Revenue Recognition (Disaggregation of Revenue by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 4,138	$ 1,050	$ 7,081	$ 2,122
E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	2,931	718	5,008	1,437
Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	1,207	332	2,073	685
Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	2,929	704	5,003	1,409
Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	4,023	983	6,778	1,980
Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	2,814	637	4,700	1,267
Intersegment Revenues | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	(2)	(14)	(5)	(28)
Intersegment Revenues | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	2,816	651	4,705	1,295
Gas sales
Disaggregation of Revenue [Line Items]
Total operating revenues	2,485	433	4,177	897
Gas sales | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	2,485	421	4,175	872
Gas sales | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Gas sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	0	12	2	25
Oil sales
Disaggregation of Revenue [Line Items]
Total operating revenues	138	106	249	187
Oil sales | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	136	105	246	185
Oil sales | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Oil sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	2	1	3	2
NGL sales
Disaggregation of Revenue [Line Items]
Total operating revenues	310	179	582	352
NGL sales | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	310	178	582	351
NGL sales | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
NGL sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	0	1	0	1
Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	1,207	332	2,073	684
Marketing | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Marketing | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	4,023	983	6,778	1,979
Marketing | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	2,816	651	4,705	1,295
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	(2)	$ 0	$ 0	2
Other | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	(2)			1
Other | Operating Segments | Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	0			1
Other | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 0			$ 0