DERIVATIVES - Derivative Financial Instruments, Average Remaining Maturity and the Weighted-Average Interest Rates being Paid and Received (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative, Notional Amount	$ 8,402,376	$ 7,586,618
Derivative Asset	308,819	112,607
Derivative Liability	$ (308,888)	(112,616)
Average Maturity (years)	3 years 1 month 6 days
Fair Value	$ (69)
Interest Rate Swap \| Derivative Financial Instruments Receive Fixed Pay Variable
Derivative [Line Items]
Derivative, Notional Amount	$ 2,094,136
Average Maturity (years)	5 years 8 months 12 days
Fair Value	$ 191,580
Interest Rate Swap \| Derivative Financial Instruments Receive Variable Pay Fixed
Derivative [Line Items]
Derivative, Notional Amount	$ 2,094,136
Average Maturity (years)	5 years 8 months 12 days
Fair Value	$ (191,649)
Foreign Exchange [Member] \| Derivative Financial Instruments Receive Fixed Pay Variable
Derivative [Line Items]
Derivative, Notional Amount	$ 2,107,052
Average Maturity (years)	6 months
Fair Value	$ (19,805)
Foreign Exchange [Member] \| Derivative Financial Instruments Receive Variable Pay Fixed
Derivative [Line Items]
Derivative, Notional Amount	$ 2,107,052
Average Maturity (years)	6 months
Fair Value	$ 19,805
Accrued interest and other assets \| Fair Value Hedges \| Matched interest rate swaps
Derivative [Line Items]
Derivative, Notional Amount	2,094,136	1,923,375
Derivative Asset	197,886	70,799
Derivative Liability	(6,306)	(2,636)
Accrued interest and other assets \| Foreign Exchange [Member] \| Matched interest rate swaps
Derivative [Line Items]
Derivative, Notional Amount	2,107,052	1,869,934
Derivative Asset	42,411	28,739
Derivative Liability	(62,216)	(10,433)
Accrued interest and other liabilities \| Fair Value Hedges \| Matched interest rate swaps
Derivative [Line Items]
Derivative, Notional Amount	2,094,136	1,923,375
Derivative Asset	6,306	2,636
Derivative Liability	(197,955)	(70,808)
Accrued interest and other liabilities \| Foreign Exchange [Member] \| Matched interest rate swaps
Derivative [Line Items]
Derivative, Notional Amount	2,107,052	1,869,934
Derivative Asset	62,216	10,433
Derivative Liability	$ (42,411)	$ (28,739)

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 55
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- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

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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

Nominal or face amount used to calculate payment on derivative.

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