ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LEASES - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Percentage of increase, housing price index	7.40%	5.30%
Percentage of increase, commercial real estate price index	3.90%	0.10%
Percentage of increase (decline), S&P volatility in next fiscal year	34.90%	(4.00%)
Percentage of increase (decline), S&P volatility in next second year	2.50%	(2.90%)
Allowance for credit loss	$ 423.0	$ 406.0
Provision for credit losses	79.8	71.8	$ 64.0
Financing receivable, charge-off	81.8	81.1
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, charge-off	31.9
Allowance for credit losses on loans and leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	$ 422.8	405.6	401.7	$ 344.3
Financing receivable, allowance for credit loss, period increase		$ 17.2
Financing receivable, allowance for credit loss, period increase, percentage		4.30%
Financing receivable, allowance for credit loss, ratio	1.25%	1.25%
Provision for credit losses	$ 79.9	$ 71.6	61.8
Financing receivable, allowance for credit loss, net charge-offs	62.7	67.7	16.2
Financing receivable, charge-off	$ 81.8	$ 81.1	$ 31.7