Product Sales - Schedule of Net Product Sales (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 5,138.5	$ 1,952.0	$ 7,667.2	$ 3,780.2
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues	4,137.8	1,226.9	5,862.1	2,463.6
UNITED STATES | EYLEA
Disaggregation of Revenue [Line Items]
Revenues	1,424.7	1,113.7	2,771.7	2,285.7
UNITED STATES | Libtayo
Disaggregation of Revenue [Line Items]
Revenues	78.0	63.3	147.1	125.0
UNITED STATES | Praluent
Disaggregation of Revenue [Line Items]
Revenues	41.9	47.2	85.2	47.2
UNITED STATES | REGEN-COV
Disaggregation of Revenue [Line Items]
Revenues	2,591.2	0.0	2,853.4	0.0
UNITED STATES | Evkeeza
Disaggregation of Revenue [Line Items]
Revenues	2.0	0.0	2.5	0.0
UNITED STATES | ARCALYST
Disaggregation of Revenue [Line Items]
Revenues	$ 0.0	$ 2.7	$ 2.2	$ 5.7