Accounts Receivable - Allowance for Credit Losses Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	$ 125	$ 173	$ 160
Commonwealth Edison Co
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	4	46	47
PECO Energy Co
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	45	45	39
Baltimore Gas and Electric Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	16	25	17
Pepco Holdings LLC
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	60	58	24
Potomac Electric Power Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	33	29	9
Delmarva Power & Light Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	10	12	5
Atlantic City Electric Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Current Period Provision for Expected Credit Losses	17	16	10
Customer accounts receivable
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	327	320
Current Period Provision for Expected Credit Losses	170	176
Writeoffs, net of recoveries	180	169
Ending balance	317	327	320
Customer accounts receivable | Commonwealth Edison Co
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	59	73
Current Period Provision for Expected Credit Losses	53	29
Writeoffs, net of recoveries	43	43
Ending balance	69	59	73
Customer accounts receivable | PECO Energy Co
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	105	105
Current Period Provision for Expected Credit Losses	48	52
Writeoffs, net of recoveries	58	52
Ending balance	95	105	105
Customer accounts receivable | Baltimore Gas and Electric Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	54	38
Current Period Provision for Expected Credit Losses	26	37
Writeoffs, net of recoveries	34	21
Ending balance	46	54	38
Customer accounts receivable | Pepco Holdings LLC
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	109	104
Current Period Provision for Expected Credit Losses	43	58
Writeoffs, net of recoveries	45	53
Ending balance	107	109	104
Customer accounts receivable | Potomac Electric Power Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	47	37
Current Period Provision for Expected Credit Losses	23	31
Writeoffs, net of recoveries	18	21
Ending balance	52	47	37
Customer accounts receivable | Delmarva Power & Light Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	21	18
Current Period Provision for Expected Credit Losses	9	12
Writeoffs, net of recoveries	11	9
Ending balance	19	21	18
Customer accounts receivable | Atlantic City Electric Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	41	49
Current Period Provision for Expected Credit Losses	11	15
Writeoffs, net of recoveries	16	23
Ending balance	36	41	49
Other Receivables
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	82	72
Current Period Provision for Expected Credit Losses	21	26
Writeoffs, net of recoveries	21	16
Ending balance	82	82	72
Other Receivables | Commonwealth Edison Co
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	17	17
Current Period Provision for Expected Credit Losses	5	3
Writeoffs, net of recoveries	5	3
Ending balance	17	17	17
Other Receivables | PECO Energy Co
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	9	7
Current Period Provision for Expected Credit Losses	4	6
Writeoffs, net of recoveries	5	4
Ending balance	8	9	7
Other Receivables | Baltimore Gas and Electric Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	10	9
Current Period Provision for Expected Credit Losses	5	6
Writeoffs, net of recoveries	8	5
Ending balance	7	10	9
Other Receivables | Pepco Holdings LLC
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	46	39
Current Period Provision for Expected Credit Losses	7	11
Writeoffs, net of recoveries	3	4
Ending balance	50	46	39
Other Receivables | Potomac Electric Power Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	25	16
Current Period Provision for Expected Credit Losses	3	9
Writeoffs, net of recoveries	0	0
Ending balance	28	25	16
Other Receivables | Delmarva Power & Light Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	7	8
Current Period Provision for Expected Credit Losses	1	(1)
Writeoffs, net of recoveries	0	0
Ending balance	8	7	8
Other Receivables | Atlantic City Electric Company
Accounts Receivable, Allowance for Credit Loss [Line Items]
Beginning balance	14	15
Current Period Provision for Expected Credit Losses	3	3
Writeoffs, net of recoveries	3	4
Ending balance	$ 14	$ 14	$ 15