Summary of Significant Accounting Policies (Effects of Adoption of Topic 606 - Unaudited Consolidated Statements of Operations) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 3,871.7	$ 3,697.6	$ 11,556.9	$ 11,015.7
Net income	$ 537.2	$ 550.8	$ 1,703.3	$ 1,166.1
Net income per share applicable to common shareholders - basic (in usd per share)	$ 0.59	$ 0.61	$ 1.87	$ 1.29
Net income per share applicable to common shareholders - diluted (in usd per share)	$ 0.58	$ 0.60	$ 1.86	$ 1.28
Before Adoption of Topic 606 | ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income	$ 535.5		$ 1,717.4
Net income per share applicable to common shareholders - basic (in usd per share)	$ 0.59		$ 1.88
Net income per share applicable to common shareholders - diluted (in usd per share)	$ 0.58		$ 1.87
Product sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 3,752.8	$ 3,533.8	$ 11,198.5	$ 10,537.9
Product sales | Before Adoption of Topic 606 | ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	3,741.5		11,162.5
Royalties and other revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	118.9	$ 163.8	358.4	$ 477.8
Royalties and other revenues | Before Adoption of Topic 606 | ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 128.0		$ 412.7