EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 44.2	$ (20.0)	$ 41.7	$ 195.1	$ 58.6	$ 20.9	$ 65.9	$ 274.6
Basic shares	161.9			167.0			163.7	167.1
Basic net income per share	$ 0.27			$ 1.17			$ 0.40	$ 1.64
Earnings Per Share, Diluted [Abstract]
Basic shares	161.9			167.0			163.7	167.1
Stock-based compensation	0.9			1.6			0.8	1.8
Diluted shares	162.8			168.6			164.5	168.9
Diluted net income per share	$ 0.27			$ 1.16			$ 0.40	$ 1.63
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	7.4			2.4			7.2	2.4