EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic and Diluted EPS Numerator:
Net income	$ 113.6		$ 84.5	$ 271.0	$ 178.6
Net loss attributable to redeemable noncontrolling interest			3.8		4.0
Net income excluding redeemable noncontrolling interest	113.6	$ 157.4	88.3	271.0	182.6
Change in redemption value of redeemable noncontrolling interest			(0.2)		(0.4)
Earnings allocated to participating securities	(0.3)		(0.5)	(0.7)	(1.1)
Net income allocated to common stockholders	$ 113.3		$ 87.6	$ 270.3	$ 181.1
Basic EPS Denominator:
Weighted average shares outstanding (in shares)	109.5		111.5	109.9	111.5
Basic Net Income Per Common Share (in dollars per share)	$ 1.04		$ 0.79	$ 2.46	$ 1.62
Diluted EPS Denominator:
Weighted average shares outstanding (in shares)	109.5		111.5	109.9	111.5
Dilutive common shares issued under stock program (in shares)	0.1		0.1	0.2	0.1
Total dilutive weighted average shares (in shares)	109.6		111.6	110.1	111.6
Diluted Net Income Per Common Share (in dollars per share)	$ 1.03		$ 0.78	$ 2.45	$ 1.62