Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capitalized interest	$ 8	$ 8	$ 7
Delmarva Power & Light Co/De [Member]
Capitalized interest	1	1	2
Atlantic City Electric Co [Member]
Capitalized interest	1	1	1
Potomac Electric Power Co [Member]
Capitalized interest	$ 7	$ 5	$ 5