Earnings Per Common Share Attributable to Pfizer Inc. Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jul. 03, 2022	Jul. 04, 2021	Jul. 03, 2022	Jul. 04, 2021
EPS Numerator––Basic
Income from continuing operations attributable to Pfizer Inc. common shareholders		$ 9,871	$ 5,799	$ 17,743	$ 10,675
Discontinued operations––net of tax		34	(236)	26	(235)
Net income attributable to Pfizer Inc. common shareholders		9,906	5,563	17,769	10,440
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		9,871	5,799	17,743	10,675
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		34	(236)	26	(235)
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 9,906	$ 5,563	$ 17,769	$ 10,440
EPS Denominator
Weighted-average number of common shares outstanding––Basic		5,593	5,598	5,605	5,591
Common-share equivalents: stock options and stock issuable under employee compensation plans (in shares)		119	80	130	79
Weighted-average number of common shares outstanding––Diluted		5,712	5,678	5,735	5,670
Anti-dilutive common stock equivalents (in shares)	[1]	1	5	0	4

[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.