Share-Based Compensation (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based compensation expense
Pre-tax compensation expense	$ 4.7	$ 4.2	$ 14.1	$ 13.1
Income tax (benefit)	(1.4)	(1.3)	(4.1)	(3.9)
Total share-based compensation expense, net of income taxes	3.3	2.9	10.0	9.2
Employee Stock Option [Member]
Share-based compensation expense
Pre-tax compensation expense	1.7	1.5	5.4	4.7
Income tax (benefit)	(0.5)	(0.5)	(1.6)	(1.4)
Total share-based compensation expense, net of income taxes	1.2	1.0	3.8	3.3
Restricted Stock Units, Restricted Stock Awards And Other Share Based Awards [Member]
Share-based compensation expense
Pre-tax compensation expense	3.0	2.7	8.7	8.4
Income tax (benefit)	(0.9)	(0.8)	(2.5)	(2.5)
Total share-based compensation expense, net of income taxes	$ 2.1	$ 1.9	$ 6.2	$ 5.9