| **Fair Value Measurements - Carrying Values and Estimated Fair Values of Financial Instruments (Details) (USD $)In Millions, unless otherwise specified**                                                                                                                                                                                    | Apr. 30, 2015                                                                                                                                                                                                                                                                                                                                                                                                                                                               | Oct. 31, 2014 |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|
| Reported Value Measurement [Member]                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Retail Notes                                                                                                                                                                                                                                                                                                                                 | $ 208us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                                                                                                                                                                                                                                                           |               | $ 275us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember |  |
| Notes Receivable                                                                                                                                                                                                                                                                                                                             | 5us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                                                                                                                                                                                                                                                               |               | 8us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember |  |
| Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Retail Notes                                                                                                                                                                                                                                                                                                                                 | 209us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                                                                                                                |               | 279us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Notes Receivable                                                                                                                                                                                                                                                                                                                             | 5us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                                                                                                                  |               | 7us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Retail Notes                                                                                                                                                                                                                                                                                                                                 | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                             |               | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Notes Receivable                                                                                                                                                                                                                                                                                                                             | 0us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                             |               | 0us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Retail Notes                                                                                                                                                                                                                                                                                                                                 | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                             |               | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Notes Receivable                                                                                                                                                                                                                                                                                                                             | 0us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                             |               | 0us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Retail Notes                                                                                                                                                                                                                                                                                                                                 | 209us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                           |               | 279us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Notes Receivable                                                                                                                                                                                                                                                                                                                             | 5us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                                                                                                                                             |               | 7us-gaap_NotesReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |  |
| Line of Credit [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 694us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                                                                                                                 |               | 694us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Line of Credit [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 694us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                               |               | 694us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Line of Credit [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 719us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                         |               | 704us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Line of Credit [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                      |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Line of Credit [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                      |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Line of Credit [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 719us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                    |               | 704us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Line of Credit [Member] | Financial Services Operations [Member]                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 1,205us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                                                                                                                           |               | 1,242us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Line of Credit [Member] | Financial Services Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 1,205us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                         |               | 1,242us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Line of Credit [Member] | Financial Services Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 1,184us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                   |               | 1,214us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Line of Credit [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                  |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Line of Credit [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                  |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Line of Credit [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 1,184us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                              |               | 1,214us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_LineOfCreditMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Debt Of Majority Owned Dealerships [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 28us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                                                                                                    |               | 30us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Debt Of Majority Owned Dealerships [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 28us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                  |               | 30us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Debt Of Majority Owned Dealerships [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 28us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                            |               | 30us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Debt Of Majority Owned Dealerships [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                        |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Debt Of Majority Owned Dealerships [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                        |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Debt Of Majority Owned Dealerships [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 28us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                       |               | 30us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_DebtOfMajorityOwnedDealershipsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financing Arrangements [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 45us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                           |               | 48us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financing Arrangements [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 21us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                     |               | 22us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financing Arrangements [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                 |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financing Arrangements [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                 |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financing Arrangements [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 21us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                |               | 22us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancingArrangementsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Tax Exempt Bond [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 225us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                                                                                                                    |               | 225us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Tax Exempt Bond [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 225us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                  |               | 225us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Tax Exempt Bond [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 243us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                            |               | 232us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Tax Exempt Bond [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                         |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Tax Exempt Bond [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 243us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                       |               | 232us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Tax Exempt Bond [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                         |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_TaxExemptBondMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Promissory Note [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 5us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                                                                                                                     |               | 10us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Promissory Note [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 5us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                   |               | 10us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Promissory Note [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 5us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                             |               | 10us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Promissory Note [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                        |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Promissory Note [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                        |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Promissory Note [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 5us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                        |               | 10us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_PromissoryNoteMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financed lease obligations [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 141us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                                                                                                         |               | 184us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financed lease obligations [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 141us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                       |               | 184us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financed lease obligations [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 141us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                 |               | 184us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financed lease obligations [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                              |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financed lease obligations [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                              |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Financed lease obligations [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 141us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                            |               | 184us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_FinancedLeaseObligationsMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Notes Payable, Other Payables [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 24us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                                                                                                     |               | 29us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Notes Payable, Other Payables [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 24us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                   |               | 29us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Notes Payable, Other Payables [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 24us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                             |               | 28us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Notes Payable, Other Payables [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                         |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Notes Payable, Other Payables [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                         |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Notes Payable, Other Payables [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 24us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                        |               | 28us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableOtherPayablesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Secured Debt [Member] | Financial Services Operations [Member]                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 986us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                                                                                                                              |               | 914us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Secured Debt [Member] | Financial Services Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 986us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                            |               | 914us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Secured Debt [Member] | Financial Services Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 984us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                      |               | 911us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Secured Debt [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                   |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Secured Debt [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                   |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Secured Debt [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 984us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                 |               | 911us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_SecuredDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Commercial Paper [Member] | Financial Services Operations [Member]                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 77us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                                                                                                                           |               | 74us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 77us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                         |               | 74us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 77us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                   |               | 74us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 77us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                             |               |   |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               | 74us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                              |               |   |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                              |               |   |  |
| Commercial Paper [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_CommercialPaperMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Borrowings Secured By Operating and Finance Leases [Member] | Financial Services Operations [Member]                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 29us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                                                                                                                  |               | 36us-gaap_LongTermDebt/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Borrowings Secured By Operating and Finance Leases [Member] | Financial Services Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 29us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                                |               | 36us-gaap_LongTermDebt/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Borrowings Secured By Operating and Finance Leases [Member] | Financial Services Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 29us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                                                                                                          |               | 36us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Borrowings Secured By Operating and Finance Leases [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                      |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Borrowings Secured By Operating and Finance Leases [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                      |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Borrowings Secured By Operating and Finance Leases [Member] | Financial Services Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 29us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember                                                                                     |               | 36us-gaap_LongTermDebtFairValue/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember/ us-gaap_StatementBusinessSegmentsAxis= nav_FinancialServicesOperationsMember |  |
| Eight Point Two Five Percent Senior Notes [Member] | Notes Payable to Banks [Member] | Manufacturing Operations [Member]                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 1,181us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                                             |               | 1,180us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Eight Point Two Five Percent Senior Notes [Member] | Notes Payable to Banks [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 1,181us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                           |               | 1,180us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Eight Point Two Five Percent Senior Notes [Member] | Notes Payable to Banks [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 1,233us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                     |               | 1,285us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Eight Point Two Five Percent Senior Notes [Member] | Notes Payable to Banks [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 1,233us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                |               | 1,285us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Eight Point Two Five Percent Senior Notes [Member] | Notes Payable to Banks [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                    |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Eight Point Two Five Percent Senior Notes [Member] | Notes Payable to Banks [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                    |               | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_EightPointTwoFivePercentSeniorNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_NotesPayableToBanksMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member]                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 183us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                       |               | 181us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 183us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                     | [1]           | 181us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 185us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                               | [1]           | 196us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember            | [1]           | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember            | [1]           | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 185us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember          | [1]           | 196us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member]                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 375us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                                                                                                                                |               | 371us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Reported Value Measurement [Member]                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt                                                                                                                                                                                                                                                                                                                               | 375us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                              | [1]           | 371us-gaap_LongTermDebt/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Estimate of Fair Value Measurement [Member]                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 383us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember                                                                                        | [1]           | 413us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember     | [1]           | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember     | [1]           | 0us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember |  |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Subordinated Debt [Member] | Manufacturing Operations [Member] | Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |   |  |
| Long-term Debt, Fair Value                                                                                                                                                                                                                                                                                                                   | $ 383us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1]           | $ 413us-gaap_LongTermDebtFairValue/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember/ us-gaap_LongtermDebtTypeAxis= us-gaap_ConvertibleSubordinatedDebtMember/ us-gaap_StatementBusinessSegmentsAxis= nav_ManufacturingOperationsMember | [1] |
|                                                                                                                                                                                                                                                                                                                                              |
| [1]The carrying value represents the consolidated financial statement amount of the debt which excludes the allocation of the conversion feature to equity, while the fair value is based on internally developed valuation techniques such as discounted cash flow modeling for Level 3 convertible notes which include the equity feature. |

| X                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Glossary Loan -URI http://asc.fasb.org/extlink&oid=6517073
+ Details**Name:**us-gaap_LoansReceivableFairValueDisclosure**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 7Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20, 22 -Article 5Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910
+ Details**Name:**us-gaap_LongTermDebt**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.
+ References
No definition available.
+ Details**Name:**us-gaap_LongTermDebtFairValue**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of an agreement for an unconditional promise by the maker to pay the holder a definite sum of money at a future date.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3 -Subparagraph b -Article 5
+ Details**Name:**us-gaap_NotesReceivableFairValueDisclosure**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=nav_EightPointTwoFivePercentSeniorNotesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=nav_BorrowingsSecuredByOperatingAndFinanceLeasesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=nav_DebtOfMajorityOwnedDealershipsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=nav_FinancedLeaseObligationsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=nav_FinancingArrangementsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=nav_PromissoryNoteMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=nav_TaxExemptBondMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=us-gaap_CommercialPaperMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableOtherPayablesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |