,264	1,737
Deferred income tax benefit	(10)	(305)	(10)
Derivative (gains) losses, net	(596)	(3)	26
Cash receipts (payments) on derivative settlements, net	884	202	(345)
Stock-based compensation	21	30	32
(Gains) losses on sales of assets	(30)	(43)	264
Impairments	8,535	11	131
Non-cash reorganization items, net	(213)	0	0
Exploration	417	49	96
(Gains) losses on investments	20	63	(139)
Gains on purchases or exchanges of debt	(65)	(79)	(263)
Other	(61)	(4)	(118)
Decrease in accounts receivable and other assets	303	376	16
(Decrease) increase in accounts payable, accrued liabilities and other	612	(630)	75
Net Cash Provided By Operating Activities	1,164	1,623	1,730
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(1,111)	(2,180)	(1,848)
Business combination, net	0	(353)	0
Acquisitions of proved and unproved properties	(9)	(35)	(128)
Proceeds from divestitures of proved and unproved properties	136	130	2,231
Additions to other property and equipment	(22)	(48)	(21)
Proceeds from sales of other property and equipment	14	6	147
Proceeds from sales of investments	0	0	74
Net Cash Provided By (Used In) Investing Activities	(992)	(2,480)	455
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from pre-petition revolving credit facility borrowings	3,656	10,676	11,697
Payments on pre-petition revolving credit facility borrowings	(3,317)	(10,180)	(12,059)
Proceeds from DIP credit facility borrowings	60	0	0
Payments on DIP credit facility borrowings	(60)	0	0
DIP credit facility and exit facilities financing costs	(109)	0	0
Proceeds from issuance of senior notes, net	0	108	1,236
Proceeds from issuance of term loan, net	0	1,455	0
Cash paid to purchase debt	(94)	(1,073)	(2,813)
Extinguishment of other financing	0	0	(122)
Cash paid for preferred stock dividends	(22)	(91)	(92)
Other	(13)	(36)	(33)
Net Cash Provided By (Used In) Financing Activities	101	859	(2,186)
Net increase (decrease) in cash and cash equivalents	273	2	(1)
Cash and cash equivalents, beginning of period	6	4	5
Cash and cash equivalents, end of period	279	6	4
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for reorganization items, net	140	0	0
Interest paid, net of capitalized interest	224	691	664
Income taxes paid, net of refunds received	0	(6)	(3)
SUPPLEMENTAL DISCLOSURE OF SIGNIFICANT NON-CASH INVESTING AND FINANCING ACTIVITIES:
Put option premium on equity backstop agreement	60	0	0
Operating lease obligations recognized	32	0	0
Common stock issued for business combination	0	2,037	0
Debt exchanged for common stock	0	693	0
Preferred stock exchanged for common stock	0	40	0
Change in senior notes exchanged	0	971	0
Acquisition of other property and equipment including assets under finance lease	0	0	27
Change in accrued drilling and completion costs
SUPPLEMENTAL DISCLOSURE OF SIGNIFICANT NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in accrued drilling and completion costs	$ (216)	$ (19)	$ 174