Share-Based Compensation Share-based compensation expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Expense [Line Items]
Share-based Compensation	$ 11.1	$ 6.5	$ 19.1	$ 15.6
Employee Stock Option [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	0.5	0.7	1.2	1.5
Restricted Stock [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	5.7	6.4	12.2	12.7
Performance Share Units [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	4.8	(0.6)	5.6	1.4
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Expense [Line Items]
Share-based Compensation	$ 0.1	$ 0.0	$ 0.1	$ 0.0