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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-02-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000814585</issuerCik>
        <issuerName>MBIA INC</issuerName>
        <issuerTradingSymbol>MBI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001334233</rptOwnerCik>
            <rptOwnerName>Fallon William C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MBIA</rptOwnerStreet1>
            <rptOwnerStreet2>113 KING STREET</rptOwnerStreet2>
            <rptOwnerCity>ARMONK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10504</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-02-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>13403</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>59.69</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13436</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock granted pursuant to a long-term incentive award under 16b-3 exemption.  The restricted stock has a three year cliff vesting period.  The number of shares of restricted stock that will ultimately vest will be tied to the growth in the Modified Book Value (MBV) of the Company during the period 1/1/06 to 12/31/08.  If the MBV target growth rate of 30% appreciation from 1/1/06 to 12/31/08 is achieved, then all of the restricted stock will vest.  If the MBV appreciation is 0 from 1/1/06 to 12/31/08, then no restricted stock will vest at the end of the vesting period, with intermediate levels of vesting to be determined by linear interpolation (e.g. MBV appreciation of 15% will result in 50% of the restricted stock vesting).</footnote>
        <footnote id="F2">Balance reflects adjustments including updated 401(k) shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Leonard I. Chubinsky, Attorney-in-Fact</signatureName>
        <signatureDate>2006-03-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
