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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-04-24</periodOfReport>

    <issuer>
        <issuerCik>0000808362</issuerCik>
        <issuerName>BAKER HUGHES INC</issuerName>
        <issuerTradingSymbol>BHI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001566186</rptOwnerCik>
            <rptOwnerName>Deskus Archana</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2929 ALLEN PARKWAY, SUITE 2100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>VP &amp; Chief Information Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2014-04-24</value>
                <footnoteId id="F2"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7403</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, $1.00 Par Value</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7403</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7403</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive without payment one share of Baker Hughes common stock.</footnote>
        <footnote id="F2">The restricted stock unit grant was approved by the compensation committee of Baker Hughes Incorporated's board of directors on January 22, 2014, subject to stockholder approval of the 2002 Director and Officer Long-Term Incentive Plan, under which the RSU was granted. Baker Hughes' stockholders approved the plan on April 24, 2014.</footnote>
        <footnote id="F3">Restricted stock units vest in three equal annual installments beginning on January 22, 2015.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Lee Whitley, Attorney-in-Fact</signatureName>
        <signatureDate>2014-04-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
