Supplemental Financial Information - Summary of Taxes other than income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Supplemental Statement of Operations Information [Line Items]
Utility	$ 878	$ 774	$ 759
Property	377	364	336
Payroll	117	124	121
Commonwealth Edison Co [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	306	246	238
Property	31	39	30
Payroll	28	27	27
PECO Energy Co [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	166	139	135
Property	17	18	16
Payroll	16	16	16
Baltimore Gas and Electric Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	94	88	87
Property	191	176	164
Payroll	17	18	17
Pepco Holdings LLC [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	312	301	299
Property	138	131	126
Payroll	25	27	25
Potomac Electric Power Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	283	278	275
Property	94	88	84
Payroll	6	7	7
Delmarva Power & Light Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	25	22	21
Property	42	40	39
Payroll	4	5	5
Atlantic City Electric Company [Member]
Supplemental Statement of Operations Information [Line Items]
Utility	4	3	3
Property	2	3	3
Payroll	$ 3	$ 3	$ 3