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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-02-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000797468</issuerCik>
        <issuerName>OCCIDENTAL PETROLEUM CORP /DE/</issuerName>
        <issuerTradingSymbol>oxy</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182479</rptOwnerCik>
            <rptOwnerName>FEICK JOHN E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MATRIX SOLUTIONS, INC.,</rptOwnerStreet1>
            <rptOwnerStreet2>230 , 319 -2 AVENUE, S.W.</rptOwnerStreet2>
            <rptOwnerCity>CALGARY</rptOwnerCity>
            <rptOwnerState>A6</rptOwnerState>
            <rptOwnerZipCode>T2P OC5</rptOwnerZipCode>
            <rptOwnerStateDescription>ONTARIO, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-02-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>69.4258</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>36000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported is an average sales price.  400 shares were sold at $69.36; 500 shares were sold at $69.37; 200 shares were sold at $69.38; 900 shares were sold at $69.39; 700 shares were sold at $69.41; 1,400 shares were sold at $69.42; 2,300 shares were sold at $69.43; 1,300 shares were sold at $69.44; 1,200 shares were sold at $69.45; 100 shares were sold at $69.46; and 1,000 shares were sold at $69.48.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Christel H. Pauli, Attorney-in-Fact for John E. Feick</signatureName>
        <signatureDate>2008-02-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
