BORROWINGS - Additional Information (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Short-term advances	$ 930,000,000	$ 1,000,000,000
Short-term advances, percentage bearing fixed interest rate	100.00%	100.00%
Other subordinated debt	$ 274,000,000	$ 248,000,000
Subordinated notes	67,000,000	68,000,000
Long-term borrowings	712,000,000	682,000,000
FHLB
Debt Instrument [Line Items]
Credit available with FHLB	9,300,000,000
Credit with FHLB utilized	900,000,000
Long-term borrowings	0	0
FHLB
Debt Instrument [Line Items]
Short-term advances	0	$ 0
Minimum | FHLB
Debt Instrument [Line Items]
Effective interest rates		0.26%
Maximum | FHLB
Debt Instrument [Line Items]
Effective interest rates		0.29%
Howard
Debt Instrument [Line Items]
Other subordinated debt	25,000,000
Subordinated notes	$ 5,000,000