DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 17,687,419	$ 17,683,691
Derivative Asset	264,544	212,970
Derivative liabilities	264,544	212,977
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,308,506	2,430,587
Derivative Asset	5,821	84,694
Derivative liabilities	95,712	7,508
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,308,506	2,430,587
Derivative Asset	95,712	7,508
Derivative liabilities	5,821	84,701
Foreign Exchange | Matched interest rate swaps | Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,550,294	6,423,085
Derivative Asset	96,449	67,988
Derivative liabilities	66,562	52,780
Foreign Exchange | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	6,520,113	6,399,432
Derivative Asset	66,562	52,780
Derivative liabilities	$ 96,449	$ 67,988