| **Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions**                        | 3 Months Ended | 9 Months Ended |        |
|--------------------------------------------------------------------------------------------------|----------------|----------------|--------|
||
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]** |           |           |   |   |   |   |
| Asset impairment charges                                                                         | $ 12           | $ 7            |   | $ 17 | $ 15 |   |
| Goodwill                                                                                         | $ 38           |           |   | 38 |   | $ 38 |
| Cash and Cash Equivalents, Maturity Term                                                         | 90 days        |           |   |   |   |   |
| Marketable Securities, Maturity Term                                                             | 90 days        |           |   |   |   |   |
| Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)                           | $ 1            | 3              |   | $ 1 | 3 |   |
| Brazilian Reporting Unit [Member]                                                                |           |           |   |   |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]** |           |           |   |   |   |   |
| Indefinite-Lived Intangible Assets (Excluding Goodwill)                                          |           | 24             |   |   | $ 24 |   |
| Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)                           | 1              | $ 3            |   |   |   |   |
| North America Truck [Member]                                                                     |           |           |   |   |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]** |           |           |   |   |   |   |
| Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)                           | $ 11           |           | $ 7    |   |   |   |

| X                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum maturity term for a cash and cash equivalent instrument
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| - Definition
Maximum maturity term for a marketable security instrument
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.
+ 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
Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.
+ References
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