Income Taxes - Schedule of a Reconciliation of the Provision for Income Taxes at the U.S. Federal Statutory Income Tax Rate to the Actual Income Tax Provision (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of provision for income taxes at U.S. federal statutory income tax rate to effective income tax rate
Provision for taxes at U.S. federal statutory rate	$ 104.1	$ 91.9	$ 83.2
State and local taxes, net of federal benefit	1.9	2.0	2.2
Foreign effective rate differential	(15.9)	(12.5)	(10.3)
Research and Development tax credits	(1.5)	(2.8)	(0.7)
Other	0.7	(2.6)	0.5
Tax Settlement			0.2
Change in valuation allowance			(1.0)
Total provision for income taxes	$ 89.3	$ 76.0	$ 74.1