ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LEASES - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Percentage of increase, housing price index	4.30%	7.40%
Percentage of increase, commercial real estate price index	(0.50%)	3.90%
Percentage of increase (decline), S&P volatility in next fiscal year	(2.20%)	34.90%
Percentage of increase (decline), S&P volatility in next second year	(7.90%)	2.50%
Allowance for credit loss	$ 439.0	$ 423.0
Provision for credit losses	86.0	79.8	$ 72.0
Financing receivable, charge-off	84.7	81.8
Allowance for credit losses on loans and leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	$ 439.5	422.8	405.6	$ 401.7
Financing receivable, allowance for credit loss, period increase		$ 16.7
Financing receivable, allowance for credit loss, period increase, percentage		4.00%
Financing receivable, allowance for credit loss, ratio	1.26%	1.25%
Provision for credit losses	$ 87.2	$ 79.9	71.6
Financing receivable, allowance for credit loss, net charge-offs	70.5	62.7	67.7
Financing receivable, charge-off	$ 84.7	$ 81.8	$ 81.1