Property, Plant and Equipment - Narrative (Details) ft² in Thousands, $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($)	Mar. 31, 2024 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2023 USD ($)
Property, Plant and Equipment [Line Items]
Depreciation expense				$ 254.2	$ 272.4	$ 235.3
Interest costs capitalized				21.7	17.1	36.3
Construction in progress				975.4	888.8
Proceeds from divestiture of Hillerød, Denmark manufacturing operations				0.0	0.0	28.1
Gain on sale of building				0.0	503.7	$ 0.0
Property, plant and equipment, net				3,309.7	3,298.6
125 Broadway Building
Property, Plant and Equipment [Line Items]
Proceeds from divestiture of Hillerød, Denmark manufacturing operations	$ 603.0
Tenant allowance	10.8
Gain on sale of building	$ 503.7
Property, plant and equipment, net							$ 79.2
125 Broadway Building | Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net							72.6
125 Broadway Building | Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net							1.6
125 Broadway Building | Machinery and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net							$ 5.0
Solothurn, Switzerland
Property, Plant and Equipment [Line Items]
Construction in progress				$ 728.8	$ 711.1
Property, plant and equipment, additions			$ 1,200.0
Solothurn, Switzerland | Subsequent Event
Property, Plant and Equipment [Line Items]
Property, plant and equipment, additions		$ 710.7
Biologics Manufacturing | Solothurn, Switzerland
Property, Plant and Equipment [Line Items]
Number of square feet | ft²				393
Warehouse, Utilities and Support Space | Solothurn, Switzerland
Property, Plant and Equipment [Line Items]
Number of square feet | ft²				290
Administrative Space | Solothurn, Switzerland
Property, Plant and Equipment [Line Items]
Number of square feet | ft²				51