| **Allowance for Doubtful Accounts - Schedule of Allowance Aging Analysis (Details) - USD ($) $ in Millions** | Apr. 30, 2020 | Oct. 31, 2019 |
|--------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Financing Receivable, Recorded Investment, Past Due [Line Items]**                                         |          |          |
| Finance Receivables, Current                                                                                 | $ 1,581       | $ 2,118       |
| 30-90 days past due                                                                                          | 44            | 77            |
| Total finance receivables                                                                                    | 1,643         | 2,220         |
| Retail Portfolio [Member]                                                                                    |          |          |
| **Financing Receivable, Recorded Investment, Past Due [Line Items]**                                         |          |          |
| Finance Receivables, Current                                                                                 | 417           | 753           |
| 30-90 days past due                                                                                          | 43            | 76            |
| Total finance receivables                                                                                    | 478           | 854           |
| Wholesale Portfolio [Member]                                                                                 |          |          |
| **Financing Receivable, Recorded Investment, Past Due [Line Items]**                                         |          |          |
| Finance Receivables, Current                                                                                 | 1,164         | 1,365         |
| 30-90 days past due                                                                                          | 1             | 1             |
| Total finance receivables                                                                                    | 1,165         | 1,366         |
| Financing Receivables, Equal to Greater than 90 Days Past Due [Member]                                       |          |          |
| **Financing Receivable, Recorded Investment, Past Due [Line Items]**                                         |          |          |
| Over 90 days past due                                                                                        | 18            | 25            |
| Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio [Member]           |          |          |
| **Financing Receivable, Recorded Investment, Past Due [Line Items]**                                         |          |          |
| Over 90 days past due                                                                                        | 18            | 25            |
| Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Wholesale Portfolio [Member]        |          |          |
| **Financing Receivable, Recorded Investment, Past Due [Line Items]**                                         |          |          |
| Over 90 days past due                                                                                        | $ 0           | $ 0           |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
'Reflects carrying amount of all categories of loans and leases held in portfolio, net of unearned income and the allowance for losses on loans and leases, due from customers, clients, lessees, borrowers, or others within one year of the balance sheet date (or the normal operating cycle, whichever is longer).
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Financing Receivables Recorded Investment 30 To 90 Days Past Due
+ References
No definition available.
+ Details**Name:**nav_FinancingReceivablesRecordedInvestment30To90DaysPastDue**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Recorded Investment in financing receivables that are past due at the balance sheet date.
+ References
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.
+ References
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522
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| X                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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