Revenue - Revenue by Species (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenue from External Customer [Line Items]
Revenue	$ 2,460	$ 2,361	$ 4,680	$ 4,551
Companion animal
Revenue from External Customer [Line Items]
Revenue	1,788	1,649	3,334	3,099
Dogs and Cats
Revenue from External Customer [Line Items]
Revenue	1,716	1,581	3,197	2,965
Horses
Revenue from External Customer [Line Items]
Revenue	72	68	137	134
Livestock
Revenue from External Customer [Line Items]
Revenue	638	694	1,283	1,414
Cattle
Revenue from External Customer [Line Items]
Revenue	320	350	678	741
Swine
Revenue from External Customer [Line Items]
Revenue	119	130	230	257
Poultry
Revenue from External Customer [Line Items]
Revenue	103	132	209	271
Fish
Revenue from External Customer [Line Items]
Revenue	74	62	127	107
Sheep and other
Revenue from External Customer [Line Items]
Revenue	22	20	39	38
Contract manufacturing & human health
Revenue from External Customer [Line Items]
Revenue	$ 34	$ 18	$ 63	$ 38