XML 45 R35.htm IDEA: XBRL DOCUMENT
v3.25.2

Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail) - USD ($) $ in Millions | 6 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Dec. 31, 2024 | Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2023
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loan allowance for losses | $ (530) | $ (687) | $ (621) | $ (579) | $ (744) | $ (832)
FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 29,800 | 33,134 |  |  |  |
Loan allowance for losses | (182) | (194) | (180) | (182) | (206) | (215)
Loans, net | 29,618 |  | 30,852 |  |  |
Credit Concentration Risk [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 29,800 | 33,134 | 31,032 |  |  |
Loan allowance for losses | (182) | (194) | (180) |  |  |
Loans, net | $ 29,618 | $ 32,940 | $ 30,852 |  |  |
Dimensions of concentration risk | 100.00% | 100.00% | 100.00% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, Current [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 81.00% | 86.50% | 81.40% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loans delinquent, percentage | 5.40% | 3.90% | 5.80% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loans delinquent, percentage | 3.50% | 2.60% | 4.10% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, 90 Days Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loans delinquent, percentage | 10.10% | 7.00% | 8.70% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, Loans In Repayment [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 83.40% | 79.70% | 81.90% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, Delinquent Loans in Repayment [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 19.00% | 13.50% | 18.60% |  |  |
Credit Concentration Risk [Member] | Financing Receivables, Forbearance, Loans In Repayment [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 12.80% | 16.80% | 14.70% |  |  |
School/Grace/Deferment [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | $ 1,280 | $ 1,403 | $ 1,262 |  |  |
Forbearance [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 3,653 | 5,320 | 4,365 |  |  |
Repayment [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 24,867 | 26,411 | 25,405 |  |  |
Repayment [Member] | Credit Concentration Risk [Member] | Financing Asset, Not Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 20,145 | 22,833 | 20,675 |  |  |
Repayment [Member] | Credit Concentration Risk [Member] | Financial Asset, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 1,333 | 1,041 | 1,479 |  |  |
Repayment [Member] | Credit Concentration Risk [Member] | Financial Asset, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 863 | 680 | 1,043 |  |  |
Repayment [Member] | Credit Concentration Risk [Member] | Financial Asset, 90 Days Past Due [Member] | Accounts Receivable [Member] | FFELP Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 2,526 | 1,857 | 2,208 |  |  |
Private Education Loans [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 15,878 | 16,731 |  |  |  |
Loan allowance for losses | (348) | (493) | (441) | $ (397) | $ (538) | $ (617)
Loans, net | 15,530 | 16,238 | 15,716 |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 15,878 | 16,731 | 16,157 |  |  |
Loan allowance for losses | (348) | (493) | (441) |  |  |
Loans, net | $ 15,530 | $ 16,238 | $ 15,716 |  |  |
Dimensions of concentration risk | 100.00% | 100.00% | 100.00% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, Current [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 93.60% | 94.80% | 93.90% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loans delinquent, percentage | 2.20% | 1.90% | 2.10% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loans delinquent, percentage | 1.20% | 1.10% | 1.30% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, 90 Days Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Loans delinquent, percentage | 3.00% | 2.20% | 2.70% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, Loans In Repayment [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 96.20% | 96.20% | 95.10% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, Delinquent Loans in Repayment [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 6.40% | 5.20% | 6.10% |  |  |
Private Education Loans [Member] | Credit Concentration Risk [Member] | Financing Receivables, Forbearance, Loans In Repayment [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Dimensions of concentration risk | 1.60% | 1.80% | 2.70% |  |  |
Private Education Loans [Member] | School/Grace/Deferment [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | $ 361 | $ 350 | $ 372 |  |  |
Private Education Loans [Member] | Forbearance [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 250 | 294 | 422 |  |  |
Private Education Loans [Member] | Repayment [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 15,267 | 16,087 | 15,363 |  |  |
Private Education Loans [Member] | Repayment [Member] | Credit Concentration Risk [Member] | Financing Asset, Not Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 14,296 | 15,250 | 14,419 |  |  |
Private Education Loans [Member] | Repayment [Member] | Credit Concentration Risk [Member] | Financial Asset, 31 to 60 Days Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 335 | 311 | 319 |  |  |
Private Education Loans [Member] | Repayment [Member] | Credit Concentration Risk [Member] | Financial Asset, 61 to 90 Days Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | 177 | 175 | 206 |  |  |
Private Education Loans [Member] | Repayment [Member] | Credit Concentration Risk [Member] | Financial Asset, 90 Days Past Due [Member] | Accounts Receivable [Member] |  |  |  |  |  |
Loans in repayment and percentage of each status: |  |  |  |  |  |
Total Loans, gross | $ 459 | $ 351 | $ 419 |  |  |

X
- Definition Concentration risk threshold percentage. + References No definition available. + Details
Name: | navi_ConcentrationRiskThresholdPercentage
Namespace Prefix: | navi_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans In Repayment And Percentage Of Each Status [Abstract] + References No definition available. + Details
Name: | navi_LoansInRepaymentAndPercentageOfEachStatusAbstract
Namespace Prefix: | navi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph c -Publisher SEC Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (1) -Publisher SEC Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (3) -Publisher SEC Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amortized cost, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + Details
Name: | us-gaap_FinancingReceivableBeforeAllowanceForCreditLossAndFee
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of financing receivable balance that is past due. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivablePercentPastDue1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 948 -SubTopic 310 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477011/948-310-45-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-13 Reference 5: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-7A Reference 6: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 29 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-29 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (1) -Publisher SEC Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (2) -Publisher SEC Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef -Name Regulation S-K (SK) -Number 229 -Section 1404 -Paragraph a -Publisher SEC Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 80 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-80 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-14 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(5)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(3)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_NotesReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesAxis=us-gaap_FederalFamilyEducationLoanProgramFfelpGuaranteedLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivablesCurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivables31To60DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivables61To90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivables90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivablesLoansInRepaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivablesDelinquentLoansInRepaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancingReceivablesForbearanceLoansInRepaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancialAsset31To60DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancialAsset61To90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=navi_FinancialAsset90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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