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Goodwill and Other Intangibles - Goodwill Activity by Segment (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Goodwill [Roll Forward] |  |
Goodwill, Beginning Balance | $ 18,284 | $ 18,162
Acquisitions | 41 | 177
Impairments | (144) | (38)
Other | 72 | (17)
Goodwill, Ending Balance | 18,253 | 18,284
Accumulated goodwill impairment losses | 369 | 225
Pharmaceutical |  |
Goodwill [Roll Forward] |  |
Goodwill, Beginning Balance | 16,066 | 16,075
Acquisitions | 0 | 0
Impairments | 0 | 0
Other | 96 | (9)
Goodwill, Ending Balance | 16,162 | 16,066
Animal Health |  |
Goodwill [Roll Forward] |  |
Goodwill, Beginning Balance | 1,877 | 1,708
Acquisitions | 17 | 177
Impairments | 0 | 0
Other | (24) | (8)
Goodwill, Ending Balance | 1,870 | 1,877
All Other |  |
Goodwill [Roll Forward] |  |
Goodwill, Beginning Balance | 341 | 379
Acquisitions | 24 | 0
Impairments | (144) | (38)
Other | 0 | 0
Goodwill, Ending Balance | $ 221 | $ 341

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