Supplemental Financial Information - Taxes Other Than Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Supplemental Statement of Operations Information [Line Items]
Utility taxes	$ 244	$ 244	$ 665	$ 667
Property	104	99	300	287
Payroll	31	28	93	92
Commonwealth Edison Co
Supplemental Statement of Operations Information [Line Items]
Utility taxes	82	84	228	233
Property	9	10	27	30
Payroll	8	7	22	21
PECO Energy Co
Supplemental Statement of Operations Information [Line Items]
Utility taxes	50	51	128	126
Property	4	4	12	12
Payroll	4	5	13	14
Baltimore Gas and Electric Company
Supplemental Statement of Operations Information [Line Items]
Utility taxes	23	22	73	70
Property	53	50	153	142
Payroll	5	4	14	13
Pepco Holdings LLC
Supplemental Statement of Operations Information [Line Items]
Utility taxes	89	87	236	238
Property	38	35	108	103
Payroll	7	7	22	21
Potomac Electric Power Company
Supplemental Statement of Operations Information [Line Items]
Utility taxes	82	79	213	216
Property	25	23	73	70
Payroll	2	2	5	5
Delmarva Power and Light Company
Supplemental Statement of Operations Information [Line Items]
Utility taxes	6	7	20	19
Property	12	11	34	31
Payroll	1	1	3	4
Atlantic City Electric Company
Supplemental Statement of Operations Information [Line Items]
Utility taxes	1	1	3	3
Property	1	1	1	2
Payroll	$ 1	$ 0	$ 3	$ 2