| **Allowance for doubtful accounts (Rollforward) (Details) (USD $)In Millions, unless otherwise specified**                                                                                                                                                                                                                                                                                                                    | 3 Months Ended | 6 Months Ended |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Receivable, Allowance for Credit Losses [Line Items]**                                                                                                                                                                                                                                                                                                                                                                      |           |                |   |  |   |  |   |  |
| Financing Receivable, Allowance for Credit Losses, Start of Period                                                                                                                                                                                                                                                                                                                                                            | $ 47           |                | $ 94 |  | $ 50 |  | $ 96 |  |
| Provision for doubtful accounts, net of recoveries                                                                                                                                                                                                                                                                                                                                                                            | 0              |                | (2) |  | 0 |  | (2) |  |
| Charge-off of accounts                                                                                                                                                                                                                                                                                                                                                                                                        | (2)            | [1]            | (16) | [1] | (5) | [1] | (18) | [1] |
| Financing Receivable, Allowance for Credit Losses, End of Period                                                                                                                                                                                                                                                                                                                                                              | 45             |                | 76 |  | 45 |  | 76 |  |
| Number of portfolio segments of finance receivables                                                                                                                                                                                                                                                                                                                                                                           | 2              |                |   |  |   |  |   |  |
| Losses recognized at time of repossession                                                                                                                                                                                                                                                                                                                                                                                     | 2              |                | 12 |  | 3 |  | 15 |  |
| Retail [Member]                                                                                                                                                                                                                                                                                                                                                                                                               |           |                |   |  |   |  |   |  |
| **Receivable, Allowance for Credit Losses [Line Items]**                                                                                                                                                                                                                                                                                                                                                                      |           |                |   |  |   |  |   |  |
| Financing Receivable, Allowance for Credit Losses, Start of Period                                                                                                                                                                                                                                                                                                                                                            | 28             |                | 54 |  | 31 |  | 58 |  |
| Provision for doubtful accounts, net of recoveries                                                                                                                                                                                                                                                                                                                                                                            | 0              |                | 1 |  | (2) |  | (1) |  |
| Charge-off of accounts                                                                                                                                                                                                                                                                                                                                                                                                        | (2)            | [1]            | (15) | [1] | (3) | [1] | (17) | [1] |
| Financing Receivable, Allowance for Credit Losses, End of Period                                                                                                                                                                                                                                                                                                                                                              | 26             |                | 40 |  | 26 |  | 40 |  |
| Number of classes of receivables in each portfolio                                                                                                                                                                                                                                                                                                                                                                            | 1              |                |   |  |   |  |   |  |
| Wholesale [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |           |                |   |  |   |  |   |  |
| **Receivable, Allowance for Credit Losses [Line Items]**                                                                                                                                                                                                                                                                                                                                                                      |           |                |   |  |   |  |   |  |
| Financing Receivable, Allowance for Credit Losses, Start of Period                                                                                                                                                                                                                                                                                                                                                            | 3              |                | 2 |  | 3 |  | 2 |  |
| Provision for doubtful accounts, net of recoveries                                                                                                                                                                                                                                                                                                                                                                            | (1)            |                | 0 |  | (1) |  | 0 |  |
| Charge-off of accounts                                                                                                                                                                                                                                                                                                                                                                                                        | 0              | [1]            | 0 | [1] | 0 | [1] | 0 | [1] |
| Financing Receivable, Allowance for Credit Losses, End of Period                                                                                                                                                                                                                                                                                                                                                              | 2              |                | 2 |  | 2 |  | 2 |  |
| Number of classes of receivables in each portfolio                                                                                                                                                                                                                                                                                                                                                                            | 1              |                |   |  |   |  |   |  |
| Trade and Other Receivables [Member]                                                                                                                                                                                                                                                                                                                                                                                          |           |                |   |  |   |  |   |  |
| **Receivable, Allowance for Credit Losses [Line Items]**                                                                                                                                                                                                                                                                                                                                                                      |           |                |   |  |   |  |   |  |
| Financing Receivable, Allowance for Credit Losses, Start of Period                                                                                                                                                                                                                                                                                                                                                            | 16             |                | 38 |  | 16 |  | 36 |  |
| Provision for doubtful accounts, net of recoveries                                                                                                                                                                                                                                                                                                                                                                            | 1              |                | (3) |  | 3 |  | (1) |  |
| Charge-off of accounts                                                                                                                                                                                                                                                                                                                                                                                                        | 0              | [1]            | (1) | [1] | (2) | [1] | (1) | [1] |
| Financing Receivable, Allowance for Credit Losses, End of Period                                                                                                                                                                                                                                                                                                                                                              | $ 17           |                | $ 34 |  | $ 17 |  | $ 34 |  |
|                                                                                                                                                                                                                                                                                                                                                                                                                               |
| [1]We repossess sold and leased vehicles on defaulted finance receivables and leases, and place them into Inventories. Losses recognized at the time of repossession and charged against the allowance for doubtful accounts were $2 million and $3 million for the three and six months ended April 30, 2012, respectively, and $12 million and $15 million for the three and six months ended April 30, 2011, respectively. |

| X                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Financing Receivable By Class Number of Portfolio Segments
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Financing Receivable Number Of Classes Of Receivables In Each Portfolio
+ References
No definition available.
+ Details**Name:**nav_FinancingReceivableNumberOfClassesOfReceivablesInEachPortfolio**Namespace Prefix:**nav_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**nav_ReceivableAllowanceForCreditLossesLineItems**Namespace Prefix:**nav_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Charge to expense for financing receivables that are expected to be uncollectible, net of recoveries.
+ References
No definition available.
+ Details**Name:**nav_ReceivableAllowanceForCreditLossesProvisionsNetOfRecoveries**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Reduction to the allowance for credit losses related to receivables deemed uncollectible.
+ References
No definition available.
+ Details**Name:**nav_ReceviablesAllowanceForCreditLossesWriteOffs**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A valuation allowance for financing receivables that are expected to be uncollectible.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953423-111524 -Subparagraph (c)(1)
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of the loss on termination of a contract for default.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 912 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6539154&loc=d3e52595-109384
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