| **Segment Reporting - Summary of Segment Operations (Details) - USD ($) $ in Millions** | 3 Months Ended | 9 Months Ended |
|-----------------------------------------------------------------------------------------|----------------|----------------|
||
| **Segment Reporting Information [Line Items]**                                          |           |           |   |   |
| External sales and revenues, net                                                        | $ 2,086        | $ 2,538        | $ 6,048 | $ 7,652 |
| Sales and revenues, net                                                                 | 2,086          | 2,538          | 6,048 | 7,652 |
| Loss from continuing operations, net of tax                                             | (34)           | (30)           | (63) | (136) |
| Income tax expense                                                                      | (14)           | (12)           | (25) | (37) |
| Interest expense                                                                        | 84             | 75             | 246 | 227 |
| Equity in income of non-consolidated affiliates                                         | 2              | 3              | 3 | 6 |
| Capital expenditures                                                                    | 30             | 27             | 83 | 72 |
| Intersegment sales and revenues                                                         | 0              | 0              | 0 | 0 |
| Segment Profit Loss                                                                     | (20)           | (18)           | (38) | (99) |
| Depreciation, Depletion and Amortization                                                | 53             | 68             | 164 | 221 |
| North America Truck [Member]                                                            |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                          |           |           |   |   |
| External sales and revenues, net                                                        | 1,386          | 1,785          | 3,926 | 5,349 |
| Sales and revenues, net                                                                 | 1,395          | 1,834          | 4,007 | 5,470 |
| Loss from continuing operations, net of tax                                             | (54)           | (36)           | (128) | (105) |
| Income tax expense                                                                      | 0              | 0              | 0 | 0 |
| Interest expense                                                                        | 0              | 0              | 0 | 0 |
| Equity in income of non-consolidated affiliates                                         | 1              | 1              | 3 | 4 |
| Capital expenditures                                                                    | 26             | 20             | 70 | 58 |
| Intersegment sales and revenues                                                         | 9              | 49             | 81 | 121 |
| Segment Profit Loss                                                                     | (54)           | (36)           | (128) | (105) |
| Depreciation, Depletion and Amortization                                                | 29             | 40             | 92 | 139 |
| Corporate And Eliminations [Member]                                                     |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                          |           |           |   |   |
| External sales and revenues, net                                                        | 4              | 2              | 8 | 7 |
| Sales and revenues, net                                                                 | (51)           | (93)           | (204) | (256) |
| Loss from continuing operations, net of tax                                             | (153)          | (145)          | (471) | (492) |
| Income tax expense                                                                      | (14)           | (12)           | (25) | (37) |
| Interest expense                                                                        | 63             | 56             | 187 | 170 |
| Equity in income of non-consolidated affiliates                                         | 0              | 0              | 0 | 0 |
| Capital expenditures                                                                    | 3              | 5              | 8 | 7 |
| Intersegment sales and revenues                                                         | (55)           | (95)           | (212) | (263) |
| Segment Profit Loss                                                                     | (139)          | (133)          | (446) | (455) |
| Depreciation, Depletion and Amortization                                                | 4              | 5              | 12 | 16 |
| North America Parts [Member]                                                            |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                          |           |           |   |   |
| External sales and revenues, net                                                        | 589            | 614            | 1,791 | 1,835 |
| Sales and revenues, net                                                                 | 597            | 625            | 1,814 | 1,864 |
| Loss from continuing operations, net of tax                                             | 152            | 151            | 478 | 429 |
| Income tax expense                                                                      | 0              | 0              | 0 | 0 |
| Interest expense                                                                        | 0              | 0              | 0 | 0 |
| Equity in income of non-consolidated affiliates                                         | 1              | 1              | 3 | 3 |
| Capital expenditures                                                                    | 0              | 1              | 2 | 1 |
| Intersegment sales and revenues                                                         | 8              | 11             | 23 | 29 |
| Segment Profit Loss                                                                     | 152            | 151            | 478 | 429 |
| Depreciation, Depletion and Amortization                                                | 3              | 4              | 10 | 11 |
| Global Operations [Member]                                                              |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                          |           |           |   |   |
| External sales and revenues, net                                                        | 73             | 100            | 221 | 353 |
| Sales and revenues, net                                                                 | 85             | 109            | 254 | 391 |
| Loss from continuing operations, net of tax                                             | (5)            | (26)           | (19) | (40) |
| Income tax expense                                                                      | 0              | 0              | 0 | 0 |
| Interest expense                                                                        | 0              | 0              | 0 | 0 |
| Equity in income of non-consolidated affiliates                                         | 0              | 1              | (3) | (1) |
| Capital expenditures                                                                    | 0              | 1              | 2 | 4 |
| Intersegment sales and revenues                                                         | 12             | 9              | 33 | 38 |
| Segment Profit Loss                                                                     | (5)            | (26)           | (19) | (40) |
| Depreciation, Depletion and Amortization                                                | 4              | 6              | 13 | 18 |
| Financial Services Operations [Member]                                                  |           |           |   |   |
| **Segment Reporting Information [Line Items]**                                          |           |           |   |   |
| External sales and revenues, net                                                        | 34             | 37             | 102 | 108 |
| Sales and revenues, net                                                                 | 60             | 63             | 177 | 183 |
| Loss from continuing operations, net of tax                                             | 26             | 26             | 77 | 72 |
| Income tax expense                                                                      | 0              | 0              | 0 | 0 |
| Interest expense                                                                        | 21             | 19             | 59 | 57 |
| Equity in income of non-consolidated affiliates                                         | 0              | 0              | 0 | 0 |
| Capital expenditures                                                                    | 1              | 0              | 1 | 2 |
| Investment Income, Interest                                                             | 43             | 46             | 127 | 135 |
| Intersegment sales and revenues                                                         | 26             | 26             | 75 | 75 |
| Segment Profit Loss                                                                     | 26             | 26             | 77 | 72 |
| Depreciation, Depletion and Amortization                                                | $ 13           | $ 13           | $ 37 | $ 37 |

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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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Amount of profit or loss recognized by the reportable segment.
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| - Definition
The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.
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| - Definition
Amount after tax of income (loss) from continuing operations attributable to the parent.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.
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| - Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
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| - Definition
Amount of the cost of borrowed funds accounted for as interest expense.
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| - Definition
Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.
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The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.
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| - Definition
Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).
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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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