EQUITY (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Aug. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Quarterly dividend on all classes of common stock (in dollars per share)		$ 1.50	$ 1.50	$ 1.50	$ 1.40	$ 1.40	$ 1.40	$ 1.40
Capital required for capital adequacy		$ 969.1			$ 917.6
Capital		1,700.0			1,500.0
Excess capital		$ 723.4			$ 583.5
6.500% Non-Cumulative Preferred Stock, Series H
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, number of shares issued	4.0
Preferred stock, dividend rate	6.50%
Preferred stock, par value (in dollars per share)	$ 25.00	$ 25			$ 25
Payments of stock issuance costs	$ 3.1