Supplemental Financial Information - Summary of Other Income (Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other, Net [Abstract]
AFUDC—Equity	$ 151	$ 150	$ 136
Non-service net periodic benefit cost	(18)	63	91
Commonwealth Edison Co
Other, Net [Abstract]
AFUDC—Equity	33	35	34
Non-service net periodic benefit cost	0	0	0
PECO Energy Co
Other, Net [Abstract]
AFUDC—Equity	31	31	26
Non-service net periodic benefit cost	0	0	0
Baltimore Gas and Electric Company
Other, Net [Abstract]
AFUDC—Equity	16	21	27
Non-service net periodic benefit cost	0	0	0
Pepco Holdings LLC
Other, Net [Abstract]
AFUDC—Equity	71	63	49
Non-service net periodic benefit cost	0	0	0
Potomac Electric Power Company
Other, Net [Abstract]
AFUDC—Equity	54	48	40
Non-service net periodic benefit cost	0	0	0
Delmarva Power & Light Company
Other, Net [Abstract]
AFUDC—Equity	10	7	6
Non-service net periodic benefit cost	0	0	0
Atlantic City Electric Company
Other, Net [Abstract]
AFUDC—Equity	7	8	3
Non-service net periodic benefit cost	$ 0	$ 0	$ 0