| **Financial Instruments and Commodity Contracts - Foreign Currency Contracts (Details) € in Millions, MXN in Millions, CAD in Millions**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | 1 Months Ended |           |           |        |           |        |           |        |           |        |           |         |        |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|-----------|-----------|--------|-----------|--------|-----------|--------|-----------|--------|-----------|---------|--------|
||
| Foreign Exchange Contract, Maturing April 2016 to October 2016 [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |           |      |      |   |      |   |      |   |      |   |      |    |   | € 3 |  |   |  |   |  |   |   |   |   |   |   |   |
| Foreign Exchange Contract [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   | 19 | [1] |   |  |   |  |   |   |   |   | € 30 |   |   |
| Foreign Exchange Contract [Member] | Canada, Dollars                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount | CAD                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  | CAD 75 | [3] |   |   |   |   |   |   | CAD 25 |
| Derivative, Notional Amount Expiring Monthly | CAD                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  | CAD 15 |  |   |   |   |   |   |   |   |
| Foreign Exchange Contract [Member] | Mexican Pesos                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount | MXN                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  | MXN 868 | [4] |   |  |   |   |   |   |   | MXN 1,270 |   |
| Derivative, Notional Amount Expiring Monthly | MXN                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  | MXN 436 |  |   |  |   |   |   |   |   |   |   |
| Foreign Exchange Contract, Maturing November 2015 to October 2016 [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | € 3      |      |      |   |      |   |      |   |      |   |      |    |   | € 2 |  |   |  |   |  | € 2 | € 2 | € 4 | € 3 |   |   |   |
| Derivative, Cash Received on Hedge                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | € 2      |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Subsequent Event [Member] | Foreign Exchange Contract, Maturing April 2016 to October 2016 [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |           |      |      |   |      |   |      |   |      |   | € 4 |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Subsequent Event [Member] | Foreign Exchange Contract [Member] | Canada, Dollars                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly | CAD                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      |   |      |   |      |   |      |   |      |    | CAD 15 |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Subsequent Event [Member] | Foreign Exchange Contract [Member] | Mexican Pesos                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly | MXN                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      |   |      |   |      |   |      |   |      | MXN 432 |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Subsequent Event [Member] | Foreign Exchange Contract, Maturing November 2015 to October 2016 [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |           |      |      |   |      |   |      |   |      |   | € 2 |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Scenario, Forecast [Member] | Foreign Exchange Contract, Maturing April 2016 to October 2016 [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |           | € 2 | € 2 |   | € 2 |   | € 2 |   | € 4 |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Scenario, Forecast [Member] | Foreign Exchange Contract [Member] | Canada, Dollars                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly | CAD                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |           |      |      | CAD 5  |      | CAD 10 |      | CAD 15 |      | CAD 15 |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Scenario, Forecast [Member] | Foreign Exchange Contract, Maturing November 2015 to October 2016 [Member] | Euro Member Countries, Euro                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| **Derivative [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |           |      |      |   |      |   |      |   |      |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
| Derivative, Notional Amount Expiring Monthly                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |           | € 2 | € 2 |   | € 2 |   | € 2 |   | € 2 |   |      |    |   |   |  |   |  |   |  |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| [1]Forward exchange contracts of €3 million matured in April 2016 but settled in May 2016, €4 million matured in May 2016, €4 million mature in June 2016, and €2 million mature each month from July 2016 through October 2016.[2](D) Forward exchange contracts of €2 million settled in November 2015, €3 million matured in November 2015, €3 million matured in December 2015, €4 million matured in January 2016, and €2 million mature each month from February 2016 through October 2016.[3](B) Forward exchange contracts of C$15 million matured in April 2016 but settled in May 2016, C$15 million matured in May 2016, C$15 million mature in June and July 2016, C$10 million mature in August 2016, and C$5 million mature in September 2016.[4](C) Forward exchange contracts of ₱436 million matured in April 2016 but settled in May 2016 and ₱432 million matured in May 2016. |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B
+ Details**Name:**invest_DerivativeNotionalAmount**Namespace Prefix:**invest_**Data Type:**xbrli:monetaryItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Derivative, Notional Amount Expiring Monthly
+ References
No definition available.
+ Details**Name:**nav_DerivativeNotionalAmountExpiringMonthly**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of cash received during the period on settlement of a hedge.
+ References
No definition available.
+ Details**Name:**us-gaap_DerivativeCashReceivedOnHedge**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
+ Details**Name:**us-gaap_DerivativeLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeInstrumentRiskAxis=nav_ForeignExchangeContractMaturingApril2016toOctober2016Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CurrencyAxis=currency_EUR**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CurrencyAxis=currency_CAD**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CurrencyAxis=currency_MXN**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeInstrumentRiskAxis=nav_ForeignExchangeContractMaturingNovember2015toOctober2016Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |