XML 116 R98.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Leases (Details Textuals) $ in Millions |  |  |  |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2017 | Jun. 30, 2016 | May 30, 2016 | May 23, 2016 USD ($) | Nov. 30, 2014 USD ($) MW | Dec. 31, 2007 | Dec. 30, 1987 | Dec. 31, 2016
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Period of lease terms on the portions sold by OE of its ownership interests in Perry Unit 1 and Beaver Valley Unit 2 in years |  |  |  |  |  |  | 29 years |
Period of lease terms on the portions sold by CEI and TE of their ownership interests in Beaver Valley Unit 2 and Bruce Mansfield Units |  |  |  |  |  |  | 30 years |
Beaver Valley Unit 2 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Percentage leased |  |  |  |  |  |  |  | 2.60%
Bruce Mansfield Unit 1 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Percentage leased |  |  |  |  |  |  |  | 93.83%
Perry Power Plant Unit 1 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Percentage of leasehold interest related to sale leaseback arrangements |  |  |  | 3.75% |  |  |  |
FG |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Percentage of undivided interest of FGCO in Bruce Mansfield Unit 1 |  |  |  |  |  | 93.825% |  |
FG | Bruce Mansfield Unit 1 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Basic terms of operating lease |  |  |  |  |  | 33 years |  |
NG | Perry Power Plant Unit 1 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Payments to acquire interest in subsidiaries |  |  |  | $ 50 |  |  |  |
Plant ownership percentage |  | 100.00% | 100.00% |  |  |  |  |
NG | Perry Power Plant Unit 1 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Purchase of lessor equity interests in sale and leaseback (in MW) | MW |  |  |  |  | 55.3 |  |  |
Purchase of lessor equity interests in sale and leaseback, value |  |  |  |  | $ 87 |  |  |
Forecast | NG | Perry Power Plant Unit 1 |  |  |  |  |  |  |  |
Leases (Textuals) [Abstract] |  |  |  |  |  |  |  |
Plant ownership percentage | 100.00% |  |  |  |  |  |  |

X
- Definition Basic terms of operating lease. + References No definition available. + Details
Name: | fe_BasicTermsOfOperatingLease
Namespace Prefix: | fe_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Leases. + References No definition available. + Details
Name: | fe_LeasesTextualsAbstract
Namespace Prefix: | fe_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating lease term of Other Subsidiaries . + References No definition available. + Details
Name: | fe_OperatingLeaseTermOfOtherSubsidiaries
Namespace Prefix: | fe_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of undivided interest of non guarantor subsidiary. + References No definition available. + Details
Name: | fe_PercentageOfUndividedInterestOfNonGuarantorSubsidiary
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Plant Ownership Percentage + References No definition available. + Details
Name: | fe_PublicUtilitiesPlantOwnershipPercentage
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Purchase of Lessor Equity Interests in Sale and Leaseback + References No definition available. + Details
Name: | fe_PurchaseOfLessorEquityInterestsInSaleAndLeaseback
Namespace Prefix: | fe_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Purchase of Lessor Equity Interests in Sale and Leaseback, Value + References No definition available. + Details
Name: | fe_PurchaseOfLessorEquityInterestsInSaleAndLeasebackValue
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Sale Leaseback Transaction, Percentage Of Leasehold Interest Related to Sale Leaseback Arrangement + References No definition available. + Details
Name: | fe_SaleLeasebackTransactionPercentageOfLeaseholdInterestRelatedtoSaleLeasebackArrangements
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Sale Leaseback Transaction, Percentage Of Undivided Interest Of Non Guarantor Subsidiary + References No definition available. + Details
Name: | fe_SaleLeasebackTransactionPercentageOfUndividedInterestOfNonGuarantorSubsidiary
Namespace Prefix: | fe_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Subsidiary one Operating lease term of Subsidiary one. + References No definition available. + Details
Name: | fe_SubsidiaryOneOperatingLeaseTermOfSubsidiaryOne
Namespace Prefix: | fe_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_PublicUtilityAxis=fe_BeaverValleyUnit2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=fe_BruceMansfieldUnit1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=fe_PerryPowerPlantUnitOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_FgcoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_FirstEnergyNuclearGenerationLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=fe_NuclearGenerationCorpMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |