| **Finance Receivables - Finance Revenues (Details) (USD $)In Millions, unless otherwise specified** | 3 Months Ended | 9 Months Ended |
|-----------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Finance Revenues [Line Items]**                                                                   |           |           |   |   |
| Retail notes and finance leases revenue                                                             | $ 16           | $ 19           | $ 49 | $ 60 |
| Gross finance revenues                                                                              | 60             | 61             | 172 | 178 |
| Less: Intercompany revenues                                                                         | (22)           | (20)           | (57) | (59) |
| Finance revenues                                                                                    | 38             | 41             | 115 | 119 |
| Financing Receivable [Member]                                                                       |           |           |   |   |
| **Finance Revenues [Line Items]**                                                                   |           |           |   |   |
| Operating lease revenue                                                                             | 15             | 13             | 44 | 37 |
| Wholesale Portfolio [Member] | Notes Receivable [Member]                                            |           |           |   |   |
| **Finance Revenues [Line Items]**                                                                   |           |           |   |   |
| Interest Income, Operating                                                                          | 22             | 21             | 59 | 60 |
| Retail And Wholesale Portfolios [Member]                                                            |           |           |   |   |
| **Finance Revenues [Line Items]**                                                                   |           |           |   |   |
| Interest Income, Operating                                                                          | $ 7            | $ 8            | $ 20 | $ 21 |

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| X                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Finance Revenues From On Balance Sheet Receivables
+ References
No definition available.
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| X                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Retail Notes And Finance Leases Revenue
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The aggregate financial services revenue and operating interest income earned during the reporting period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(d)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.
+ References
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