Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Jul. 02, 2024	Dec. 31, 2023	Sep. 27, 2023	Sep. 26, 2023
Business Combination [Line Items]
Goodwill(1)	$ 6,491.1	$ 6,478.9		$ 6,219.2
Measurement Period Adjustments, Other current assets	1.0
Measurement Period Adjustments, Accrued expense and other	8.8
Measurement Period Adjustments, Goodwill	4.7
Measurement Period Adjustments, Deferred income taxes, decrease	3.1
Reata Pharmaceuticals, Inc
Business Combination [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
Accounts payable	(110.3)
Debt payable	(159.9)
Contingent payable to Blackstone	(300.0)
Deferred tax liability(1)	(909.3)
Operating lease liabilities	(151.8)				(151.8)
Other assets and liabilities, net	(2.5)
Total identifiable net assets	6,724.2
Goodwill(1)	469.2				469.2
Total assets acquired and liabilities assumed	7,193.4
Reata Pharmaceuticals, Inc | Completed technology for SKYCLARYS (U.S.)
Business Combination [Line Items]
Intangible assets:	4,200.0				4,200.0	4,200.0
Reata Pharmaceuticals, Inc | In-process research and development (omaveloxolone)
Business Combination [Line Items]
Intangible assets:	2,300.0				2,300.0
Reata Pharmaceuticals, Inc | Priority review voucher
Business Combination [Line Items]
Intangible assets:	100.0					$ 100.0
Reata Pharmaceuticals, Inc | Other clinical programs
Business Combination [Line Items]
Intangible assets:	40.0				$ 40.0
Human Immunology Biosciences
Business Combination [Line Items]
Cash and cash equivalents			$ 62.5
Intangible assets:			1,600.0
Prepaid expense and other assets(1)			1.4
Operating lease assets			1.2
Accounts payable			(1.1)
Accrued liabilities			(35.0)
Deferred tax liability(1)			(309.3)
Operating lease liabilities			(1.2)
Total identifiable net assets			1,361.4
Goodwill(1)			261.0
Total assets acquired and liabilities assumed			1,622.4
Prepaid expense and other	0.4
Deferred tax liability	4.9
Goodwill	$ 4.5
Human Immunology Biosciences | Other clinical programs
Business Combination [Line Items]
Intangible assets:			7.9
Felzartamab (IgAN) | Human Immunology Biosciences
Business Combination [Line Items]
Intangible assets:			920.0
Felzartamab (IgAN) | Human Immunology Biosciences | In-process research and development (omaveloxolone)
Business Combination [Line Items]
Intangible assets:			920.0
Felzartamab (AMR) | Human Immunology Biosciences
Business Combination [Line Items]
Intangible assets:			450.0
Felzartamab (AMR) | Human Immunology Biosciences | In-process research and development (omaveloxolone)
Business Combination [Line Items]
Intangible assets:			450.0
Felzartamab (PMN) | Human Immunology Biosciences
Business Combination [Line Items]
Intangible assets:			265.0
Felzartamab (PMN) | Human Immunology Biosciences | In-process research and development (omaveloxolone)
Business Combination [Line Items]
Intangible assets:			$ 265.0