Variable Interest Entities (Details Textuals) (USD $)	3 Months Ended		9 Months Ended					3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended				9 Months Ended	0 Months Ended					0 Months Ended	3 Months Ended	1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 contracts	Sep. 30, 2012 entities	Sep. 30, 2011	Sep. 30, 2012 Power Purchase Agreements agreements	Aug. 24, 2012 PJM	Sep. 30, 2012 JCP&L	Sep. 30, 2011 JCP&L	Sep. 30, 2012 JCP&L	Sep. 30, 2011 JCP&L contracts	Sep. 30, 2012 JCP&L Power Purchase Agreements	Sep. 30, 2011 JCP&L Power Purchase Agreements	Sep. 30, 2012 JCP&L Power Purchase Agreements	Sep. 30, 2011 JCP&L Power Purchase Agreements	Oct. 31, 2012 JCP&L Power Purchase Agreements Cancellation of Contract [Member] contracts	Sep. 30, 2012 PE Power Purchase Agreements	Sep. 30, 2011 PE Power Purchase Agreements	Sep. 30, 2012 PE Power Purchase Agreements	Sep. 30, 2011 PE Power Purchase Agreements	Sep. 30, 2012 WP Power Purchase Agreements	Sep. 30, 2011 WP Power Purchase Agreements	Sep. 30, 2012 WP Power Purchase Agreements	Sep. 30, 2011 WP Power Purchase Agreements	Oct. 18, 2011 Signal Peak FEV	Sep. 30, 2012 Signal Peak FEV Global Holding	Sep. 30, 2012 Variable Interest Entity, Not Primary Beneficiary	Aug. 24, 2012 PATH	Aug. 24, 2012 PATH-Allegheny	Aug. 24, 2012 Path-WV	Sep. 30, 2012 Path-WV	Sep. 30, 2012 Oyster Creek Nuclear Generating Station	Aug. 24, 2012 Beaver Valley Unit 2 Nuclear Generation Corp	Sep. 30, 2012 Bruce Mansfield Plant FGCO	Nov. 08, 2012 Bruce Mansfield Plant FGCO Acquisition [Member]
Variable Interest Entities (Textuals) [Abstract]
Bondable stranded costs																																$ 253,000,000
Environmental control bond	493,000,000		493,000,000	493,000,000
Income (loss) attributable to noncontrolling interest	0	(2,000,000)		1,000,000	(17,000,000)																						1,000,000
Distributions to owners																											4,000,000
Joint venture, ownership percentage by parent																									50.00%
Ownership interest																										33.33%
Remaining Recovery Period of Regulatory Assets																												5 years
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%
Regulatory asset expansion, canceled							2,100,000,000
Cost recovery, PP&E reclassified to Regulatory Assets																												121,000,000	62,000,000	59,000,000
Return on equity for cost recovery																												10.90%
Base return on equity for cost recovery																												10.40%
Return on equity for cost recovery from RTO membership																												0.50%
Number of long-term power purchase agreements maintained by FirstEnergy with NUG entities						21
Number of Contracts, Ended in Period, Power Purchase Agreement with Non-Utility Generation Entity																1
Number of contracts that may contain variable interest			3	3							4
Purchased power	1,312,000,000	1,349,000,000		3,815,000,000	3,755,000,000			331,000,000	429,000,000	849,000,000	1,127,000,000	19,000,000	44,000,000	46,000,000	164,000,000		30,000,000	31,000,000	89,000,000	89,000,000	16,000,000	14,000,000	49,000,000	40,000,000
Reserve for adverse purchase power commitment																					45,000,000		45,000,000
Current liability included in adverse purchase power commitment																					11,000,000		11,000,000
Purchase of lessor equity interests in sale and leaseback																																	108,000,000	95,400,000	37,600,000
Early buyout option exercise																																			23,600,000
Net present value of FirstEnergy's consolidated sale and leaseback operating lease commitments	$ 1,400,000,000		$ 1,400,000,000	$ 1,400,000,000