Guarantor Obligations, Curing Period

No definition available.

Name:	fe_GuarantorObligationsCuringPeriod
Namespace Prefix:	fe_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=fe_AtCurrentCreditRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=fe_UponFurtherDowngradeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_SuretyBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=fe_RegulatedDistributionandRegulatedTransmissionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidatedEntitiesAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_FesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=fe_LittleBullRunMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=fe_PennsylvaniaDepartmentofEnvironmentalProtectionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=fe_OhioEnvironmentalProtectionAgencyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fe_AeSupplyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments, Guarantees and Contingencies (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jan. 31, 2017
Guarantor Obligations [Line Items]
Guarantor obligations	$ 420,000,000
At Current Credit Rating
Guarantor Obligations [Line Items]
Guarantor obligations	8,000,000
Upon Further Downgrade
Guarantor Obligations [Line Items]
Guarantor obligations	43,000,000
Surety Bond (Collateralized Amount)
Guarantor Obligations [Line Items]
Guarantor obligations	$ 369,000,000
Curing period	30 days
Regulated
Guarantor Obligations [Line Items]
Guarantor obligations	$ 135,000,000
Regulated \| At Current Credit Rating
Guarantor Obligations [Line Items]
Guarantor obligations	0
Regulated \| Upon Further Downgrade
Guarantor Obligations [Line Items]
Guarantor obligations	43,000,000
Regulated \| Surety Bond (Collateralized Amount)
Guarantor Obligations [Line Items]
Guarantor obligations	92,000,000
FirstEnergy
Guarantor Obligations [Line Items]
Guarantor obligations	187,000,000
FirstEnergy \| At Current Credit Rating
Guarantor Obligations [Line Items]
Guarantor obligations	0
FirstEnergy \| Upon Further Downgrade
Guarantor Obligations [Line Items]
Guarantor obligations	0
FirstEnergy \| Surety Bond (Collateralized Amount)
Guarantor Obligations [Line Items]
Guarantor obligations	187,000,000
FES
Guarantor Obligations [Line Items]
Guarantor obligations	71,000,000
FES \| At Current Credit Rating
Guarantor Obligations [Line Items]
Guarantor obligations	6,000,000
FES \| Upon Further Downgrade
Guarantor Obligations [Line Items]
Guarantor obligations	0
FES \| Surety Bond (Collateralized Amount)
Guarantor Obligations [Line Items]
Guarantor obligations	65,000,000
FES \| Surety Bond (Collateralized Amount) \| Little Bull Run \| PA DEP
Guarantor Obligations [Line Items]
Amount of surety bond		$ 169,000,000
FES \| Surety Bond (Collateralized Amount) \| Little Bull Run \| Ohio Environmental Protection Agency
Guarantor Obligations [Line Items]
Amount of surety bond		$ 12,000,000
AE Supply
Guarantor Obligations [Line Items]
Guarantor obligations	27,000,000
AE Supply \| At Current Credit Rating
Guarantor Obligations [Line Items]
Guarantor obligations	2,000,000
AE Supply \| Upon Further Downgrade
Guarantor Obligations [Line Items]
Guarantor obligations	0
AE Supply \| Surety Bond (Collateralized Amount)
Guarantor Obligations [Line Items]
Guarantor obligations	$ 25,000,000