Goodwill and Intangible Assets (Changes in Carrying Amount of Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2021
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	$ 12,732.0
Accumulated impairment losses, beginning balance	(385.0)
Foreign currency translation	(293.1)
Goodwill, net, beginning balance	12,347.0
Accumulated impairment losses, ending balance	(385.0)
Goodwill, gross, ending balance	12,292.3
Goodwill, net, ending balance	12,347.0	$ 11,907.3
Upjohn Inc.
Goodwill [Roll Forward]
Goodwill, net, beginning balance	2,107.5
Goodwill, net, ending balance	2,107.5	1,960.9
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill	(146.6)
Developed Markets
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	9,569.5
Accumulated impairment losses, beginning balance	(385.0)
Foreign currency translation	(328.0)
Goodwill, net, beginning balance	9,184.5
Accumulated impairment losses, ending balance	(385.0)
Goodwill, gross, ending balance	9,192.4
Goodwill, net, ending balance	9,184.5	8,807.4
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill	(49.1)
Greater China
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	738.3
Accumulated impairment losses, beginning balance	0.0
Foreign currency translation	5.4
Goodwill, net, beginning balance	738.3
Accumulated impairment losses, ending balance	0.0
Goodwill, gross, ending balance	698.3
Goodwill, net, ending balance	738.3	698.3
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill	(45.4)
JANZ
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	864.0
Accumulated impairment losses, beginning balance	0.0
Foreign currency translation	(30.4)
Goodwill, net, beginning balance	864.0
Accumulated impairment losses, ending balance	0.0
Goodwill, gross, ending balance	818.5
Goodwill, net, ending balance	864.0	818.5
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill	(15.1)
Emerging Markets
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	1,560.2
Accumulated impairment losses, beginning balance	0.0
Foreign currency translation	59.9
Goodwill, net, beginning balance	1,560.2
Accumulated impairment losses, ending balance	0.0
Goodwill, gross, ending balance	1,583.1
Goodwill, net, ending balance	1,560.2	$ 1,583.1
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill	$ (37.0)