Revenue Recognition (Disaggregation of Revenue by Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 6,522	$ 15,002	$ 6,667
Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	4,167	10,583	4,701
Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	2,355	4,419	1,966
Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenues	6,522
Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	4,109	10,577	4,640
Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	6,277	14,521	6,189
Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	3,864	10,096	4,162
Intersegment Revenues | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	(58)	(6)	(61)
Intersegment Revenues | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	3,922	10,102	4,223
Gas sales
Disaggregation of Revenue [Line Items]
Total operating revenues	3,089	9,101	3,412
Gas sales | Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	3,036	9,100	3,358
Gas sales | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0
Gas sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	(53)	(1)	(54)
Oil sales
Disaggregation of Revenue [Line Items]
Total operating revenues	379	439	394
Oil sales | Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	374	434	389
Oil sales | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0
Oil sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	(5)	(5)	(5)
NGL sales
Disaggregation of Revenue [Line Items]
Total operating revenues	702	1,046	890
NGL sales | Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	702	1,046	888
NGL sales | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0
NGL sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	(2)
Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	2,355	4,419	1,963
Marketing | Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0
Marketing | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	6,277	14,521	6,186
Marketing | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	3,922	10,102	4,223
Marketing | Intersegment Revenues | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	(3,900)	(10,100)	(4,200)
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	(3)	(3)	8
Other | Operating Segments | Exploration and Production
Disaggregation of Revenue [Line Items]
Total operating revenues	(3)	(3)	5
Other | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	3
Other | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 0	$ 0	$ 0