| **Summary of Significant Accounting Policies - Product Warranty Liability (Details) (USD $)In Millions, except Per Share data, unless otherwise specified** | 3 Months Ended                                                                                                                                                                                                |                                                                                                                                                                                                             |                                                                                                            |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------|
||
| **Product Liability Contingency [Line Items]**                                                                                                              |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| Product Warranty Accrual                                                                                                                                    | $ 1,083us-gaap_ProductWarrantyAccrual                                                                                                                                                                         | $ 1,338us-gaap_ProductWarrantyAccrual                                                                                                                                                                       | $ 1,197us-gaap_ProductWarrantyAccrual                                                                      | $ 1,349us-gaap_ProductWarrantyAccrual |
| Product Warranty Accrual, Warranties Issued                                                                                                                 | 50us-gaap_ProductWarrantyAccrualWarrantiesIssued                                                                                                                                                              | 71us-gaap_ProductWarrantyAccrualWarrantiesIssued                                                                                                                                                            |                                                                                                       |   |
| Product Warranty Accrual, Currency Translation, Increase (Decrease)                                                                                         | (2)us-gaap_ProductWarrantyAccrualCurrencyTranslationIncreaseDecrease                                                                                                                                          | (2)us-gaap_ProductWarrantyAccrualCurrencyTranslationIncreaseDecrease                                                                                                                                        |                                                                                                       |   |
| **Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:**                                          |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| Adjustments to pre-existing warranties(A)(B)                                                                                                                | (57)us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease                                                                                                                                                 | 52us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease                                                                                                                                                 |                                                                                                       |   |
| **Extended Warranty Program:**                                                                                                                              |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| Product Warranty Accrual, Payments                                                                                                                          | (105)us-gaap_ProductWarrantyAccrualPayments                                                                                                                                                                   | (132)us-gaap_ProductWarrantyAccrualPayments                                                                                                                                                                 |                                                                                                       |   |
| Product Warranty Accrual, Current                                                                                                                           | 497us-gaap_ProductWarrantyAccrualClassifiedCurrent                                                                                                                                                            | 602us-gaap_ProductWarrantyAccrualClassifiedCurrent                                                                                                                                                          |                                                                                                       |   |
| Product Warranty Accrual, Noncurrent                                                                                                                        | 586us-gaap_ProductWarrantyAccrualNoncurrent                                                                                                                                                                   | 736us-gaap_ProductWarrantyAccrualNoncurrent                                                                                                                                                                 |                                                                                                       |   |
| Extended Warranty Programs [Member]                                                                                                                         |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| **Extended Warranty Program:**                                                                                                                              |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| Deferred Revenue, Revenue Recognized                                                                                                                        | 37us-gaap_DeferredRevenueRevenueRecognized/ us-gaap_DeferredRevenueArrangementTypeAxis= nav_ExtendedWarrantyProgramsMember                                                                                    | 27us-gaap_DeferredRevenueRevenueRecognized/ us-gaap_DeferredRevenueArrangementTypeAxis= nav_ExtendedWarrantyProgramsMember                                                                                  |                                                                                                       |   |
| Deferred Revenue                                                                                                                                            | 427us-gaap_DeferredRevenue/ us-gaap_DeferredRevenueArrangementTypeAxis= nav_ExtendedWarrantyProgramsMember                                                                                                    |                                                                                                                                                                                                        | 437us-gaap_DeferredRevenue/ us-gaap_DeferredRevenueArrangementTypeAxis= nav_ExtendedWarrantyProgramsMember |   |
| Product Warranty Accrual [Member]                                                                                                                           |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| **Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:**                                          |                                                                                                                                                                                                          |                                                                                                                                                                                                        |                                                                                                       |   |
| Adjustments to pre-existing warranties(A)(B)                                                                                                                | $ (57)us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease/ us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis= nav_ProductWarrantyAccrualMember               | $ 52us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease/ us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis= nav_ProductWarrantyAccrualMember               |                                                                                                       |   |
| Product Warranty Accrual, Preexisting Increase Decrease Per Share, Net of Tax                                                                               | $ (0.70)nav_ProductWarrantyAccrualPreexistingIncreaseDecreasePerShareNetOfTax/ us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis= nav_ProductWarrantyAccrualMember | $ 0.64nav_ProductWarrantyAccrualPreexistingIncreaseDecreasePerShareNetOfTax/ us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis= nav_ProductWarrantyAccrualMember |                                                                                                       |   |

| X                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Product Warranty Accrual, Preexisting Increase Decrease Per Share, Net of Tax
+ References
No definition available.
+ Details**Name:**nav_ProductWarrantyAccrualPreexistingIncreaseDecreasePerShareNetOfTax**Namespace Prefix:**nav_**Data Type:**num:perShareItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section AReference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 13.A.4(a).Q1 Response) -URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780
+ Details**Name:**us-gaap_DeferredRevenue**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of previously reported deferred or unearned revenue that was recognized as revenue during the period. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 13.A.4(a).Q1) -URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section A
+ Details**Name:**us-gaap_DeferredRevenueRevenueRecognized**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ExtendedProductWarrantyDisclosureAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_MovementInStandardAndExtendedProductWarrantyIncreaseDecreaseRollForward**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ProductLiabilityContingencyLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15(5)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Subparagraph 5 -Article 9Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph ((c)(5)) -URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249
+ Details**Name:**us-gaap_ProductWarrantyAccrual**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers. For classified balance sheets, represents the current portion of the liabilities (due within one year or within the normal operating cycle if longer).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.20) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 25 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6397716&loc=d3e11281-110244Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12524-110249
+ Details**Name:**us-gaap_ProductWarrantyAccrualClassifiedCurrent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total Increase or Decrease in the standard and extended product warranty liability due to currency translation.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249
+ Details**Name:**us-gaap_ProductWarrantyAccrualCurrencyTranslationIncreaseDecrease**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying value as of the balance sheet date of obligations incurred through that date and due after one year (or beyond the operating cycle if longer) for estimated claims under standard and extended warranty protection rights granted to customers.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.24) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 24 -Article 5Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14394-108349
+ Details**Name:**us-gaap_ProductWarrantyAccrualNoncurrent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the aggregate decrease in the liability related to payments to satisfy claims for standard and extended product warranties.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph ((c)(2)) -URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249
+ Details**Name:**us-gaap_ProductWarrantyAccrualPayments**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting standard and extended product warranties (including adjustments for changes in estimates).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph ((c)(4)) -URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249
+ Details**Name:**us-gaap_ProductWarrantyAccrualPreexistingIncreaseDecrease**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the aggregate increase in the liability for accruals related to standard and extended product warranties issued during the reporting period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph ((c)(3)) -URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249
+ Details**Name:**us-gaap_ProductWarrantyAccrualWarrantiesIssued**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DeferredRevenueArrangementTypeAxis=nav_ExtendedWarrantyProgramsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis=nav_ProductWarrantyAccrualMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |