<SEC-DOCUMENT>0001127602-25-016650.txt : 20250603
<SEC-HEADER>0001127602-25-016650.hdr.sgml : 20250603
<ACCEPTANCE-DATETIME>20250603213449
ACCESSION NUMBER:		0001127602-25-016650
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250319
FILED AS OF DATE:		20250603
DATE AS OF CHANGE:		20250603

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TIERNEY BRIAN X
		CENTRAL INDEX KEY:			0001423515
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	333-21011
		FILM NUMBER:		251021771

	MAIL ADDRESS:	
		STREET 1:		76 S. MAIN ST.
		CITY:			AKRON
		STATE:			OH
		ZIP:			44308

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRSTENERGY CORP
		CENTRAL INDEX KEY:			0001031296
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		ORGANIZATION NAME:           	01 Energy & Transportation
		EIN:				341843785
		STATE OF INCORPORATION:			OH
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		341 WHITE POND DRIVE
		CITY:			AKRON
		STATE:			OH
		ZIP:			44320
		BUSINESS PHONE:		330-761-7837

	MAIL ADDRESS:	
		STREET 1:		341 WHITE POND DRIVE
		CITY:			AKRON
		STATE:			OH
		ZIP:			44320
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-03-19</periodOfReport>

    <issuer>
        <issuerCik>0001031296</issuerCik>
        <issuerName>FIRSTENERGY CORP</issuerName>
        <issuerTradingSymbol>FE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001423515</rptOwnerCik>
            <rptOwnerName>TIERNEY BRIAN X</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>341 WHITE POND DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>AKRON</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44320</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <officerTitle>Board Chair, President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-03-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>103110</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>384408.891</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-06-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16625</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>41.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>367783.891</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>713.408</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Savings Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These securities are restricted stock units (&quot;RSUs&quot;), each representing a contingent right to receive one share of common stock, par value $0.10 per share, of FirstEnergy Corp. (the &quot;Company&quot;). The RSUs were granted under the Company's 2020 Incentive Compensation Plan and will vest in full on March 1, 2028. This transaction is being reported late due to an inadvertent administrative error and not any error of the Reporting Person.</footnote>
        <footnote id="F2">Balance includes dividends accrued on time-based equity awards.</footnote>
        <footnote id="F3">This Form 4 is being filed to report the number of shares withheld to satisfy the reporting person's tax withholding obligation upon the vesting of 36,630 shares of restricted common stock granted pursuant to the terms of the Restricted Stock Award Agreement, dated June 1, 2023, between the Company and the reporting person.</footnote>
        <footnote id="F4">The Company's 401(k) Savings Plan (&quot;401(k) Plan&quot;) includes a unitized fund invested in shares of common stock of the Company, in which the reporting person may invest, and includes dividend reinvestment and company match features. The number of shares reported as indirectly held in the 401(k) Plan in this row is an estimate of the number of shares of the Company's common stock held in the unitized stock fund since the reporting person's last filed Form 4 and as allocated to the reporting person's account as of May 31, 2025.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Mary M. Swann, attorney-in-fact</signatureName>
        <signatureDate>2025-06-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
