Earnings Per Common Share Attributable to Pfizer Inc. Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
EPS Numerator––Basic
Income from continuing operations		$ 2,202	$ 7,680	$ 9,046	$ 16,625
Less: Net income attributable to noncontrolling interests		8	4	25	19
Income from continuing operations attributable to Pfizer Inc.		2,194	7,676	9,022	16,606
Less: Preferred stock dividends––net of tax		0	0	0	1
Income from continuing operations attributable to Pfizer Inc. common shareholders		2,194	7,676	9,021	16,605
Discontinued operations––net of tax		0	4	0	4
Net income attributable to Pfizer Inc. common shareholders		2,194	7,680	9,021	16,609
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		2,194	7,676	9,022	16,606
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		0	4	0	4
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 2,194	$ 7,680	$ 9,022	$ 16,609
EPS Denominator
Weighted-average number of common shares outstanding––Basic (shares)		5,557	5,545	5,552	5,581
Common-share equivalents: stock options, stock issuable under employee compensation plans and convertible preferred stock (shares)		76	104	70	110
Weighted-average number of common shares outstanding––Diluted (shares)		5,633	5,649	5,622	5,690
Anti-dilutive common stock equivalents (shares)	[1]	7	3	5	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.