Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Effective Income Tax Rate, Continuing Operations	10.50%	10.60%	12.50%	14.00%
Cash, cash equivalents, and short-term investments	$ 5,346.9		$ 5,346.9
Unrecognized Tax Benefits, Excluding Offsetting Tax Benefits	87.3		87.3
Offsetting tax benefits not recognized	10.6		10.6
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	82.6		82.6
Unrecognized Tax Benefits that Would Impact Effective Tax Rate, Including Interest	90.1		90.1
Reduction in total unrecognized tax benefits reasonably possible within next 12 months, minimum	7.0		7.0
Reduction in total unrecognized tax benefits reasonably possible within next 12 months, maximum	9.0		9.0
Unrecognized Tax Benefits, Interest on Income Taxes Expense	0.4		1.6
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	7.5		7.5
International [Member]
Cash, cash equivalents, and short-term investments	$ 2,694.0		$ 2,694.0
Ireland [Member]
Effective Income Tax Rate, Foreign Subsidiary Statutory Rate			12.50%