| **VARIABLE INTEREST ENTITIES (Tables)**                     | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
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| **Variable Interest Entity and Securitizations [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| Schedule of Variable Interest Entities                      | The following table summarizes the assets and liabilities related to the above mentioned VIEs that are included in the Company's Condensed Consolidated Financial Statements as of the date indicated:   March 31, 2016 December 31, 2015  (in thousands)Restricted cash $1,982,611 $1,842,877Loans(1) 23,577,939 23,726,979Leased vehicles, net 7,298,521 6,516,030Various other assets 581,758 620,482Notes payable 30,515,797 30,628,837Various other liabilities 7,654 5,379(1) Includes $1.3 billion and $1.5 billion of RICs held for sale at March 31, 2016 and December 31, 2015, respectively.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Summary of Cash Flows Received                              | A summary of the cash flows received from the off-balance sheet Trusts for the periods indicated is as follows:  Three-Month PeriodEnded March 31,   2016 2015  (in thousands)Assets securitized $— $—     Net proceeds from new securitizations $— $—Cash received for servicing fees 15,701 5,304Total cash received from securitization trusts $15,701 $5,304Below is a summary of the cash flows received from the Trusts for the period indicated:       Three-Month PeriodEnded March 31,    2016 2015   (in thousands)Assets securitized $3,621,496 $3,981,855       Net proceeds from new securitizations (1) 2,633,626 3,060,862 Cash received for servicing fees (2) 194,365 159,802 Net distributions from Trusts (2) 431,591 300,487 Total cash received from securitization trusts $3,259,582 $3,521,151 (1)  Includes additional advances on existing securitizations.(2) These amounts are not reflected in the accompanying Condensed Consolidated Statements of Cash Flows because the cash flows are between the VIEs and other entities included in the consolidation |

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Schedule of Cash Flows Between Transferor and Transferee [Table Text Block]
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Variable Interest Entity and Securitizations [Abstract]
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Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.
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