Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Effective tax rates	39.00%	36.00%		40.00%	34.00%
2012 Federal R&D credit recognized			$ 3.1
Unrecognized tax benefits	83.1			83.1		68.2
Reduction in provision for income taxes due to impact of effective tax rate	68.6			68.6
Gross interest and penalties accrued	4.6			4.6
Deferred tax assets, other current assets	14.9			14.9		21.5
Deferred tax assets, other non-current assets	113.2			113.2		69.1
Income tax benefits attributable to the exercise of employee stock options recorded directly to Additional paid-in-capital	$ 21.0	$ 19.7		$ 68.1	$ 51.1