Fresh Start Accounting - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Feb. 09, 2021
Current assets:
Cash and cash equivalents	$ 17	$ 905	$ 612	$ 40
Restricted cash				86
Accounts receivable, net				843
Short-term derivative assets	2	5		0
Other current assets				61
Total current assets	2,010	2,103		1,030
Property and equipment:
Proved natural gas and oil properties	10,816	7,682		4,686
Unproved properties	2,211	1,530		483
Other property and equipment	498	495		499
Total property and equipment	13,525	9,707		5,668
Less: accumulated depreciation, depletion and amortization	(1,747)	(908)		0
Property and equipment held for sale, net	5	3		2
Total property and equipment, net	11,783	8,802		5,670
Other long-term assets	93	104		114
Total assets	13,899	11,009		6,814
Current liabilities:
Accounts payable	414	308		415
Current maturities of long-term debt, net				0
Accrued interest	38	38		0
Short-term derivative liabilities	2,059	899		398
Other current liabilities	1,730	1,202		769
Total current liabilities	4,241	2,447		1,582
Long-term debt, net				1,313
Long-term derivative liabilities	446	249		90
Asset retirement obligations, net of current portion	337	349		236
Other long-term liabilities				7
Liabilities subject to compromise				0
Total liabilities	8,091	5,338		3,228
Contingencies and commitments (Note 7)
Stockholders’ equity (deficit):
Predecessor preferred stock				0
Successor additional paid-in capital	5,619	4,845
Successor common stock, $0.01 par value, 450,000,000 shares authorized: 121,590,256 and 117,917,349 shares issued	1	1		1
Successor additional paid-in-capital				3,585
Accumulated other comprehensive income				0
Retained earnings	188	825		0
Total stockholders' equity	5,808	5,671		3,586
Total liabilities and stockholders' equity	$ 13,899	$ 11,009		6,814
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 natural gas and oil 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 7)
Stockholders’ equity (deficit):
Predecessor preferred stock				1,631
Successor additional paid-in capital				16,940
Successor common stock, $0.01 par value, 450,000,000 shares authorized: 121,590,256 and 117,917,349 shares issued				0
Successor additional paid-in-capital				0
Accumulated other comprehensive income				48
Retained earnings				(25,199)
Total stockholders' equity				(6,580)
Total liabilities and stockholders' equity				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 natural gas and oil 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 7)
Stockholders’ equity (deficit):
Predecessor preferred stock				(1,631)
Successor additional paid-in capital				(16,940)
Successor common stock, $0.01 par value, 450,000,000 shares authorized: 121,590,256 and 117,917,349 shares issued				1
Successor additional paid-in-capital				3,585
Accumulated other comprehensive income				0
Retained earnings				24,941
Total stockholders' equity				9,956
Total liabilities and stockholders' equity				(140)
Fresh Start Adjustments
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 natural gas and oil 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				97
Liabilities subject to compromise				0
Total liabilities				149
Contingencies and commitments (Note 7)
Stockholders’ equity (deficit):
Predecessor preferred stock				0
Successor additional paid-in capital				0
Successor common stock, $0.01 par value, 450,000,000 shares authorized: 121,590,256 and 117,917,349 shares issued				0
Successor additional paid-in-capital				0
Accumulated other comprehensive income				(48)
Retained earnings				258
Total stockholders' equity				210
Total liabilities and stockholders' equity				$ 359