Property, Plant and Equipment - Summary of Capitalized Interest and AFUDC (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	$ 256	$ 215	$ 189
Commonwealth Edison Co
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	72	54	47
PECO Energy Co
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	46	42	34
Baltimore Gas and Electric Company
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	25	29	36
Pepco Holdings LLC
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	113	90	72
Potomac Electric Power Company
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	85	69	59
Delmarva Power & Light Company
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	16	10	8
Atlantic City Electric Company
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	$ 12	$ 11	$ 5