Revenue from Contracts with Customers - Change in Contract with Customer, Asset and Liability (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021
Contract Liabilities [Roll Forward]
Contract with Customer, Liability, Current	$ 100	$ 107	$ 101	$ 109
Revenues recognized, contract liabilities	(1)	(2)
Pepco Holdings LLC [Member]
Contract Liabilities [Roll Forward]
Contract with Customer, Liability, Current	100	107	101	109
Revenues recognized, contract liabilities	(1)	(2)
Potomac Electric Power Company [Member]
Contract Liabilities [Roll Forward]
Contract with Customer, Liability, Current	80	85	81	87
Revenues recognized, contract liabilities	(1)	(2)
Delmarva Power and Light Company [Member]
Contract Liabilities [Roll Forward]
Contract with Customer, Liability, Current	10	11	10	11
Revenues recognized, contract liabilities	0	0
Atlantic City Electric Company [Member]
Contract Liabilities [Roll Forward]
Contract with Customer, Liability, Current	10	11	$ 10	$ 11
Revenues recognized, contract liabilities	$ 0	$ 0