Supplemental Financial Information - Taxes Other Than Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Supplemental Statement of Operations Information [Line Items]
Utility taxes	$ 201	$ 203	$ 421	$ 424
Property	96	94	196	188
Payroll	31	28	63	64
Commonwealth Edison Co [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	71	71	146	149
Property	8	10	18	20
Payroll	7	7	14	13
PECO Energy Co [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	38	39	78	77
Property	4	4	8	9
Payroll	4	5	9	8
Baltimore Gas and Electric Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	22	20	50	47
Property	49	46	100	92
Payroll	5	4	9	9
Pepco Holdings LLC [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	70	73	147	151
Property	35	33	70	67
Payroll	7	7	14	14
Potomac Electric Power Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	63	67	131	137
Property	24	23	48	46
Payroll	2	1	4	3
Delmarva Power and Light Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	6	5	14	12
Property	10	10	21	20
Payroll	1	1	2	2
Atlantic City Electric Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	1	1	2	2
Property	1	0	1	1
Payroll	$ 1	$ 1	$ 2	$ 2