Pension and Other Postemployment Benefits (Details 4) - Pensions - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Reconciliation of changes in the fair value of pension investments
Beginning balance	$ 5,732
Actual return on plan assets:
Ending balance	5,345	$ 5,732
Private equity funds
Reconciliation of changes in the fair value of pension investments
Beginning balance	25
Actual return on plan assets:
Ending balance	24	25
Real estate funds
Reconciliation of changes in the fair value of pension investments
Beginning balance	421
Actual return on plan assets:
Ending balance	587	421
Level 3
Reconciliation of changes in the fair value of pension investments
Beginning balance	446
Actual return on plan assets:
Ending balance	611	446
Level 3 \| Private equity funds
Reconciliation of changes in the fair value of pension investments
Beginning balance	25	27
Actual return on plan assets:
Unrealized gains (losses)	0	(2)
Realized gains (losses)	(1)	1
Transfers in (out)	0	(1)
Ending balance	24	25
Level 3 \| Real estate funds
Reconciliation of changes in the fair value of pension investments
Beginning balance	421	385
Actual return on plan assets:
Unrealized gains (losses)	42	17
Realized gains (losses)	16	14
Transfers in (out)	108	5
Ending balance	$ 587	$ 421

Defined Benefit Plan Actual Return On Plan Assets Realized Gains Losses.

No definition available.

Name:	fe_DefinedBenefitPlanActualReturnOnPlanAssetsRealizedGainsLosses
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Defined Benefit Plan Actual Return On Plan Assets Unrealized Gains Losses.

+ References

No definition available.

+ Details

Name:	fe_DefinedBenefitPlanActualReturnOnPlanAssetsUnrealizedGainsLosses
Namespace Prefix:	fe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Transfers in and out of Level 3. For example, transfers due to changes in the observability of significant inputs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(02)(C)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(iv)(02)(C)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanTransfersBetweenMeasurementLevels
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 1
-Subparagraph a, f, g
-Article 7

+ Details

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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