Stock-Based Compensation (Share-based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 16.0	$ 15.7	$ 16.4
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3.9	3.7	3.0
RSU compensation expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	4.7	6.6	5.5
PSU compensation expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 7.4	$ 5.4	$ 7.9