EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 195.1	$ 52.7	$ 274.6	$ 60.2
Basic shares	167.0	166.3	167.1	166.0
Basic net income per share	$ 1.17	$ 0.32	$ 1.64	$ 0.36
Earnings Per Share, Diluted [Abstract]
Basic shares	167.0	166.3	167.1	166.0
Stock-based compensation	1.6	2.2	1.8	2.2
Diluted shares	168.6	168.5	168.9	168.2
Diluted net income per share	$ 1.16	$ 0.31	$ 1.63	$ 0.36
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2.4	1.6	2.4	1.6