| **Loss Per Share Attributable to Navistar International Corporation - Narrative (Details)**                          | 1 Months Ended | 3 Months Ended | 12 Months Ended |            |
|----------------------------------------------------------------------------------------------------------------------|----------------|----------------|-----------------|------------|
||
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Shares of Warrants Unwound                                                                                           |           | 1,939,376      | 6,523,319       |       |   |   |   |
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount                                      |           |           |            | 15,700,000 | 24,800,000 | 29,900,000 |   |
| Shares related to warrants                                                                                           |           |           |            |       | 6,400,000 | 11,300,000 |   |
| Three Point Zero Percent Senior Subordinated Convertible Notes [Member]                                              |           |           |            |       |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Shares of Warrants Unwound                                                                                           |           | 1,939,376      | 6,523,319       |       |   |   |   |
| Class of Warrant or Right, Outstanding                                                                               |           |           |            |       |   |   | 2,900,000 |
| Shares related to convertible notes                                                                                  |           |           |            |       | 4,500,000 | 11,300,000 |   |
| Three Point Zero Percent Senior Subordinated Convertible Notes [Member] | Convertible Debt Securities [Member]       |           |           |            |       |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Debt Instrument, Convertible, Conversion Ratio                                                                       |           |           |            | 19.891     |   |   |   |
| Debt Instrument Convertible Conversion Ratio Basis | $                                                               |           |           |            | $ 1,000    |   |   |   |
| Option Indexed to Issuer's Equity, Strike Price | $ / shares                                                         | $ 50.27        |           |            |       |   |   |   |
| Investment Warrants, Exercise Price | $ / shares                                                                     |           |           |            | $ 60.14    |   |   |   |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member]                                                  |           |           |            |       |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Shares related to convertible notes                                                                                  |           |           |            | 3,400,000  | 3,400,000 | 900,000 |   |
| Four Point Five Zero Senior Subordinated Convertible Notes [Member] | Convertible Debt Securities [Member]           |           |           |            |       |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Debt Instrument, Convertible, Conversion Ratio                                                                       |           |           |            | 17.1233    |   |   |   |
| Debt Instrument Convertible Conversion Ratio Basis | $                                                               |           |           |            | $ 1,000    |   |   |   |
| Debt Instrument, Convertible, Conversion Price | $ / shares                                                          |           |           |            | $ 58.40    |   |   |   |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member]                                        |           |           |            |       |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Debt Instrument, Convertible, Conversion Ratio                                                                       |           |           |            | 18.4946    |   |   |   |
| Option Indexed to Issuer's Equity, Strike Price | $ / shares                                                         |           |           |            | $ 54.07    |   |   |   |
| Shares related to convertible notes                                                                                  |           |           |            | 7,600,000  | 5,700,000 |   |   |
| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member] | Convertible Debt Securities [Member] |           |           |            |       |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |           |           |            |       |   |   |   |
| Debt Instrument Convertible Conversion Ratio Basis | $                                                               |           |           |            | $ 1,000    |   |   |   |

| X                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Exercise price of the warrants.
+ References
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Shares of Warrants Unwound
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.
+ References
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| - 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.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of warrants or rights outstanding.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The price per share of the conversion feature embedded in the debt instrument.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.
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| - Definition
Exercise or strike price stated in the contract for options indexed to the issuer's equity shares.
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