Earnings Per Common Share Attributable to Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
EPS Numerator––Basic
Income from continuing operations	[1]	$ 3,434	$ 5,056	$ 6,845	$ 8,945
Less: Net income attributable to noncontrolling interests		8	10	17	15
Income from continuing operations attributable to Pfizer Inc.		3,426	5,046	6,828	8,929
Less: Preferred stock dividends––net of tax		0	0	0	0
Income from continuing operations attributable to Pfizer Inc. common shareholders		3,426	5,045	6,828	8,929
Discontinued operations––net of tax	[1]	0	0	0	0
Net income attributable to Pfizer Inc. common shareholders		3,426	5,045	6,828	8,929
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		3,426	5,046	6,828	8,929
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		0	0	0	0
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 3,426	$ 5,046	$ 6,828	$ 8,929
EPS Denominator
Weighted-average number of common shares outstanding––Basic (shares)	[1]	5,554	5,562	5,550	5,598
Common-share equivalents: stock options, stock issuable under employee compensation plans and convertible preferred stock (shares)		65	110	66	112
Weighted-average number of common shares outstanding––Diluted (shares)	[1]	5,619	5,672	5,616	5,711
Anti-dilutive common stock equivalents (shares)	[2]	6	1	4	2

[1] Amounts may not add due to rounding.

[2] 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.