<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-11-06</periodOfReport>
    <issuer>
        <issuerCik>0001137411</issuerCik>
        <issuerName>ROCKWELL COLLINS INC</issuerName>
        <issuerTradingSymbol>COL</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001237337</rptOwnerCik>
            <rptOwnerName>KIRCHENBAUER RONALD W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>M/S 124-223</rptOwnerStreet1>
            <rptOwnerStreet2>400 COLLINS ROAD NE</rptOwnerStreet2>
            <rptOwnerCity>CEDAR RAPIDS</rptOwnerCity>
            <rptOwnerState>IA</rptOwnerState>
            <rptOwnerZipCode>52498-0001</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Sr. VP, Human Resources</officerTitle></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to Buy)</value><footnoteId id="F1"/></securityTitle><conversionOrExercisePrice><value>27.97</value></conversionOrExercisePrice><transactionDate><value>2003-11-06</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>24000</value></transactionShares><transactionPricePerShare><footnoteId id="F1"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-11-06</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>2013-11-06</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>24000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>24000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Employee stock options granted pursuant to the Rockwell Collins, Inc. 2001 Long-Term Incentives Plan.</footnote><footnote id="F2">The options vest in three substantially equal annual installments beginning 11/06/2004.</footnote></footnotes><remarks/><ownerSignature><signatureName>Gary R. Chadick, Attorney-in-Fact</signatureName><signatureDate>2003-11-10</signatureDate></ownerSignature></ownershipDocument>

