Revenue from Contracts with Customers - Change in Contract with Customer, Asset and Liability (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	$ 133	$ 101
Revenues recognized	(2)	(1)
Ending Balance - Contract Liabilities	131	100
Pepco Holdings LLC
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	133	101
Revenues recognized	(2)	(1)
Ending Balance - Contract Liabilities	131	100
Potomac Electric Power Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	107	81
Revenues recognized	(2)	(1)
Ending Balance - Contract Liabilities	105	80
Delmarva Power and Light Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	13	10
Revenues recognized	0	0
Ending Balance - Contract Liabilities	13	10
Atlantic City Electric Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	13	10
Revenues recognized	0	0
Ending Balance - Contract Liabilities	$ 13	$ 10