Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Premium on Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [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, 2012	$ 4,414	$ 2	$ 3,383	$ 1,077	$ (48)	$ 1,643		$ 755	$ 888	$ 985		$ 407	$ 578	$ 802	$ 26	$ 576	$ 200
Balance, Shares at Dec. 31, 2012		230,015,427					100				1,000				8,546,017
Net Income (Loss)	(212)			(212)		150			150	89			89	50			50
Other comprehensive income (loss)	14				14
Capital contribution from Parent						175		175						75		75
Dividends on common stock	(270)			(270)		(46)			(46)	(30)			(30)	(60)			(60)
Issuance of common stock:
Original issue shares, net	332	$ 1	331
Original issue shares, net, shares		18,734,128
DRP original issue shares	$ 30		30
DRP original issue shares, shares	2,000,000	1,575,343
Net activity related to stock-based awards	$ 7		7
Balance at Dec. 31, 2013	4,315	$ 3	3,751	595	(34)	1,922		930	992	1,044		407	637	867	$ 26	651	190
Balance, Shares at Dec. 31, 2013		250,324,898					100				1,000				8,546,017
Net Income (Loss)	242			242		171			171	104			104	45			45
Other comprehensive income (loss)	(12)				(12)
Capital contribution from Parent						80		80		130		130
Dividends on common stock	(272)			(272)		(86)			(86)	(100)			(100)	(26)			(26)
Issuance of common stock:
Original issue shares, net	14		14
Original issue shares, net, shares		1,310,276
DRP original issue shares	$ 28		28
DRP original issue shares, shares	1,000,000	1,122,575
Net activity related to stock-based awards	$ 7		7
Net activity related to stock-based awards, shares		(29,065)
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 (Loss)	$ 327			327		$ 187			187	$ 76			76	$ 38			38
Other comprehensive income (loss)	10				10
Capital contribution from Parent						112		112		75		75		95		95
Dividends on common stock	(275)			(275)		(146)			(146)	(92)			(92)	(12)			(12)
Issuance of common stock:
Original issue shares, net	15		15
Original issue shares, net, shares		1,157,203
DRP original issue shares	$ 11		11
DRP original issue shares, shares	1,000,000	397,939
Net activity related to stock-based awards	$ 3		3
Net activity related to stock-based awards, shares		5,435
Balance at Dec. 31, 2015	$ 4,413	$ 3	$ 3,829	$ 617	$ (36)	$ 2,240		$ 1,122	$ 1,118	$ 1,237		$ 612	$ 625	$ 1,007	$ 26	$ 746	$ 235
Balance, Shares at Dec. 31, 2015	254,289,261	254,289,261				100	100			1,000	1,000			8,546,017	8,546,017