Organization, Basis of Presentation and Significant Accounting Policies (Details Textuals) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Feb. 24, 2011
Summary of Significant Accounting Policies (Textuals) [Abstract]
Regulatory assets that do not earn a current return	$ 413,000,000
Number of shares of FirstEnergy common stock issued				113
Net plant in service	28,283,000,000	18,993,000,000
Goodwill acquired from merger with Allegheny	866,000,000
Goodwill	6,441,000,000	5,575,000,000	5,575,000,000
Other-than-temporary impairments	19,000,000	33,000,000	62,000,000
Liabilities, Noncurrent	13,456,000,000	9,296,000,000
Greater of Market Value of Plan Assets or Plans' Projected Benefit Obligation [Member]
Summary of Significant Accounting Policies (Textuals) [Abstract]
Actuarial Gain (Loss) Recognition Threshold	10.00%
Regulated Distribution [Member]
Summary of Significant Accounting Policies (Textuals) [Abstract]
Goodwill acquired from merger with Allegheny	0
Goodwill	5,551,000,000	5,551,000,000	5,551,000,000
Decrease in fair value required to indicate potential impairment	44.00%
Competitive Energy Services [Member]
Summary of Significant Accounting Policies (Textuals) [Abstract]
Plant generation capacity	17,000
Goodwill acquired from merger with Allegheny	866,000,000
Goodwill	890,000,000	24,000,000	24,000,000
Decrease in fair value required to indicate potential impairment	53.00%
Bath County, Virginia
Summary of Significant Accounting Policies (Textuals) [Abstract]
Plant generation capacity	2,773
Allegheny
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net regulatory liabilities	381,000,000
Met-Ed
Summary of Significant Accounting Policies (Textuals) [Abstract]
Regulatory assets that do not earn a current return	182,000,000
Deferral of above-market costs for power included in regulatory transition costs	105,000,000
Net plant in service	1,588,704,000	1,530,984,000
Goodwill	416,499,000	416,499,000
Decrease in fair value required to indicate potential impairment	62.00%
Accumulated impairment charges	355,000,000
Liabilities, Noncurrent	1,008,851,000	1,003,684,000
Met-Ed | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		1,530,984,000,000
Met-Ed | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	40,000,000
Penelec
Summary of Significant Accounting Policies (Textuals) [Abstract]
Regulatory assets that do not earn a current return	115,000,000
Net plant in service	1,832,109,000	1,759,227,000
Goodwill	768,628,000	768,628,000
Decrease in fair value required to indicate potential impairment	58.00%
Liabilities, Noncurrent	1,082,356,000	920,877,000
Penelec | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		1,759,227,000,000
Penelec | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	40,000,000
JCP&L
Summary of Significant Accounting Policies (Textuals) [Abstract]
Regulatory assets that do not earn a current return	122,000,000
Deferral of above-market costs for power included in regulatory transition costs	142,000,000
Net plant in service	3,129,000,000	3,101,000,000
Goodwill	1,811,000,000	1,811,000,000
Decrease in fair value required to indicate potential impairment	38.00%
Liabilities, Noncurrent	1,750,000,000	1,747,000,000
JCP&L | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		3,101,000,000
JCP&L | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	76,000,000
AGC | Bath County, Virginia
Summary of Significant Accounting Policies (Textuals) [Abstract]
Pumped storage hydroelectric station, Ownership percentage	40.00%
Plant generation capacity	1,109
Net plant in service	468,000,000
Virginia Electric and Power Company | Bath County, Virginia
Summary of Significant Accounting Policies (Textuals) [Abstract]
Pumped storage hydroelectric station, Ownership percentage	60.00%
CEI
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service	1,581,388,000	1,515,500,000
Goodwill	1,688,521,000	1,688,521,000
Decrease in fair value required to indicate potential impairment	20.00%
Liabilities, Noncurrent	916,935,000	902,828,000
CEI | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		1,515,500,000,000
CEI | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	56,000,000
TE
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service	534,942,000	511,897,000
Goodwill	500,576,000	500,576,000
Decrease in fair value required to indicate potential impairment	16.00%
Liabilities, Noncurrent	518,760,000	539,915,000
TE | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		511,897,000,000
TE | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	32,000,000
FES
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service	6,873,000,000	7,389,000,000
Goodwill	24,000,000	24,000,000
Decrease in fair value required to indicate potential impairment	62.00%
Other-than-temporary impairments	17,000,000	32,000,000	57,000,000
Liabilities, Noncurrent	3,205,000,000	2,916,000,000
FES | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		7,389,000,000
FES | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	331,000,000
OE
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service	2,091,000,000	2,004,000,000
Liabilities, Noncurrent	1,349,000,000	1,270,000,000
OE | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net plant in service		2,004,000,000
OE | Affiliates | As Revised
Summary of Significant Accounting Policies (Textuals) [Abstract]
Liabilities, Noncurrent	80,000,000
Asset removal costs [Member] | Allegheny
Summary of Significant Accounting Policies (Textuals) [Abstract]
Net regulatory liabilities	$ 366,000,000