Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective tax rates	(189.00%)	(35.00%)
2012 Federal R&D credit recognized	$ 3.1
Unrecognized tax benefits			43.3
Increase in gross unrecognized tax benefits	8.6
Reduction in provision for income taxes due to impact of effective tax rate	43.6
Gross interest and penalties accrued	3.3
Deferred tax assets, other current assets	11.6		11.0
Deferred tax assets, other non-current assets	63.2		56.9
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	$ 11.3	$ 3.7