Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Premium on Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Potomac Electric Power Co [Member]	Potomac Electric Power Co [Member] Common Stock [Member]	Potomac Electric Power Co [Member] Premium on Stock [Member]	Potomac Electric Power Co [Member] Retained Earnings [Member]	Delmarva Power & Light Co/De [Member]	Delmarva Power & Light Co/De [Member] Common Stock [Member]	Delmarva Power & Light Co/De [Member] Premium on Stock [Member]	Delmarva Power & Light Co/De [Member] Retained Earnings [Member]	Atlantic City Electric Co [Member]	Atlantic City Electric Co [Member] Common Stock [Member]	Atlantic City Electric Co [Member] Premium on Stock [Member]	Atlantic City Electric Co [Member] Retained Earnings [Member]
Balance at Dec. 31, 2014	$ 4,322	$ 3	$ 3,800	$ 565	$ (46)	$ 2,087		$ 1,010	$ 1,077	$ 1,178		$ 537	$ 641	$ 886	$ 26	$ 651	$ 209
Balance, Shares at Dec. 31, 2014	252,728,684	252,728,684				100	100			1,000	1,000			8,546,017	8,546,017
Net Income	$ 53			53		$ 26			26	$ 32			32	$ 4			4
Other comprehensive income	1				1
Capital contribution from Parent						112		112
Dividends on common stock	(68)			(68)						(62)			(62)	(12)			(12)
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	1,148		537	611	878	$ 26	651	201
Balance, Shares at Mar. 31, 2015		253,043,362					100				1,000				8,546,017
Balance at Dec. 31, 2014	$ 4,322	$ 3	3,800	565	(46)	$ 2,087		1,010	1,077	$ 1,178		537	641	$ 886	$ 26	651	209
Balance, Shares at Dec. 31, 2014	252,728,684	252,728,684				100	100			1,000	1,000			8,546,017	8,546,017
Net Income	$ 197					$ 128				$ 55				$ 28
Other comprehensive income	5
Balance at Sep. 30, 2015	$ 4,348	$ 3	3,830	556	(41)	$ 2,236		1,122	1,114	$ 1,228		612	616	$ 902	$ 26	651	225
Balance, Shares at Sep. 30, 2015	253,590,612	253,590,612				100	100			1,000	1,000			8,546,017	8,546,017
Balance at Mar. 31, 2015	$ 4,317	$ 3	3,809	550	(45)	$ 2,225		1,122	1,103	$ 1,148		537	611	$ 878	$ 26	651	201
Balance, Shares at Mar. 31, 2015		253,043,362					100				1,000				8,546,017
Net Income	53			53		42			42	8			8	10			10
Other comprehensive income	3				3
Capital contribution from Parent										75		75
Dividends on common stock	(69)			(69)		(31)			(31)
Issuance of common stock:
Original issue shares, net	4		4
Original issue shares, net, shares		155,891
DRP original issue shares	6		6
DRP original issue shares, shares		236,793
Net activity related to stock-based awards	4		4
Balance at Jun. 30, 2015	4,318	$ 3	3,823	534	(42)	2,236		1,122	1,114	1,231		612	619	888	$ 26	651	211
Balance, Shares at Jun. 30, 2015		253,436,046					100				1,000				8,546,017
Net Income	91			91		60			60	15			15	14			14
Other comprehensive income	1
Other comprehensive income	1				1
Dividends on common stock	(69)			(69)		(60)			(60)	(18)			(18)
Issuance of common stock:
Original issue shares, net	4		4
Original issue shares, net, shares		154,566
Net activity related to stock-based awards	3		3
Balance at Sep. 30, 2015	$ 4,348	$ 3	$ 3,830	$ 556	$ (41)	$ 2,236		$ 1,122	$ 1,114	$ 1,228		$ 612	$ 616	$ 902	$ 26	$ 651	$ 225
Balance, Shares at Sep. 30, 2015	253,590,612	253,590,612				100	100			1,000	1,000			8,546,017	8,546,017