Share-Based Compensation Share-based compensation expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Expense [Line Items]
Share-based Compensation	$ 8.0	$ 9.1
Employee Stock Option [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	0.7	0.8
Restricted Stock [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	6.5	6.3
Performance Share Units [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	0.8	2.0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	$ 0.0	$ 0.0