| **Finance Receivables - Schedule of Finance Revenues (Details) (USD $)In Millions, unless otherwise specified** | 3 Months Ended                                                                                                                                                                                                                                      | 6 Months Ended                                                                                                                                                                                                                                      |
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| **Finance Revenues [Line Items]**                                                                               |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| Retail notes and finance leases revenue                                                                         | $ 12nav_RetailNotesAndFinanceLeasesRevenue                                                                                                                                                                                                          | $ 16nav_RetailNotesAndFinanceLeasesRevenue                                                                                                                                                                                                          | $ 25nav_RetailNotesAndFinanceLeasesRevenue | $ 33nav_RetailNotesAndFinanceLeasesRevenue |
| Gross finance revenues                                                                                          | 60nav_FinanceRevenuesFromOnBalanceSheetReceivables                                                                                                                                                                                                  | 57nav_FinanceRevenuesFromOnBalanceSheetReceivables                                                                                                                                                                                                  | 120nav_FinanceRevenuesFromOnBalanceSheetReceivables | 112nav_FinanceRevenuesFromOnBalanceSheetReceivables |
| Less: Intercompany revenues                                                                                     | (25)us-gaap_RevenueFromRelatedParties                                                                                                                                                                                                               | (19)us-gaap_RevenueFromRelatedParties                                                                                                                                                                                                               | (49)us-gaap_RevenueFromRelatedParties | (35)us-gaap_RevenueFromRelatedParties |
| Finance revenues                                                                                                | 35us-gaap_FinancialServicesRevenue                                                                                                                                                                                                                  | 38us-gaap_FinancialServicesRevenue                                                                                                                                                                                                                  | 71us-gaap_FinancialServicesRevenue | 77us-gaap_FinancialServicesRevenue |
| Financing Receivable [Member]                                                                                   |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| **Finance Revenues [Line Items]**                                                                               |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| Operating lease revenue                                                                                         | 15us-gaap_OperatingLeasesIncomeStatementLeaseRevenue/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_FinanceReceivablesMember                                                                                        | 15us-gaap_OperatingLeasesIncomeStatementLeaseRevenue/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_FinanceReceivablesMember                                                                                        | 30us-gaap_OperatingLeasesIncomeStatementLeaseRevenue/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_FinanceReceivablesMember | 29us-gaap_OperatingLeasesIncomeStatementLeaseRevenue/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_FinanceReceivablesMember |
| Wholesale Portfolio [Member] | Notes Receivable [Member]                                                        |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| **Finance Revenues [Line Items]**                                                                               |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| Interest Income, Operating                                                                                      | 24us-gaap_InterestIncomeOperating/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_NotesReceivableMember/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_WholesalePortfolioMember | 19us-gaap_InterestIncomeOperating/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_NotesReceivableMember/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_WholesalePortfolioMember | 48us-gaap_InterestIncomeOperating/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_NotesReceivableMember/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_WholesalePortfolioMember | 37us-gaap_InterestIncomeOperating/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis= us-gaap_NotesReceivableMember/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_WholesalePortfolioMember |
| Retail And Wholesale Portfolios [Member]                                                                        |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| **Finance Revenues [Line Items]**                                                                               |                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                |   |   |
| Interest Income, Operating                                                                                      | $ 9us-gaap_InterestIncomeOperating/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_RetailAndWholesalePortfoliosMember                                                                                           | $ 7us-gaap_InterestIncomeOperating/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_RetailAndWholesalePortfoliosMember                                                                                           | $ 17us-gaap_InterestIncomeOperating/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_RetailAndWholesalePortfoliosMember | $ 13us-gaap_InterestIncomeOperating/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis= nav_RetailAndWholesalePortfoliosMember |

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| X                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Finance Revenues From On Balance Sheet Receivables
+ References
No definition available.
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| X                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Retail Notes And Finance Leases Revenue
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The aggregate financial services revenue and operating interest income earned during the reporting period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(d)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| - Definition
Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Related Parties -URI http://asc.fasb.org/extlink&oid=16382449Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07.1(c)) -URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 07 -Paragraph b -Subparagraph 1 -Article 6
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| X                                                                                                                                                                                             |
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| X                                                                                                                                                                                                            |
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| X                                                                                                                                                                                                  |
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