DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 19,137,369	$ 19,828,103
Derivative Asset	304,416	357,698
Derivative liabilities	304,302	357,698
Gross amounts of recognized liabilities	304,302	357,698
Derivative Liability, Fair Value, Gross Asset	(402,219)	(415,993)
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral	(97,917)	(58,295)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	18,837,369	19,828,103
Derivative Asset	303,950	357,698
Derivative liabilities	(303,950)	(357,698)
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 300,000	$ 0
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities	Other Liabilities
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 2,261,185	$ 2,206,351
Derivative Asset	6,988	5,057
Derivative liabilities	145,118	147,759
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,261,185	2,206,351
Derivative Asset	145,118	147,759
Derivative liabilities	6,988	5,057
Gross amounts of recognized liabilities	152,106	152,816
Derivative Liability, Fair Value, Gross Asset	(339,500)	(314,048)
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral	(187,394)	(161,232)
Fair Value Hedges | Foreign Exchange | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of recognized liabilities	151,844	204,882
Derivative Liability, Fair Value, Gross Asset	(62,253)	(101,945)
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral	89,591	102,937
Fair Value Hedges | Cash Flow Hedging | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of recognized liabilities	352	0
Derivative Liability, Fair Value, Gross Asset	(466)	0
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral	(114)	0
Foreign Exchange | Matched interest rate swaps | Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,179,984	7,734,395
Derivative Asset	90,652	111,078
Derivative liabilities	61,192	93,804
Foreign Exchange | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,135,015	7,681,006
Derivative Asset	61,192	93,804
Derivative liabilities	$ 90,652	$ 111,078
Cash Flow Hedging | Interest Rate Floor
Derivatives, Fair Value [Line Items]
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities	Other Liabilities
Cash Flow Hedging | Interest Rate Floor | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 300,000	$ 0