Leases (Details Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended		12 Months Ended	0 Months Ended	12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2007 FGCO	Dec. 31, 2012 FGCO Bruce Mansfield Plant MW	Aug. 24, 2012 Nuclear Generation Corp Beaver Valley Unit 2	Dec. 31, 2012 Nuclear Generation Corp Beaver Valley Unit 2 MW	Dec. 31, 2008 Nuclear Generation Corp Beaver Valley Unit 2 MW	Dec. 31, 2008 Nuclear Generation Corp Perry Plant MW	Dec. 31, 2012 TE and CEI MW	Dec. 31, 2008 TE and CEI Beaver Valley Unit 2 MW
Leases (Textuals) [Abstract]
Period of lease terms on the portions sold by OE of its ownership interests in Perry Unit 1 and Beaver Valley Unit 2 in years	29 years
Period of lease terms on the portions sold by CEI and TE of their ownership interests in Beaver Valley Unit 2 and Bruce Mansfield Units	30 years
Power Liable Under Early Buyout Option								320
Percentage of undivided interest of FGCO in Bruce Mansfield Unit 1		93.825%
Basic terms of operating lease	33 years
Purchase of lessor equity interests in sale and leaseback (in MW)			441.9		70.1	43.5	56.8		158.5
Purchase of lessor equity interests in sale and leaseback, value			$ 262.2	$ 129.0