Asset Retirement Obligations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
FE
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	$ 2,112		$ 1,973
Changes to the asset retirement obligations
Beginning Balance	1,407	[1]	1,425	[1]
Liabilities assumed from Allegheny merger	60	[1],[2]
Liabilities settled	(15)	[1],[2]	(11)	[1]
Accretion	97	[1]	93	[1]
Revisions in estimated cash flows	(52)	[1],[3]	(100)	[1],[4]
Ending Balance	1,497	[1]	1,407	[1]
Asset Retirement Obligations (Textuals) [Abstract]
Reduced ARO liability resulting from deconsolidation	10
FES
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	1,223		1,146
Changes to the asset retirement obligations
Beginning Balance	892		921
Liabilities assumed from Allegheny merger	0
Liabilities settled	(1)	[2]	0
Accretion	59		59
Revisions in estimated cash flows	(46)	[3]	(88)	[4]
Ending Balance	904		892
OE
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	137		127
Changes to the asset retirement obligations
Beginning Balance	74		86
Liabilities assumed from Allegheny merger	0
Liabilities settled	(2)	[2]	(10)		0
Accretion	5		5
Revisions in estimated cash flows	(6)	[3]	(7)	[4]
Ending Balance	71		74		86
CEI
Changes to the asset retirement obligations
Beginning Balance	2		2
Liabilities assumed from Allegheny merger	0
Liabilities settled	0	[2]	0
Accretion	1		0
Revisions in estimated cash flows	0	[3]	0	[4]
Ending Balance	3		2
TE
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	83		76
Changes to the asset retirement obligations
Beginning Balance	29		32
Liabilities assumed from Allegheny merger	0
Liabilities settled	0	[2]	0
Accretion	2		2
Revisions in estimated cash flows	0	[3]	(5)	[4]
Ending Balance	31		29
JCP&L
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	193		182
Changes to the asset retirement obligations
Beginning Balance	108		102
Liabilities assumed from Allegheny merger	0
Liabilities settled	0	[2]	0
Accretion	7		6
Revisions in estimated cash flows	0	[3]	0	[4]
Ending Balance	115		108
Met-Ed
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	310		289
Changes to the asset retirement obligations
Beginning Balance	193		180
Liabilities assumed from Allegheny merger	0
Liabilities settled	0	[2]	0
Accretion	13		13
Revisions in estimated cash flows	0	[3]	0	[4]
Ending Balance	206		193
Penelec
Fair values of the decommissioning trust assets
Legally restricted decommissioning assets	166		153
Changes to the asset retirement obligations
Beginning Balance	98		92
Liabilities assumed from Allegheny merger	0
Liabilities settled	0	[2]	0
Accretion	7		6
Revisions in estimated cash flows	0	[3]	0	[4]
Ending Balance	$ 105		$ 98

[1] The 2011 changes include activity relating to Allegheny, which merged with FE in February 2011.

[2] Includes approximately $10 million in reduced ARO liabilities for FirstEnergy as a result of deconsolidation of the Signal Peak joint venture (See Note 8, Variable Interest Entities).

[3] During 2011, studies were completed to reassess the estimated cost of decommissioning the Perry and Davis-Besse nuclear generating facilities. The cost studies resulted in revisions to the estimated cash flows associated with the ARO liabilities and reduced the discounted liabilities as shown. These revisions had no significant impact on accretion of the obligations during 2011, as compared to 2010.

[4] During the second quarter of 2010, studies were completed to reassess the estimated cost of decommissioning the Beaver Valley nuclear generating facilities. The cost studies resulted in a revision to the estimated cash flows associated with the ARO liabilities and reduced the discounted liabilities as shown.