Fresh Start Accounting - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2021	Feb. 09, 2021	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 905	$ 40	$ 279	$ 6
Restricted cash		86
Accounts receivable, net		843
Short-term derivative assets		0
Other current assets		61
Total current assets	2,103	1,030	1,108
Property and equipment:
Proved oil and natural gas properties		4,686
Unproved properties		483
Other property and equipment	495	499	1,754
Total property and equipment		5,668
Less: accumulated depreciation, depletion and amortization	(908)	0	(23,806)
Property and equipment held for sale, net		2
Total property and equipment, net	8,802	5,670	5,242
Other long-term assets	104	114	234
Assets	11,009	6,814	6,584
Current liabilities:
Accounts payable	308	415	346
Current maturities of long-term debt, net	0	0	1,929
Accrued interest		0
Short-term derivative liabilities		398
Other current liabilities	1,202	769	723
Total current liabilities	2,447	1,582	3,094
Debt		1,313
Long-term derivative liabilities		90
Asset retirement obligations, net of current portion		236
Other long-term liabilities		7
Liabilities subject to compromise	0	0	8,643
Total liabilities	5,338	3,228	11,925
Contingencies and commitments (Note 6)
Stockholders’ equity (deficit):
Predecessor preferred stock		0	1,631
Additional paid-in capital	4,845		16,937
Common stock	1	1	0
Successor additional paid-in-capital		3,585
Predecessor accumulated other comprehensive income		0	45
Retained earnings (accumulated deficit)	825	0	(23,954)
Total stockholders’ equity (deficit)	5,671	3,586	(5,341)
Total liabilities and stockholders’ equity (deficit)	11,009	6,814	$ 6,584
Predecessor
Current assets:
Cash and cash equivalents		243
Restricted cash		0
Accounts receivable, net		861
Short-term derivative assets		0
Other current assets		66
Total current assets		1,170
Property and equipment:
Proved oil and natural gas properties		25,794
Unproved properties		1,546
Other property and equipment		1,755
Total property and equipment		29,095
Less: accumulated depreciation, depletion and amortization		(23,877)
Property and equipment held for sale, net		9
Total property and equipment, net		5,227
Other long-term assets		198
Assets		6,595
Current liabilities:
Accounts payable		391
Current maturities of long-term debt, net		1,929
Accrued interest		4
Short-term derivative liabilities		398
Other current liabilities		645
Total current liabilities		3,367
Debt		0
Long-term derivative liabilities		90
Asset retirement obligations, net of current portion		139
Other long-term liabilities		5
Liabilities subject to compromise		9,574
Total liabilities		13,175
Contingencies and commitments (Note 6)
Stockholders’ equity (deficit):
Predecessor preferred stock		1,631
Additional paid-in capital		16,940
Common stock		0
Successor additional paid-in-capital		0
Predecessor accumulated other comprehensive income		48
Retained earnings (accumulated deficit)		(25,199)
Total stockholders’ equity (deficit)		(6,580)
Total liabilities and stockholders’ equity (deficit)		6,595
Reorganization Adjustments
Current assets:
Cash and cash equivalents		(203)
Restricted cash		86
Accounts receivable, net		(18)
Short-term derivative assets		0
Other current assets		(5)
Total current assets		(140)
Property and equipment:
Proved oil and natural gas properties		0
Unproved properties		0
Other property and equipment		0
Total property and equipment		0
Less: accumulated depreciation, depletion and amortization		0
Property and equipment held for sale, net		0
Total property and equipment, net		0
Other long-term assets		0
Assets		(140)
Current liabilities:
Accounts payable		24
Current maturities of long-term debt, net		(1,929)
Accrued interest		(4)
Short-term derivative liabilities		0
Other current liabilities		124
Total current liabilities		(1,785)
Debt		1,261
Long-term derivative liabilities		0
Asset retirement obligations, net of current portion		0
Other long-term liabilities		2
Liabilities subject to compromise		(9,574)
Total liabilities		(10,096)
Contingencies and commitments (Note 6)
Stockholders’ equity (deficit):
Predecessor preferred stock		(1,631)
Additional paid-in capital		(16,940)
Common stock		1
Successor additional paid-in-capital		3,585
Predecessor accumulated other comprehensive income		0
Retained earnings (accumulated deficit)		24,941
Total stockholders’ equity (deficit)		9,956
Total liabilities and stockholders’ equity (deficit)		(140)
Reorganization, Chapter 11, Fresh-Start Adjustment
Current assets:
Cash and cash equivalents		48
Restricted cash		8
Accounts receivable, net		0
Short-term derivative assets		0
Other current assets		0
Total current assets		0
Property and equipment:
Proved oil and natural gas properties		(21,108)
Unproved properties		(1,063)
Other property and equipment		(1,256)
Total property and equipment		(23,427)
Less: accumulated depreciation, depletion and amortization		23,877
Property and equipment held for sale, net		(7)
Total property and equipment, net	(443)	443
Other long-term assets	84	(84)
Assets		359
Current liabilities:
Accounts payable		0
Current maturities of long-term debt, net		0
Accrued interest		0
Short-term derivative liabilities		0
Other current liabilities		0
Total current liabilities		0
Debt	(52)	52
Long-term derivative liabilities		0
Asset retirement obligations, net of current portion		97
Other long-term liabilities		97
Liabilities subject to compromise		0
Total liabilities		149
Contingencies and commitments (Note 6)
Stockholders’ equity (deficit):
Predecessor preferred stock		0
Additional paid-in capital		0
Common stock		0
Successor additional paid-in-capital		0
Predecessor accumulated other comprehensive income	(9)	(48)
Retained earnings (accumulated deficit)		258
Total stockholders’ equity (deficit)		210
Total liabilities and stockholders’ equity (deficit)	$ 201	$ 359