Earnings Per Common Share Attributable to Common Shareholders (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
EPS Numerator––Basic
Income from continuing operations	[1]	$ 7,680	$ 4,111	$ 16,625	$ 11,562
Less: Net income attributable to noncontrolling interests		4	8	19	25
Income from continuing operations attributable to Pfizer Inc.		7,676	4,103	16,606	11,537
Less: Preferred stock dividends––net of tax		0	0	1	1
Income from continuing operations attributable to Pfizer Inc. common shareholders		7,676	4,103	16,605	11,536
Discontinued operations––net of tax	[1]	4	11	4	10
Net income attributable to Pfizer Inc. common shareholders		7,680	4,114	16,609	11,546
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		7,676	4,103	16,606	11,537
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		4	11	4	10
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 7,680	$ 4,114	$ 16,609	$ 11,546
EPS Denominator
Weighted-average number of common shares outstanding––Basic (shares)	[1]	5,545	5,875	5,581	5,899
Common-share equivalents: stock options, stock issuable under employee compensation plans, convertible preferred stock and accelerated share repurchase agreements (shares)		104	112	110	99
Weighted-average number of common shares outstanding––Diluted (shares)	[1]	5,649	5,986	5,690	5,998
Cash dividends declared per share (in dollars per share)		$ 0.36	$ 0.34	$ 1.08	$ 1.02
Equity Option [Member]
EPS Denominator
Stock options that had exercise prices greater than the average market price of our common stock issuable under employee compensation plans (shares)	[2]	3	5	2	3

[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.