Fair Value Measurements - Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2022
Other current liabilities:
Contingent consideration obligations	$ 294.3	$ 291.2
Other non-current liabilities:
Contingent consideration obligations	228.1
Samsung Bioepis
Other non-current liabilities:
Equity, ownership interest			49.90%
Fair Value, Measurements Recurring
Assets:
Cash equivalents	2,109.0	1,664.9
Marketable equity securities	146.9	179.7
Derivative contracts	40.2	62.5
Plan assets for deferred compensation	47.8	42.8
Total	2,343.9	1,949.9
Other current liabilities:
Derivative contracts	32.5
Contingent consideration obligations	294.3	291.2
Other non-current liabilities:
Derivative contracts	0.8
Contingent consideration obligations	228.1	221.6
Total	555.7	524.5
Derivative contracts		11.7
Total	555.7	524.5
Quoted Prices in Active Markets (Level 1) | Fair Value, Measurements Recurring
Assets:
Cash equivalents	0.0	0.0
Marketable equity securities	146.9	179.7
Derivative contracts	0.0	0.0
Plan assets for deferred compensation	0.0	0.0
Total	146.9	179.7
Other current liabilities:
Derivative contracts	0.0
Contingent consideration obligations	0.0	0.0
Other non-current liabilities:
Derivative contracts	0.0
Contingent consideration obligations	0.0	0.0
Total	0.0	0.0
Derivative contracts		0.0
Total	0.0	0.0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements Recurring
Assets:
Cash equivalents	2,109.0	1,664.9
Marketable equity securities	0.0	0.0
Derivative contracts	40.2	62.5
Plan assets for deferred compensation	47.8	42.8
Total	2,197.0	1,770.2
Other current liabilities:
Derivative contracts	32.5
Contingent consideration obligations	0.0	0.0
Other non-current liabilities:
Derivative contracts	0.8
Contingent consideration obligations	0.0	0.0
Total	33.3	11.7
Derivative contracts		11.7
Total	33.3	11.7
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements Recurring
Assets:
Cash equivalents	0.0	0.0
Marketable equity securities	0.0	0.0
Derivative contracts	0.0	0.0
Plan assets for deferred compensation	0.0	0.0
Total	0.0	0.0
Other current liabilities:
Derivative contracts	0.0
Contingent consideration obligations	294.3	291.2
Other non-current liabilities:
Derivative contracts	0.0
Contingent consideration obligations	228.1	221.6
Total	522.4	512.8
Derivative contracts		0.0
Total	$ 522.4	$ 512.8