Earnings Per Common Share Attributable to Common Shareholders (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
EPS Numerator––Basic
Income from continuing operations	[1]	$ 5,056	$ 3,879	$ 8,945	$ 7,450
Less: Net income attributable to noncontrolling interests		10	7	15	16
Income from continuing operations attributable to Pfizer Inc.		5,046	3,872	8,929	7,434
Less: Preferred stock dividends––net of tax		0	0	0	1
Income from continuing operations attributable to Pfizer Inc. common shareholders		5,045	3,871	8,929	7,433
Discontinued operations––net of tax	[1]	0	0	0	(1)
Net income attributable to Pfizer Inc. common shareholders		5,045	3,871	8,929	7,432
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		5,046	3,872	8,929	7,434
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		0	0	0	(1)
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 5,046	$ 3,872	$ 8,929	$ 7,432
EPS Denominator
Weighted-average number of common shares outstanding––Basic (shares)	[1]	5,562	5,866	5,598	5,911
Common-share equivalents: stock options, stock issuable under employee compensation plans, convertible preferred stock and accelerated share repurchase agreements (shares)		110	86	112	93
Weighted-average number of common shares outstanding––Diluted (shares)	[1]	5,672	5,952	5,711	6,004
Cash dividends declared per share (in dollars per share)		$ 0.36	$ 0.34	$ 0.72	$ 0.68
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]	1	3	2	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.