Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended						0 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 FES	Jun. 30, 2012 FES	Jun. 30, 2013 FES	Jun. 30, 2012 FES	Jun. 30, 2013 Operating Loss Carryforward [Member]	Jun. 30, 2013 Operating Loss Carryforward [Member] FirstEnergy and AE Supply	Jun. 30, 2013 Subsequent Event	Jul. 08, 2013 Subsequent Event FirstEnergy and AE Supply plant	Dec. 31, 2012 Federal	Dec. 31, 2012 State and local	Jul. 09, 2013 State and local Subsequent Event PENNSYLVANIA After December 31, 2013	Jul. 09, 2013 State and local Subsequent Event PENNSYLVANIA After December 31, 2014
Income Taxes (Textuals) [Abstract]
Unrecognized tax benefits	$ 4		$ 4
Accrued interest	9		9		9
Deferred tax assets, current														319
Deferred tax assets, long-term														466	389
Deferred tax assets, portion not expected to be recognized in next fiscal year														268
Impairment of Long-lived Assets, Number of Plants to be Deactivated													2
Valuation Allowance, Deferred Tax Asset, Change in Amount										22	20
Operating Loss Carryforward, Limitations on Use, Percent of Taxable Income																25.00%	30.00%
Operating Loss Carryforward, Limitations on Use, Amount																4	5
Valuation Allowance, Deferred Tax Asset, Change in Amount, Next Fiscal Quarter												11
Effective tax rate	26.10%		64.40%
Loss on debt redemptions	$ 24	$ 0	$ 141	$ 0		$ 32	$ 0	$ 103	$ 0