Earnings Per Common Share Attributable to Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Apr. 01, 2018	Apr. 02, 2017
EPS Numerator––Basic
Income from continuing operations	[1]	$ 3,571	$ 3,130
Less: Net income attributable to noncontrolling interests		9	9
Income from continuing operations attributable to Pfizer Inc.		3,562	3,121
Less: Preferred stock dividends––net of tax		0	0
Income from continuing operations attributable to Pfizer Inc. common shareholders		3,562	3,121
Discontinued operations––net of tax	[1]	(1)	0
Net income attributable to Pfizer Inc. common shareholders		3,560	3,121
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		3,562	3,121
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		(1)	0
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 3,561	$ 3,121
EPS Denominator
Weighted-average number of common shares outstanding––Basic	[1]	5,957	6,006
Common-share equivalents: stock options, stock issuable under employee compensation plans, convertible preferred stock and accelerated share repurchase agreements (shares)		100	86
Weighted-average number of common shares outstanding––Diluted	[1]	6,057	6,092
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]	2	48

[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.