XML 84 R65.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Organization and Basis of Presentation (Details Textuals) customer in Millions |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 02, 2018 USD ($) | Dec. 13, 2017 USD ($) | Oct. 20, 2017 | Aug. 30, 2017 USD ($) Natural_gas_plant | Jul. 22, 2016 MW | Aug. 31, 2017 USD ($) Natural_gas_plant MW | Jan. 31, 2017 USD ($) MW | Dec. 31, 2017 USD ($) transmission_center MW | Dec. 31, 2016 USD ($) | Sep. 30, 2016 USD ($) | Jun. 30, 2018 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) customer transmission_center company mi MW | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Jan. 31, 2018 USD ($) | Mar. 06, 2017 USD ($) MW | Jan. 18, 2017
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate amount of capacity (in MWs) | MW |  |  |  |  |  |  |  |  |  |  |  |  | 16,000 |  |  |  |  |
Length of transmission lines | mi |  |  |  |  |  |  |  |  |  |  |  |  | 24,500 |  |  |  |  |
Number of regional transmission centers | transmission_center |  |  |  |  |  |  |  | 2 |  |  |  |  | 2 |  |  |  |  |
Impairment of assets |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 42,000,000 |  |  |
Regulatory assets that do not earn a current return |  |  |  |  |  |  |  | $ 7,000,000 | $ 153,000,000 |  |  |  | $ 7,000,000 | $ 153,000,000 |  |  |  |
Capitalized financing costs |  |  |  |  |  |  |  |  |  |  |  |  | 35,000,000 | 37,000,000 | 49,000,000 |  |  |
Interest costs capitalized |  |  |  |  |  |  |  |  |  |  |  |  | 44,000,000 | 66,000,000 | 68,000,000 |  |  |
Property, plant and equipment |  |  |  |  |  |  |  | $ 28,879,000,000 | 29,387,000,000 |  |  |  | 28,879,000,000 | 29,387,000,000 |  |  |  |
Other than temporary impairments |  |  |  |  |  |  |  |  |  |  |  |  | 13,000,000 | 21,000,000 | 102,000,000 |  |  |
Impairments of long-lived assets |  |  |  |  |  |  |  |  |  |  |  |  | 2,406,000,000 | 10,665,000,000 | 42,000,000 |  |  |
Net cash used for financing activities |  |  |  |  |  |  |  |  |  |  |  |  | (702,000,000) | (34,000,000) | (292,000,000) |  |  |
Net cash provided by (used in) operating activities |  |  |  |  |  |  |  |  |  |  |  |  | $ 3,808,000,000 | 3,383,000,000 | 3,460,000,000 |  |  |
Regulated Distribution |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of existing utility operating companies | company |  |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |  |
Number of customers served by utility operating companies | customer |  |  |  |  |  |  |  |  |  |  |  |  | 6 |  |  |  |  |
Plant generation capacity (in MW's) | MW |  |  |  |  |  |  |  | 3,790 |  |  |  |  | 3,790 |  |  |  |  |
Impairment of assets |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8,000,000 |  |  |
Property, plant and equipment, net |  |  |  |  |  |  |  | $ 2,100,000,000 |  |  |  |  | $ 2,100,000,000 |  |  |  |  |
Property, plant and equipment |  |  |  |  |  |  |  | $ 18,916,000,000 | 18,282,000,000 |  |  |  | $ 18,916,000,000 | 18,282,000,000 |  |  |  |
Competitive Energy Services |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant generation capacity (in MW's) | MW |  |  |  |  |  |  |  | 12,303 |  |  |  |  | 12,303 |  |  |  |  |
Impairment of assets |  |  |  |  |  |  |  |  | 9,218,000,000 |  |  |  |  |  | 34,000,000 |  |  |
Impairment of assets |  |  |  |  |  |  |  |  |  |  |  |  | $ 193,000,000 |  |  |  |  |
Property, plant and equipment |  |  |  |  |  |  |  | $ 972,000,000 | 2,866,000,000 |  |  |  | $ 972,000,000 | 2,866,000,000 |  |  |  |
Bath County, Virginia |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant generation capacity (in MW's) | MW |  |  |  |  |  |  |  | 3,003 |  |  |  |  | 3,003 |  |  |  |  |
MP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (percent) |  |  |  |  |  |  |  |  |  |  |  |  | 41.00% |  |  |  |  |
Virginia Electric and Power Company | Bath County, Virginia |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate ownership share (percent) |  |  |  |  |  |  |  | 60.00% |  |  |  |  | 60.00% |  |  |  |  |
FES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment of assets |  |  |  |  |  |  |  | $ 2,045,000,000 |  |  |  |  |  |  | 33,000,000 |  |  |
Interest costs capitalized |  |  |  |  |  |  |  |  |  |  |  |  | $ 26,000,000 | 34,000,000 | 35,000,000 |  |  |
Property, plant and equipment |  |  |  |  |  |  |  | 694,000,000 | 1,555,000,000 |  |  |  | 694,000,000 | 1,555,000,000 |  |  |  |
Other than temporary impairments |  |  |  |  |  |  |  |  |  |  |  |  | 13,000,000 | 19,000,000 | 90,000,000 |  |  |
Impairments of long-lived assets |  |  |  |  |  |  |  |  |  |  |  |  | 2,031,000,000 | 8,622,000,000 | 33,000,000 |  |  |
Net cash used for financing activities |  |  |  |  |  |  |  |  |  |  |  |  | (166,000,000) | 56,000,000 | (273,000,000) |  |  |
Net cash provided by (used in) operating activities |  |  |  |  |  |  |  |  |  |  |  |  | $ 727,000,000 | 786,000,000 | 1,152,000,000 |  |  |
FES | Competitive Energy Services |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment of assets |  |  |  |  |  |  |  | 2,000,000,000 | 8,082,000,000 |  |  |  |  |  |  |  |  |
Impairment of assets |  |  |  |  |  |  |  | $ 2,000,000,000 |  |  |  |  |  |  |  |  |  |
AGC | Bath County, Virginia |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant generation capacity (in MW's) | MW |  |  |  |  |  |  |  | 1,200 |  |  |  |  | 1,200 |  |  |  |  |
Proportionate ownership share (percent) |  |  |  |  |  |  |  | 40.00% |  |  |  |  | 40.00% |  |  |  |  |
Property, plant and equipment |  |  |  |  |  |  |  | $ 531,000,000 |  |  |  |  | $ 531,000,000 |  |  |  |  |
AGC | Bath County, Virginia | Competitive Energy Services |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment |  |  |  |  |  |  |  | $ 365,000,000 |  |  |  |  | $ 365,000,000 |  |  |  |  |
Signal Peak | Global Holding | FEV |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (percent) |  |  |  |  |  |  |  | 33.33% |  |  |  |  | 33.33% |  |  |  |  |
Impairments of long-lived assets |  |  |  |  |  |  |  |  |  |  |  |  |  | 362,000,000 |  |  |  |
Bay Shore Unit 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant capacity (in MW's) | MW |  |  |  |  | 136 |  |  |  |  |  |  |  |  |  |  |  |  |
Sammis Power Plant Units 1-4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant capacity (in MW's) | MW |  |  |  |  | 720 |  |  |  |  |  |  |  |  |  |  |  |  |
Pleasants Power Station |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant generation capacity (in MW's) | MW |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,300 |
Assets purchase agreement consideration to be received |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 195,000,000 |
Impairment of assets |  |  |  |  |  |  |  | $ 120,000,000 |  |  |  |  |  |  |  |  |  |
Forecast | FES | Competitive Energy Services |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt that needs to be refinanced |  |  |  |  |  |  |  |  |  |  |  | $ 515,000,000 |  |  |  |  |  |
Principal payment | $ 100,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase Agreement with Subsidiary of LS Power |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant generation capacity (in MW's) | MW |  |  |  |  |  | 1,615 |  | 756 |  |  |  |  | 756 |  |  |  |  |
Cash purchase price |  |  |  |  |  | $ 825,000,000 | $ 825,000,000 |  |  |  |  |  |  |  |  |  |  |
Plant capacity (in MW's) | MW |  |  |  |  |  |  | 1,615 |  |  |  |  |  |  |  |  |  |  |
Purchase Agreement with Subsidiary of LS Power | AE Supply |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of gas generating plants | Natural_gas_plant |  |  |  | 4 |  | 4 |  |  |  |  |  |  |  |  |  |  |  |
Discharge of note indenture |  |  |  | $ 305,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Make-whole premiums |  |  |  |  |  |  |  |  |  |  |  |  | $ 95,000,000 |  |  |  |  |
Ownership interest (percent) |  |  |  |  |  |  |  |  |  |  |  |  | 59.00% |  |  |  |  |
Purchase Agreement with Subsidiary of LS Power | AE Supply | Bath County, Virginia |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proportionate ownership share (percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 23.75%
Purchase Agreement with Subsidiary of LS Power | AGC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Plant ownership percentage |  |  | 59.00% | 59.00% |  | 59.00% |  |  |  |  |  |  |  |  |  |  |  |
Make-whole premiums |  |  |  |  |  |  |  |  |  |  |  |  | $ 95,000,000 |  |  |  |  |
Purchase Agreement with Subsidiary of LS Power | Natural Gas Generating Plants |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash purchase price |  | $ 388,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase Agreement with Subsidiary of LS Power | Forecast | Bath County Hydroelectric Power Station and Buchanan Generating Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash purchase price |  |  |  |  |  |  |  |  |  |  | $ 375,000,000 |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount borrowed under revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 5,000,000,000 |  |
Subsequent Event | FES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount borrowed under revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 500,000,000 |  |
Line of Credit | Revolving Credit Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount borrowed under revolving credit facility |  |  |  |  |  |  |  | $ 5,000,000,000 | 500,000,000 |  |  |  | 5,000,000,000 | 500,000,000 |  |  |  |
Line of Credit | Revolving Credit Facility | FES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount borrowed under revolving credit facility |  |  |  |  |  |  |  |  | 500,000,000 |  |  |  |  | 500,000,000 |  |  |  |
Line of Credit | Revolving Credit Facility | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount borrowed under revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,000,000,000 |  |
Line of Credit | Revolving Credit Facility | Subsequent Event | FES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount borrowed under revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 500,000,000 |  |
Utilization of Accelerated Useful Life |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Out-of period adjustment |  |  |  |  |  |  |  |  |  | $ 21,000,000 |  |  |  | 19,000,000 |  |  |  |
Accounting Standards Update 2016-09 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net cash used for financing activities |  |  |  |  |  |  |  |  |  |  |  |  |  | 12,000,000 | 13,000,000 |  |  |
Net cash provided by (used in) operating activities |  |  |  |  |  |  |  |  |  |  |  |  |  | (12,000,000) | (13,000,000) |  |  |
Accounting Standards Update 2017-07 | Pro Forma |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reclassification of non-service costs |  |  |  |  |  |  |  |  |  |  |  |  | 62,000,000 |  |  |  |  |
Retained Earnings (Accumulated Deficit) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based compensation accounting change (Note 1) |  |  |  |  |  |  |  | (6,000,000) |  |  |  |  | (6,000,000) |  |  |  |  |
Retained Earnings (Accumulated Deficit) | Accounting Standards Update 2016-09 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based compensation accounting change (Note 1) |  |  |  |  |  |  |  |  | $ 6,000,000 |  |  |  |  | 6,000,000 |  |  |  |
Retained Earnings (Accumulated Deficit) | Accounting Standards Update 2016-01 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based compensation accounting change (Note 1) |  |  |  |  |  |  |  | 115,000,000 |  |  |  |  | 115,000,000 |  |  |  |  |
Retained Earnings (Accumulated Deficit) | Accounting Standards Update 2016-01 | FES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based compensation accounting change (Note 1) |  |  |  |  |  |  |  | $ 115,000,000 |  |  |  |  | $ 115,000,000 |  |  |  |  |
Deferred Purchased Power and Fuel Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Prior period reclassification adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  | (30,000,000) | (105,000,000) |  |  |
Amortization of Regulatory Assets, Net |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Prior period reclassification adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 30,000,000 | $ 105,000,000 |  |  |
PCRB | Purchase Agreement with Subsidiary of LS Power | AE Supply |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Discharge of note indenture |  |  |  | $ 142,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Notes | Purchase Agreement with Subsidiary of LS Power | AGC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Discharge of note indenture |  |  |  | $ 100,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Aggregate Amount of Capacity + References No definition available. + Details
Name: | fe_AggregateAmountofCapacity
Namespace Prefix: | fe_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Asset Purchase Agreement, Consideration + References No definition available. + Details
Name: | fe_AssetPurchaseAgreementConsideration
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Number of Gas Generating Plants + References No definition available. + Details
Name: | fe_DisposalGroupIncludingDiscontinuedOperationNumberofGasGeneratingPlants
Namespace Prefix: | fe_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Impairment of Long-Lived Assets to be Disposed of, Plant Capacity + References No definition available. + Details
Name: | fe_ImpairmentofLongLivedAssetstobeDisposedofPlantCapacity
Namespace Prefix: | fe_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Length of Transmission Lines + References No definition available. + Details
Name: | fe_LengthofTransmissionLines
Namespace Prefix: | fe_
Data Type: | num:lengthItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Customers. + References No definition available. + Details
Name: | fe_NumberOfCustomers
Namespace Prefix: | fe_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of existing utility operating companies. + References No definition available. + Details
Name: | fe_NumberOfExistingUtilityOperatingCompanies
Namespace Prefix: | fe_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Regional Transmission Centers + References No definition available. + Details
Name: | fe_NumberofRegionalTransmissionCenters
Namespace Prefix: | fe_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Payments of Debt Redemption Make-whole Premiums + References No definition available. + Details
Name: | fe_PaymentsofDebtRedemptionMakewholePremiums
Namespace Prefix: | fe_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Plant Capacity + References No definition available. + Details
Name: | fe_PlantCapacity
Namespace Prefix: | fe_
Data Type: | num:powerItemType
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 Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
Name: | us-gaap_AssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611 + Details
Name: | us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption. + References No definition available. + Details
Name: | us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the required periodic payments applied to principal. + 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 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 958 -SubTopic 225 -Section 45 -Paragraph 11 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84241808&loc=d3e92212-112881 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2921-110230 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2611-110228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest capitalized during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 + Details
Name: | us-gaap_InterestCostsCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The proportionate share of interest (percent) in a jointly owned utility plant. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 + Details
Name: | us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- 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

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: 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(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 26 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3574-108585 + Details
Name: | us-gaap_NetCashProvidedByUsedInFinancingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585 + Details
Name: | us-gaap_NetCashProvidedByUsedInOperatingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the effect of a change in accounting principle on net income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22583-107794 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22580-107794 + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnNetIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 8A -URI http://asc.fasb.org/extlink&oid=82896770&loc=SL6284422-111562 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of a reclassification adjustment made to prior period financial statement amounts. + References No definition available. + Details
Name: | us-gaap_PriorPeriodReclassificationAdjustment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the amount received from the sale of a business segment or subsidiary or sale of an entity that is related to it but not strictly controlled during the period (for example, an unconsolidated subsidiary, affiliate, joint venture or equity method investment). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. + 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(13)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: 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(14)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(8)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
Name: | us-gaap_PropertyPlantAndEquipmentNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501569&loc=d3e55921-110430 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501662&loc=d3e56162-110433 + Details
Name: | us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Period end amount of property, plant and equipment (PPE) related to generation or processing owned by public utility. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesPropertyPlantAndEquipmentGenerationOrProcessing
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of each individual error being corrected in the correcting adjustment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 1.N) -URI http://asc.fasb.org/extlink&oid=26874127&loc=d3e30840-122693 + Details
Name: | us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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_RegulatoryAssetLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Remaining balance of regulatory assets for which no return on investment during recovery is provided. In some cases, a regulator may permit an enterprise to include a cost that would be charged to expense by an unregulated enterprise as an allowable cost over a period of time by amortizing that cost for rate-making purposes, but the regulator does not include the unrecovered amount in the rate base. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 55 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82849221&loc=d3e44360-110383 + Details
Name: | us-gaap_RemainingAmountsOfRegulatoryAssetsForWhichNoReturnOnInvestmentDuringRecoveryPeriodIsProvided
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=77990344&loc=SL6759159-111685 + Details
Name: | us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=fe_RegulatedDistributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=fe_CompetitiveEnergyServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=stpr_VA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | fe_BusinessUnitsAxis=fe_SignalPeakMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=fe_GlobalHoldingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_PublicUtilityAxis=fe_BayShoreUnit1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=fe_SammisPowerPlantUnits14Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=fe_PleasantsPowerStationMember
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: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=fe_PurchaseAgreementwithSubsidiaryofLSPowerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortTermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis=fe_UtilizationofAcceleratedUsefulLifeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201609Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=fe_AccountingStandardsUpdate201707Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201601Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=fe_DeferredPurchasedPowerandFuelCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=fe_AmortizationofRegulatoryAssetsNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=fe_PcrbMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |