XML 46 R52.htm IDEA: XBRL DOCUMENT
v3.19.3

Fair Value Measurements - Level 3 Rollforward (Details) - Level 3 - USD ($) $ in Millions | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2019 | Dec. 31, 2018
NUG contracts |  |
Reconciliation of changes in the fair value of FTRs contracts |  |
Beginning Balance, Derivative Assets | $ 0 | $ 0
Beginning Balance, Derivative Liabilities | (44) | (79)
Beginning Balance, Net | (44) | (79)
Unrealized gain (loss), Derivative Assets | 0 | 0
Unrealized loss, Derivative Liabilities | (8) | 2
Unrealized loss, Net | (8) | 2
Purchases, Derivative Assets | 0 | 0
Purchases, Derivative Liabilities | 0 | 0
Purchases, Net | 0 | 0
Settlements, Derivative Assets | 0 | 0
Settlements, Derivative Liabilities | 28 | 33
Settlements, Net | 28 | 33
Ending Balance, Derivative Assets | 0 | 0
Ending Balance, Derivative Liabilities | (24) | (44)
Ending Balance, Net | (24) | (44)
FTRs |  |
Reconciliation of changes in the fair value of FTRs contracts |  |
Beginning Balance, Derivative Assets | 10 | 3
Beginning Balance, Derivative Liabilities | (1) | 0
Beginning Balance, Net | 9 | 3
Unrealized gain (loss), Derivative Assets | 0 | 8
Unrealized loss, Derivative Liabilities | (1) | 1
Unrealized loss, Net | (1) | 9
Purchases, Derivative Assets | 6 | 5
Purchases, Derivative Liabilities | (4) | (5)
Purchases, Net | 2 | 0
Settlements, Derivative Assets | (10) | (6)
Settlements, Derivative Liabilities | 3 | 3
Settlements, Net | (7) | (3)
Ending Balance, Derivative Assets | 6 | 10
Ending Balance, Derivative Liabilities | (3) | (1)
Ending Balance, Net | $ 3 | $ 9

X
- Definition Fair value measurement with unobservable inputs reconciliation recurring basis asset and liability purchases total. + References No definition available. + Details
Name: | fe_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityPurchases
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value measurement with unobservable inputs reconciliation recurring basis asset and (liability) settlements total. + References No definition available. + Details
Name: | fe_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitySettlements
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset unrealized gain loss + References No definition available. + Details
Name: | fe_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetunrealizedgainloss
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability unrealized gain loss. + References No definition available. + Details
Name: | fe_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityUnrealizedGainLoss
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value measurement with unobservable inputs reconciliation recurring basis unrealized gain (loss) total. + References No definition available. + Details
Name: | fe_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisUnrealizedGainLoss
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value measurements with unobservable inputs reconciliation recurring basis asset and liability net value. + References No definition available. + Details
Name: | fe_FairValueMeasurementsWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityNetValue
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of purchases of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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