|**DESCRIPTION OF BUSINESS, BASIS OF PRESENTATION AND ACCOUNTING POLICIES (Recently Adopted Accounting Standards) (Details) - USD ($) $ in Thousands**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | Jun. 30, 2020                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Mar. 31, 2020                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | Jan. 01, 2020 | Dec. 31, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------- | ------------- | ------------- | ------------- | -------------
|**New Accounting Pronouncements or Change in Accounting Principle [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               |               |               |              
|Financing receivable, allowance for credit loss                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | $ 7,112,739                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | $ 6,623,736   |               | $ 3,646,189   | [1]           | $ 3,783,833  
|Decrease in stockholders' equity                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | 20,226,777                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | 22,223,973    |               | 24,398,830    |               | $ 24,504,820 
|Deferred tax liabilities, net                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | $ (101,000)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               | (1,000,000)   |               |              
|Cumulative Effect, Period of Adoption, Adjustment                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               |               |               |              
|**New Accounting Pronouncements or Change in Accounting Principle [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               |               |               |              
|Financing receivable, allowance for credit loss                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               | 2,535,883     |               |              
|Decrease in stockholders' equity                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | $ (132)       |               | $ (1,785,464) |               |              
|ASU 2016-13                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               |               |               |              
|**New Accounting Pronouncements or Change in Accounting Principle [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               |               |               |               |              
|Financing receivable, allowance for credit loss                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               | $ 2,500,000   |               |               |              
|Deferred tax liabilities, net                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |               | $ 700,000     |               |               |              
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
|[1]
The Company has interests in certain Trusts that are considered VIEs for accounting purposes. At June 30, 2020 and December 31, 2019, LHFI included $22.5 billionand $26.5 billion, Operating leases assets, net included$16.2 billionand $16.5 billion, restricted cash included $1.6 billionand $1.6 billion, other assets included$703.2 millionand $625.4 million, Borrowings and other debt obligations included$32.3 billionand $34.2 billion, and Other liabilities included$101.1 millionand $188.1 million of assets or liabilities that were included within VIEs, respectively. See Note 7 to these Condensed Consolidated Financial Statements for additional information. | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | The Company has interests in certain Trusts that are considered VIEs for accounting purposes. At June 30, 2020 and December 31, 2019, LHFI included $22.5 billionand $26.5 billion, Operating leases assets, net included$16.2 billionand $16.5 billion, restricted cash included $1.6 billionand $1.6 billion, other assets included$703.2 millionand $625.4 million, Borrowings and other debt obligations included$32.3 billionand $34.2 billion, and Other liabilities included$101.1 millionand $188.1 million of assets or liabilities that were included within VIEs, respectively. See Note 7 to these Condensed Consolidated Financial Statements for additional information.
|[1]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | The Company has interests in certain Trusts that are considered VIEs for accounting purposes. At June 30, 2020 and December 31, 2019, LHFI included $22.5 billionand $26.5 billion, Operating leases assets, net included$16.2 billionand $16.5 billion, restricted cash included $1.6 billionand $1.6 billion, other assets included$703.2 millionand $625.4 million, Borrowings and other debt obligations included$32.3 billionand $34.2 billion, and Other liabilities included$101.1 millionand $188.1 million of assets or liabilities that were included within VIEs, respectively. See Note 7 to these Condensed Consolidated Financial Statements for additional information.

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