Consolidated Statement of Changes in Shareholders Equity (Unaudited) (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other comprehensive income, income taxes	$ 1	$ (59)	$ 70	$ 87
Accumulated Other Comprehensive (Loss) Income, Net
Other comprehensive income, income taxes			70
Exelon Generation Co L L C [Member]
Other comprehensive income, income taxes	(27)	(102)	(177)	(107)
Exelon Generation Co L L C [Member] | Accumulated Other Comprehensive (Loss) Income, Net
Other comprehensive income, income taxes			$ 177