Consolidated Statements of Equity (USD $) In Millions, except Share data, unless otherwise specified	Total USD ($)	Common Stock [Member] USD ($)	Premium on Stock [Member] USD ($)	Retained Earnings [Member] USD ($)	Accumulated Other Comprehensive Loss [Member] USD ($)	Potomac Electric Power Co [Member] USD ($)	Potomac Electric Power Co [Member] Common Stock [Member]	Potomac Electric Power Co [Member] Premium on Stock [Member] USD ($)	Potomac Electric Power Co [Member] Retained Earnings [Member] USD ($)	Atlantic City Electric Co [Member] USD ($)	Atlantic City Electric Co [Member] Common Stock [Member] USD ($)	Atlantic City Electric Co [Member] Premium on Stock [Member] USD ($)	Atlantic City Electric Co [Member] Retained Earnings [Member] USD ($)	Delmarva Power & Light Co/De [Member] USD ($)	Delmarva Power & Light Co/De [Member] Common Stock [Member]	Delmarva Power & Light Co/De [Member] Premium on Stock [Member] USD ($)	Delmarva Power & Light Co/De [Member] Retained Earnings [Member] USD ($)
Balance at Dec. 31, 2014	$ 4,322	$ 3	$ 3,800	$ 565	$ (46)	$ 2,087		$ 1,010	$ 1,077	$ 886	$ 26	$ 651	$ 209	$ 1,178		$ 537	$ 641
Balance, Shares at Dec. 31, 2014	252,728,684	252,728,684				100	100			8,546,017	8,546,017			1,000	1,000
Net Income	53			53		26			26	4			4	32			32
Other comprehensive income	1				1
Capital contribution from Parent						112		112
Dividends on common stock	(68)			(68)						(12)			(12)	(62)			(62)
Issuance of common stock:
Original issue shares, net	4		4
Original issue shares, net, shares		153,532
DRP original issue shares	7		7
DRP original issue shares, shares		161,146
Net activity related to stock-based awards	(2)		(2)
Balance at Mar. 31, 2015	$ 4,317	$ 3	$ 3,809	$ 550	$ (45)	$ 2,225		$ 1,122	$ 1,103	$ 878	$ 26	$ 651	$ 201	$ 1,148		$ 537	$ 611
Balance, Shares at Mar. 31, 2015	253,043,362	253,043,362				100	100			8,546,017	8,546,017			1,000	1,000