| **Postretirement Benefits - Allocation of Plan Assets (Details) (Health and Life Insurance Benefits, USD $)In Millions, unless otherwise specified** | Oct. 31, 2014                                                                                                                                                                                                                                                                                                                                                  | Oct. 31, 2013 | Oct. 31, 2012                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | $ 415us-gaap_DefinedBenefitPlanFairValueOfPlanAssets                                                                                                                                                                                                                                                                                                           |               | $ 447us-gaap_DefinedBenefitPlanFairValueOfPlanAssets                                                                                                                                                                                                                                                                                                           |  | $ 437us-gaap_DefinedBenefitPlanFairValueOfPlanAssets |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                                                | 414nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables                                                                                                                                                                                                                                                                                             | [1]           | 446nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables                                                                                                                                                                                                                                                                                             | [1] |   |
| Fair Value, Inputs, Level 1 [Member]                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                                                | 183nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                            | [1]           | 216nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                | 186nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                            | [1]           | 183nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                | 45nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                             | [1]           | 47nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 16us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                       |               | 32us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                       |  |   |
| 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                                                                                                      | 16us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member  |               | 32us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CashAndCashEquivalentsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member   |  |   |
| US Large Cap [Member]                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 28us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                       |               | 28us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                       |  |   |
| US Large Cap [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                         |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 28us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                  |               | 28us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                   |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsLargeCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                   |  |   |
| US Smid Cap [Member]                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 60us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                        |               | 69us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                        |  |   |
| US Smid Cap [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                          |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 60us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                   |               | 69us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_UsSmidCapMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                    |  |   |
| International Equity [Member]                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 60us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                              |               | 65us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                              |  |   |
| International Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                                                                 |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 60us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member         |               | 65us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member          |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member          |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_InternationalEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member          |  |   |
| Emerging Markets Equity [Member]                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 19us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                            |               | 22us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                            |  |   |
| Emerging Markets Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                                                              |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 19us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member       |               | 22us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member        |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member        |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= nav_EmergingMarketsEquityMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member        |  |   |
| Corporate Bond Securities [Member]                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 55us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                      |               | 52us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                      |  |   |
| 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member  |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 55us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member |               | 52us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member  |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CorporateBondSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 49us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                      |               | 43us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                      |  |   |
| 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member  |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 49us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member |               | 43us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member  |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_USTreasuryAndGovernmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member  |  |   |
| Asset-backed Securities [Member]                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 3us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                         |               | 4us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                         |  |   |
| 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 3us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member    |               | 4us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AssetBackedSecuritiesMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |  |   |
| Common Stock [Member]                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 69us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                  |               | 71us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                  |  |   |
| Common 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= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member              |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member              |  |   |
| Common Stock [Member] | Fair Value, Inputs, Level 2 [Member]                                                                                         |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 69us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member             |               | 71us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member             |  |   |
| Common 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= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member              |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommonStockMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member              |  |   |
| Commodities Investment [Member]                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 10us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                        |               | 13us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                        |  |   |
| 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 10us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member   |               | 13us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_CommoditiesInvestmentMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member    |  |   |
| Hedge Funds [Member]                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 22us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                   |               | 21us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                                   |  |   |
| 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member               |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member               |  |   |
| Hedge 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_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member               |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member               |  |   |
| Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                                                                          |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 22us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member              |               | 21us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member              |  | 19us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_HedgeFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member |
| Private Equity Funds [Member]                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                     |                                                                                                                                                                                                                                                                                                                                                           |               |                                                                                                                                                                                                                                                                                                                                                           |  |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                                                      | 23us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                           |               | 26us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember                                                                                           |  |   |
| 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member       |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member       |               | 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | 23us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member      |               | 26us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member      |  | 23us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_PrivateEquityFundsMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ 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                                                                                                      | $ 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AccountsReceivableMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member     |               | $ 1us-gaap_DefinedBenefitPlanFairValueOfPlanAssets/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis= us-gaap_AccountsReceivableMember/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member     |  |   |
|                                                                                                                                                      |
| [1](A)For both October 31, 2014 and 2013, the totals exclude $1 million of receivables, which are included in the change in plan asset table.        |

| X                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables
+ References
No definition available.
+ Details**Name:**nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanDisclosureLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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
+ Details**Name:**us-gaap_DefinedBenefitPlanFairValueOfPlanAssets**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |