Share-Based Payments - Summary of Share-based Compensation Expense Associated with Each Share-based Compensating Programs (Details) - USD ($) $ in Millions		12 Months Ended
	Jul. 02, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		$ (301.5)	$ (274.4)	$ (263.5)
Subtotal		352.7	668.4	273.6
Capitalized share-based compensation costs		(10.3)	(10.2)	(9.3)
Share-based compensation expense included in total cost and expense		342.4	658.2	264.3
Human Immunology Biosciences
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 56.4	56.4	0.0	0.0
Time-vested restricted stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		236.4	220.0	202.3
Performance stock units settled in stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		48.4	35.5	35.0
Performance stock units settled in cash
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		(2.5)	6.8	10.1
Employee stock purchase plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		9.7	10.5	12.7
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		3.7	3.7	0.3
Market stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		0.6	4.9	13.2
Equity Awards Of Acquired Company
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		$ 0.0	$ 387.0	$ 0.0