Other Consolidated Financial Statement Detail (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accrued Expenses and Other
Current portion of contingent consideration obligations and milestones	$ 516.8		$ 580.8
Revenue-related reserves for discounts and allowances	676.5		605.5
Royalties and licensing fees	181.0		195.8
Employee compensation and benefits	160.5		282.9
Construction Payable	116.2		134.0
Collaboration expenses accrual	89.8		130.9
Accrued TECFIDERA litigation settlement and license charges	0.0		454.8
Other	475.0		685.7
Total accrued expenses and other	2,044.6		2,903.5
Other Income (Expense), Net
Interest income	16.7	$ 11.2
Interest expense	(63.4)	(63.3)
Gain (loss) on sales of investments, net	2.4	1.6
Foreign exchange gains (losses), net	4.0	2.1
Other, net	2.7	(4.4)
Other income (expense), net	(37.6)	$ (52.8)
Component of accrued expenses and other
Accrued Expenses and Other
Revenue-related reserves for discounts and allowances	$ 505.3		$ 438.6