| **FAIR VALUE (Fair Value Adjustments) (Details) - Nonrecurring - USD ($) $ in Thousands** | 3 Months Ended | 9 Months Ended |
|-------------------------------------------------------------------------------------------|----------------|----------------|
||
| Impaired LHFI | Provision for credit losses                                               |           |           |   |   |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**         |           |           |   |   |
| Fair value adjustment                                                                     | $ (45,515)     | $ 617          | $ (44,936) | $ (26,070) |
| Foreclosed assets | Miscellaneous income, net                                             |           |           |   |   |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**         |           |           |   |   |
| Fair value adjustment                                                                     | (5,750)        | (777)          | (10,351) | (5,448) |
| LHFS | Provision for credit losses                                                        |           |           |   |   |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**         |           |           |   |   |
| Fair value adjustment                                                                     | 0              | 0              | (387) | (13,200) |
| LHFS | Miscellaneous income, net                                                          |           |           |   |   |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**         |           |           |   |   |
| Fair value adjustment                                                                     | (86,838)       | (84,840)       | (236,549) | (246,882) |
| Auto loans impaired due to bankruptcy | Provision for credit losses                       |           |           |   |   |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**         |           |           |   |   |
| Fair value adjustment                                                                     | (5,034)        | (17,471)       | (93,846) | (65,584) |
| MSRs | Miscellaneous income, net                                                          |           |           |   |   |
| **Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**         |           |           |   |   |
| Fair value adjustment                                                                     | $ (940)        | $ 123          | $ (560) | $ 320 |

| X                                                                                                                                                                                                                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.
+ References
No definition available.
+ Details**Name:**us-gaap_AssetsFairValueAdjustment**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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.
+ References
No definition available.
+ Details**Name:**us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
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