<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.7.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>479</ContextCount>
  <ElementCount>276</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>108</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>101 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DocumentandEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>103 - Statement - Consolidated Balance Sheets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfFinancialPositionUnclassified-InvestmentBasedOperations</Role>
      <ShortName>Consolidated Balance Sheets (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>104 - Statement - Consolidated Balance Sheets (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfFinancialPositionUnclassified-InvestmentBasedOperationsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>105 - Statement - Consolidated Statements of Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfIncome</Role>
      <ShortName>Consolidated Statements of Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>106 - Statement - Consolidated Statements of Comprehensive Income (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfOtherComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>107 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>108 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfShareholdersEquityAndOtherComprehensiveIncomeParenthetical</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>109 - Statement - Consolidated Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/StatementOfCashFlowsIndirectInvestmentBasedOperations</Role>
      <ShortName>Consolidated Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>110 - Disclosure - Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlock</Role>
      <ShortName>Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>111 - Disclosure - Allowance for Loan Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsAllowanceForCreditLossesTextBlock</Role>
      <ShortName>Allowance for Loan Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>112 - Disclosure - Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlock</Role>
      <ShortName>Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>113 - Disclosure - Derivative Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsDerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock</Role>
      <ShortName>Derivative Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>114 - Disclosure - Other Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsOtherAssetsDisclosureTextBlock</Role>
      <ShortName>Other Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>115 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>116 - Disclosure - Earnings per Common Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlock</Role>
      <ShortName>Earnings per Common Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>117 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsFairValueMeasurementInputsDisclosureTextBlock</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>118 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsCommitmentsAndContingenciesDisclosureTextBlock</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>119 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>120 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlockPolicies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsSignificantAccountingPoliciesTextBlock</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>121 - Disclosure - Allowance for Loan Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsAllowanceForCreditLossesTextBlockTables</Role>
      <ShortName>Allowance for Loan Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsAllowanceForCreditLossesTextBlock</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>122 - Disclosure - Borrowings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlockTables</Role>
      <ShortName>Borrowings (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsDebtDisclosureTextBlock</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>123 - Disclosure - Derivative Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsDerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlockTables</Role>
      <ShortName>Derivative Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsDerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>124 - Disclosure - Other Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsOtherAssetsDisclosureTextBlockTables</Role>
      <ShortName>Other Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsOtherAssetsDisclosureTextBlock</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>125 - Disclosure - Stockholders' Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlockTables</Role>
      <ShortName>Stockholders' Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsStockholdersEquityNoteDisclosureTextBlock</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>126 - Disclosure - Earnings per Common Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlockTables</Role>
      <ShortName>Earnings per Common Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsEarningsPerShareTextBlock</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>127 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsFairValueMeasurementInputsDisclosureTextBlockTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsFairValueMeasurementInputsDisclosureTextBlock</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>128 - Disclosure - Segment Reporting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlockTables</Role>
      <ShortName>Segment Reporting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.navientcorp.com/taxonomy/role/NotesToFinancialStatementsSegmentReportingDisclosureTextBlock</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>129 - Disclosure - Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSignificantAccountingPoliciesAdditionalInformation</Role>
      <ShortName>Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>130 - Disclosure - Allowance for Loan Losses - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesAdditionalInformation</Role>
      <ShortName>Allowance for Loan Losses - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>131 - Disclosure - Allowance for Loan Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesAllowanceForCreditLossesAndRecordedInvestmentsInLoans</Role>
      <ShortName>Allowance for Loan Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>132 - Disclosure - Allowance for Loan Losses - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesPrivateEducationLoanPortfolioStratifiedByKeyCreditQualityIndicators</Role>
      <ShortName>Allowance for Loan Losses - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>133 - Disclosure - Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesAgeAnalysisOfPastDueLoansDelinquencies</Role>
      <ShortName>Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>134 - Disclosure - Allowance for Loan Losses - Receivable for Partially Charged-Off Private Education Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesReceivableForPartiallyChargedOffPrivateEducationLoans</Role>
      <ShortName>Allowance for Loan Losses - Receivable for Partially Charged-Off Private Education Loans (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>135 - Disclosure - Allowance for Loan Losses - Recorded Investment, Unpaid Principal Balance and Related Allowance for TDR Loans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesRecordedInvestmentUnpaidPrincipalBalanceAndRelatedAllowanceForTDRLoans</Role>
      <ShortName>Allowance for Loan Losses - Recorded Investment, Unpaid Principal Balance and Related Allowance for TDR Loans (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>136 - Disclosure - Allowance for Loan Losses - Average Recorded Investment and Interest Income Recognized for TDR (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesAverageRecordedInvestmentAndInterestIncomeRecognizedForTDR</Role>
      <ShortName>Allowance for Loan Losses - Average Recorded Investment and Interest Income Recognized for TDR (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>137 - Disclosure - Allowance for Loan Losses - Loans Modified Accounts for TDR (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesLoansModifiedAccountsForTDR</Role>
      <ShortName>Allowance for Loan Losses - Loans Modified Accounts for TDR (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>138 - Disclosure - Allowance for Loan Losses - Accrued Interest Receivable (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureAllowanceForLoanLossesAccruedInterestReceivable</Role>
      <ShortName>Allowance for Loan Losses - Accrued Interest Receivable (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>139 - Disclosure - Borrowings - Company's Borrowings (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureBorrowingsCompanysBorrowings</Role>
      <ShortName>Borrowings - Company's Borrowings (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>140 - Disclosure - Borrowings - Company's Borrowings (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureBorrowingsCompanysBorrowingsParenthetical</Role>
      <ShortName>Borrowings - Company's Borrowings (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>141 - Disclosure - Borrowings - Financing VIEs (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureBorrowingsFinancingVIEs</Role>
      <ShortName>Borrowings - Financing VIEs (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>142 - Disclosure - Borrowings - Financing VIEs (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureBorrowingsFinancingVIEsParenthetical</Role>
      <ShortName>Borrowings - Financing VIEs (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>143 - Disclosure - Derivative Financial Instruments - Impact of Derivatives on Consolidated Balance Sheet (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureDerivativeFinancialInstrumentsImpactOfDerivativesOnConsolidatedBalanceSheet</Role>
      <ShortName>Derivative Financial Instruments - Impact of Derivatives on Consolidated Balance Sheet (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>144 - Disclosure - Derivative Financial Instruments - Gross Positions without Impact of Master Netting Agreements (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureDerivativeFinancialInstrumentsGrossPositionsWithoutImpactOfMasterNettingAgreements</Role>
      <ShortName>Derivative Financial Instruments - Gross Positions without Impact of Master Netting Agreements (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>145 - Disclosure - Derivative Financial Instruments - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureDerivativeFinancialInstrumentsAdditionalInformation</Role>
      <ShortName>Derivative Financial Instruments - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>146 - Disclosure - Derivative Financial Instruments - Derivative Notional Values (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureDerivativeFinancialInstrumentsDerivativeNotionalValues</Role>
      <ShortName>Derivative Financial Instruments - Derivative Notional Values (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>147 - Disclosure - Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureDerivativeFinancialInstrumentsImpactOfDerivativesOnConsolidatedStatementsOfIncome</Role>
      <ShortName>Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Income (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>148 - Disclosure - Derivative Financial Instruments - Collateral Held and Pledged (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureDerivativeFinancialInstrumentsCollateralHeldAndPledged</Role>
      <ShortName>Derivative Financial Instruments - Collateral Held and Pledged (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>149 - Disclosure - Other Assets - Schedule of Other Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureOtherAssetsScheduleOfOtherAssets</Role>
      <ShortName>Other Assets - Schedule of Other Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>150 - Disclosure - Stockholders' Equity - Common Share Repurchases and Issuances (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureStockholdersEquityCommonShareRepurchasesAndIssuances</Role>
      <ShortName>Stockholders' Equity - Common Share Repurchases and Issuances (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>151 - Disclosure - Stockholders' Equity - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureStockholdersEquityAdditionalInformation</Role>
      <ShortName>Stockholders' Equity - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>152 - Disclosure - Earnings per Common Share - Schedule of Earnings per Common Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureEarningsPerCommonShareScheduleOfEarningsPerCommonShare</Role>
      <ShortName>Earnings per Common Share - Schedule of Earnings per Common Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>153 - Disclosure - Earnings per Common Share - Schedule of Earnings per Common Share (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureEarningsPerCommonShareScheduleOfEarningsPerCommonShareParenthetical</Role>
      <ShortName>Earnings per Common Share - Schedule of Earnings per Common Share (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>154 - Disclosure - Fair Value Measurements - Valuation of Financial Instruments that are Marked-to-Market on Recurring Basis (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureFairValueMeasurementsValuationOfFinancialInstrumentsThatAreMarkedtoMarketOnRecurringBasis</Role>
      <ShortName>Fair Value Measurements - Valuation of Financial Instruments that are Marked-to-Market on Recurring Basis (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>155 - Disclosure - Fair Value Measurements - Change in Balance Sheet Carrying Value Associated with Level 3 Financial Instruments Carried at Fair Value on Recurring Basis (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureFairValueMeasurementsChangeInBalanceSheetCarryingValueAssociatedWithLevel3FinancialInstrumentsCarriedAtFairValueOnRecurringBasis</Role>
      <ShortName>Fair Value Measurements - Change in Balance Sheet Carrying Value Associated with Level 3 Financial Instruments Carried at Fair Value on Recurring Basis (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>156 - Disclosure - Fair Value Measurements - Included in Earnings (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureFairValueMeasurementsIncludedInEarnings</Role>
      <ShortName>Fair Value Measurements - Included in Earnings (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>157 - Disclosure - Fair Value Measurements - Unobservable Data Used in Recurring Valuations of Level 3 (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureFairValueMeasurementsUnobservableDataUsedInRecurringValuationsOfLevel3</Role>
      <ShortName>Fair Value Measurements - Unobservable Data Used in Recurring Valuations of Level 3 (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>158 - Disclosure - Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureFairValueMeasurementsFairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstruments</Role>
      <ShortName>Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>159 - Disclosure - Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureFairValueMeasurementsFairValuesOfFinancialAssetsAndLiabilitiesIncludingDerivativeFinancialInstrumentsParenthetical</Role>
      <ShortName>Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>160 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformation</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>161 - Disclosure - Segment Reporting - Asset Information for Loans Segment (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSegmentReportingAssetInformationForLoansSegment</Role>
      <ShortName>Segment Reporting - Asset Information for Loans Segment (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>162 - Disclosure - Segment Reporting - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSegmentReportingAdditionalInformation</Role>
      <ShortName>Segment Reporting - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>163 - Disclosure - Segment Reporting - Segment Results and Reconciliations to GAAP (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSegmentReportingSegmentResultsAndReconciliationsToGAAP</Role>
      <ShortName>Segment Reporting - Segment Results and Reconciliations to GAAP (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>164 - Disclosure - Segment Reporting - Segment Result and Reconciliations to GAAP - Core Earnings Adjustments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSegmentReportingSegmentResultAndReconciliationsToGAAPCoreEarningsAdjustments</Role>
      <ShortName>Segment Reporting - Segment Result and Reconciliations to GAAP - Core Earnings Adjustments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>165 - Disclosure - Segment Reporting - Core Earnings Adjustments to GAAP (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSegmentReportingCoreEarningsAdjustmentsToGAAP</Role>
      <ShortName>Segment Reporting - Core Earnings Adjustments to GAAP (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="navi-20170331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>166 - Disclosure - Segment Reporting - Core Earnings Adjustments to GAAP (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.navientcorp.com/taxonomy/role/DisclosureSegmentReportingCoreEarningsAdjustmentsToGAAPParenthetical</Role>
      <ShortName>Segment Reporting - Core Earnings Adjustments to GAAP (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>navi-20170331.xml</File>
    <File>navi-20170331.xsd</File>
    <File>navi-20170331_cal.xml</File>
    <File>navi-20170331_def.xml</File>
    <File>navi-20170331_lab.xml</File>
    <File>navi-20170331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
