Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total operating revenues	$ 1,269	$ 4,138	$ 3,387	$ 7,081
Depreciation, depletion and amortization expense	328	288	641	563
Operating income (loss)	(57)	2,131	549	3,430
Interest expense	34	48	70	89
Gain on derivatives	317	(879)	1,718	(4,806)
Loss on early extinguishment of debt	0	(4)	(19)	(6)
Other loss, net	0	(1)	(1)	(1)
Provision from income taxes	(5)	26	7	30
Assets	13,001	12,932	13,001	12,932	$ 12,926
Capital investments	595	585	1,260	1,129
Increase (decrease) in accrued expenditures	(22)	34	(28)	77
Merger-related expenses	0	2	0	27
Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	739	2,814	2,091	4,700
E&P
Segment Reporting Information [Line Items]
Total operating revenues	794	2,931	2,233	5,008
Depreciation, depletion and amortization expense	326	286	638	560
Operating income (loss)	(70)	2,120	508	3,398
Interest expense	34	48	70	89
Gain on derivatives	317	(879)	1,718	(4,804)
Loss on early extinguishment of debt		0	0	0
Other loss, net		0	(1)	0
Provision from income taxes	(5)	26	7	30
Assets	12,413	11,115	12,413	11,115
Capital investments	593	585	1,257	1,129
Merger-related expenses		2		27
E&P | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	(17)	(2)	(27)	(5)
Marketing
Segment Reporting Information [Line Items]
Total operating revenues	475	1,207	1,154	2,073
Depreciation, depletion and amortization expense	2	2	3	3
Operating income (loss)	13	11	41	32
Interest expense	0	0	0	0
Gain on derivatives	0	0	0	0
Loss on early extinguishment of debt		0	0	0
Other loss, net		(1)	0	(1)
Provision from income taxes	0	0	0	0
Assets	438	1,664	438	1,664
Capital investments	0	0	0	0
Marketing | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	756	2,816	2,118	4,705
Other
Segment Reporting Information [Line Items]
Total operating revenues	0	0	0	0
Depreciation, depletion and amortization expense	0	0	0	0
Operating income (loss)	0	0	0	0
Interest expense	0	0	0	0
Gain on derivatives	0	0	0	(2)
Loss on early extinguishment of debt		(4)	(19)	(6)
Other loss, net		0	0	0
Provision from income taxes	0	0	0	0
Assets	150	153	150	153
Capital investments	2	0	3	0
Other | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	$ 0	$ 0	$ 0	$ 0