Earnings/(Loss) Per Common Share Attributable to Pfizer Inc. Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Oct. 01, 2023	Oct. 02, 2022	Oct. 01, 2023	Oct. 02, 2022
EPS/(LPS) Numerator
Income/(loss) from continuing operations attributable to Pfizer Inc. common shareholders		$ (2,394)	$ 8,630	$ 5,477	$ 26,373
Discontinued operations––net of tax		12	(21)	11	4
Net income/(loss) attributable to Pfizer Inc. common shareholders		(2,382)	8,608	5,488	26,378
EPS/(LPS) Numerator––Diluted
Income/(loss) from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		(2,394)	8,630	5,477	26,373
Net income/(loss) attributable to Pfizer Inc. common shareholders and assumed conversions		$ (2,382)	$ 8,608	$ 5,488	$ 26,378
EPS/(LPS) Denominator
Weighted-average common shares outstanding––Basic		5,646	5,607	5,642	5,606
Common-share equivalents (in shares)	[1]	0	111	72	124
Weighted-average common shares outstanding––Diluted		5,646	5,718	5,714	5,729

[1] For the three months ended October 1, 2023, due to the net loss attributable to Pfizer Inc. common shareholders, weighted average common-share equivalents of 56 million shares were not included in the computation of diluted LPS because their inclusion would have had an anti-dilutive effect.