Revenue - Revenue by Major Species (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024		Sep. 30, 2023
Revenue from External Customer [Line Items]
Revenue	$ 2,388	$ 2,151	$ 6,939		$ 6,331
Contract manufacturing & human health
Revenue from External Customer [Line Items]
Revenue	21	21	59		58
Companion animal
Revenue from External Customer [Line Items]
Revenue	1,609	1,414	4,708		4,128
Companion animal | U.S.
Revenue from External Customer [Line Items]
Revenue	1,068	908	3,046		2,588
Companion animal | International
Revenue from External Customer [Line Items]
Revenue	541	506	1,662		1,540
Livestock
Revenue from External Customer [Line Items]
Revenue	758	716	2,172		2,145
Livestock | U.S.
Revenue from External Customer [Line Items]
Revenue	278	266	771		756
Livestock | International
Revenue from External Customer [Line Items]
Revenue	480	450	1,401		1,389
Operating Segments | U.S.
Revenue from External Customer [Line Items]
Revenue	1,346	1,174	3,817		3,344
Operating Segments | International
Revenue from External Customer [Line Items]
Revenue	$ 1,021	$ 956	$ 3,063	[1]	$ 2,929	[1]

[1] Revenue denominated in euros was $694 million and $627 million for the nine months ended September 30, 2024 and 2023, respectively.