Taxes (Details) (Textuals) (USD $)	1 Months Ended	3 Months Ended								12 Months Ended				12 Months Ended		12 Months Ended	3 Months Ended								12 Months Ended				3 Months Ended	12 Months Ended				12 Months Ended			12 Months Ended
	Dec. 31, 2012 subsidiary	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012 subsidiary	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 New federal tax accounting method	Jul. 08, 2013 FirstEnergy and AE Supply plant	Dec. 31, 2012 Two unregulated subsidiaries	Dec. 31, 2013 FES	Sep. 30, 2013 FES	Jun. 30, 2013 FES	Mar. 31, 2013 FES	Dec. 31, 2012 FES	Sep. 30, 2012 FES	Jun. 30, 2012 FES	Mar. 31, 2012 FES	Dec. 31, 2013 FES	Dec. 31, 2012 FES	Dec. 31, 2011 FES	Dec. 31, 2010 FES	Dec. 31, 2012 AE Companies	Dec. 31, 2013 AE Companies	Dec. 31, 2012 AE Companies	Dec. 31, 2013 Operating Loss Carryforward	Dec. 31, 2013 Federal	Dec. 31, 2013 Federal Tax Year 2010	Dec. 31, 2012 State and Local	Dec. 31, 2013 State and Local	Dec. 31, 2012 State and Local New federal tax accounting method	Dec. 31, 2013 State and Local PENNSYLVANIA After December 31, 2013	Dec. 31, 2013 State and Local PENNSYLVANIA After December 31, 2014
Provision for Income Tax [Line Items]
Impairment of Long-lived Assets, Number of Plants to be Deactivated															2
Income Taxes (Textuals) [Abstract]
Reduction in income tax expense due to reversal of valuation allowance												$ 27,000,000				$ (50,000,000)																$ (20,000,000)
Operating Loss Carryforward, Limitations on Use, Percent of Taxable Income																																						25.00%	30.00%
Operating Loss Carryforward, Limitations on Use, Amount																																						4,000,000	5,000,000
Valuation Allowance, Deferred Tax Asset, Change in Amount, Next Fiscal Quarter										(8,000,000)
Deferred Tax Liabilities, Decreases Resulting from Changes to State Apportionment Factors										9,000,000
Deferred Tax Liabilities, Decreases Resulting from Changes in Assessment of Business Operations										22,000,000
Number of unregulated subsidiaries involved in tax judgment											2
Number of subsidiaries converted from corporations to limited liability companies (LLCs)	2
Decrease in taxable income		208,000,000	286,000,000	(230,000,000)	306,000,000	(258,000,000)	729,000,000	307,000,000	522,000,000					(417,000,000)			114,000,000	56,000,000	(117,000,000)	(1,000,000)	(74,000,000)	161,000,000	(6,000,000)	195,000,000													12,000,000
Unrecognized tax benefits	43,000,000	48,000,000				43,000,000				48,000,000	43,000,000	117,000,000	45,000,000				3,000,000				3,000,000				3,000,000	3,000,000	45,000,000	41,000,000
Unrecognized tax benefits, portion expected to be resolved in the next fiscal year		35,000,000								35,000,000
Unrecognized Tax Benefits, Resulting From Various Tax Positions, Resulting Reduction To Effective Tax Rate										5,000,000	37,000,000	35,000,000													0	13,000,000	4,000,000			5,000,000
Previously unrecognized tax benefit, impact on effective tax rate from settlement with authorities						34,000,000					38,000,000															35,000,000					21,000,000			1,000,000,000
Proceeds from Income Tax Refunds																																		110,000,000
Pre-tax net operating loss carryforwards for state and local income tax purposes		9,800,000,000								9,800,000,000																								65,000,000
Unrecognized tax benefits, decreases resulting from settlements with taxing authorities, resulting reduction to effective tax rate						10,000,000																							7,000,000					2,000,000	3,000,000
Reduction in effective tax rate											4,000,000	7,000,000
Deferred tax assets, gross		1,100,000,000								1,100,000,000
Operating loss carryforwards, not subject to expiration																																	25,000,000
Operating loss carryforwards, subject to expiration																																				418,000,000
Pre-tax net operating loss carryforwards expected to utilized		$ 6,300,000,000								$ 6,300,000,000