Variable Interest Entities (Details Textuals) (USD $)	12 Months Ended									3 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended						0 Months Ended	12 Months Ended
	Dec. 31, 2012 entities	Dec. 31, 2012 contracts	Dec. 31, 2011 contracts	Dec. 31, 2010 contracts	Dec. 31, 2012 Power Purchase Agreements agreements	Dec. 31, 2012 OE	Dec. 31, 2012 JCP&L	Dec. 31, 2011 JCP&L	Dec. 31, 2010 JCP&L	Dec. 31, 2012 JCP&L Power Purchase Agreements	Dec. 31, 2011 JCP&L Power Purchase Agreements	Dec. 31, 2010 JCP&L Power Purchase Agreements	Dec. 31, 2012 Other FE subsidiaries Power Purchase Agreements	Dec. 31, 2011 Other FE subsidiaries Power Purchase Agreements	Dec. 31, 2012 WP Power Purchase Agreements	Dec. 31, 2011 Signal Peak	Oct. 18, 2011 Signal Peak FEV	Dec. 31, 2008 Signal Peak FEV	Dec. 31, 2012 Signal Peak FEV Global Holding	Dec. 31, 2012 Path-WV	Dec. 31, 2012 Oyster Creek Nuclear Generating Station	Aug. 24, 2012 Beaver Valley Unit 2 Nuclear Generation Corp	Dec. 31, 2012 Bruce Mansfield Plant FGCO
Variable Interest Entities (Textuals) [Abstract]
Bondable stranded costs	$ 243,000,000	$ 243,000,000	$ 287,000,000																		$ 243,000,000
Environmental control bond	493,000,000	493,000,000	513,000,000
Income (loss) attributable to noncontrolling interest		1,000,000	(16,000,000)	(24,000,000)
Distributions to owners		11,000,000
Equity Investments																		134,000,000
Joint venture, ownership percentage by parent																	50.00%
Proceeds from deconsolidation																258,000,000
Deconsolidation of Signal Peak																569,000,000
Gain (loss) on divestiture, net of tax																370,000,000
Gain on remeasurements of retained interest																379,000,000
Equity interest by unaffiliated third party in PNBV	3.00%	3.00%
Equity interest by OES Ventures in PNBV						3.00%
Ownership interest																			33.33%
Percentage of high-voltage transmission line project owned by subsidiary of AE on the Allegheny Series																				100.00%
Percentage of high-voltage transmission line project owned by subsidiary of AE on the West Virginia Series																				50.00%
Number of long-term power purchase agreements maintained by FirstEnergy with NUG entities					20
Number of contracts that may contain variable interest	3	3	4	2
Purchased power		4,237,000,000	4,875,000,000	4,624,000,000			1,069,000,000	1,382,000,000	1,736,000,000	67,000,000	176,000,000	243,000,000	186,000,000	151,000,000
Reserve For Adverse Purchase Power Commitment, Pretax Loss															17,000,000
Reserve for adverse purchase power commitment, pretax loss															17,000,000
Reserve for adverse purchase power commitment															60,000,000
Purchase of lessor equity interests in sale and leaseback, value																						129,000,000	262,200,000
Net present value of FirstEnergy's consolidated sale and leaseback operating lease commitments	$ 1,200,000,000	$ 1,200,000,000