Accounts Receivable - Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	$ (70)	$ (78)
Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	0	(17)
PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	(37)	(27)
Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	(18)	(18)
Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	(15)	(18)
Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	(7)	(9)
Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	(5)	(6)
Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current period provision for expected credit losses	(3)	(3)
Customer accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	327	320
Current period provision for expected credit losses	108	110
Writeoffs, net of recoveries	46	41
Ending balance	389	389
Customer accounts receivable | Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	59	73
Current period provision for expected credit losses	22	26
Writeoffs, net of recoveries	7	7
Ending balance	74	92
Customer accounts receivable | PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	105	105
Current period provision for expected credit losses	39	31
Writeoffs, net of recoveries	14	11
Ending balance	130	125
Customer accounts receivable | Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	54	38
Current period provision for expected credit losses	30	26
Writeoffs, net of recoveries	11	5
Ending balance	73	59
Customer accounts receivable | Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	109	104
Current period provision for expected credit losses	17	27
Writeoffs, net of recoveries	14	18
Ending balance	112	113
Customer accounts receivable | Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	47	37
Current period provision for expected credit losses	9	11
Writeoffs, net of recoveries	7	8
Ending balance	49	40
Customer accounts receivable | Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	21	18
Current period provision for expected credit losses	7	7
Writeoffs, net of recoveries	2	1
Ending balance	26	24
Customer accounts receivable | Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	41	49
Current period provision for expected credit losses	1	9
Writeoffs, net of recoveries	5	9
Ending balance	37	49
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	82	72
Current period provision for expected credit losses	14	14
Writeoffs, net of recoveries	5	5
Ending balance	91	81
Other receivables | Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	17	17
Current period provision for expected credit losses	2	4
Writeoffs, net of recoveries	1	1
Ending balance	18	20
Other receivables | PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	9	7
Current period provision for expected credit losses	3	3
Writeoffs, net of recoveries	1	1
Ending balance	11	9
Other receivables | Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	10	9
Current period provision for expected credit losses	4	3
Writeoffs, net of recoveries	2	1
Ending balance	12	11
Other receivables | Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	46	39
Current period provision for expected credit losses	5	4
Writeoffs, net of recoveries	1	2
Ending balance	50	41
Other receivables | Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	25	16
Current period provision for expected credit losses	3	2
Writeoffs, net of recoveries	0	0
Ending balance	28	18
Other receivables | Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	7	8
Current period provision for expected credit losses	1	1
Writeoffs, net of recoveries	0	0
Ending balance	8	9
Other receivables | Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	14	15
Current period provision for expected credit losses	1	1
Writeoffs, net of recoveries	1	2
Ending balance	$ 14	$ 14