| **Postretirement Benefits - Schedule of Plan Assets (Details) (Pension Benefits, USD $)In Millions, unless otherwise specified**                                                                                                                                                                                                                                                                                                                                                     | Oct. 31, 2014                                                                                                                                                                                                                                                                                                                                | Oct. 31, 2013 | Oct. 31, 2012                                                                                                                                                                                                                                                                                                                                 |
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| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | $ 2,627us-gaap_DefinedBenefitPlanFairValueOfPlanAssets                                                                                                                                                                                                                                                                                       |               | $ 2,519us-gaap_DefinedBenefitPlanFairValueOfPlanAssets                                                                                                                                                                                                                                                                                        |  | $ 2,411us-gaap_DefinedBenefitPlanFairValueOfPlanAssets |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                                                                                                                                                                                                                                                                                                                                                                                | 2,609nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables                                                                                                                                                                                                                                                                         | [1]           | 2,574nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables                                                                                                                                                                                                                                                                          | [1] |   |
| Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                                                                                                                                                                                                                                                                                                                                                                                | 1,086nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                           | [1]           | 1,154nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                            | [1] |   |
| Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                                                                                                                                                                                                                                                                                                                                                                                | 1,427nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                           | [1]           | 1,300nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                            | [1] |   |
| Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                                                                                                                                                                                                                                                                                                                                                                                | 96nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                              | [1]           | 120nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                              | [1] |   |
| Cash and Cash Equivalents [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 112us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                       |               | 107us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                        |  |   |
| Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 112us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member  |               | 107us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member   |  |   |
| Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member     |  |   |
| Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member     |  |   |
| US Large Cap [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 227us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                       |               | 207us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                        |  |   |
| US Large Cap [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 227us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                  |               | 207us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                   |  |   |
| US Large Cap [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                     |  |   |
| US Large Cap [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                     |  |   |
| US Smid Cap [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 313us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                        |               | 350us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                         |  |   |
| US Smid Cap [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 313us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                   |               | 350us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                    |  |   |
| US Smid Cap [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                     |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                      |  |   |
| US Smid Cap [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                     |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                      |  |   |
| Canadian Equity [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 44us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                    |               | 93us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                     |  |   |
| Canadian Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 44us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member               |               | 93us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                |  |   |
| Canadian Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                 |  |   |
| Canadian Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CanadianEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                 |  |   |
| International Equity [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 244us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                              |               | 254us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                               |  |   |
| International Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 244us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member         |               | 254us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member          |  |   |
| International Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member           |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member            |  |   |
| International Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member           |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member            |  |   |
| Emerging Markets Equity [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 108us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                            |               | 105us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                             |  |   |
| Emerging Markets Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 108us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member       |               | 105us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member        |  |   |
| Emerging Markets Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member         |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member          |  |   |
| Emerging Markets Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member         |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member          |  |   |
| Equity [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | (106)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                     |               | (72)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                       |  |   |
| Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                     |  |   |
| Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                     |  |   |
| Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | (106)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                |               | (72)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                  |  | 4us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_EquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |
| Corporate Bond Securities [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 200us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                      |               | 147us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                       |  |   |
| Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member    |  |   |
| Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 200us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member |               | 147us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member  |  |   |
| Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |  |   |
| US Treasury and Government [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 630us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                      |               | 494us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                       |  |   |
| US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member    |  |   |
| US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 630us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member |               | 494us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member  |  |   |
| US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |  |   |
| Asset-backed Securities [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 8us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                          |               | 8us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                           |  |   |
| Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member     |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member      |  |   |
| Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 8us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member     |               | 8us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member      |  |   |
| Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member     |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member      |  |   |
| Fixed Income Interest Rate [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                        |               | (13)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                      |  |   |
| Fixed Income Interest Rate [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member    |  |   |
| Fixed Income Interest Rate [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member    |  |   |
| Fixed Income Interest Rate [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member   |               | (13)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |  | 19us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_FixedIncomeInterestRateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |
| Common And Preferred Stock [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 531us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                          |               | 583us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                           |  |   |
| Common And Preferred Stock [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member       |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member        |  |   |
| Common And Preferred Stock [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 531us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member     |               | 583us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member      |  |   |
| Common And Preferred Stock [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member       |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_CommonAndPreferredStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member        |  |   |
| Commodities Investment [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 58us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                         |               | 68us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                          |  |   |
| Commodities Investment [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member     |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member      |  |   |
| Commodities Investment [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 58us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member    |               | 68us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member     |  |   |
| Commodities Investment [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member     |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member      |  |   |
| Hedge Funds [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 106us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                   |               | 101us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                    |  |   |
| Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                 |  |   |
| Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
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| Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
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| Private Equity Funds [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 94us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                            |               | 103us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                            |  |   |
| Private Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member        |               |                                                                                                                                                                                                                                                                                                                                     |  |   |
| Private Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member        |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member         |  |   |
| Private Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 94us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member       |               | 103us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member       |  | 92us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |
| Exchange Traded Funds [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                       |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 9us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                            |               | 6us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                             |  |   |
| Exchange Traded Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 9us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member       |               | 6us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member        |  |   |
| Exchange Traded Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member       |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member        |  |   |
| Exchange Traded Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member       |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_ExchangeTradedFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member        |  |   |
| Mutual Funds [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 29us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                       |               | 32us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                        |  |   |
| Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 29us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                  |               | 32us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                   |  |   |
| Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                    |  |   |
| Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_MutualFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                    |  |   |
| Real Estate [Member]                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                     |               | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember                                                                                                      |  |   |
| Real Estate [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                 |  |   |
| Real Estate [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                 |  |   |
| Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                |               | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                 |  | 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_RealEstateMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |
| Accounts Receivable [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                         |               |                                                                                                                                                                                                                                                                                                                                          |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                                                                                                                                                                                                                                                                                                                                                      | $ 9us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AccountsReceivableMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member      |               | $ 8us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AccountsReceivableMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_PensionPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member       |  |   |
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| [1](A)For October 31, 2014 and 2013, the totals exclude $9 million and $8 million of receivables, respectively, which are included in the change in plan assets table. In addition, the table above includes the fair value of Canadian pension assets translated at the exchange rates as of October 31, 2014 and 2013, respectively, while the change in plan asset table includes the fair value of Canadian pension assets translated at historical foreign currency rates. |

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| - Definition
Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables
+ References
No definition available.
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| - Definition
Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930
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