Revenue - Revenue by 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
Dogs and Cats
Revenue from External Customer [Line Items]
Revenue	1,551	1,354	4,516	3,931
Horses
Revenue from External Customer [Line Items]
Revenue	58	60	192	197
Cattle
Revenue from External Customer [Line Items]
Revenue	391	374	1,132	1,102
Swine
Revenue from External Customer [Line Items]
Revenue	131	129	388	404
Poultry
Revenue from External Customer [Line Items]
Revenue	139	127	410	397
Fish
Revenue from External Customer [Line Items]
Revenue	70	57	177	158
Sheep and other
Revenue from External Customer [Line Items]
Revenue	27	29	65	84
Livestock
Revenue from External Customer [Line Items]
Revenue	758	716	2,172	2,145
Companion animal
Revenue from External Customer [Line Items]
Revenue	1,609	1,414	4,708	4,128
Other pharmaceutical
Revenue from External Customer [Line Items]
Revenue	$ 169	$ 166	$ 478	$ 514