Acquisitions - Preliminaty Purchase Price Allocation (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Jul. 02, 2024	Dec. 31, 2023	Sep. 26, 2023
Business Acquisition [Line Items]
Goodwill	$ 6,485.8			$ 6,219.2
Reata Pharmaceuticals, Inc
Business Acquisition [Line Items]
Cash and cash equivalents	267.3
Accounts receivable	15.9
Inventory	1,259.0				$ 1,300.0
Other current assets(1)	54.6
Operating lease assets	121.2				121.2
Accrued expense and other(1)	(110.3)
Debt payable	(159.9)
Contingent payable to Blackstone	(300.0)
Deferred tax liabilities	(909.3)
Operating lease liabilities	(151.8)				(151.8)
Other assets and liabilities, net	(2.5)
Total identifiable net assets	6,724.2
Goodwill	469.2				469.2
Total assets acquired and liabilities assumed	7,193.4
Adjustment, accrued expense and other	3.9	$ 4.9
Deferred tax liability	7.2	4.1
Adjustment, goodwill	4.3	$ 9.0
Other current assets	1.0
Reata Pharmaceuticals, Inc | Completed technology for SKYCLARYS (U.S.)
Business Acquisition [Line Items]
Intangible assets:	4,200.0				4,200.0
Reata Pharmaceuticals, Inc | In-process research and development
Business Acquisition [Line Items]
Intangible assets:	2,300.0				2,300.0
Reata Pharmaceuticals, Inc | Priority review voucher
Business Acquisition [Line Items]
Intangible assets:	100.0				100.0
Reata Pharmaceuticals, Inc | Other clinical programs
Business Acquisition [Line Items]
Intangible assets:	40.0				$ 40.0
Human Immunology Biosciences
Business Acquisition [Line Items]
Cash and cash equivalents			$ 62.5
Intangible assets:			1,600.0
Prepaid expense and other assets			1.0
Operating lease assets			1.2
Accounts payable			(1.1)
Accrued liabilities			(35.0)
Deferred tax liabilities			(304.4)
Operating lease liabilities			(1.2)
Total identifiable net assets			1,365.9
Goodwill			256.5
Total assets acquired and liabilities assumed			1,622.4
Human Immunology Biosciences | Felzartamab (IgAN)
Business Acquisition [Line Items]
Intangible assets:			920.0
Human Immunology Biosciences | Felzartamab (AMR)
Business Acquisition [Line Items]
Intangible assets:			450.0
Human Immunology Biosciences | Felzartamab (PMN)
Business Acquisition [Line Items]
Intangible assets:			265.0
Human Immunology Biosciences | In-process research and development
Business Acquisition [Line Items]
Intangible assets:	$ 1,600.0
Human Immunology Biosciences | In-process research and development | Felzartamab (IgAN)
Business Acquisition [Line Items]
Intangible assets:			920.0
Human Immunology Biosciences | In-process research and development | Felzartamab (AMR)
Business Acquisition [Line Items]
Intangible assets:			450.0
Human Immunology Biosciences | In-process research and development | Felzartamab (PMN)
Business Acquisition [Line Items]
Intangible assets:			265.0
Human Immunology Biosciences | Other clinical programs
Business Acquisition [Line Items]
Intangible assets:			$ 7.9