Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		27 Months Ended	39 Months Ended	48 Months Ended	51 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2009	Dec. 31, 2010	Sep. 30, 2011	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Effective income tax rates	22.00%	21.00%	23.00%	21.10%
Impact of the expiration of the U.S. federal research and development tax credit		2.20%		2.20%
Prior period reclassification adjustment to decrease deferred tax liability and increase additional paid-in capital					$ 499.6	$ 467.1	$ 357.2	$ 352.6
Unrecognized Tax Benefits	314.6		314.6
Unrecognized Tax Benefits, Period Increase (Decrease)	112.6
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 308.9		$ 308.9