Supplemental Financial Information - Summary of Taxes other than income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Supplemental Statement of Operations Information [Line Items]
Utility	$ 875	$ 878	$ 774
Property	401	377	364
Payroll	124	117	124
Commonwealth Edison Co
Supplemental Statement of Operations Information [Line Items]
Utility	299	306	246
Property	33	31	39
Payroll	31	28	27
PECO Energy Co
Supplemental Statement of Operations Information [Line Items]
Utility	166	166	139
Property	16	17	18
Payroll	17	16	16
Baltimore Gas and Electric Company
Supplemental Statement of Operations Information [Line Items]
Utility	97	94	88
Property	205	191	176
Payroll	18	17	18
Pepco Holdings LLC
Supplemental Statement of Operations Information [Line Items]
Utility	313	312	301
Property	147	138	131
Payroll	27	25	27
Potomac Electric Power Company
Supplemental Statement of Operations Information [Line Items]
Utility	283	283	278
Property	101	94	88
Payroll	6	6	7
Delmarva Power & Light Company
Supplemental Statement of Operations Information [Line Items]
Utility	26	25	22
Property	44	42	40
Payroll	5	4	5
Atlantic City Electric Company
Supplemental Statement of Operations Information [Line Items]
Utility	4	4	3
Property	2	2	3
Payroll	$ 3	$ 3	$ 3