Revenue from Contracts with Customers - Change in Contract with Customer, Asset and Liability (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	$ 98	$ 100	$ 101	$ 105	$ 107	$ 109
Revenues recognized	(2)	(2)	(1)	(2)	(2)	(2)
Ending Balance - Contract Liabilities	96	98	100	103	105	107
Pepco Holdings LLC
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	98	100	101	105	107	109
Revenues recognized	(2)	(2)	(1)	(2)	(2)	(2)
Ending Balance - Contract Liabilities	96	98	100	103	105	107
Potomac Electric Power Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	78	80	81	84	85	87
Revenues recognized	(1)	(2)	(1)	(1)	(1)	(2)
Ending Balance - Contract Liabilities	77	78	80	83	84	85
Delmarva Power and Light Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	10	10	10	11	11	11
Revenues recognized	0	0	0	(1)	0	0
Ending Balance - Contract Liabilities	10	10	10	10	11	11
Atlantic City Electric Company
Contract Liabilities [Roll Forward]
Beginning Balance - Contract Liabilities	10	10	10	10	11	11
Revenues recognized	(1)	0	0	0	(1)	0
Ending Balance - Contract Liabilities	$ 9	$ 10	$ 10	$ 10	$ 10	$ 11