Share-Based Compensation and Equity - Share-based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Document Period End Date	Dec. 31, 2016
Pre-tax compensation expense	$ 22.2	$ 12.4	$ 21.5
Tax benefit	(7.0)	(3.8)	(7.2)
Stock option expense, net of tax	15.2	8.6	14.3
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	2.7	3.6	2.7
Tax benefit	(0.9)	(1.3)	(1.0)
Stock option expense, net of tax	1.8	2.3	1.7
Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	10.7	8.6	6.0
Tax benefit	(3.1)	(2.4)	(1.9)
Stock option expense, net of tax	7.6	6.2	4.1
Performance Shares [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	8.8	0.2	12.5
Tax benefit	(3.0)	(0.1)	(4.2)
Stock option expense, net of tax	5.8	0.1	8.3
Director Deferred Shares [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	0.0	0.0	0.3
Tax benefit	0.0	0.0	(0.1)
Stock option expense, net of tax	$ 0.0	$ 0.0	$ 0.2