Fresh Start Accounting - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2021	Feb. 09, 2021
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
Total 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
Long-term debt, net		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
Predecessor additional paid-in capital		16,940
Successor common stock		0
Accumulated other comprehensive income		48
Accumulated deficit		(25,199)
Total stockholders’ equity (deficit)		(6,580)
Total liabilities and stockholders’ equity (deficit)		6,595
Current assets:
Cash and cash equivalents		40
Restricted cash		86
Accounts receivable, net		843
Short-term derivative assets		0
Other current assets		61
Total current assets		1,030
Property and equipment:
Proved oil and natural gas properties		4,686
Unproved properties		483
Other property and equipment		499
Total property and equipment		5,668
Less: accumulated depreciation, depletion and amortization		0
Property and equipment held for sale, net		2
Total property and equipment, net		5,670
Other long-term assets		114
Total assets		6,814
Current liabilities:
Accounts payable		415
Current maturities of long-term debt, net		0
Accrued interest		0
Short-term derivative liabilities		398
Other current liabilities		769
Total current liabilities		1,582
Long-term debt, net		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
Total liabilities		3,228
Contingencies and commitments (Note 6)
Stockholders’ equity (deficit):
Predecessor preferred stock		0
Successor common stock		1
Successor additional paid-in-capital		3,585
Accumulated other comprehensive income		0
Accumulated deficit		0
Total stockholders’ equity (deficit)		3,586
Total liabilities and stockholders’ equity (deficit)		6,814
Current assets:
Cash and cash equivalents		48
Restricted cash		8
Property and equipment:
Total property and equipment, net	$ 443
Other long-term assets	(84)
Current liabilities:
Accounts payable		24
Other current liabilities		124
Long-term debt, net	52	1,261
Other long-term liabilities		97
Stockholders’ equity (deficit):
Accumulated other comprehensive income	9
Accumulated deficit		24,941
Total liabilities and stockholders’ equity (deficit)	$ (201)
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
Total 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)
Long-term debt, net		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)
Predecessor additional paid-in capital		(16,940)
Successor common stock		1
Successor additional paid-in-capital		3,585
Accumulated other comprehensive income		0
Accumulated deficit		24,941
Total stockholders’ equity (deficit)		9,956
Total liabilities and stockholders’ equity (deficit)		(140)
Fresh Start Adjustments
Current assets:
Cash and cash equivalents		0
Restricted cash		0
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
Other long-term assets		(84)
Total 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
Long-term debt, net		52
Long-term derivative liabilities		0
Asset retirement obligations, net of current portion		97
Other long-term liabilities		0
Liabilities subject to compromise		0
Total liabilities		149
Contingencies and commitments (Note 6)
Stockholders’ equity (deficit):
Predecessor preferred stock		0
Predecessor additional paid-in capital		0
Successor common stock		0
Successor additional paid-in-capital		0
Accumulated other comprehensive income		(48)
Accumulated deficit		258
Total stockholders’ equity (deficit)		210
Total liabilities and stockholders’ equity (deficit)		$ 359