Supplemental Financial Information - Taxes Other Than Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Supplemental Statement of Operations Information [Line Items]
Utility taxes	$ 220	$ 221
Property	99	94
Payroll	32	37
Commonwealth Edison Co [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	74	78
Property	10	10
Payroll	7	7
PECO Energy Co [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	40	38
Property	4	4
Payroll	5	4
Baltimore Gas and Electric Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	29	27
Property	50	46
Payroll	5	4
Pepco Holdings LLC [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	77	78
Property	35	34
Payroll	7	7
Potomac Electric Power Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	68	70
Property	24	23
Payroll	2	2
Delmarva Power and Light Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	8	7
Property	11	10
Payroll	1	1
Atlantic City Electric Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility taxes	1	1
Property	0	1
Payroll	$ 1	$ 1