Regulatory Matters (Narrative) (Details) (USD $)	1 Months Ended		12 Months Ended				0 Months Ended						1 Months Ended			0 Months Ended	3 Months Ended	0 Months Ended			24 Months Ended		12 Months Ended
	Oct. 31, 2010	Jun. 30, 2005 years	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 31, 2012 Delmarva Power & Light Co/De [Member]	Dec. 09, 2011 Delmarva Power & Light Co/De [Member]	Dec. 02, 2011 Delmarva Power & Light Co/De [Member]	Jun. 21, 2011 Delmarva Power & Light Co/De [Member]	Feb. 02, 2011 Delmarva Power & Light Co/De [Member]	Aug. 31, 2010 Delmarva Power & Light Co/De [Member]	Jul. 31, 2010 Delmarva Power & Light Co/De [Member]	Jul. 02, 2012 Delmarva Power & Light Co/De [Member]	May 31, 2010 DCPSC [Member]	Aug. 05, 2011 Atlantic City Electric Co [Member]	Sep. 30, 2011 Atlantic City Electric Co [Member]	Dec. 16, 2011 Potomac Electric Power Co [Member]	Jul. 08, 2011 Potomac Electric Power Co [Member]	Dec. 21, 2011 Potomac Electric Power Co [Member] years	Dec. 31, 2013 Scenario, Forecast [Member]	Dec. 31, 2012 Scenario, Forecast [Member]	Dec. 31, 2011 Minimum [Member]	Dec. 31, 2011 Maximum [Member]
Transition bond maturity, lower range						2013
Transition bond maturity, upper range						2023
Regulatory asset, amortization period, years																							1	20
Depreciation reserve, amortization period, years		8.25
Disallowed costs to be refunded to customers															$ 11,000,000
Initial fine																				1,000,000
Detailed work plan, number of years																				5
Effect of proposed change on gas cost rate	0.10%
Interest foregone associated with amortization																					171,000	171,000
Requested rate change								25,200,000	31,800,000				10,200,000			70,500,000		68,400,000	42,000,000
Return on equity, percentage								10.75%	10.75%	10.00%			11.00%			10.75%		10.75%	10.75%
Rate increase implemented							2,500,000			5,800,000	7,700,000	2,500,000
Contingent rate increase														29,300,000
Requested rate change, net																58,900,000
Base rate																17,000,000
Increase in sales-and-use taxes																4,900,000
Adjustments to regulatory asset recovery charge																500,000
Estimated recoverable capital expenditures			81,000,000	94,000,000	63,000,000
Incremental Storm Costs						$ 6,000,000											$ 8,000,000