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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-03-03</periodOfReport>

    <issuer>
        <issuerCik>0001593538</issuerCik>
        <issuerName>NAVIENT CORP</issuerName>
        <issuerTradingSymbol>NAVI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002060146</rptOwnerCik>
            <rptOwnerName>GREEN DAVID S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>535 MISSION ST.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1663</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>EVP, Cnsmr Lend &amp; CEO, Earnest</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-03-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1146</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.91</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>152320.685</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents performance stock units (&quot;PSUs&quot;) awarded to the reporting person under the Navient Corporation 2014 Omnibus Incentive Plan and previously reported as of February 4, 2022. Each PSU represents the right to receive one share of Navient Corporation (&quot;Navient&quot;) common stock in the future, which target amount vests at a specified percentage and is settled based upon achieving certain performance conditions over a three-year performance period ending on the final day of fiscal year 2024. On January 23, 2025, the Compensation and Human Resources Committee approved the achievement of the 2022-2024 PSUs at 46% of target resulting in the settling on March 3, 2025, of 2,839.120 shares of such PSUs and an additional 362.297 shares were issued to the reporting person upon the vesting of the related dividend equivalent rights.</footnote>
        <footnote id="F2">In connection with this settlement, 1,146 shares were withheld by Navient (as approved by the Navient Compensation and Human Resources Committee) to satisfy the reporting person's tax withholding obligations.</footnote>
        <footnote id="F3">The reporting person's common stock balance reflects the forfeiture of 3,758.186 PSUs from the reporting person's beneficial ownership because the Company failed to meet the threshold performance level established for the PSUs granted for the 2022 - 2024 performance period.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Elizabeth Han (POA) for David Green</signatureName>
        <signatureDate>2025-03-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
