XML 51 R39.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Income Taxes (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016
Income Taxes (Textuals) [Abstract] |  |
Effective tax rate (percent) | 38.10% | 39.40%
Unrecognized tax benefits from lapse of statute of limitations | $ 51 |
Unrecognized tax benefits that would impact effective tax rate | $ 26 |
FES |  |
Income Taxes (Textuals) [Abstract] |  |
Effective tax rate (percent) | 33.90% | 38.50%

X
- Definition Provision for Income Tax. + References No definition available. + Details
Name: | fe_ProvisionForIncomeTaxLineItems
Namespace Prefix: | fe_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32698-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32687-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateContinuingOperations
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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