Merger (Details 3) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Summary of consolidated results of operations
Revenue	$ 17,449	$ 18,569
Earnings available to FirstEnergy	$ 979	$ 1,183
Basic Earnings Per Share	$ 2.34	$ 2.83
Diluted Earnings Per Share	$ 2.33	$ 2.82