XML 48 R35.htm IDEA: XBRL DOCUMENT
v3.19.2

Allowance for Loan Losses - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail) - USD ($) $ in Millions | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
With Cosigner [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 67.00% | 67.00%
Private Education Loans - TDRs [Member] | With Cosigner [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 62.00% | 62.00%
Private Education Loans - TDRs [Member] | Original Winning FICO Scores [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 9,636 | $ 9,969
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - TDRs [Member] | Original Winning FICO Scores [Member] | FICO 640 and Above [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 8,828 | $ 9,133
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 92.00% | 92.00%
Private Education Loans - TDRs [Member] | Original Winning FICO Scores [Member] | FICO Below 640 [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 808 | $ 836
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 8.00% | 8.00%
Private Education Loans - TDRs [Member] | School Type [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 9,636 | $ 9,969
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - TDRs [Member] | School Type [Member] | Not For Profit [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 7,651 | $ 7,888
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 79.00% | 79.00%
Private Education Loans - TDRs [Member] | School Type [Member] | For Profit [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 1,985 | $ 2,081
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 21.00% | 21.00%
Private Education Loans - TDRs [Member] | Cosigners [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 9,636 | $ 9,969
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - TDRs [Member] | Cosigners [Member] | With Cosigner [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 5,998 | $ 6,172
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 62.00% | 62.00%
Private Education Loans - TDRs [Member] | Cosigners [Member] | Without Cosigner [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 3,638 | $ 3,797
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 38.00% | 38.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 9,636 | $ 9,969
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 1-12 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 282 | $ 335
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 3.00% | 3.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 13-24 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 363 | $ 436
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 4.00% | 4.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 25-36 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 556 | $ 660
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 6.00% | 7.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | 37-48 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 784 | $ 934
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 8.00% | 10.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | More than 48 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 7,280 | $ 7,178
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 75.00% | 72.00%
Private Education Loans - TDRs [Member] | Seasoning [Member] | Not Yet in Repayment [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 371 | $ 426
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 4.00% | 4.00%
Private Education Loans - Non-TDRs [Member] | Original Winning FICO Scores [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 13,130 | $ 13,562
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - Non-TDRs [Member] | Original Winning FICO Scores [Member] | FICO 640 and Above [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 12,715 | $ 13,087
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 97.00% | 96.00%
Private Education Loans - Non-TDRs [Member] | Original Winning FICO Scores [Member] | FICO Below 640 [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 415 | $ 475
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 3.00% | 4.00%
Private Education Loans - Non-TDRs [Member] | School Type [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 13,130 | $ 13,562
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - Non-TDRs [Member] | School Type [Member] | Not For Profit [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 11,648 | $ 11,953
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 89.00% | 88.00%
Private Education Loans - Non-TDRs [Member] | School Type [Member] | For Profit [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 1,482 | $ 1,609
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 11.00% | 12.00%
Private Education Loans - Non-TDRs [Member] | Cosigners [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 13,130 | $ 13,562
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - Non-TDRs [Member] | Cosigners [Member] | With Cosigner [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 5,979 | $ 6,961
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 46.00% | 51.00%
Private Education Loans - Non-TDRs [Member] | Cosigners [Member] | Without Cosigner [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 7,151 | $ 6,601
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 54.00% | 49.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 13,130 | $ 13,562
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 100.00% | 100.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 1-12 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 3,205 | $ 3,353
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 24.00% | 25.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 13-24 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 1,285 | $ 486
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 10.00% | 3.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 25-36 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 465 | $ 322
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 4.00% | 2.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | 37-48 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 280 | $ 383
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 2.00% | 3.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | More than 48 Payments [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 7,580 | $ 8,626
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 58.00% | 64.00%
Private Education Loans - Non-TDRs [Member] | Seasoning [Member] | Not Yet in Repayment [Member] |  |
Accounts Notes And Loans Receivable [Line Items] |  |
Total Private Education Loan Credit Quality Indicators | $ 315 | $ 392
Total Private Education Loan Credit Quality Indicators, Excluding Refinance Loans, Percent | 2.00% | 3.00%

X
- Definition Loans and leases receivable gross carrying amount percent. + References No definition available. + Details
Name: | navi_LoansAndLeasesReceivableGrossCarryingAmountPercent
Namespace Prefix: | navi_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_CosignerLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=navi_PrivateEducationLoansTroubledDebtRestructuringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=navi_OriginalWinningFicoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_FicoSixFourZeroAndAboveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_FicoBelowSixFourZeroMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=navi_SchoolTypeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_NotForProfitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_ForProfitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=navi_CosignersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_NonCosignerLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=navi_RepaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_SeasoningOneThruTwelveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_SeasoningThirteenThruTwentyFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_SeasoningTwentyFiveThruThirtySixMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_SeasoningThirtySevenThruFortyEightMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_SeasoningMoreThanFortyEightMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=navi_SeasoningNotYetInRepaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=navi_PrivateEducationLoansNonTroubledDebtRestructuringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |