INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
INCOME TAXES
Effective income tax rate (as a percent)	21.80%	17.40%
Statutory U.S. rate (as a percent)	21.00%		35.00%
Estimated one-time transition tax	$ 11.3
Excess tax benefits, share-based compensation	6.8	$ 16.0
Recognized discrete tax expense (benefit)	$ (4.6)
Recognized discrete tax benefits, release of reserves for uncertain tax positions		$ 6.8