Fair Value Measurements (Details) (USD $)																																																					12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Carrying Value		Dec. 31, 2010 Carrying Value		Dec. 31, 2011 Fair Value		Dec. 31, 2010 Fair Value		Dec. 31, 2011 FES	Dec. 31, 2010 FES	Dec. 31, 2011 FES Carrying Value	Dec. 31, 2010 FES Carrying Value	Dec. 31, 2011 FES Fair Value	Dec. 31, 2010 FES Fair Value	Dec. 31, 2011 OE	Dec. 31, 2010 OE	Dec. 31, 2011 OE Carrying Value	Dec. 31, 2010 OE Carrying Value	Dec. 31, 2011 OE Fair Value	Dec. 31, 2010 OE Fair Value	Dec. 31, 2011 CEI	Dec. 31, 2010 CEI	Dec. 31, 2011 CEI Carrying Value	Dec. 31, 2010 CEI Carrying Value	Dec. 31, 2011 CEI Fair Value	Dec. 31, 2010 CEI Fair Value	Dec. 31, 2011 TE	Dec. 31, 2010 TE	Dec. 31, 2011 TE Carrying Value	Dec. 31, 2010 TE Carrying Value	Dec. 31, 2011 TE Fair Value	Dec. 31, 2010 TE Fair Value	Dec. 31, 2011 JCP&L	Dec. 31, 2010 JCP&L	Dec. 31, 2011 JCP&L Carrying Value	Dec. 31, 2010 JCP&L Carrying Value	Dec. 31, 2011 JCP&L Fair Value	Dec. 31, 2010 JCP&L Fair Value	Dec. 31, 2011 Met-Ed	Dec. 31, 2010 Met-Ed	Dec. 31, 2011 Met-Ed Carrying Value	Dec. 31, 2010 Met-Ed Carrying Value	Dec. 31, 2011 Met-Ed Fair Value	Dec. 31, 2010 Met-Ed Fair Value	Dec. 31, 2011 Penelec	Dec. 31, 2010 Penelec	Dec. 31, 2011 Penelec Carrying Value	Dec. 31, 2010 Penelec Carrying Value	Dec. 31, 2011 Penelec Fair Value	Dec. 31, 2010 Penelec Fair Value	Dec. 31, 2011 Allegheny Carrying Value	Dec. 31, 2011 Allegheny Fair Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	$ 15,716,000,000	$ 12,579,000,000	$ 17,165,000,000	[1]	$ 13,928,000,000	[1]	$ 19,320,000,000	[1]	$ 14,845,000,000	[1]	$ 2,799,000,000	$ 3,181,000,000	$ 3,675,000,000	$ 4,279,000,000	$ 3,931,000,000	$ 4,403,000,000	$ 1,155,000,000	$ 1,152,000,000	$ 1,157,000,000	$ 1,159,000,000	$ 1,434,000,000	$ 1,321,000,000	$ 1,834,890,000	$ 1,852,530,000	$ 1,831,000,000	$ 1,853,000,000	$ 2,162,000,000	$ 2,035,000,000	$ 598,869,000	$ 600,493,000	$ 600,000,000	$ 600,000,000	$ 741,000,000	$ 653,000,000	$ 1,736,000,000	$ 1,770,000,000	$ 1,777,000,000	$ 1,810,000,000	$ 2,080,000,000	$ 1,962,000,000	$ 703,525,000	$ 718,860,000	$ 729,000,000	$ 742,000,000	$ 824,000,000	$ 821,000,000	$ 1,075,781,000	$ 1,072,262,000	$ 1,120,000,000	$ 1,120,000,000	$ 1,251,000,000	$ 1,189,000,000
Noncash or Part Noncash Acquisition, Debt Assumed																																																					$ 4,355,000,000	$ 4,561,000,000

[1] Includes debt assumed in the AE merger (see Note 2, Merger) with a carrying value and a fair value as of December 31, 2011, of $4,355 million and $4,561 million, respectively.