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Estimated additional payments upon achievement of development and commercial milestones.

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Payments To Acquire Business, Gross, Non-Vested Equity Awards

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Amount of expense for acquisition-related cost incurred to effect business combination. Includes, but is not limited to, finder's fee; advisory, legal, accounting, valuation, and other professional and consulting fees; and general administrative cost, including cost of maintaining internal acquisition department.

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Maximum amount of estimate for undiscounted range of outcomes in contingent consideration arrangement in business combination.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled within one year or the normal operating cycle, if longer.

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Value of input used to measure liability in contingent consideration arrangement in business combination.

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Amount of identifiable finite-lived intangible asset acquired in business combination and recognized at acquisition date.

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Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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Acquisitions - Narrative (Details) $ in Millions		3 Months Ended		9 Months Ended
Acquisitions - Narrative (Details) $ in Millions	Jul. 02, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Oct. 31, 2025 USD ($)	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Business Combination [Line Items]
Investment owned, cost		$ 5.0		$ 5.0
Contingent consideration obligations		148.6		148.6				$ 291.2
Contingent consideration obligations		242.6		242.6				221.6
Goodwill		6,490.7		6,490.7				$ 6,478.9
Milestone Payment, Future Development
Business Combination [Line Items]
Estimated additional payments upon achievement of development and commercial milestones		250.0		250.0
Milestone Payment, Future Development \| Felzartamab And Izastobart/HIB210 \| Human Immunology Biosciences Pre-Existing In License Commitments
Business Combination [Line Items]
Estimated additional payments upon achievement of development and commercial milestones		130.0		130.0
Milestone Payment, Regulatory \| Felzartamab And Izastobart/HIB210 \| Human Immunology Biosciences Pre-Existing In License Commitments
Business Combination [Line Items]
Estimated additional payments upon achievement of development and commercial milestones		230.0		230.0
Milestone Payment, Commercial \| Felzartamab And Izastobart/HIB210 \| Human Immunology Biosciences Pre-Existing In License Commitments
Business Combination [Line Items]
Estimated additional payments upon achievement of development and commercial milestones		640.0		640.0
Research and development
Business Combination [Line Items]
Share-based payment arrangement, expense		28.8	$ 69.8	91.0	$ 124.5
Selling, general and administrative
Business Combination [Line Items]
Share-based payment arrangement, expense		49.6	61.3	149.6	150.9
Human Immunology Biosciences
Business Combination [Line Items]
Total transaction value	$ 1,137.3
Range of outcomes, value, high	650.0
Non-vested equity awards	74.5
Share-based payment arrangement, expense	56.4	0.0	$ 56.4	0.0	$ 56.4
Working capital adjustment	43.7
Contingent consideration obligations	485.1
Contingent consideration obligations	279.3
Contingent consideration obligations	205.8
Intangible assets:	1,600.0
Goodwill	261.0
Acquisition related costs		$ 2.8		$ 2.8
Human Immunology Biosciences \| Felzartamab (IgAN)
Business Combination [Line Items]
Intangible assets:	920.0
Human Immunology Biosciences \| Felzartamab (AMR)
Business Combination [Line Items]
Intangible assets:	450.0
Human Immunology Biosciences \| Felzartamab (PMN)
Business Combination [Line Items]
Intangible assets:	$ 265.0
Human Immunology Biosciences \| Discount rate
Business Combination [Line Items]
Measurement input	0.145
Human Immunology Biosciences \| Measurement Input, Probability Rate
Business Combination [Line Items]
Discount rate	0.670	0.700		0.700
Human Immunology Biosciences \| Minimum \| Discount rate
Business Combination [Line Items]
Discount rate	0.062
Human Immunology Biosciences \| Maximum \| Phase 3 Clinical Trial, Felzartamab One
Business Combination [Line Items]
Contingent consideration obligations	$ 150.0
Human Immunology Biosciences \| Maximum \| Phase 3 Clinical Trial, Felzartamab Two
Business Combination [Line Items]
Contingent consideration obligations	$ 150.0
Human Immunology Biosciences \| Maximum \| Phase 3 Clinical Trial, Felzartamab AMR
Business Combination [Line Items]
Contingent consideration obligations							$ 150.0
Human Immunology Biosciences \| Maximum \| Phase 3 Clinical Trial, Felzartamab IgAN \| Subsequent Event
Business Combination [Line Items]
Contingent consideration obligations						$ 150.0
Human Immunology Biosciences \| Maximum \| Discount rate
Business Combination [Line Items]
Discount rate	0.070
Human Immunology Biosciences \| Research and development
Business Combination [Line Items]
Share-based payment arrangement, expense		$ 42.5		$ 42.5
Human Immunology Biosciences \| Selling, general and administrative
Business Combination [Line Items]
Share-based payment arrangement, expense		$ 13.9		$ 13.9
Human Immunology Biosciences \| Previously Reported
Business Combination [Line Items]
Total transaction value	$ 1,150.0
Alcyone Therapeutics, Inc.
Business Combination [Line Items]
Payments to acquire productive assets	$ 85.0