INCOME TAXES - Summary of Components of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
U.S. federal	$ 39.8	$ 53.7	$ 79.1
U.S. states	2.7	4.2	2.4
Non-U.S.	130.1	156.3	130.6
Total current income tax expense	172.6	214.2	212.1
U.S. federal	44.2	(6.9)	(6.4)
U.S. states	3.3	(1.3)	1.9
Non-U.S.	(4.2)	(6.8)	27.5
Total deferred income tax expense/(benefit)	43.3	(15.0)	23.0
Total	$ 215.9	$ 199.2	$ 235.1