Share-Based Compensation Share-based compensation expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Expense [Line Items]
Share-based Compensation	$ 9.9	$ 7.7	$ 29.0	$ 23.3
Employee Stock Option [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	0.6	0.7	1.8	2.2
Restricted Stock [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	6.0	6.8	18.2	19.5
Performance Share Units [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	3.2	0.2	8.8	1.6
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	$ 0.1	$ 0.0	$ 0.2	$ 0.0