Fair Value Measurements (Details) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	$ 15,823,000		$ 12,579,000
FES
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	2,892,000		3,181,000
FES | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	3,738,000		4,279,000
FES | 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	3,975,000		4,403,000
OE
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,146,000		1,152,000
OE | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,158,000		1,159,000
OE | 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	1,404,000		1,321,000
CEI
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,831,032		1,852,530
CEI | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,831,000		1,853,000
CEI | 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	2,096,000		2,035,000
TE
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	597,609		600,493
TE | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	600,000		600,000
TE | 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	720,000		653,000
JCP&L
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,746,000		1,770,000
JCP&L | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,787,000		1,810,000
JCP&L | 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	2,074,000		1,962,000
Met-Ed
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	699,747		718,860
Met-Ed | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	729,000		742,000
Met-Ed | 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	818,000		821,000
Penelec
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,072,494		1,072,262
Penelec | Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	1,120,000		1,120,000
Penelec | 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	1,245,000		1,189,000
Carrying Value
Fair value and related carrying amounts of long-term debt and other long-term obligations
Long-term debt and other long-term obligations	17,870,000	[1]	13,928,000	[1]
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	$ 19,703,000	[1]	$ 14,845,000	[1]

[1] Includes debt assumed in the AE merger (see Note 2) with a carrying value and a fair value as of September 30, 2011, of $4,375 million and $4,515 million, respectively, and debt classified as liabilities related to assets pending sale (see Note 15) with a carrying value and a fair value as of September 30, 2011, of $363 million.