Segment Information (Details) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment					2
Number of operating segments | segment					2
Revenues from contracts with customers	$ 2,168		$ 1,254		$ 3,929	$ 2,431
Net gain (loss) on commodity derivatives	(27)		(166)		(170)	(319)
Income from equity method investments	152		49		279	93
Net loss on disposal of assets	(1)		1		(1)	1
Other income	11		5		19	8
Less costs and expenses:
Production	164		126		316	247
Shipping, handling and other operating	191		167		376	319
Exploration	8		25		19	46
Depreciation, depletion and amortization	436		532		859	1,028
Impairments	2		46		2	47
Taxes other than income	140		74		244	148
General and administrative	68		68		141	157
Net interest and other	54		59		76	72
Other net periodic benefit costs	(5)		1		(9)	(2)
Loss on early extinguishment of debt	0		19		0	19
Income tax provision (benefit)	279		10		(238)	20
Segment income (loss)	966	$ 1,304	16	$ 97	2,270	113
Total assets	18,286		17,800		18,286	17,800	$ 16,994
Capital expenditures	375		289		723	473
Long-lived assets held for use impairment	0		24		0	25
Impairments	2				2	22
Loss on lease termination						13
Severance costs						12
Valuation allowance released					685
Eagle Ford | Central Facilities
Less costs and expenses:
Long-lived assets held for use impairment			24			24
Gulf of Mexico
Less costs and expenses:
Impairments			22
Gulf of Mexico | Non Producing Property
Less costs and expenses:
Impairments			22			22
Interest Rate Contract, Maturing June 1, 2025 | Not Designated as Hedges
Less costs and expenses:
Gain on interest rate swap			31			31
Interest Rate Contract, Maturing June 1, 2025 | Cash Flow Hedges
Less costs and expenses:
Gain on interest rate swap	17				17
Interest Rate Contract, Maturing November 1, 2022 | Not Designated as Hedges
Less costs and expenses:
Loss on interest rate swap			22
Gain on interest rate swap						19
Not Allocated to Segments
Segment Reporting Information [Line Items]
Revenues from contracts with customers	0		0		0	0
Net gain (loss) on commodity derivatives	43		(75)		(71)	(157)
Income from equity method investments	0		0		0	0
Net loss on disposal of assets	(1)		1		(1)	1
Other income	7		0		9	1
Less costs and expenses:
Production	0		0		0	0
Shipping, handling and other operating	3		12		29	16
Exploration	0		7		0	7
Depreciation, depletion and amortization	5		8		9	13
Impairments	2		46		2	47
Taxes other than income	1		(2)		6	(2)
General and administrative	38		37		78	101
Net interest and other	54		59		76	72
Other net periodic benefit costs	(5)		1		(9)	(2)
Loss on early extinguishment of debt			19			19
Income tax provision (benefit)	(9)		(2)		(742)	(2)
Segment income (loss)	(40)		(259)		488	(424)
Total assets	1,470		1,006		1,470	1,006
Capital expenditures	2		3		5	4
United States E&P
Segment Reporting Information [Line Items]
Revenues from contracts with customers	2,089		1,189		3,803	2,321
United States E&P | Eagle Ford
Segment Reporting Information [Line Items]
Revenues from contracts with customers	656		417		1,194	751
United States E&P | Operating Segments
Segment Reporting Information [Line Items]
Revenues from contracts with customers	2,089		1,189		3,803	2,321
Net gain (loss) on commodity derivatives	(70)		(91)		(99)	(162)
Income from equity method investments	0		0		0	0
Net loss on disposal of assets	0		0		0	0
Other income	2		3		6	4
Less costs and expenses:
Production	150		113		291	224
Shipping, handling and other operating	187		153		337	297
Exploration	8		18		19	39
Depreciation, depletion and amortization	415		506		819	978
Impairments	0		0		0	0
Taxes other than income	139		76		238	150
General and administrative	27		27		57	50
Net interest and other	0		0		0	0
Other net periodic benefit costs	0		0		0	0
Loss on early extinguishment of debt			0			0
Income tax provision (benefit)	249		1		442	6
Segment income (loss)	846		207		1,507	419
Total assets	15,757		15,747		15,757	15,747
Capital expenditures	372		284		718	467
Int'l E&P | Operating Segments
Segment Reporting Information [Line Items]
Revenues from contracts with customers	79		65		126	110
Net gain (loss) on commodity derivatives	0		0		0	0
Income from equity method investments	152		49		279	93
Net loss on disposal of assets	0		0		0	0
Other income	2		2		4	3
Less costs and expenses:
Production	14		13		25	23
Shipping, handling and other operating	1		2		10	6
Exploration	0		0		0	0
Depreciation, depletion and amortization	16		18		31	37
Impairments	0		0		0	0
Taxes other than income	0		0		0	0
General and administrative	3		4		6	6
Net interest and other	0		0		0	0
Other net periodic benefit costs	0		0		0	0
Loss on early extinguishment of debt			0			0
Income tax provision (benefit)	39		11		62	16
Segment income (loss)	160		68		275	118
Total assets	1,059		1,047		1,059	1,047
Capital expenditures	$ 1		$ 2		$ 0	$ 2