Goodwill and Other Intangibles - Goodwill Activity by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 21,197	$ 21,204
Acquisitions	518
Other	(47)	(7)
Goodwill, ending balance	21,668	21,197
Accumulated goodwill impairment losses	531	531
Pharmaceutical
Goodwill [Roll Forward]
Goodwill, beginning balance	17,922	17,936
Acquisitions	0
Other	(19)	(14)
Goodwill, ending balance	17,903	17,922
Animal Health
Goodwill [Roll Forward]
Goodwill, beginning balance	3,275	3,268
Acquisitions	518
Other	(28)	7
Goodwill, ending balance	$ 3,765	$ 3,275