Commitments and Contingencies (Collaborative Arrangements) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Out-licensing arrangements
Milestone payments received				$ 6.8
Milestone income recognized	4.1	4.9	16.5	20.4
Product sales	1,054.5	1,018.4	3,309.1	2,901.0
In-licensing Arrangement | Sangamo
In-licensing arrangements
Upfront payment			13.0	0
Out-licensing Arrangement
Out-licensing arrangements
Milestone payments received			6.0
Milestone income recognized			6.7	10.1
Product sales			57.6	46.2
Out-licensing Arrangement | Development Milestone
Out-licensing arrangements
Maximum milestone payment receivable	39.0		39.0
Out-licensing Arrangement | Sales Milestone
Out-licensing arrangements
Maximum milestone payment receivable	$ 79.0		$ 79.0