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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-07-26</periodOfReport>

    <issuer>
        <issuerCik>0000316709</issuerCik>
        <issuerName>SCHWAB CHARLES CORP</issuerName>
        <issuerTradingSymbol>SCH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001296455</rptOwnerCik>
            <rptOwnerName>Sasson Gideon</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE CHARLES SCHWAB CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>120 KEARNY STREET</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94108</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President &amp; CIO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-07-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>117028</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>284347</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares were granted under the Company's 2004 Stock Incentive Plan and vest 25% on the second and third anniversary of the grant date and 50% on the fourth anniversary of the grant date.</footnote>
        <footnote id="F2">The reporting person also has an indirect beneficial ownership interest in 32,500 shares held in trust, 1,358 shares held by his spouse, 1,361 shares held as custodian for his daughter, 1011 shares held as custodian for his son, 2,246 shares held by ESOP and 156 shares held in a 401(k).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Gideon Sasson</signatureName>
        <signatureDate>2004-07-27</signatureDate>
    </ownerSignature>
</ownershipDocument>

