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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-02-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001404912</issuerCik>
        <issuerName>KKR &amp; Co. L.P.</issuerName>
        <issuerTradingSymbol>KKR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001494539</rptOwnerCik>
            <rptOwnerName>Sorkin David</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KKR &amp; CO. L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>9 WEST 57TH STREET, 42ND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>General Counsel and Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>KKR Group Partnership Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-02-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>31819</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Units</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>31819</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3417216</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person's interests in KKR Group Partnership Units (which term refers collectively to Class A partner interests in each of KKR Management Holdings L.P. and KKR Fund Holdings L.P.) are represented by units of KKR Holdings L.P., the entity that indirectly owns the KKR Group Partnership Units.  Units of KKR Holdings L.P. are exchangeable for KKR Group Partnership Units on a one-for-one basis, and KKR Group Partnership Units are exchangeable for KKR &amp; Co. L.P. common units on a one-for-one basis.</footnote>
        <footnote id="F2">These interests were granted by KKR Holdings L.P. to the Reporting Person for his service to KKR &amp; Co. L.P. and its affiliates, will vest in equal annual installments over a four-year period with the initial 25% vesting on April 1, 2012 and will be subject to additional one- and two-year transfer restrictions based on the Reporting Person's compliance with his confidentiality and restrictive covenant agreement.  The amount of the grant was calculated in accordance with a formula, the result of which became fixed after the close of trading on December 31, 2010.</footnote>
    </footnotes>

    <remarks>Pursuant to Rule 16a-1(a)(4), of the Securities Exchange Act of 1934, as amended, the Reporting Person states that this filing shall not be an admission that the Reporting Person is the beneficial owner of any of the securities reported herein, and the Reporting Person disclaims beneficial ownership of such securities except to the extent of the Reporting Person's pecuniary interest therein.</remarks>

    <ownerSignature>
        <signatureName>/s/ David J. Sorkin</signatureName>
        <signatureDate>2011-02-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
