Other Arrangements (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2014	Jun. 30, 2014	Dec. 31, 2008	Dec. 31, 2016
Sale of HIV Protease Inhibitor Royalty Stream
Gross proceeds from sale of royalty rights receivable from GlaxoSmithKline			$ 160.0
Royalty purchase agreement deferred revenue				$ 12.6
Other nonoperating Income	$ 36.7	$ 36.7