Supplemental Oil and Gas Disclosures (Unaudited) (Summary of Changes in Reserves) (Details) - Mcfe Mcfe in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Proved Developed and Undeveloped Reserve (Energy) [Roll Forward]
Proved reserves, beginning of period, (bcfe)	11,990	12,721	11,921
Net revisions
Price revisions	415	(4,370)	(717)
Performance and production revisions	269	1,424	1,102
Total net revisions	684	(2,946)	385
Extensions, discoveries and other additions
Proved developed	451	267	191
Proved undeveloped	3,511	474	1,004
Total reserve additions	3,962	741	1,195
Production	(1,240)	(880)	(778)
Acquisition of reserves in place	5,753	2,354	0
Disposition of reserves in place	(1)	0	(2)
Proved reserves, end of period, (bcfe)	21,148	11,990	12,721
Proved and unproved reserves reclassified			109
Proved Undeveloped Reserves, Additions (Energy) Drilling Program	1,768
Proved Undeveloped Reserves, Additions (Energy) SEC Pricing	1,743
Appalachia
Proved Developed and Undeveloped Reserve (Energy) [Roll Forward]
Proved reserves, beginning of period, (bcfe)	11,989	12,720	11,920
Net revisions
Price revisions	415	(4,370)	(717)
Performance and production revisions	270	1,424	1,102
Total net revisions	685	(2,946)	385
Extensions, discoveries and other additions
Proved developed	451	267	191
Proved undeveloped	3,511	474	1,004
Total reserve additions	3,962	741	1,195
Production	(1,108)	(880)	(778)
Acquisition of reserves in place	0	2,354	0
Disposition of reserves in place	(1)	0	(2)
Proved reserves, end of period, (bcfe)	15,527	11,989	12,720
Haynesville
Proved Developed and Undeveloped Reserve (Energy) [Roll Forward]
Proved reserves, beginning of period, (bcfe)	0	0	0
Net revisions
Price revisions	0	0	0
Performance and production revisions	0	0	0
Total net revisions	0	0	0
Extensions, discoveries and other additions
Proved developed	0	0	0
Proved undeveloped	0	0	0
Total reserve additions	0	0	0
Production	(132)	0	0
Acquisition of reserves in place	5,753	0	0
Disposition of reserves in place	0	0	0
Proved reserves, end of period, (bcfe)	5,621	0	0
Other
Proved Developed and Undeveloped Reserve (Energy) [Roll Forward]
Proved reserves, beginning of period, (bcfe)	1	1	1
Net revisions
Price revisions	0	0	0
Performance and production revisions	(1)	0	0
Total net revisions	(1)	0	0
Extensions, discoveries and other additions
Proved developed	0	0	0
Proved undeveloped	0	0	0
Total reserve additions	0	0	0
Production	0	0	0
Acquisition of reserves in place	0	0	0
Disposition of reserves in place	0	0	0
Proved reserves, end of period, (bcfe)	0	1	1