Basis of Presentation and Significant Accounting Policies - Summary of Change in Accounting Principle (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Consolidated Statements of Income:
(Gain) on completion of Consumer Healthcare JV transaction		$ 0	$ (6)	$ (8,107)
Other (income)/deductions––net		(4,878)	1,219	3,497
Income from continuing operations before provision/(benefit) for taxes on income	[1],[2],[3]	24,311	7,036	11,321
Provision/(benefit) for taxes on income		1,852	370	583
Discontinued operations––net of tax		(434)	2,529	5,318
Net income before allocation to noncontrolling interests		22,025	9,195	16,056
Net income attributable to Pfizer Inc. common shareholders		$ 21,979	$ 9,159	$ 16,026
Earnings per common share––basic:
Income from continuing operations attributable to Pfizer Inc. common shareholders (in dollars per share)		$ 4.00	$ 1.19	$ 1.92
Discontinued operations––net of tax (in dollars per share)		(0.08)	0.46	0.95
Net income attributable to Pfizer Inc. common shareholders (in dollars per share)		3.92	1.65	2.88
Earnings per common share––diluted:
Income from continuing operations attributable to Pfizer Inc. common shareholders (in dollars per share)		3.93	1.18	1.89
Discontinued operations––net of tax (in dollars per share)		(0.08)	0.45	0.94
Net income attributable to Pfizer Inc. common shareholders (in dollars per share)		$ 3.85	$ 1.63	$ 2.82
Consolidated Statements of Comprehensive Income:
Foreign currency translation adjustments, net		$ (682)	$ 772	$ 675
Benefit plans: actuarial gains/(losses), net		0	0	0
Reclassification adjustments related to amortization		0	0	0
Reclassification adjustments related to settlements, net		0	0	0
Other		0	0	0
Tax provision/(benefit) on other comprehensive income/(loss)		71	(227)	178
Consolidated Statements of Cash Flows:
Deferred taxes from continuing operations		(4,293)	(1,575)	561
Benefit plan contributions in excess of expense/income		(3,123)	(1,242)	(55)
Consolidated Balance Sheets:
Noncurrent deferred tax assets and other noncurrent tax assets		3,341	2,383
Other noncurrent assets		7,679	4,879
Pension benefit obligations		3,489	4,766
Retained earnings		103,394	90,392
Accumulated other comprehensive loss		(5,897)	(5,310)
Previous Accounting Principle [Member]
Consolidated Statements of Income:
(Gain) on completion of Consumer Healthcare JV transaction		0	(6)	(8,086)
Other (income)/deductions––net		(2,820)	672	3,264
Income from continuing operations before provision/(benefit) for taxes on income		22,253	7,584	11,533
Provision/(benefit) for taxes on income		1,399	496	631
Discontinued operations––net of tax		(434)	2,564	5,400
Net income before allocation to noncontrolling interests		20,420	9,652	16,302
Net income attributable to Pfizer Inc. common shareholders		$ 20,374	$ 9,616	$ 16,273
Earnings per common share––basic:
Income from continuing operations attributable to Pfizer Inc. common shareholders (in dollars per share)		$ 3.71	$ 1.27	$ 1.95
Discontinued operations––net of tax (in dollars per share)		(0.08)	0.46	0.97
Net income attributable to Pfizer Inc. common shareholders (in dollars per share)		3.63	1.73	2.92
Earnings per common share––diluted:
Income from continuing operations attributable to Pfizer Inc. common shareholders (in dollars per share)		3.65	1.25	1.92
Discontinued operations––net of tax (in dollars per share)		(0.08)	0.46	0.95
Net income attributable to Pfizer Inc. common shareholders (in dollars per share)		$ 3.57	$ 1.71	$ 2.87
Consolidated Statements of Comprehensive Income:
Foreign currency translation adjustments, net		$ (731)	$ 957	$ 654
Benefit plans: actuarial gains/(losses), net		1,565	(1,128)	(826)
Reclassification adjustments related to amortization		285	276	241
Reclassification adjustments related to settlements, net		209	278	274
Other		49	(189)	22
Tax provision/(benefit) on other comprehensive income/(loss)		545	(349)	115
Consolidated Statements of Cash Flows:
Deferred taxes from continuing operations		(4,746)	(1,449)	609
Benefit plan contributions in excess of expense/income		(1,065)	(1,790)	(288)
Consolidated Balance Sheets:
Noncurrent deferred tax assets and other noncurrent tax assets		3,320		2,383
Other noncurrent assets		7,679		4,879
Pension benefit obligations		3,489		4,766
Retained earnings		101,789		96,770
Accumulated other comprehensive loss		(4,313)		(11,688)
Impact of Change [Member]
Consolidated Statements of Income:
(Gain) on completion of Consumer Healthcare JV transaction		0	0	(21)
Other (income)/deductions––net		(2,058)	547	233
Income from continuing operations before provision/(benefit) for taxes on income		2,058	(547)	(212)
Provision/(benefit) for taxes on income		453	(125)	(48)
Discontinued operations––net of tax		0	(35)	(82)
Net income before allocation to noncontrolling interests		1,605	(457)	(246)
Net income attributable to Pfizer Inc. common shareholders		$ 1,605	$ (457)	$ (246)
Earnings per common share––basic:
Income from continuing operations attributable to Pfizer Inc. common shareholders (in dollars per share)		$ 0.29	$ (0.08)	$ (0.03)
Discontinued operations––net of tax (in dollars per share)		0	(0.01)	(0.01)
Net income attributable to Pfizer Inc. common shareholders (in dollars per share)		0.29	(0.08)	(0.04)
Earnings per common share––diluted:
Income from continuing operations attributable to Pfizer Inc. common shareholders (in dollars per share)		0.28	(0.07)	(0.03)
Discontinued operations––net of tax (in dollars per share)		0	(0.01)	(0.01)
Net income attributable to Pfizer Inc. common shareholders (in dollars per share)		$ 0.28	$ (0.08)	$ (0.04)
Consolidated Statements of Comprehensive Income:
Foreign currency translation adjustments, net		$ 49	$ (185)	$ 21
Benefit plans: actuarial gains/(losses), net		(1,565)	1,128	826
Reclassification adjustments related to amortization		(285)	(276)	(241)
Reclassification adjustments related to settlements, net		(209)	(278)	(274)
Other		(49)	189	(22)
Tax provision/(benefit) on other comprehensive income/(loss)		(475)	122	63
Consolidated Statements of Cash Flows:
Deferred taxes from continuing operations		453	(125)	(48)
Benefit plan contributions in excess of expense/income		(2,058)	$ 547	233
Consolidated Balance Sheets:
Noncurrent deferred tax assets and other noncurrent tax assets		22		0
Other noncurrent assets		0		0
Pension benefit obligations		0		0
Retained earnings		1,605		(6,378)
Accumulated other comprehensive loss		$ (1,583)		$ 6,378

[1] Income from continuing operations before provision/(benefit) for taxes on income. Biopharma’s earnings include dividend income from our investment in ViiV of $166 million in 2021, $278 million in 2020 and $220 million in 2019.

[2] 2020 v. 2019––The domestic loss in 2020 versus domestic income in 2019 was mainly related to the non-recurrence of the gain on the completion of the Consumer Healthcare JV transaction as well as higher asset impairment charges and higher R&D expenses. The increase in the international income was primarily related to the non-recurrence of the write off of assets contributed to the Consumer Healthcare JV as well as lower asset impairment charges and lower amortization of intangible assets.

[3] 2021 v. 2020––The domestic income in 2021 versus domestic loss in 2020 was mainly related to Comirnaty income, lower asset impairment charges, net periodic benefit credits in 2021 versus net periodic benefit costs in 2020 and higher net gains from equity securities, partially offset by higher R&D expenses. The increase in the international income was primarily related to Comirnaty income, net periodic benefit credits in 2021 versus net periodic benefit costs in 2020 and lower asset impairment charges.