EMPLOYEE STOCK BENEFIT PLANS (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Stock-based compensation expense
Total pre-tax stock-based compensation expense	$ 7.8	$ 9.0
Net tax benefit related to stock-based compensation expense	(2.7)	(3.1)
Stock options
Stock-based compensation expense
Total pre-tax stock-based compensation expense	2.1	1.9
Performance share awards
Stock-based compensation expense
Total pre-tax stock-based compensation expense	2.3	4.4
Restricted stock units
Stock-based compensation expense
Total pre-tax stock-based compensation expense	$ 3.4	$ 2.7