<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2019-12-06</periodOfReport>

    <dateOfOriginalSubmission>2019-12-10</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000092230</issuerCik>
        <issuerName>TRUIST FINANCIAL CORP</issuerName>
        <issuerTradingSymbol>TFC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001789902</rptOwnerCik>
            <rptOwnerName>Maguire Michael Baron</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>214 N. TRYON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-12-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2891</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2020-02-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2020-02-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2891</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2891</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents phantom stock units issued under the SunTrust Banks, Inc. 2009 Stock Plan or the SunTrust Banks Inc. 2018 Omnibus Incentive Compensation Plan. Pursuant to the Merger Agreement, at the effective time of the Merger, each outstanding SunTrust phantom stock  unit automatically converted into a BB&amp;T phantom stock unit in respect of shares of BB&amp;T common stock, with the number of underlying shares of BB&amp;T common stock determined as set forth in the Merger Agreement. Following and in connection with the Merger, BB&amp;T changed its name to Truist. Each Truist phantom stock unit is subject to the same terms and conditions (including service-based vesting terms) as applied to the corresponding SunTrust stock unit immediately prior to the effective time of the Merger.</footnote>
        <footnote id="F2">Consists of time-vested phantom stock settled in cash.</footnote>
    </footnotes>

    <remarks>This Amendment is being filed to correctly state the title of the derivative security as Phantom Stock inadvertently reported as Restricted Stock on the previous amendment and to clarify that the award will settle in cash rather than Truist shares.</remarks>

    <ownerSignature>
        <signatureName>Carla Brenwald, Attorney-in-Fact</signatureName>
        <signatureDate>2020-02-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
