Consolidated Statements of Changes in Shareholders Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions	Total	Correcting Adjustment [Member]	Common Stock [Member]	Common Stock [Member] Correcting Adjustment [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	Commonwealth Edison Co [Member]	Commonwealth Edison Co [Member] Common Stock [Member]	Commonwealth Edison Co [Member] Retained Earnings [Member]	Commonwealth Edison Co [Member] Other Paid-in-Capital [Member]	PECO Energy Co [Member]	PECO Energy Co [Member] Common Stock [Member]	PECO Energy Co [Member] Retained Earnings [Member]	Baltimore Gas and Electric Company [Member]	Baltimore Gas and Electric Company [Member] Common Stock [Member]	Baltimore Gas and Electric Company [Member] Retained Earnings [Member]	Pepco Holdings LLC [Member]	Pepco Holdings LLC [Member] Retained Earnings [Member]	Pepco Holdings LLC [Member] Membership Interest [Member]	Potomac Electric Power Company [Member]	Potomac Electric Power Company [Member] Common Stock [Member]	Potomac Electric Power Company [Member] Retained Earnings [Member]	Delmarva Power and Light Company [Member]	Delmarva Power and Light Company [Member] Common Stock [Member]	Delmarva Power and Light Company [Member] Retained Earnings [Member]	Atlantic City Electric Company [Member]	Atlantic City Electric Company [Member] Common Stock [Member]	Atlantic City Electric Company [Member] Retained Earnings [Member]
Beginning balance (in shares) at Dec. 31, 2020	977,466
Beginning balance at Dec. 31, 2020	$ 34,868		$ 19,373		$ (123)	$ 16,735	$ (3,400)	$ 2,283
Beginning Balance at Dec. 31, 2020																			$ 10,044	$ (68)	$ 10,112
Beginning Balance at Dec. 31, 2020									$ 11,329	$ 1,588	$ 1,456	$ 8,285	$ 4,533	$ 3,014	$ 1,519	$ 4,197	$ 2,318	$ 1,879				$ 3,203	$ 2,058	$ 1,145	$ 1,676	$ 1,089	$ 587	$ 1,398	$ 1,271	$ 127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (264)					(289)		25	197		197		167		167	209		209	128	128		59		59	56		56	14		14
Long -Term Incentive Plan Activity (shares)	640
Long-Term Incentive Plan Activity		$ 5		$ 5
Employee stock purchase plan issuances (shares)	902
Employee stock purchase plan issuances	$ 34		34
Changes in equity of noncontrolling interests	$ (10)							(10)
Common Stock, Dividends, Per Share, Declared	$ 0.38
Common stock dividends	$ (374)					(374)			(127)		(127)		(85)		(85)	(74)		(74)				(28)		(28)	(40)		(40)	(14)		(14)
Distributions to member																			(81)	(81)
Contributions from parent									198			198							560		560	138	138		120	120		303	303
Other comprehensive income (loss), net of income taxes	$ 54						54
Ending balance (in shares) at Mar. 31, 2021	979,008
Ending balance at Mar. 31, 2021	$ 34,313		19,412		(123)	16,072	(3,346)	2,298
Ending Balance at Mar. 31, 2021																			10,651	(21)	10,672
Ending Balance at Mar. 31, 2021									11,597	1,588	1,526	8,483	4,615	3,014	1,601	4,332	2,318	2,014				3,372	2,196	1,176	1,812	1,209	603	1,701	1,574	127
Beginning balance (in shares) at Dec. 31, 2021	981,291
Beginning balance at Dec. 31, 2021	$ 34,795		20,324		(123)	16,942	(2,750)	402
Beginning Balance at Dec. 31, 2021																			10,585	(210)	10,795
Beginning Balance at Dec. 31, 2021	34,393								12,355	1,588	1,691	9,076	5,112	3,428	1,684	4,570	2,575	1,995				3,475	2,302	1,173	1,777	1,209	568	1,575	1,590	(15)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 598					597		1	188		188		206		206	198		198	130	130		46		46	56		56	26		26
Long -Term Incentive Plan Activity (shares)	540
Long-Term Incentive Plan Activity	$ (13)		(13)
Employee stock purchase plan issuances (shares)	211
Employee stock purchase plan issuances	$ 9		9
Changes in equity of noncontrolling interests	$ (7)							(7)
Common Stock, Dividends, Per Share, Declared	$ 0.34
Distribution of Constellation	$ (11,573)		(21)			(13,179)	2,023	(396)
Common stock dividends	(332)					(332)			(144)		(144)		(100)		(100)	(76)		(76)				(42)		(42)	(41)		(41)	(19)		(19)
Distributions to member																			(102)	(102)
Contributions from parent									167			167	227	227					704		704	387	387		144	144		173	173
Other comprehensive income (loss), net of income taxes	$ 14						14
Ending balance (in shares) at Mar. 31, 2022	982,042
Ending balance at Mar. 31, 2022	$ 23,491		$ 20,299		$ (123)	$ 4,028	$ (713)	$ 0
Ending Balance at Mar. 31, 2022																			$ 11,317	$ (182)	$ 11,499
Ending Balance at Mar. 31, 2022	$ 23,491								$ 12,566	$ 1,588	$ 1,735	$ 9,243	$ 5,445	$ 3,655	$ 1,790	$ 4,692	$ 2,575	$ 2,117				$ 3,866	$ 2,689	$ 1,177	$ 1,936	$ 1,353	$ 583	$ 1,755	$ 1,763	$ (8)