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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-04-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001130310</issuerCik>
        <issuerName>CENTERPOINT ENERGY INC</issuerName>
        <issuerTradingSymbol>CNP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001328399</rptOwnerCik>
            <rptOwnerName>Wareing Peter S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1111 LOUISIANA</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77002</rptOwnerZipCode>
            <rptOwnerStateDescription></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>2009-04-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28000</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60000</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Elizabeth B. Wareing 1976 Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This common stock is time-based restricted stock awarded to outside directors then in office as of May 1, 2009.  Shares will vest in one-third increments on May 1, 2010, May 1, 2011 and May 1, 2012 if the reporting person is a director of Issuer through such dates; provided however, the shares become fully vested in the event of a change of control of issuer.</footnote>
        <footnote id="F2">Price is not applicable.</footnote>
        <footnote id="F3">Includes 1,000 shares of time-based restricted stock awarded in 2006 that will vest in 2009; 2,666 shares of time-based restricted stock awarded in 2007 that will vest in 1,333 share increments on June 1, 2009 and June 1, 2010; and 4,000 shares of time-based restricted stock awarded in 2008 that will vest in one-third increments on May 1, 2009, May 1, 2010 and May 1, 2011 if the reporting person is a director of Issuer through such dates; provided however, the shares become fully vested in the event of a change of control of issuer.</footnote>
        <footnote id="F4">Shares of CNP common stock held in trust, of which reporting person's spouse is a trustee and the beneficiary.  The filing of this Form 4 shall not be deemed an admission that the reporting person is, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, the beneficial owner of such equity securities.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Peter S. Wareing</signatureName>
        <signatureDate>2009-04-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
