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Goodwill and Other Intangibles - Goodwill Activity by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 18,253	$ 18,284
Acquisitions	1,341	41
Impairments	(162)	(144)
Other	(7)	72
Goodwill, Ending Balance	19,425	18,253
Accumulated goodwill impairment losses	531	369
Pharmaceutical
Goodwill [Roll Forward]
Goodwill, Beginning Balance	16,162	16,066
Acquisitions	19	0
Impairments	0	0
Other	0	96
Goodwill, Ending Balance	16,181	16,162
Animal Health
Goodwill [Roll Forward]
Goodwill, Beginning Balance	1,870	1,877
Acquisitions	1,322	17
Impairments	0	0
Other	0	(24)
Goodwill, Ending Balance	3,192	1,870
All Other
Goodwill [Roll Forward]
Goodwill, Beginning Balance	221	341
Acquisitions	0	24
Impairments	(162)	(144)
Other	(7)	0
Goodwill, Ending Balance	$ 52	$ 221

X

- Definition

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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