Segment Information - Reconciliation to Consolidated Financial Statements (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 4,845			$ 4,863			$ 14,412	$ 13,514
Income (Loss) before income taxes	768			492			1,978	1,383
Income taxes	92			35			356	76
Net income (loss)	676	$ 465	$ 598	1,229	$ 476	$ (264)	1,739	1,441
Capital expenditures							5,179	5,970
Assets	93,455						93,455		$ 133,013
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	676			457			1,622	1,307
Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenues	1,598			1,470			4,223	3,854
Revenue from Related Parties	3			3			9	10
Income (Loss) before income taxes	291			264			528	538
Income taxes	2			(2)			10	3
Net income (loss)	289	$ 100	$ 130	266	$ 141	$ 128	518	535
Capital expenditures							1,174	1,299
Assets	25,655						25,655		24,744
Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	4,845			4,863			14,412	13,514
Revenue from Related Parties	0			36			6	48
Depreciation and Amortization	825			758			2,472	2,253
Operating Expenses	3,834			4,107			11,804	11,357
Interest expense, net	365			324			1,063	967
Income (Loss) before income taxes	768			492			1,978	1,383
Income taxes	92			35			356	76
Capital expenditures	1,672			1,563			4,952	4,872
Assets	93,455						93,455		86,669
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	676			457			1,622	1,307
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	(396)			(518)			(1,376)	(1,554)
Revenue from Related Parties	(393)			(516)			(1,377)	(1,549)
Depreciation and Amortization	0			0			0	1
Operating Expenses	(380)			(353)			(1,288)	(1,067)
Interest expense, net	0			0			0	(1)
Income (Loss) before income taxes	0			(154)			(42)	(447)
Income taxes	0			(6)			(9)	(26)
Capital expenditures	0			0			0	0
Assets	(4,103)						(4,103)		(8,319)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(1)			(149)			(33)	(422)
Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenues	(94)			(93)			(290)	(283)
Revenue from Related Parties	(94)			(93)			(290)	(283)
Depreciation and Amortization	0			0			0	0
Operating Expenses	(95)			(93)			(290)	(283)
Interest expense, net	1			0			1	0
Income (Loss) before income taxes	0			0			0	0
Income taxes	0			0			0	0
Net income (loss)	0			0			0	0
Capital expenditures	0			0			0	0
Assets	(86)						(86)		(60)
Commonwealth Edison Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,378			1,789			4,536	4,840
Depreciation and Amortization	333			304			982	893
Operating Expenses	913			1,428			3,357	3,833
Interest expense, net	104			98			308	292
Income (Loss) before income taxes	375			276			909	750
Income taxes	84			56			203	141
Capital expenditures	593			561			1,801	1,723
Assets	38,582						38,582		36,470
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	291			220			706	609
Commonwealth Edison Co [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	6			9			14	19
PECO Energy Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,014			818			2,877	2,399
Depreciation and Amortization	92			86			277	259
Operating Expenses	798			677			2,230	1,908
Interest expense, net	45			40			129	119
Income (Loss) before income taxes	179			108			541	392
Income taxes	44			(3)			67	9
Capital expenditures	333			301			991	878
Assets	14,048						14,048		13,824
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	135			111			474	383
PECO Energy Co [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	3			2			5	6
Baltimore Gas and Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	870			770			2,810	2,426
Depreciation and Amortization	148			142			470	434
Operating Expenses	810			709			2,446	2,080
Interest expense, net	39			36			110	103
Income (Loss) before income taxes	26			32			270	266
Income taxes	(7)			(4)			3	(24)
Capital expenditures	340			287			918	907
Assets	12,932						12,932		12,324
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	33			36			267	290
Baltimore Gas and Electric Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	3			7			13	20
Pepco Holdings LLC [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	1,598			1,470			4,223	3,854
Depreciation and Amortization	238			210			697	614
Operating Expenses	1,254			1,155			3,535	3,167
Interest expense, net	72			67			216	201
Income (Loss) before income taxes	291			264			528	538
Income taxes	2			(2)			10	3
Net income (loss)	289			266			518	535
Capital expenditures	398			410			1,174	1,299
Assets	25,655						25,655		24,744
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	289			266			518	535
Pepco Holdings LLC [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	3			3			9	10
Potomac Electric Power Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	724			660			1,919	1,736
Depreciation and Amortization	99			104			312	302
Operating Expenses	555			501			1,588	1,396
Interest expense, net	37			35			111	104
Income (Loss) before income taxes	146			136			259	273
Income taxes	1			6			(2)	9
Net income (loss)	145			130			261	264
Capital expenditures	193			202			595	641
Assets	10,349						10,349		9,903
Potomac Electric Power Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	2			2			4	4
Delmarva Power and Light Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	412			360			1,176	1,040
Depreciation and Amortization	59			53			172	157
Operating Expenses	345			295			999	858
Interest expense, net	16			15			48	47
Income (Loss) before income taxes	54			53			138	144
Income taxes	2			3			8	9
Net income (loss)	52			50			130	135
Capital expenditures	100			109			294	320
Assets	5,710						5,710		5,412
Delmarva Power and Light Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	1			2			5	6
Atlantic City Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	462			451			1,120	1,080
Depreciation and Amortization	74			46			192	133
Operating Expenses	353			359			947	911
Interest expense, net	17			14			49	43
Income (Loss) before income taxes	95			79			133	129
Income taxes	1			(11)			2	(12)
Net income (loss)	94			90			131	141
Capital expenditures	105			97			284	336
Assets	4,966						4,966		4,556
Atlantic City Electric Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	0			1			2	2
Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenues	381			534			1,342	1,549
Depreciation and Amortization	14			16			46	52
Operating Expenses	439			491			1,524	1,436
Interest expense, net	105			83			300	253
Income (Loss) before income taxes	(103)			(34)			(228)	(116)
Income taxes	(31)			(6)			82	(27)
Capital expenditures	8			4			68	65
Assets	6,341						6,341		7,626
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(71)			(27)			(310)	(88)
Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenues	94			92			298	281
Depreciation and Amortization	6			7			21	22
Operating Expenses	96			93			291	285
Interest expense, net	1			3			7	7
Income (Loss) before income taxes	(4)			(4)			(2)	(8)
Income taxes	(2)			0			2	(3)
Net income (loss)	(2)			(4)			(4)	(5)
Capital expenditures	0			2			1	2
Assets	4,716						4,716		$ 4,933
Corporate and Other [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	378			531			1,342	1,542
Corporate and Other [Member] | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Related Parties	94			91			288	281
Rate-regulated electric revenues [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	4,557			4,736			12,972	12,344
Rate-regulated electric revenues [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,568			1,438			4,090	3,632
Rate-regulated electric revenues [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	4,621			4,692			13,082	12,470
Rate-regulated electric revenues [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	(12)			20			(24)	5
Rate-regulated electric revenues [Member] | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	(3)			(4)			0	(12)
Rate-regulated electric revenues [Member] | Commonwealth Edison Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,378			1,789			4,536	4,840
Rate-regulated electric revenues [Member] | PECO Energy Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	941			762			2,390	2,033
Rate-regulated electric revenues [Member] | Baltimore Gas and Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	757			677			2,122	1,866
Rate-regulated electric revenues [Member] | Pepco Holdings LLC [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,557			1,444			4,058	3,726
Rate-regulated electric revenues [Member] | Potomac Electric Power Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	724			660			1,919	1,736
Rate-regulated electric revenues [Member] | Delmarva Power and Light Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	374			337			1,019	922
Rate-regulated electric revenues [Member] | Atlantic City Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	462			451			1,120	1,080
Rate-regulated electric revenues [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated electric revenues [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated natural gas revenues [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	224			174			1,348	1,041
Rate-regulated natural gas revenues [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	38			23			157	118
Rate-regulated natural gas revenues [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	224			171			1,330	1,044
Rate-regulated natural gas revenues [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			(1)			(2)	0
Rate-regulated natural gas revenues [Member] | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated natural gas revenues [Member] | Commonwealth Edison Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated natural gas revenues [Member] | PECO Energy Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	73			56			487	366
Rate-regulated natural gas revenues [Member] | Baltimore Gas and Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	113			93			688	560
Rate-regulated natural gas revenues [Member] | Pepco Holdings LLC [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	38			23			157	118
Rate-regulated natural gas revenues [Member] | Potomac Electric Power Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated natural gas revenues [Member] | Delmarva Power and Light Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	38			23			157	118
Rate-regulated natural gas revenues [Member] | Atlantic City Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated natural gas revenues [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Rate-regulated natural gas revenues [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	(384)			(537)			(1,350)	(1,559)
Shared service and other revenues [Member] | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	(91)			(89)			(290)	(271)
Shared service and other revenues [Member] | Commonwealth Edison Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | PECO Energy Co [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Baltimore Gas and Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Pepco Holdings LLC [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	3			3			8	10
Shared service and other revenues [Member] | Potomac Electric Power Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Delmarva Power and Light Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Atlantic City Electric Company [Member] | Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0			0			0	0
Shared service and other revenues [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	381			534			1,342	1,549
Shared service and other revenues [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 94			$ 92			$ 298	$ 281