Consolidated Statement of Changes in Shareholders Equity (Unaudited) (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive (Loss) Income, Net
Other comprehensive income, income taxes	$ 468	$ (41)	$ (221)
Exelon Generation Co L L C [Member]
Other comprehensive income, income taxes	(261)	(64)	(102)
PECO Energy Co [Member]
Other comprehensive income, income taxes	0	1	0
Commonwealth Edison Co [Member]
Other comprehensive income, income taxes	$ 0	$ 0	$ 3