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Revenues - Other Revenues (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 2,852.6	$ 3,376.1	$ 3,681.6	$ 3,534.3	$ 3,671.3	$ 3,600.1	$ 3,616.7	$ 3,489.8	$ 13,444.6	$ 14,377.9	$ 13,452.9
Royalty
Disaggregation of Revenue [Line Items]
Total revenues									33.9	17.0	38.7
Other corporate
Disaggregation of Revenue [Line Items]
Total revenues									719.1	584.5	459.4
Total other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 132.0	$ 125.7	$ 407.6	$ 109.3	$ 145.7	$ 109.6	$ 160.0	$ 292.4	774.6	707.7	585.9
Collaborative Arrangement | Samsung Bioepis
Disaggregation of Revenue [Line Items]
Total revenues									20.9	106.2	96.4
Collaborative Arrangement | Other Relationships
Disaggregation of Revenue [Line Items]
Total revenues									$ 0.7	$ 0.0	$ (8.6)

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