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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

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

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001409902</rptOwnerCik>
            <rptOwnerName>Donahue Paul D</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>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-12-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2923</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2923</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2923</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-12-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1371</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1371</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1371</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. 2018 Omnibus Incentive Compensation Plan. Pursuant to the Agreement and Plan of Merger by and between SunTrust Banks, Inc. (&quot;SunTrust&quot;) and BB&amp;T Corporation (BB&amp;T), dated February 7, 2019 and amended as of June 14, 2019 (the &quot;Merger Agreement&quot;), SunTrust was merged with and into BB&amp;T on December 6, 2019 (the &quot;Merger&quot;). Pursuant to the Merger, each issued and outstanding share of SunTrust common stock was converted into the right to receive 1.295 shares of BB&amp;T common stock. The closing price of BB&amp;T common stock on the New York Stock Exchange on the effective date of the Merger was $54.24. Following and in connection with the Merger, BB&amp;T changed its name to Truist Financial Corporation (&quot;Truist&quot;).</footnote>
        <footnote id="F2">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 phantom stock unit immediately prior to the effective time of the Merger.</footnote>
        <footnote id="F3">These phantom stock units replaced SunTrust phantom stock units in respect of an aggregate 2,257.322 shares of SunTrust common stock.</footnote>
        <footnote id="F4">Represents phantom stock units issued under the SunTrust Banks, Inc. Directors' Deferred 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 phantom stock unit immediately prior to the effective time of the Merger.</footnote>
        <footnote id="F5">These phantom stock units replaced SunTrust phantom stock units in respect of an aggregate 1,058.856 shares of SunTrust common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Carla Brenwald, Attorney-in-fact</signatureName>
        <signatureDate>2019-12-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
