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Capitalization (Details 4) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Schedule of Capitalization [Line Items]  
Aggregate LOC Amount $ 93fe_LineOfCreditFacilityPcrbRelatedAmountOutstanding
Annual Fees 1.65%fe_LineOfCreditFacilityAnnualFeesPayable
FES  
Schedule of Capitalization [Line Items]  
Aggregate LOC Amount $ 93fe_LineOfCreditFacilityPcrbRelatedAmountOutstanding
/ dei_LegalEntityAxis
= fe_FesMember
Annual Fees 1.65%fe_LineOfCreditFacilityAnnualFeesPayable
/ dei_LegalEntityAxis
= fe_FesMember