Earnings Per Common Share Attributable to Pfizer Inc. Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Apr. 03, 2022	Apr. 04, 2021
EPS Numerator––Basic
Income from continuing operations attributable to Pfizer Inc. common shareholders		$ 7,872	$ 4,876
Discontinued operations––net of tax		(9)	1
Net income attributable to Pfizer Inc. common shareholders		7,864	4,877
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		7,872	4,876
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		(9)	1
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 7,864	$ 4,877
EPS Denominator
Weighted-average number of common shares outstanding––Basic		5,617	5,584
Common-share equivalents: stock options and stock issuable under employee compensation plans (in shares)		141	78
Weighted-average number of common shares outstanding––Diluted		5,758	5,662
Anti-dilutive common stock equivalents (in shares)	[1]	0	2

[1] 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.