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Goodwill and Other Intangibles - Goodwill Activity by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 19,425	$ 18,253
Acquisitions	847	1,341
Divestitures	(54)
Impairments		(162)
Other	20	(7)
Goodwill, Ending Balance	20,238	19,425
Accumulated goodwill impairment losses	531	531
Pharmaceutical
Goodwill [Roll Forward]
Goodwill, Beginning Balance	16,181	16,162
Acquisitions	742	19
Divestitures	0
Impairments		0
Other	47	0
Goodwill, Ending Balance	16,970	16,181
Animal Health
Goodwill [Roll Forward]
Goodwill, Beginning Balance	3,192	1,870
Acquisitions	105	1,322
Divestitures	0
Impairments		0
Other	(29)	0
Goodwill, Ending Balance	3,268	3,192
All Other
Goodwill [Roll Forward]
Goodwill, Beginning Balance	52	221
Acquisitions	0	0
Divestitures	(54)
Impairments		(162)
Other	2	(7)
Goodwill, Ending Balance	$ 0	$ 52

X

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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