| **Loss Per Share Attributable to Navistar International Corporation - Narrative (Details) (USD $)**                  | 3 Months Ended                                                                                                                                                | 6 Months Ended                                                                          | 12 Months Ended                                                                         | 3 Months Ended                                                                          | 1 Months Ended                                                                                                                                                                                                                                                                                         |
|----------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| Shares of Warrants Unwound                                                                                           | 6,523,319nav_SharesofWarrantsUnwound                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount                                      |                                                                                                                                                          | 24,800,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount | 29,900,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount | 28,500,000us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| Shares related to warrants                                                                                           |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 6,400,000nav_SharesRelatedToWarrants                                                                                                                                                                                                                                                                   | 11,300,000nav_SharesRelatedToWarrants | 11,300,000nav_SharesRelatedToWarrants |   |   |
| Three Point Zero Percent Senior Subordinated Convertible Notes [Member]                                              |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| Shares of Warrants Unwound                                                                                           | 6,523,319nav_SharesofWarrantsUnwound/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember                           |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| Class of Warrant or Right, Outstanding                                                                               |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 4,800,000us-gaap_ClassOfWarrantOrRightOutstanding/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember                                                                                                                                                       |   |   | 4,800,000us-gaap_ClassOfWarrantOrRightOutstanding/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember |   |
| Option Indexed to Issuer's Equity, Shares Expired in Period                                                          | 8,000,000nav_OptionIndexedtoIssuersEquitySharesExpiredinPeriod/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   | 3,300,000nav_OptionIndexedtoIssuersEquitySharesExpiredinPeriod/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember |   |
| Shares related to convertible notes                                                                                  |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 4,500,000nav_SharesRelatedToConvertibleNotes/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember                                                                                                                                                            | 11,300,000nav_SharesRelatedToConvertibleNotes/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember | 11,300,000nav_SharesRelatedToConvertibleNotes/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember |   |   |
| 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                                                                       |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 19.891us-gaap_DebtInstrumentConvertibleConversionRatio1/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember   |   |   |   |   |
| Debt Instrument Convertible Conversion Ratio Basis                                                                   |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 1,000nav_DebtInstrumentConvertibleConversionRatioBasis/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember    |   |   |   |   |
| Option Indexed to Issuer's Equity, Strike Price                                                                      |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   | $ 50.27us-gaap_OptionIndexedToIssuersEquityStrikePrice1/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember |
| Investment Warrants, Exercise Price                                                                                  |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 60.14invest_InvestmentWarrantsExercisePrice/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember               |   |   |   |   |
| Three Point Zero Percent Senior Subordinated Convertible Notes [Member] | Call Option [Member]                       |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| **Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]**                             |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   |   |
| Option Indexed to Issuer's Equity, Indexed Shares                                                                    |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    |                                                                                                                                                                                                                                                                                                   |   |   |   | 11,337,870us-gaap_OptionIndexedToIssuersEquityIndexedShares/ us-gaap_DebtInstrumentAxis= nav_ThreePointZeroPercentSeniorSubordinatedConvertibleNotesMember/ us-gaap_OptionIndexedToIssuersEquityEquityAxis= us-gaap_CallOptionMember |
| 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                                                                                  |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 5,700,000nav_SharesRelatedToConvertibleNotes/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember                                                                                                                                                                | 900,000nav_SharesRelatedToConvertibleNotes/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember |   |   |   |
| 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                                                                       |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 17.1233us-gaap_DebtInstrumentConvertibleConversionRatio1/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember      |   |   |   |   |
| Debt Instrument Convertible Conversion Ratio Basis                                                                   |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 1,000nav_DebtInstrumentConvertibleConversionRatioBasis/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember        |   |   |   |   |
| Debt Instrument, Convertible, Conversion Price                                                                       |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 58.40us-gaap_DebtInstrumentConvertibleConversionPrice1/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember        |   |   | 58.40us-gaap_DebtInstrumentConvertibleConversionPrice1/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_FourPointFiveZeroSeniorSubordinatedConvertibleNotesMember |   |
| 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                                                                       |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 18.4946us-gaap_DebtInstrumentConvertibleConversionRatio1/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember                                                                                                                                             |   |   |   |   |
| Option Indexed to Issuer's Equity, Strike Price                                                                      |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 54.07us-gaap_OptionIndexedToIssuersEquityStrikePrice1/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember                                                                                                                                                |   |   |   |   |
| Shares related to convertible notes                                                                                  |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 4,400,000nav_SharesRelatedToConvertibleNotes/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember                                                                                                                                                         |   |   |   |   |
| 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                                                                   |                                                                                                                                                          |                                                                                    |                                                                                    |                                                                                    | 1,000nav_DebtInstrumentConvertibleConversionRatioBasis/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis= us-gaap_ConvertibleDebtSecuritiesMember/ us-gaap_DebtInstrumentAxis= nav_FourPointSevenFiveSeniorSubordinatedConvertibleNotesMemberMember |   |   |   |   |

| X                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Exercise price of the warrants.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The basis for applying ratio applied to the debt for purposes of determining the number of shares of the equity security into which the debt will be converted.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Option Indexed to Issuer's Equity, Shares Expired in Period
+ References
No definition available.
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| X                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Shares of Warrants Unwound
+ References
No definition available.
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| X                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Shares related to convertible notes
+ References
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| X                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Shares related to warrants
+ References
No definition available.
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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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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of warrants or rights outstanding.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The price per share of the conversion feature embedded in the debt instrument.
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of issuer's shares to which the option contract is indexed.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Exercise or strike price stated in the contract for options indexed to the issuer's equity shares.
+ References
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| X                                                                                                                                                                                       |
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