Business Segments - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest	$ 220,600	$ 574,100	$ 409,500	$ (65,500)	$ 204,000	$ 137,300	$ (27,000)	$ (266,800)	$ 1,138,719	$ 47,528	$ (1,262,445)
Revenues from external customers									3,932,662	2,299,281	1,967,341
Other income (expense)									14,310	(16,771)	(17,303)
Interest expense, net of capitalization									(150,759)	(221,773)	(169,423)
Income tax expense (benefit)									309,464	(5,862)	(293,741)
Impairment of assets									0	196,296	1,206,284
Depreciation, depletion and amortization									776,817	795,105	987,239
Accretion of asset retirement obligations									46,243	46,613	42,136
Amortization of undeveloped leases									13,300	18,925	26,743
Deferred income tax expense (benefit)									286,079	(4,146)	(278,042)
Additions to property, plant, equipment									1,063,300	585,300	756,600
Total assets at year-end	10,308,952				10,304,940				10,308,952	10,304,940	10,620,900
Discontinued Operations
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest									(2,100)	(1,200)	(7,200)
Revenues from external customers									0	0	0
Other income (expense)									0	0	0
Interest expense, net of capitalization									0	0	0
Income tax expense (benefit)									0	0	0
Impairment of assets										0	0
Depreciation, depletion and amortization									0	0	0
Accretion of asset retirement obligations									0	0	0
Amortization of undeveloped leases									0	0	0
Deferred income tax expense (benefit)									0	0	0
Additions to property, plant, equipment									0	0	0
Total assets at year-end	800				800				800	800	700
Corporate and Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest									(438,300)	(668,000)	(120,300)
Revenues from external customers									(314,400)	(519,400)	207,900
Other income (expense)									23,300	(6,500)	(9,100)
Interest expense, net of capitalization									(150,400)	(221,600)	(168,500)
Income tax expense (benefit)									(107,800)	(178,600)	(30,200)
Impairment of assets										7,000	14,100
Depreciation, depletion and amortization									12,900	13,000	22,300
Accretion of asset retirement obligations									0	0	0
Amortization of undeveloped leases									0	0	0
Deferred income tax expense (benefit)									(112,000)	(170,500)	(25,100)
Additions to property, plant, equipment									21,900	0	0
Total assets at year-end	1,034,600				1,220,800				1,034,600	1,220,800	1,032,900
Exploration and Production | Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest									1,579,100	716,700	(1,134,900)
Revenues from external customers									4,247,100	2,818,700	1,759,400
Other income (expense)									(9,000)	(10,300)	(8,200)
Interest expense, net of capitalization									(400)	(200)	(900)
Income tax expense (benefit)									417,300	172,700	(263,500)
Impairment of assets										189,300	1,192,200
Depreciation, depletion and amortization									763,900	782,100	964,900
Accretion of asset retirement obligations									46,200	46,600	42,100
Amortization of undeveloped leases									13,300	18,900	26,700
Deferred income tax expense (benefit)									398,100	166,400	(252,900)
Additions to property, plant, equipment									1,041,400	585,300	756,600
Total assets at year-end	9,273,600				9,083,300				9,273,600	9,083,300	9,587,300
Exploration and Production | Operating Segments | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest									1,521,900	766,300	(1,014,300)
Revenues from external customers									3,461,200	2,337,500	1,411,800
Other income (expense)									(6,600)	(11,600)	(9,900)
Interest expense, net of capitalization									(100)	0	0
Income tax expense (benefit)									370,800	183,900	(244,200)
Impairment of assets										0	1,152,500
Depreciation, depletion and amortization									617,000	616,500	749,400
Accretion of asset retirement obligations									36,500	36,900	36,600
Amortization of undeveloped leases									8,700	11,100	17,200
Deferred income tax expense (benefit)									362,700	176,300	(244,200)
Additions to property, plant, equipment									838,600	519,500	623,100
Total assets at year-end	6,930,600				6,591,600				6,930,600	6,591,600	6,915,500
Exploration and Production | Operating Segments | Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest									134,200	(16,100)	(35,000)
Revenues from external customers									762,900	476,300	345,800
Other income (expense)									(1,900)	(1,900)	800
Interest expense, net of capitalization									0	0	(500)
Income tax expense (benefit)									43,600	(1,700)	(21,400)
Impairment of assets										171,300	0
Depreciation, depletion and amortization									141,500	163,800	213,200
Accretion of asset retirement obligations									9,600	9,700	5,500
Amortization of undeveloped leases									200	200	400
Deferred income tax expense (benefit)									34,800	(1,900)	(10,600)
Additions to property, plant, equipment									208,500	52,700	118,300
Total assets at year-end	2,125,600				2,231,900				2,125,600	2,231,900	2,404,100
Exploration and Production | Operating Segments | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net income (loss) including noncontrolling interest									(77,000)	(33,500)	(85,600)
Revenues from external customers									23,000	4,900	1,800
Other income (expense)									(500)	3,200	800
Interest expense, net of capitalization									(300)	(200)	(400)
Income tax expense (benefit)									2,900	(9,500)	2,100
Impairment of assets										18,000	39,700
Depreciation, depletion and amortization									5,400	1,800	2,300
Accretion of asset retirement obligations									100	0	0
Amortization of undeveloped leases									4,400	7,600	9,100
Deferred income tax expense (benefit)									600	(8,000)	1,900
Additions to property, plant, equipment									(5,700)	13,100	15,200
Total assets at year-end	$ 217,400				$ 259,800				$ 217,400	$ 259,800	$ 267,700