EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income
Net Income, Basic	$ 297.1	$ 1,063.9	$ 927.4
Net Income, Diluted	$ 297.1	$ 1,063.9	$ 927.4
Weighted Average Common Shares
Basic (in shares)	35.3	39.0	42.8
Effect of Dilutive Securities (in shares)	0.4	0.3	0.4
Diluted (in shares)	35.7	39.3	43.2
Per Common Share Amount
Net income, Basic (in dollars per share)	$ 8.42	$ 27.28	$ 21.67
Effect of dilutive securities (in dollars per shares)	(0.10)	(0.21)	(0.20)
Net income, Diluted (in dollars per share)	$ 8.32	$ 27.07	$ 21.47