Revenue - Revenue by Species (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from External Customer [Line Items]
Revenue	$ 2,151	$ 2,002	$ 6,331	$ 6,040
Contract manufacturing & human health
Revenue from External Customer [Line Items]
Revenue	21	23	58	59
Dogs and Cats
Revenue from External Customer [Line Items]
Revenue	1,354	1,213	3,931	3,715
Horses
Revenue from External Customer [Line Items]
Revenue	60	58	197	185
Cattle
Revenue from External Customer [Line Items]
Revenue	374	371	1,102	1,063
Swine
Revenue from External Customer [Line Items]
Revenue	129	129	404	427
Poultry
Revenue from External Customer [Line Items]
Revenue	127	116	397	361
Fish
Revenue from External Customer [Line Items]
Revenue	57	60	158	151
Sheep and other
Revenue from External Customer [Line Items]
Revenue	29	32	84	79
Livestock
Revenue from External Customer [Line Items]
Revenue	716	708	2,145	2,081
Companion animal
Revenue from External Customer [Line Items]
Revenue	1,414	1,271	4,128	3,900
Other pharmaceuticals
Revenue from External Customer [Line Items]
Revenue	$ 313	$ 252	$ 922	$ 771