Investments in Variable Interest Entities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Variable Interest Entity [Line Items]
Net income (loss) attributable to noncontrolling interests, net of tax	$ 53,871	$ (738)	$ 49,053	$ 7,660
Investment in Variable Interest Entities (Textual) [Abstract]
Research and development	519,863	417,174	1,471,140	1,393,331
Investment in biotechnology companies that are determined to be unconsolidated variable interest entities	10,700		10,700		$ 7,900
Neurimmune
Variable Interest Entity [Line Items]
Net income (loss) attributable to noncontrolling interests, net of tax			60,000
Investment in Variable Interest Entities (Textual) [Abstract]
Remaining potential development milestone payments and royalties on commercial sales under the terms of collaboration agreement			275,000
Research and development	$ 39,700	$ 7,400	$ 87,500	$ 29,100