Earnings Per Common Share Attributable to Common Shareholders (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
EPS Numerator––Basic
Income from continuing operations	[1]	$ 4,111	$ 2,858	$ 11,562	$ 9,064
Less: Net income attributable to noncontrolling interests		8	18	25	32
Income from continuing operations attributable to Pfizer Inc.		4,103	2,840	11,537	9,032
Less: Preferred stock dividends––net of tax		0	0	1	1
Income from continuing operations attributable to Pfizer Inc. common shareholders		4,103	2,839	11,536	9,032
Discontinued operations––net of tax	[1]	11	0	10	1
Net income attributable to Pfizer Inc. common shareholders		4,114	2,839	11,546	9,033
EPS Numerator––Diluted
Income from continuing operations attributable to Pfizer Inc. common shareholders and assumed conversions		4,103	2,840	11,537	9,032
Discontinued operations––net of tax, attributable to Pfizer Inc. common shareholders and assumed conversions		11	0	10	1
Net income attributable to Pfizer Inc. common shareholders and assumed conversions		$ 4,114	$ 2,840	$ 11,546	$ 9,034
EPS Denominator
Weighted-average number of common shares outstanding––Basic	[1]	5,875	5,951	5,899	5,972
Common-share equivalents: stock options, stock issuable under employee compensation plans, convertible preferred stock and accelerated share repurchase agreements (shares)		112	89	99	85
Weighted-average number of common shares outstanding––Diluted	[1]	5,986	6,041	5,998	6,057
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]	5	47	3	47

[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.