Condensed Combined Debtor-in-Possession Financial Information - Condensed Consolidated Statements of Cash Flows (Details) (Details) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Cash Provided By Operating Activities	$ 773	$ 853
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(843)	(1,070)
Business combination, net	0	(353)
Acquisitions of proved and unproved properties	(9)	(17)
Proceeds from divestitures of proved and unproved properties	7	82
Additions to other property and equipment	(15)	(18)
Proceeds from sales of other property and equipment	4	4
Net Cash Used In Investing Activities	(856)	(1,372)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from pre-petition revolving credit facility borrowings	3,806	6,416
Payments on pre-petition revolving credit facility borrowings	(3,467)	(5,452)
Cash paid to purchase debt	(95)	(381)
DIP credit facility financing costs	(55)	0
Cash paid for preferred stock dividends	(22)	(46)
Other financing activities	(8)	(18)
Net Cash Provided By Financing Activities	159	519
Net increase in cash and cash equivalents	76	0
Cash and cash equivalents, beginning of period	6	4
Cash and cash equivalents, end of period	82	4
Debtor-in-Possession
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Cash Provided By Operating Activities	771	850
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(843)	(1,070)
Business combination, net	0	(353)
Acquisitions of proved and unproved properties	(9)	(17)
Proceeds from divestitures of proved and unproved properties	7	82
Additions to other property and equipment	(15)	(18)
Proceeds from sales of other property and equipment	4	4
Net Cash Used In Investing Activities	(856)	(1,372)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from pre-petition revolving credit facility borrowings	3,806	6,416
Payments on pre-petition revolving credit facility borrowings	(3,467)	(5,452)
Cash paid to purchase debt	(95)	(381)
DIP credit facility financing costs	(55)	0
Cash paid for preferred stock dividends	(22)	(46)
Other financing activities	(6)	(16)
Net Cash Provided By Financing Activities	161	521
Net increase in cash and cash equivalents	76	(1)
Cash and cash equivalents, beginning of period	4	3
Cash and cash equivalents, end of period	$ 80	$ 2