XML 65 R53.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Derivative Instruments (Details 4) - Not Designated as Hedging Instrument - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016
Outstanding net asset (liability) [Roll Forward] |  |
Outstanding net asset (liability), Beginning Balance | $ (105) | $ (135)
Unrealized loss | (6) | (13)
Settlements | 6 | 11
Outstanding net asset (liability), Ending Balance | (105) | (137)
NUGs |  |
Outstanding net asset (liability) [Roll Forward] |  |
Outstanding net asset (liability), Beginning Balance | (107) | (136)
Unrealized loss | (5) | (12)
Settlements | 9 | 13
Outstanding net asset (liability), Ending Balance | (103) | (135)
Regulated FTRs |  |
Outstanding net asset (liability) [Roll Forward] |  |
Outstanding net asset (liability), Beginning Balance | 2 | 1
Unrealized loss | (1) | (1)
Settlements | (3) | (2)
Outstanding net asset (liability), Ending Balance | $ (2) | $ (2)

X
- Definition Settled Contracts. + References No definition available. + Details
Name: | fe_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsSettledContracts
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Derivative instruments not designated as hedging instruments unrealized gain (loss). + References No definition available. + Details
Name: | fe_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsUnrealizedGainLoss
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Derivatives not designated as hedging instruments at fair value net. + References No definition available. + Details
Name: | fe_DerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Outstanding Net Asset (Liability) [Roll Forward] + References No definition available. + Details
Name: | fe_OutstandingNetAssetLiabilityRollForward
Namespace Prefix: | fe_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=fe_NugsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=fe_RegulatedFtrsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |