<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>529</ContextCount>
  <ElementCount>419</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>149</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>17</UnitCount>
  <MyReports>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001002 - Statement - Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedStatementsofIncome</Role>
      <ShortName>Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002003 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedStatementsofComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003004 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004005 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005006 - Statement - Consolidated Statements of Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedStatementsofStockholdersEquity</Role>
      <ShortName>Consolidated Statements of Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1006007 - Statement - Consolidated Statements of Stockholders' Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedStatementsofStockholdersEquityParenthetical</Role>
      <ShortName>Consolidated Statements of Stockholders' Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1007008 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/ConsolidatedStatementsofCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>1108106 - Statement - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/AccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Accumulated Other Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>1309306 - Statement - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/AccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Tables)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>1410408 - Statement - Accumulated Other Comprehensive Income - Changes in AOCI (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/AccumulatedOtherComprehensiveIncomeChangesinAOCIDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income - Changes in AOCI (Details)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>1411409 - Statement - Accumulated Other Comprehensive Income - Amounts Reclassified (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/AccumulatedOtherComprehensiveIncomeAmountsReclassifiedDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income - Amounts Reclassified (Details)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2101101 - Disclosure - Organization and Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentation</Role>
      <ShortName>Organization and Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2106102 - Disclosure - Revenue</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/Revenue</Role>
      <ShortName>Revenue</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2109103 - Disclosure - Discontinued Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/DiscontinuedOperations</Role>
      <ShortName>Discontinued Operations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2113104 - Disclosure - Earnings Per Share Of Common Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/EarningsPerShareOfCommonStock</Role>
      <ShortName>Earnings Per Share Of Common Stock</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2116105 - Disclosure - Pension and Other Post-Employment Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/PensionandOtherPostEmploymentBenefits</Role>
      <ShortName>Pension and Other Post-Employment Benefits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2119107 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2121108 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2130109 - Disclosure - Regulatory Matters</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/RegulatoryMatters</Role>
      <ShortName>Regulatory Matters</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2134110 - Disclosure - Commitments, Guarantees and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/CommitmentsGuaranteesandContingencies</Role>
      <ShortName>Commitments, Guarantees and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2138111 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Organization and Basis of Presentation (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentationPolicies</Role>
      <ShortName>Organization and Basis of Presentation (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - Organization and Basis of Presentation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentationTables</Role>
      <ShortName>Organization and Basis of Presentation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentation</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2307302 - Disclosure - Revenue (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/RevenueTables</Role>
      <ShortName>Revenue (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/Revenue</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2310303 - Disclosure - Discontinued Operations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/DiscontinuedOperationsTables</Role>
      <ShortName>Discontinued Operations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/DiscontinuedOperations</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2314304 - Disclosure - Earnings Per Share Of Common Stock (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/EarningsPerShareOfCommonStockTables</Role>
      <ShortName>Earnings Per Share Of Common Stock (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/EarningsPerShareOfCommonStock</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2317305 - Disclosure - Pension and Other Post-Employment Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/PensionandOtherPostEmploymentBenefitsTables</Role>
      <ShortName>Pension and Other Post-Employment Benefits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/PensionandOtherPostEmploymentBenefits</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2322307 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/FairValueMeasurements</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2335308 - Disclosure - Commitments, Guarantees and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/CommitmentsGuaranteesandContingenciesTables</Role>
      <ShortName>Commitments, Guarantees and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/CommitmentsGuaranteesandContingencies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2339309 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/SegmentInformation</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2404401 - Disclosure - Organization and Basis of Presentation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentationDetails</Role>
      <ShortName>Organization and Basis of Presentation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentationTables</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Organization and Basis of Presentation - Activity in Uncollectable Accounts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/OrganizationandBasisofPresentationActivityinUncollectableAccountsDetails</Role>
      <ShortName>Organization and Basis of Presentation - Activity in Uncollectable Accounts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/RevenueDetails</Role>
      <ShortName>Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/RevenueTables</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2411404 - Disclosure - Discontinued Operations - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/DiscontinuedOperationsNarrativeDetails</Role>
      <ShortName>Discontinued Operations - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2412405 - Disclosure - Discontinued Operations - Summarized Results (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/DiscontinuedOperationsSummarizedResultsDetails</Role>
      <ShortName>Discontinued Operations - Summarized Results (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2415406 - Disclosure - Earnings Per Share Of Common Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/EarningsPerShareOfCommonStockDetails</Role>
      <ShortName>Earnings Per Share Of Common Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/EarningsPerShareOfCommonStockTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2418407 - Disclosure - Pension and Other Post-Employment Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/PensionandOtherPostEmploymentBenefitsDetails</Role>
      <ShortName>Pension and Other Post-Employment Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/PensionandOtherPostEmploymentBenefitsTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2420410 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/IncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstenergycorp.com/role/IncomeTaxes</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2423411 - Disclosure - Fair Value Measurements - Recurring Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsRecurringAssetsandLiabilitiesDetails</Role>
      <ShortName>Fair Value Measurements - Recurring Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2424412 - Disclosure - Fair Value Measurements - Level 3 Rollforward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsLevel3RollforwardDetails</Role>
      <ShortName>Fair Value Measurements - Level 3 Rollforward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2425413 - Disclosure - Fair Value Measurements - Level 3 Quantitative Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsLevel3QuantitativeInformationDetails</Role>
      <ShortName>Fair Value Measurements - Level 3 Quantitative Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2426414 - Disclosure - Fair Value Measurements - Investments Held in Trusts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsInvestmentsHeldinTrustsDetails</Role>
      <ShortName>Fair Value Measurements - Investments Held in Trusts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2427415 - Disclosure - Fair Value Measurements - Proceeds from the Sale of Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsProceedsfromtheSaleofInvestmentsDetails</Role>
      <ShortName>Fair Value Measurements - Proceeds from the Sale of Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2428416 - Disclosure - Fair Value Measurements - Carrying Amounts of Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsCarryingAmountsofLongtermDebtDetails</Role>
      <ShortName>Fair Value Measurements - Carrying Amounts of Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2429417 - Disclosure - Fair Value Measurements - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/FairValueMeasurementsNarrativeDetails</Role>
      <ShortName>Fair Value Measurements - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2431418 - Disclosure - Regulatory Matters - Maryland and New Jersey (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/RegulatoryMattersMarylandandNewJerseyDetails</Role>
      <ShortName>Regulatory Matters - Maryland and New Jersey (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2432419 - Disclosure - Regulatory Matters - Ohio (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/RegulatoryMattersOhioDetails</Role>
      <ShortName>Regulatory Matters - Ohio (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2433420 - Disclosure - Regulatory Matters - Pennsylvania and West Virginia (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/RegulatoryMattersPennsylvaniaandWestVirginiaDetails</Role>
      <ShortName>Regulatory Matters - Pennsylvania and West Virginia (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2436421 - Disclosure - Commitments, Guarantees and Contingencies - Potential Collateral Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/CommitmentsGuaranteesandContingenciesPotentialCollateralObligationsDetails</Role>
      <ShortName>Commitments, Guarantees and Contingencies - Potential Collateral Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2437422 - Disclosure - Commitments, Guarantees and Contingencies - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/CommitmentsGuaranteesandContingenciesNarrativeDetails</Role>
      <ShortName>Commitments, Guarantees and Contingencies - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2440423 - Disclosure - Segment Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/SegmentInformationNarrativeDetails</Role>
      <ShortName>Segment Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="fe-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2441424 - Disclosure - Segment Information - Financial Data (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstenergycorp.com/role/SegmentInformationFinancialDataDetails</Role>
      <ShortName>Segment Information - Financial Data (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="fe-20200630.htm">fe-20200630.htm</File>
    <File>fe-20200630.xsd</File>
    <File>fe-20200630_cal.xml</File>
    <File>fe-20200630_def.xml</File>
    <File>fe-20200630_lab.xml</File>
    <File>fe-20200630_pre.xml</File>
    <File>q22020-ex311.htm</File>
    <File>q22020-ex312.htm</File>
    <File>q22020-ex32.htm</File>
    <File>q22020-ex32axfirstener.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/stpr/2018-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
