Fair Value Measurements - Summary of Assets and Liabilities Recorded at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Assets:
Cash equivalents	$ 2,233.2	$ 1,664.9
Marketable debt securities:	1,239.1
Marketable equity securities	$ 118.1	$ 179.7
Other current assets:
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Derivative contracts	$ 10.0	$ 62.5
Other non-current assets:
Convertible notes	35.0
Plan assets for deferred compensation	52.2	42.8
Derivative contracts	0.4
Total	$ 3,688.0	$ 1,949.9
Other current liabilities:
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Derivative contracts	$ 56.7	$ 11.7
Contingent consideration obligations		291.2
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent
Other non-current liabilities:
Derivative contracts	$ 2.2
Contingent consideration obligations	246.4	221.6
Total	305.3	524.5
City Therapeutics, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Other non-current liabilities:
Collaborative arrangements, investments in counterparty	30.0
Neela Therapeutics, Inc | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Other non-current liabilities:
Collaborative arrangements, investments in counterparty	5.0
Corporate debt securities
Assets:
Marketable debt securities:	537.6
Government securities
Assets:
Marketable debt securities:	648.8
Asset-backed Securities [Member]
Assets:
Marketable debt securities:	52.7
Quoted Prices in Active Markets (Level 1)
Assets:
Cash equivalents	0.0	0.0
Marketable equity securities	118.1	179.7
Other current assets:
Derivative contracts	0.0	0.0
Other non-current assets:
Convertible notes	0.0
Plan assets for deferred compensation	0.0	0.0
Derivative contracts	0.0
Total	118.1	179.7
Other current liabilities:
Derivative contracts	0.0	0.0
Contingent consideration obligations		0.0
Other non-current liabilities:
Derivative contracts	0.0
Contingent consideration obligations	0.0	0.0
Total	0.0	0.0
Quoted Prices in Active Markets (Level 1) | Corporate debt securities
Assets:
Marketable debt securities:	0.0
Quoted Prices in Active Markets (Level 1) | Government securities
Assets:
Marketable debt securities:	0.0
Quoted Prices in Active Markets (Level 1) | Asset-backed Securities [Member]
Assets:
Marketable debt securities:	0.0
Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	2,233.2	1,664.9
Marketable equity securities	0.0	0.0
Other current assets:
Derivative contracts	10.0	62.5
Other non-current assets:
Convertible notes	0.0
Plan assets for deferred compensation	52.2	42.8
Derivative contracts	0.4
Total	3,534.9	1,770.2
Other current liabilities:
Derivative contracts	56.7	11.7
Contingent consideration obligations		0.0
Other non-current liabilities:
Derivative contracts	2.2
Contingent consideration obligations	0.0	0.0
Total	58.9	11.7
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Assets:
Marketable debt securities:	537.6
Significant Other Observable Inputs (Level 2) | Government securities
Assets:
Marketable debt securities:	648.8
Significant Other Observable Inputs (Level 2) | Asset-backed Securities [Member]
Assets:
Marketable debt securities:	52.7
Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0.0	0.0
Marketable equity securities	0.0	0.0
Other current assets:
Derivative contracts	0.0	0.0
Other non-current assets:
Convertible notes	35.0
Plan assets for deferred compensation	0.0	0.0
Derivative contracts	0.0
Total	35.0	0.0
Other current liabilities:
Derivative contracts	0.0	0.0
Contingent consideration obligations		291.2
Other non-current liabilities:
Derivative contracts	0.0
Contingent consideration obligations	246.4	221.6
Total	246.4	$ 512.8
Significant Unobservable Inputs (Level 3) | Corporate debt securities
Assets:
Marketable debt securities:	0.0
Significant Unobservable Inputs (Level 3) | Government securities
Assets:
Marketable debt securities:	0.0
Significant Unobservable Inputs (Level 3) | Asset-backed Securities [Member]
Assets:
Marketable debt securities:	$ 0.0