Share-Based Compensation (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based compensation expense
Pre-tax compensation expense	$ 4.7	$ 4.3	$ 9.4	$ 8.9
Income tax (benefit)	(1.4)	(1.3)	(2.7)	(2.7)
Total share-based compensation expense, net of income taxes	3.3	3.0	6.7	6.2
Employee Stock Option [Member]
Share-based compensation expense
Pre-tax compensation expense	1.7	1.6	3.7	3.2
Income tax (benefit)	(0.5)	(0.5)	(1.0)	(1.0)
Total share-based compensation expense, net of income taxes	1.2	1.1	2.7	2.2
Restricted Stock Units R S U Restricted Stock Awards And Other Share Based Awards [Member]
Share-based compensation expense
Pre-tax compensation expense	3.0	2.7	5.7	5.7
Income tax (benefit)	(0.9)	(0.8)	(1.7)	(1.7)
Total share-based compensation expense, net of income taxes	$ 2.1	$ 1.9	$ 4.0	$ 4.0