Property, Plant and Equipment - Summary of Capitalized Interest and AFUDC (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	$ 215	$ 189	$ 150
Commonwealth Edison Co [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	54	47	42
PECO Energy Co [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	42	34	23
Baltimore Gas and Electric Company [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	29	36	30
Pepco Holdings LLC [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	90	72	55
Potomac Electric Power Company [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	69	59	42
Delmarva Power & Light Company [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	10	8	6
Atlantic City Electric Company [Member]
Capitalized Interest And AFUDC [Line Items]
Allowance for Funds Used During Construction, Capitalized Interest	$ 11	$ 5	$ 7