Accounts Receivable - Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	$ 97	$ 63
Commonwealth Edison Co
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	11	2
PECO Energy Co
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	43	27
Baltimore Gas and Electric Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	14	12
Pepco Holdings LLC
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	29	22
Potomac Electric Power Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	10	16
Delmarva Power and Light Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	9	3
Atlantic City Electric Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current period provision for expected credit losses	10	3
Customer accounts receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	406	317
Current period provision for expected credit losses	133	79
Writeoffs, net of recoveries	53	50
Ending balance	486	346
Customer accounts receivable | Commonwealth Edison Co
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	109	69
Current period provision for expected credit losses	33	22
Writeoffs, net of recoveries	17	9
Ending balance	125	82
Customer accounts receivable | PECO Energy Co
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	133	95
Current period provision for expected credit losses	41	23
Writeoffs, net of recoveries	14	11
Ending balance	160	107
Customer accounts receivable | Baltimore Gas and Electric Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	56	46
Current period provision for expected credit losses	23	15
Writeoffs, net of recoveries	7	9
Ending balance	72	52
Customer accounts receivable | Pepco Holdings LLC
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	108	107
Current period provision for expected credit losses	36	19
Writeoffs, net of recoveries	15	21
Ending balance	129	105
Customer accounts receivable | Potomac Electric Power Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	59	52
Current period provision for expected credit losses	17	12
Writeoffs, net of recoveries	7	12
Ending balance	69	52
Customer accounts receivable | Delmarva Power and Light Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	17	19
Current period provision for expected credit losses	10	3
Writeoffs, net of recoveries	4	5
Ending balance	23	17
Customer accounts receivable | Atlantic City Electric Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	32	36
Current period provision for expected credit losses	9	4
Writeoffs, net of recoveries	4	4
Ending balance	37	36
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	107	82
Current period provision for expected credit losses	15	18
Writeoffs, net of recoveries	9	4
Ending balance	113	96
Other receivables | Commonwealth Edison Co
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	34	17
Current period provision for expected credit losses	2	3
Writeoffs, net of recoveries	2	1
Ending balance	34	19
Other receivables | PECO Energy Co
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	18	8
Current period provision for expected credit losses	9	5
Writeoffs, net of recoveries	5	0
Ending balance	22	13
Other receivables | Baltimore Gas and Electric Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6	7
Current period provision for expected credit losses	1	2
Writeoffs, net of recoveries	1	2
Ending balance	6	7
Other receivables | Pepco Holdings LLC
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	49	50
Current period provision for expected credit losses	3	8
Writeoffs, net of recoveries	1	1
Ending balance	51	57
Other receivables | Potomac Electric Power Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27	28
Current period provision for expected credit losses	0	7
Writeoffs, net of recoveries	0	0
Ending balance	27	35
Other receivables | Delmarva Power and Light Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	9	8
Current period provision for expected credit losses	0	0
Writeoffs, net of recoveries	0	0
Ending balance	9	8
Other receivables | Atlantic City Electric Company
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	13	14
Current period provision for expected credit losses	3	1
Writeoffs, net of recoveries	1	1
Ending balance	$ 15	$ 14