COMPREHENSIVE INCOME - ADDITIONAL INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustments	$ (92.8)	$ 76.0	$ 94.0	$ (112.9)
Cumulative foreign currency translation adjustments	(200.3)		(200.3)		$ (307.5)
Cumulative foreign currency translation adjustment losses on loans designated as hedges of net investments	(107.0)		(107.0)		(93.7)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustments	91.4	(74.9)	107.2	(113.7)
Foreign currency translation, tax adjustments	185.5		185.5		$ 169.3
Foreign Currency Translation Adjustments | Net Investment Hedging
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation gain (losses) on loans designated as hedges of net investments	$ (1.6)	$ (0.4)	$ (13.3)	$ (1.2)