Revenue from Contracts with Customers (All Registrants) - Change in Contract with Customer, Asset and Liability (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	$ 101	$ 109
Revenues recognized	(7)	(8)
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract	39
Ending Balance - Contract Liabilities	133	101
Pepco Holdings LLC
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	101	109
Revenues recognized	(7)	(8)
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract	39
Ending Balance - Contract Liabilities	133	101
Potomac Electric Power Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	81	87
Revenues recognized	(5)	(6)
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract	31
Ending Balance - Contract Liabilities	107	81
Delmarva Power & Light Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	10	11
Revenues recognized	(1)	(1)
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract	4
Ending Balance - Contract Liabilities	13	10
Atlantic City Electric Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	10	11
Revenues recognized	(1)	(1)
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract	4
Ending Balance - Contract Liabilities	$ 13	$ 10