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

    <documentType>4</documentType><periodOfReport>2003-09-19</periodOfReport>
    <issuer>
        <issuerCik>0001094093</issuerCik>
        <issuerName>PROGRESS ENERGY INC</issuerName>
        <issuerTradingSymbol>PGN</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180427</rptOwnerCik>
            <rptOwnerName>MCCOY WILLIAM O</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1450 RALEIGH ROAD, SUITE 300</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHAPEL HILL</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>27517</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Units based on value of Common Stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F1"/></conversionOrExercisePrice><transactionDate><value>2003-09-19</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>35</value></transactionShares><transactionPricePerShare><value>43.245</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F3"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>35</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>12309</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Units based on value of Common Stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F4"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>3345</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3345</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Director's Deferred Compensation Plan units convertible at a rate of 1 for 1.</footnote><footnote id="F2">Will be settled 100 percent in cash following the undersigned's retirement from the Board.</footnote><footnote id="F3">Based upon payment schedule selected.</footnote><footnote id="F4">Director's Stock Unit Plan units convertible at a rate of 1 for 1.</footnote><footnote id="F5">Will be settled 100 percent in cash following the undersigned's retirement from the Board.</footnote><footnote id="F6">Based upon payment schedule selected.</footnote></footnotes><remarks/><ownerSignature><signatureName>William O. McCoy by Robert M. Williams pursuant to POA</signatureName><signatureDate>2003-09-22</signatureDate></ownerSignature></ownershipDocument>

