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Income Taxes
 3 Months Ended
Mar. 31, 2024
Income Tax Disclosure [Abstract]  
Income Taxes Income TaxesThe effective tax rate was 22% for the three months ended March 31, 2024 compared to 49% for the three months ended March 31, 2023. The effective tax rate in each period differed from the U.S. statutory tax rate of 21% principally due to the impact of foreign operations which reflects the impact of lower income tax rates in locations outside the United States, changes in fair value of contingent consideration and business development activities, including ImmunoGen acquisition-related costs. The decrease in the effective tax rate for the three months ended March 31, 2024 over the prior year was primarily due to changes in fair value of contingent consideration and impairment of certain intangible assets in the prior year.It is reasonably possible that the company’s gross unrecognized tax benefits balance may change within the next 12 months by up to $162 million.