Earnings Per Common Share Attributable to Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019
EPS Numerator––Basic
Income from continuing operations	[1]	$ 3,410	$ 3,889
Less: Net income attributable to noncontrolling interests		9	6
Income from continuing operations attributable to Pfizer Inc.		3,401	3,884
Less: Preferred stock dividends––net of tax		0	0
Income from continuing operations attributable to Pfizer Inc. common shareholders		3,401	3,883
Discontinued operations––net of tax	[1]	0	0
Net income attributable to Pfizer Inc. common shareholders		3,401	3,883
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		3,401	3,884
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		0	0
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 3,401	$ 3,884
EPS Denominator
Weighted-average number of common shares outstanding––Basic (shares)	[1]	5,545	5,635
Common-share equivalents: stock options, stock issuable under employee compensation plans and convertible preferred stock (shares)		68	115
Weighted-average number of common shares outstanding––Diluted (shares)	[1]	5,613	5,750
Equity Option [Member]
EPS Denominator
Anti-dilutive common stock equivalents (shares)	[2]	3	2

[1] Amounts may not add due to rounding.

[2] These common stock equivalents were outstanding for the periods presented, but were not included in the computation of diluted EPS for those periods because their inclusion would have had an anti-dilutive effect.