EMPLOYEE STOCK BENEFIT PLANS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Stock-based compensation expense
Total pre-tax stock-based compensation expense	$ 9.0	$ 7.3
Net tax benefit related to stock-based compensation expense	(3.1)	(2.6)
Stock options
Stock-based compensation expense
Total pre-tax stock-based compensation expense	1.9	1.7
Performance share awards
Stock-based compensation expense
Total pre-tax stock-based compensation expense	4.4	3.2
Restricted stock units
Stock-based compensation expense
Total pre-tax stock-based compensation expense	$ 2.7	$ 2.4