Leases (Details) (Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended									12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2011 Wind Purchased Power Agreements [Member]	Dec. 31, 2010 Wind Purchased Power Agreements [Member]	Dec. 31, 2009 Wind Purchased Power Agreements [Member]	Dec. 31, 2008 Nuclear Generation Corp [Member] Perry Plant [Member] MW	Dec. 31, 2008 Nuclear Generation Corp [Member] Beaver Valley Unit 2 [Member] MW	Dec. 31, 2007 FGCO	Dec. 31, 2011 FGCO Bruce Mansfield Plant [Member]	Dec. 31, 2011 CEI	Dec. 31, 2008 CEI Beaver Valley Unit 2 [Member] MW	Dec. 31, 2011 TE		Dec. 31, 2011 TE Beaver Valley Unit 2 [Member]
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
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
Pertcentage of undivided interest of FGCO in Bruce Mansfield Unit 1							93.825%
Basic terms of operating lease (approximately)	33
Purchase of lessor equity interests in sale and leaseback					56.8	43.5				158.5
Rentals for leases classified as capital		$ 29	$ 30	$ 16
Unamortized market lease liability	3,147							217	19		334	[1]	199
Current portion of unamortized market lease liability								$ 46					$ 37

[1] Includes certain minimum lease payments associated with NGC's lessor equity interests in Perry and Beaver Valley Unit 2 that are eliminated in consolidation.