Investments in Variable Interest Entities (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Net income attributable to noncontrolling interests, net of tax			$ 46.2	$ 6.8	$ 0.0
Investment in Variable Interest Entities (Textual)
Additional investments committed to if certain development milestones are achieved	$ 559.0		559.0
Investment in biotechnology companies that are determined to be unconsolidated variable interest entities	29.2		29.2	$ 7.9
Neurimmune
Variable Interest Entity [Line Items]
Net income attributable to noncontrolling interests, net of tax		$ 60.0
Investment in Variable Interest Entities (Textual)
Remaining potential development milestone payments and royalties on commercial sales under the terms of collaboration agreement			$ 275.0
Percentage of funding for R&D cost required in support of the collaboration agreement			100.00%
Rodin Therapeutics
Investment in Variable Interest Entities (Textual)
Payments to acquire interest in peferred stock of an affiliates	8.0
Additional investments committed to if certain development milestones are achieved	4.0		$ 4.0
In-process research and development	8.7
Minority interest in our stockholder's equity	$ 10.9		$ 10.9