Product Sales - Schedule of Net Product Sales (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 3,145.0	$ 3,162.1
Net product sales
Disaggregation of Revenue [Line Items]
Revenues	1,761.3	1,668.0
Libtayo
Disaggregation of Revenue [Line Items]
Revenues	263.9	176.9
Inmazeb
Disaggregation of Revenue [Line Items]
Revenues	1.0	2.2
U.S. | ELYEA HD And EYLEA
Disaggregation of Revenue [Line Items]
Revenues	1,401.6	1,433.8
U.S. | ELYEA HD
Disaggregation of Revenue [Line Items]
Revenues	200.0	0.0
U.S. | EYLEA
Disaggregation of Revenue [Line Items]
Revenues	1,201.6	1,433.8
U.S. | Libtayo
Disaggregation of Revenue [Line Items]
Revenues	159.2	109.7
U.S. | Praluent
Disaggregation of Revenue [Line Items]
Revenues	70.0	40.2
U.S. | Evkeeza
Disaggregation of Revenue [Line Items]
Revenues	24.8	14.9
Rest Of World | Libtayo
Disaggregation of Revenue [Line Items]
Revenues	$ 104.7	$ 67.2