| **Summary of significant accounting policies (Variable Interest Entities) (Details) (USD $)In Millions, unless otherwise specified** | Apr. 30, 2012 | Oct. 31, 2011 |
|--------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| Variable Interest Entity Primary Beneficiary Blue Diamond Parts And Blue Diamond Truck [Member]                                      |          |          |
| **Variable Interest Entity [Line Items]**                                                                                            |          |          |
| Assets                                                                                                                               | $ 227         | $ 306         |
| Liabilities                                                                                                                          | 119           | 158           |
| Cash and cash equivalents                                                                                                            | 33            | 38            |
| Securitizations Treated as Borrowings [Member] | Financial Services [Member]                                                         |          |          |
| **Variable Interest Entity [Line Items]**                                                                                            |          |          |
| Assets                                                                                                                               | 1,400         | 1,800         |
| Liabilities                                                                                                                          | 1,100         | 1,500         |
| Transaction Does Not Qualify for Sale Accounting [Member] | Financial Services [Member]                                              |          |          |
| **Variable Interest Entity [Line Items]**                                                                                            |          |          |
| Assets                                                                                                                               | 488           | 468           |
| Liabilities                                                                                                                          | $ 202         | $ 216         |

| X                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Variable Interest Entity Consolidated Carrying Amount Cash And Cash Equivalents
+ References
No definition available.
+ Details**Name:**nav_VariableInterestEntityConsolidatedCarryingAmountCashAndCashEquivalents**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=6970148&loc=d3e5710-111685
+ Details**Name:**us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=6970148&loc=d3e5710-111685
+ Details**Name:**us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_VariableInterestEntityLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |