| **Investments in Non-consolidated Affiliates - Summarized Financial Information of Non-consolidated Affiliate (Details) (USD $)In Millions, unless otherwise specified** | 12 Months Ended | 11 Months Ended |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|-----------------|
||
| **Schedule of Equity Method Investments [Line Items]**                                                                                                                   |            |            |   |   |
| Net revenue                                                                                                                                                              | $ 448           | $ 704           | $ 938 | $ 235 |
| Net expenses                                                                                                                                                             |            |            |   | 318 |
| Loss before tax expense                                                                                                                                                  |            |            |   | (83) |
| Net loss                                                                                                                                                                 | $ 36            | $ (22)          | $ (131) | $ (83) |

| X                                                                                                                                                                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of income (loss) continuing operations before taxes reported by an equity method investment of the entity.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total amount of expenses, including cost of sales, reported by an equity method investment of the entity.
+ References
No definition available.
+ Details**Name:**nav_EquityMethodInvestmentSummarizedFinancialInformationNetExpenses**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of net income (loss) reported by an equity method investment of the entity.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(g)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33912-111571Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 28 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph bb -Article 1Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph g -Subparagraph 1, 2 -Article 4Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph w -Article 1
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| X                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.
+ References
No definition available.
+ Details**Name:**us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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