| **Fair Value Measurements - Narrative (Details) (USD $)In Millions, unless otherwise specified**                                                       | 12 Months Ended                                                                                                                | 3 Months Ended | 12 Months Ended                                                                                                                                                         | 3 Months Ended                                                                                                                 |                                                                                                                                                                         |
|--------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------|----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                       |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Goodwill                                                                                                                                               | $ 38us-gaap_Goodwill                                                                                                           |                | $ 184us-gaap_Goodwill                                                                                                                                                   |                                                                                                                           | $ 184us-gaap_Goodwill                                                                                                                                                   |  | $ 280us-gaap_Goodwill |  |   | $ 319us-gaap_Goodwill |
| Cash and Cash Equivalents, Maturity Term                                                                                                               | 90 days                                                                                                                        |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Marketable Securities, Maturity Term                                                                                                                   | 90 days                                                                                                                        |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Indefinite-Lived Intangible Assets (Excluding Goodwill)                                                                                                | 34us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill                                                                     |                | 46us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill                                                                                                              |                                                                                                                           | 46us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill                                                                                                              |  |   |  |   |   |
| Impairment of Long-Lived Assets Held-for-use                                                                                                           |                                                                                                                           |                | 20us-gaap_ImpairmentOfLongLivedAssetsHeldForUse                                                                                                                         |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Goodwill, Impairment Loss                                                                                                                              | 142us-gaap_GoodwillImpairmentLoss                                                                                              |                | 81us-gaap_GoodwillImpairmentLoss                                                                                                                                        |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Reported Value Measurement [Member]                                                                                                                    |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                       |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Property, Plant, and Equipment and Intangible Assets, Fair Value Disclosure                                                                            |                                                                                                                           |                | 25nav_PropertyPlantandEquipmentandIntangibleAssetsFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember |                                                                                                                           | 25nav_PropertyPlantandEquipmentandIntangibleAssetsFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember |  |   |  |   |   |
| Estimate of Fair Value Measurement [Member]                                                                                                            |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                       |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Property, Plant, and Equipment, Fair Value Disclosure                                                                                                  |                                                                                                                           |                | 5us-gaap_PropertyPlantAndEquipmentFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                    |                                                                                                                           | 5us-gaap_PropertyPlantAndEquipmentFairValueDisclosure/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                    |  |   |  |   |   |
| Brazilian Reporting Unit [Member]                                                                                                                      |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                       |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Goodwill                                                                                                                                               |                                                                                                                           |                |                                                                                                                                                                    | 142us-gaap_Goodwill/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember                                                   |                                                                                                                                                                    |  |   |  |   |   |
| Indefinite-Lived Intangible Assets (Excluding Goodwill)                                                                                                |                                                                                                                           |                |                                                                                                                                                                    | 43us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember            |                                                                                                                                                                    |  |   |  |   |   |
| Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)                                                                                 | 7us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember |                |                                                                                                                                                                    | 7us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember | 0us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember                                          |  | 0us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember |  |   |   |
| Goodwill, Impairment Loss                                                                                                                              | 142us-gaap_GoodwillImpairmentLoss/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember                                     | [1]            |                                                                                                                                                                    |                                                                                                                           | 81us-gaap_GoodwillImpairmentLoss/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember                                                                               | [1] | 0us-gaap_GoodwillImpairmentLoss/ nav_ReportingUnitAxis= nav_BrazilianReportingUnitMember | [1] |   |   |
| North America Truck [Member]                                                                                                                           |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                       |                                                                                                                           |                |                                                                                                                                                                    |                                                                                                                           |                                                                                                                                                                    |  |   |  |   |   |
| Goodwill                                                                                                                                               | 0us-gaap_Goodwill/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember                                          |                | 0us-gaap_Goodwill/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember                                                                                   |                                                                                                                           | 0us-gaap_Goodwill/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember                                                                                   |  | 82us-gaap_Goodwill/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember |  |   | 82us-gaap_Goodwill/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember |
| Goodwill, Impairment Loss                                                                                                                              | $ 0us-gaap_GoodwillImpairmentLoss/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember                          |                | $ 81us-gaap_GoodwillImpairmentLoss/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember                                                                  |                                                                                                                           | $ (77)us-gaap_GoodwillImpairmentLoss/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember                                                                |  |   |  | $ (4)us-gaap_GoodwillImpairmentLoss/ us-gaap_StatementBusinessSegmentsAxis= nav_NorthAmericaTruckMember |   |
|                                                                                                                                                        |
| [1](A)For more information, see Note 8, Goodwill and Other Intangible Assets, Net, and includes $4 million related to discontinued operations in 2013. |

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Maximum maturity term for a cash and cash equivalent instrument
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Maximum maturity term for a marketable security instrument
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| - Definition
Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
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| - Definition
Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).
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| - Definition
Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.
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| - Definition
Fair value portion of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.
+ References
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