| **Financial Instruments and Commodity Contracts - Foreign Currency Contracts (Details)In Millions, unless otherwise specified**                                                                                                                 | 3 Months Ended                                |                                              |                                                                                                                 |                                                                                                                         |                                                                                                                 | 3 Months Ended                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------|----------------------------------------------|-----------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------|
||
| **Derivative [Line Items]**                                                                                                                                                                                                                     |                                          |                                         |                                                                                                            |                                                                                                                    |                                                                                                            |                                                                                                                   |  |   |   |   |   |   |   |   |   |   |   |   |   |
| Derivative Instruments,Derivative, Gain (Loss) on Derivative, Net                                                                                                                                                                               | $ 13us-gaap_DerivativeGainLossOnDerivativeNet | $ 0us-gaap_DerivativeGainLossOnDerivativeNet |                                                                                                            |                                                                                                                    |                                                                                                            |                                                                                                                   |  |   |   |   |   | $ 0us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_IncomeStatementLocationAxis= us-gaap_InterestExpenseMember | $ (1)us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_IncomeStatementLocationAxis= us-gaap_InterestExpenseMember | $ 2us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CrossCurrencyInterestRateContractMember/ us-gaap_IncomeStatementLocationAxis= nav_OtherIncomeExpenseNetMember | $ 1us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CrossCurrencyInterestRateContractMember/ us-gaap_IncomeStatementLocationAxis= nav_OtherIncomeExpenseNetMember | $ 1us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_IncomeStatementLocationAxis= nav_OtherIncomeExpenseNetMember | $ 0us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_IncomeStatementLocationAxis= nav_OtherIncomeExpenseNetMember | $ (10)us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CommodityContractMember/ us-gaap_IncomeStatementLocationAxis= us-gaap_CostOfSalesMember | $ 0us-gaap_DerivativeGainLossOnDerivativeNet/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_CommodityContractMember/ us-gaap_IncomeStatementLocationAxis= us-gaap_CostOfSalesMember |
| Derivative, Notional Amount                                                                                                                                                                                                                     |                                          |                                         | $ 6invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | € 12invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | $ 4invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | € 9invest_DerivativeNotionalAmount/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | [1] | $ 6invest_DerivativeNotionalAmount/ nav_DerivativeInstrumentContractAxis= nav_Contract1Member/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | 6invest_DerivativeNotionalAmount/ nav_DerivativeInstrumentContractAxis= nav_Contract1Member/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | $ 4invest_DerivativeNotionalAmount/ nav_DerivativeInstrumentContractAxis= nav_Contract1Member/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember | 5invest_DerivativeNotionalAmount/ nav_DerivativeInstrumentContractAxis= nav_Contract1Member/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember |   |   |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                 |
| [1](A) Forward exchange contracts of €2 expire on the last day of each month from May 2015 through October 2015.(B)Forward exchange contracts of €1 expire on the last day of each month from February 2015 through October 2015. |

| 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
Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5618551-113959Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959
+ Details**Name:**us-gaap_DerivativeGainLossOnDerivativeNet**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DerivativeLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |