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

    <documentType>4</documentType>
    <periodOfReport>2003-08-22</periodOfReport>
    <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000811156</issuerCik>
        <issuerName>CMS ENERGY CORP</issuerName>
        <issuerTradingSymbol>CMS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180043</rptOwnerCik>
            <rptOwnerName>MENGEBIER DAVID G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>212 WEST MICHIGAN AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>JACKSON</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>49201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>
  <nonDerivativeTable>
   <nonDerivativeTransaction>
      <securityTitle>
          <value>Common Stock (CMS)</value>
      </securityTitle>
      <transactionDate>
          <value>2003-08-22</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>A</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
      <value />
      </transactionTimeliness>
      <transactionAmounts>
          <transactionShares>
              <value>16000</value>
          </transactionShares>
          <transactionPricePerShare>
              <value>6.35</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>A</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>29996</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
   <nonDerivativeTransaction>
      <securityTitle>
          <value>Common Stock (CMS)</value>
      </securityTitle>
      <transactionDate>
          <value>2003-08-22</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>J</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
              <footnoteId id="F1" />
      </transactionCoding>
      <transactionTimeliness>
      <value />
      </transactionTimeliness>
      <transactionAmounts>
          <transactionShares>
              <value>2000</value>
          </transactionShares>
          <transactionPricePerShare>
              <value>0</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>D</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>27996</value>
              <footnoteId id="F2" />
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
    <nonDerivativeHolding>
      <securityTitle>
          <value>Common Stock (CMS)</value>
      </securityTitle>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>3774</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>I</value>
          </directOrIndirectOwnership>
          <natureOfOwnership>
              <value>401(k)</value>
          </natureOfOwnership>
      </ownershipNature>
   </nonDerivativeHolding>
  </nonDerivativeTable>
  <derivativeTable>
   <derivativeTransaction>
      <securityTitle>
          <value>Emp Stock Options-2003</value>
      </securityTitle>
      <conversionOrExercisePrice>
          <value>6</value>
      </conversionOrExercisePrice>
      <transactionDate>
          <value>2003-08-22</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>A</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
          <transactionShares>
              <value>68000</value>
          </transactionShares>
          <transactionPricePerShare>
              <value>6.35</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>A</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
          <value>2003-08-22</value>
      </exerciseDate>
      <expirationDate>
          <value>2013-09-21</value>
      </expirationDate>
      <underlyingSecurity>
          <underlyingSecurityTitle>
              <value>Common Stock (CMS)</value>
          </underlyingSecurityTitle>
          <underlyingSecurityShares>
              <value>68000</value>
          </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>68000</value>
              <footnoteId id="F3" />
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </derivativeTransaction>
  </derivativeTable>
<footnotes>
   <footnote id="F1">Forfeiture of Restricted Stock granted in 2000 pursuant to provisions of CMS Performance Incentive Stock Plan.</footnote>
   <footnote id="F2">Total includes 27,000 shares of Restricted Stock, of which 3,000 shares are nominal.  (The actual number of nominal shares received will be determined by the passage of time and achievement of performance objectives under CMS Performance Incentive Stock Plan.)</footnote>
   <footnote id="F3">In addition, previous options were granted on various dates at various prices for 76,000 shares of Common Stock, totalling 144,400 options held directly; and 78 units considered phanton stock are held indirectly pursuant to the Deferred Salary Savings Plan of CMS.</footnote>
</footnotes>
    <ownerSignature>
       <signatureName>/s/MDVanHemert, Attny in Fact</signatureName>
       <signatureDate>2003-08-26</signatureDate>
    </ownerSignature>
</ownershipDocument>

