Earnings Per Common Share Attributable to Pfizer Inc. Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Apr. 02, 2023	Apr. 03, 2022
EPS Numerator––Basic
Income from continuing operations attributable to Pfizer Inc. common shareholders		$ 5,542	$ 7,872
Discontinued operations––net of tax		1	(9)
Net income attributable to Pfizer Inc. common shareholders		5,543	7,864
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		5,542	7,872
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		1	(9)
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 5,543	$ 7,864
EPS Denominator
Weighted-average number of common shares outstanding––Basic		5,634	5,617
Common-share equivalents (in shares)		93	141
Weighted-average number of common shares outstanding––Diluted		5,727	5,758
Anti-dilutive common stock equivalents (in shares)	[1]	2	0

[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.