Accounts Receivable - Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			$ (130)	$ (155)
Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(40)	(34)
PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(32)	(36)
Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(18)	(7)
Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(42)	(18)
Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(21)	(9)
Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(9)	(3)
Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses			(12)	(6)
Customer accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 354	$ 320	320	334
Current period provision for expected credit losses	38	37	141	65
Writeoffs, net of recoveries	51	32	120	74
Ending balance	341	325	341	325
Customer accounts receivable | Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	81	89	73	97
Current period provision for expected credit losses	10	11	31	23
Writeoffs, net of recoveries	17	12	30	32
Ending balance	74	88	74	88
Customer accounts receivable | PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	107	111	105	116
Current period provision for expected credit losses	12	1	33	7
Writeoffs, net of recoveries	16	11	35	22
Ending balance	103	101	103	101
Customer accounts receivable | Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	57	27	38	35
Current period provision for expected credit losses	2	7	30	2
Writeoffs, net of recoveries	5	3	14	6
Ending balance	54	31	54	31
Customer accounts receivable | Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	109	93	104	86
Current period provision for expected credit losses	14	18	47	33
Writeoffs, net of recoveries	12	6	40	14
Ending balance	111	105	111	105
Customer accounts receivable | Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	42	38	37	32
Current period provision for expected credit losses	6	5	23	15
Writeoffs, net of recoveries	4	2	16	6
Ending balance	44	41	44	41
Customer accounts receivable | Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	22	19	18	22
Current period provision for expected credit losses	1	3	8	4
Writeoffs, net of recoveries	3	4	6	8
Ending balance	20	18	20	18
Customer accounts receivable | Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	45	36	49	32
Current period provision for expected credit losses	7	10	16	14
Writeoffs, net of recoveries	5	0	18	0
Ending balance	47	46	47	46
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	81	71	72	71
Current period provision for expected credit losses	8	6	24	11
Writeoffs, net of recoveries	5	4	12	9
Ending balance	84	73	84	73
Other receivables | Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	18	18	17	21
Current period provision for expected credit losses	2	2	5	0
Writeoffs, net of recoveries	2	1	4	2
Ending balance	18	19	18	19
Other receivables | PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	10	7	7	8
Current period provision for expected credit losses	2	1	6	2
Writeoffs, net of recoveries	1	1	2	3
Ending balance	11	7	11	7
Other receivables | Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	11	8	9	9
Current period provision for expected credit losses	2	1	6	2
Writeoffs, net of recoveries	1	1	3	3
Ending balance	12	8	12	8
Other receivables | Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	42	38	39	33
Current period provision for expected credit losses	2	2	7	7
Writeoffs, net of recoveries	1	0	3	0
Ending balance	43	40	43	40
Other receivables | Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	20	16	16	13
Current period provision for expected credit losses	2	1	6	4
Writeoffs, net of recoveries	0	0	0	0
Ending balance	22	17	22	17
Other receivables | Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	8	9	8	9
Current period provision for expected credit losses	(1)	(1)	(1)	(1)
Writeoffs, net of recoveries	0	0	0	0
Ending balance	7	8	7	8
Other receivables | Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	14	13	15	11
Current period provision for expected credit losses	1	2	2	4
Writeoffs, net of recoveries	1	0	3	0
Ending balance	$ 14	$ 15	$ 14	$ 15