Variable Interest Entities (Details Textuals) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended					3 Months Ended		6 Months Ended		12 Months Ended		1 Months Ended
	Mar. 31, 2013	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 entities	Jun. 30, 2012	Jun. 30, 2013 Power Purchase Agreements agreements	Jun. 30, 2013 OE	Jun. 30, 2013 Other FE subsidiaries	Jun. 30, 2013 Other FE subsidiaries Power Purchase Agreements	Jun. 30, 2012 Other FE subsidiaries Power Purchase Agreements	Jun. 30, 2013 Other FE subsidiaries Power Purchase Agreements	Jun. 30, 2012 Other FE subsidiaries Power Purchase Agreements	Dec. 31, 2012 Nuclear Generation Corp Beaver Valley Unit 2	Dec. 31, 2012 FGCO Bruce Mansfield Plant	Jun. 30, 2013 Ohio Funding Companies	Jun. 30, 2013 Ohio Funding Companies Existing Taxable Bonds	Jun. 30, 2013 Ohio Funding Companies Existing Taxable Bonds Year 2013	Jun. 30, 2013 Ohio Funding Companies Existing Taxable Bonds Year 2015	Jun. 30, 2013 Ohio Funding Companies Existing Taxable Bonds Year 2020	Jun. 30, 2013 Ohio Funding Companies Phase In Recovery Bonds	Jun. 30, 2013 Signal Peak FEV Global Holding	Jun. 30, 2013 Path-WV
Variable Interest Entities (Textuals) [Abstract]
Debt Instrument, Face Amount																$ 410,000,000	$ 225,000,000	$ 150,000,000	$ 35,000,000	$ 445,000,000
Weighted average interest rate on debt																5.71%				2.48%
Make-whole premiums paid on debt redemptions				61,000,000	0										30,000,000
Distributions to owners				5,000,000
Equity interest by unaffiliated third party in PNBV				3.00%
Equity interest by OES Ventures in PNBV							3.00%
Ownership interest								0.00%													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						18
Number of contracts that may contain variable interest				2
Purchased power		862,000,000	1,042,000,000	1,805,000,000	2,301,000,000				41,000,000	58,000,000	90,000,000	118,000,000
Purchase of lessor equity interests in sale and leaseback, value	221,000,000												129,000,000	262,000,000
Net present value of FirstEnergy's consolidated sale and leaseback operating lease commitments		$ 1,200,000,000		$ 1,200,000,000