Revenues Other Revenues (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total Revenues	$ 3,671.3	$ 3,600.1	$ 3,616.7	$ 3,489.8	$ 3,526.3	$ 3,439.0	$ 3,356.5	$ 3,131.1	$ 14,377.9	$ 13,452.9	$ 12,273.9
Royalty
Disaggregation of Revenue [Line Items]
Total Revenues									17.0	38.7	69.8
Other corporate revenues
Disaggregation of Revenue [Line Items]
Total Revenues									584.5	459.4	253.7
Other revenue
Disaggregation of Revenue [Line Items]
Total Revenues	$ 145.7	$ 109.6	$ 160.0	$ 292.4	$ 165.7	$ 147.2	$ 108.6	$ 164.4	707.7	585.9	360.0
Collaborative Arrangement | AbbVie
Disaggregation of Revenue [Line Items]
Total Revenues									0.0	(8.6)	(16.9)
Collaborative Arrangement | Samsung Bioepis
Disaggregation of Revenue [Line Items]
Total Revenues									106.2	96.4	42.7
Collaborative Arrangement | Sobi
Disaggregation of Revenue [Line Items]
Total Revenues									$ 0.0	$ 0.0	$ 10.7