BORROWINGS - Additional Information (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Short-term advances	$ 900,000,000	$ 1,000,000,000
Short-term advances, percentage bearing fixed interest rate	100.00%	100.00%
Subordinated notes	$ 68,000,000	$ 68,000,000
Other subordinated debt	274,000,000	248,000,000
Long-term borrowings	713,000,000	682,000,000
Howard
Debt Instrument [Line Items]
Subordinated notes	5,000,000
Other subordinated debt	25,000,000
FHLB
Debt Instrument [Line Items]
Credit available with FHLB	8,700,000,000
Credit with FHLB utilized	900,000,000
Long-term borrowings	$ 0	$ 0
Minimum | FHLB
Debt Instrument [Line Items]
Effective interest rates		0.26%
Maximum | FHLB
Debt Instrument [Line Items]
Effective interest rates		0.29%