| **BORROWINGS (Secured Structured Financings) (Details) - USD ($) $ in Thousands** | Mar. 31, 2020 | Dec. 31, 2019 |
|-----------------------------------------------------------------------------------|---------------|---------------|
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Note Amounts Issued                                                       | $ 169,900     | $ 89,600      |
| SC                                                                                |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Balance                                                                           | 28,043,124    | 28,141,885    |
| Initial Note Amounts Issued                                                       | 53,194,063    | 54,379,783    |
| Collateral                                                                        | 35,063,682    | 36,745,375    |
| Restricted Cash                                                                   | 1,611,653     | 1,627,524     |
| Private issuances of notes backed by vehicle leases                               | $ 11,100,000  | $ 10,200,000  |
| SC | Minimum                                                                      |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Weighted Average Interest Rate Range                                      | 1.28%         | 1.05%         |
| SC | Maximum                                                                      |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Weighted Average Interest Rate Range                                      | 3.90%         | 3.90%         |
| SC | SC public securitizations, maturing on various dates                         |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Balance                                                                           | $ 18,156,699  | $ 18,807,773  |
| Initial Note Amounts Issued                                                       | 42,846,500    | 43,982,220    |
| Collateral                                                                        | 23,001,847    | 24,697,158    |
| Restricted Cash                                                                   | $ 1,591,799   | $ 1,606,646   |
| SC | SC public securitizations, maturing on various dates | Minimum               |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Weighted Average Interest Rate Range                                      | 1.35%         | 1.35%         |
| SC | SC public securitizations, maturing on various dates | Maximum               |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Weighted Average Interest Rate Range                                      | 3.42%         | 3.42%         |
| SC | SC privately issued amortizing notes, maturing on various dates              |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Balance                                                                           | $ 9,886,425   | $ 9,334,112   |
| Initial Note Amounts Issued                                                       | 10,347,563    | 10,397,563    |
| Collateral                                                                        | 12,061,835    | 12,048,217    |
| Restricted Cash                                                                   | $ 19,854      | $ 20,878      |
| SC | SC privately issued amortizing notes, maturing on various dates | Minimum    |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Weighted Average Interest Rate Range                                      | 1.28%         | 1.05%         |
| SC | SC privately issued amortizing notes, maturing on various dates | Maximum    |          |          |
| **Debt Instrument [Line Items]**                                                  |          |          |
| Initial Weighted Average Interest Rate Range                                      | 3.90%         | 3.90%         |

| X                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Pledged Restricted Cash Separately Reported Securities Pledged Under Letter Of Credit Facilities At Fair Value
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.
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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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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The sum of the fair values, as of the date of each statement of financial position presented, of securities that are restricted as collateral for the payment of related debt obligations, primarily secured borrowings and repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.
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| - Definition
Amount of collateralized debt obligations classified as other.
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