EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Net income	$ 218.5	$ 140.4	$ 209.5	$ 208.2	$ 167.8	$ 173.4	$ 568.4	$ 549.4
Basic earnings per share numerator:
Net income allocated to participating securities	(1.1)			(1.1)			(3.0)	(2.7)
Net income allocated to common stockholders	$ 217.4			$ 207.1			$ 565.4	$ 546.7
Basic earnings per share denominator:
Weighted average shares outstanding (in shares)	104,700,000			105,700,000			105,200,000	105,800,000
Basic earnings per share (in USD per share)	$ 2.08			$ 1.96			$ 5.38	$ 5.17
Diluted earnings per share numerator:
Net income allocated to participating securities	$ (1.1)			$ (1.1)			$ (3.0)	$ (2.7)
Net income allocated to common stockholders	$ 217.4			$ 207.1			$ 565.4	$ 546.7
Diluted earnings per share denominator:
Weighted average shares outstanding (in shares)	104,700,000			105,700,000			105,200,000	105,800,000
Dilutive common shares issued under stock program (in shares)	400,000			400,000			400,000	400,000
Total dilutive weighted average shares (in shares)	105,100,000			106,100,000			105,600,000	106,200,000
Diluted earnings per share (in USD per share)	$ 2.07			$ 1.95			$ 5.36	$ 5.15
Anti-dilutive shares excluded from the computation of diluted earnings per share (in shares)	0			0			0	0