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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-11-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001389170</issuerCik>
        <issuerName>Targa Resources Corp.</issuerName>
        <issuerTradingSymbol>TRGP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001157334</rptOwnerCik>
            <rptOwnerName>Warburg Pincus Private Equity VIII, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001332737</rptOwnerCik>
            <rptOwnerName>Warburg Pincus Private Equity IX, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001342445</rptOwnerCik>
            <rptOwnerName>Warburg Pincus IX LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001322709</rptOwnerCik>
            <rptOwnerName>Warburg Pincus Partners LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000929408</rptOwnerCik>
            <rptOwnerName>WARBURG PINCUS &amp; CO.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001162870</rptOwnerCik>
            <rptOwnerName>WARBURG PINCUS LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001239318</rptOwnerCik>
            <rptOwnerName>KAYE CHARLES R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001220638</rptOwnerCik>
            <rptOwnerName>Landy Joseph P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARBURG PINCUS &amp; CO.</rptOwnerStreet1>
            <rptOwnerStreet2>450 LEXINGTON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2012-11-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1248947</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4708304</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On November 6, 2012, Warburg Pincus Private Equity VIII, L.P., a Delaware limited partnership (&quot;WP VIII&quot;, and together with its two affiliated partnerships Warburg Pincus Netherlands Private Equity VIII C.V. I, a company formed under the laws of the Netherlands, and WP-WPVIII Investors, L.P., a Delaware limited partnership, the &quot;WP VIII Funds&quot;) and Warburg Pincus Private Equity IX, L.P., a Delaware limited partnership (&quot;WP IX&quot;, and together with the WP VIII Funds, the &quot;Funds&quot;), distributed an aggregate of 1,248,947 shares of the common stock (the &quot;Shares&quot;) of Targa Resources Corp. (the &quot;Issuer&quot;) to their partners on a pro rata basis (the &quot;WP Distribution&quot;), with no consideration being paid in connection therewith.</footnote>
        <footnote id="F2">These Shares are owned by the Funds. The general partner of WP VIII is Warburg Pincus Partners LLC, a New York limited liability company (&quot;WP Partners LLC&quot;), and the general partner of WP IX is Warburg Pincus IX, LLC, a New York limited liability company (&quot;WP IX LLC&quot;), of which WP Partners LLC is the sole member. Warburg Pincus &amp; Co., a New York general partnership (&quot;WP&quot;), is the managing member of WP Partners LLC. The Funds are managed by Warburg Pincus LLC, a New York limited liability company (&quot;WP LLC&quot;). Charles R. Kaye and Joseph P. Landy, each a Managing General Partner of WP and a Co-President and Managing Member of WP LLC, may be deemed to control the WP VIII Funds, WP IX, WP IX LLC, WP Partners LLC, WP and WP LLC.</footnote>
        <footnote id="F3">Each of the WP VIII Funds, WP IX, WP IX LLC, WP Partners LLC, WP, WP LLC, and Messrs. Charles R. Kaye and Joseph P. Landy is a &quot;Reporting Person&quot; and collectively, the &quot;Warburg Pincus Reporting Persons&quot;. By reason of the provisions of Rule 16a-1 of the Securities Exchange Act of 1934, as amended, each of the Warburg Pincus Reporting Persons, other than the Funds, may be deemed to be the beneficial owners of any securities that may be deemed to be beneficially owned by the Funds.  Each of the Warburg Pincus Reporting Persons, other than the Funds, disclaim beneficial ownership of all Shares of the Issuer except to the extent of any indirect pecuniary interest therein.  Pursuant to Rule 16a-1(a)(4) of the Exchange Act, each of the Warburg Pincus Reporting Persons, other than the Funds, herein states that this Form 4 shall not be deemed an admission that it or he is the beneficial owner of any of the Shares of the Issuer reported in this Form 4.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>WARBURG PINCUS PRIVATE EQUITY VIII, L.P. By: Warburg Pincus Partners LLC, its General Partner By: Warburg Pincus &amp; Co., its Managing Member By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Partner</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WARBURG PINCUS PRIVATE EQUITY IX, L.P. By: Warburg Pincus IX LLC, Its General Partner By: Warburg Pincus Partners LLC, its Sole Member By: Warburg Pincus &amp; Co., its Managing Member By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Partner</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WARBURG PINCUS IX LLC By: Warburg Pincus Partners LLC, its Sole Member By: Warburg Pincus &amp; Co., its Managing Member By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Partner</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WARBURG PINCUS PARTNERS LLC By: Warburg Pincus &amp; Co., its Managing Member By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Partner</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WARBURG PINCUS &amp; CO. By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Partner</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WARBURG PINCUS LLC By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Managing Director</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>CHARLES R. KAYE By: /s/ Scott A. Arenare Name: Charles R. Kaye By: Scott A. Arenare, Attorney-in-Fact*</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>JOSEPH P. LANDY By: /s/ Scott A. Arenare Name: Joseph P. Landy By: Scott A. Arenare, Attorney-in-Fact*</signatureName>
        <signatureDate>2012-11-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
