CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended
		Apr. 04, 2021	Mar. 29, 2020
Statement of Comprehensive Income [Abstract]
Net income before allocation to noncontrolling interests		$ 4,886	$ 3,364
Foreign currency translation adjustments, net		465	(1,256)
Unrealized holding gains/(losses) on derivative financial instruments, net		214	(501)
Reclassification adjustments for (gains)/losses included in net income	[1]	259	19
Other comprehensive income (loss), derivatives qualifying as hedges, before tax, total		473	(482)
Unrealized holding gains/(losses) on available-for-sale securities, net		79	(51)
Reclassification adjustments for (gains)/losses included in net income	[2]	(242)	15
Other comprehensive income (loss), available-for-sale securities, before tax, total		(163)	(36)
Reclassification adjustments related to amortization of prior service costs and other, net		(40)	(45)
Other		(3)	(1)
Defined benefit plan, amounts recognized in other comprehensive income (loss), net prior service cost, before tax		(43)	(45)
Other comprehensive income/(loss), before tax		732	(1,821)
Tax provision/(benefit) on other comprehensive income/(loss)		84	(380)
Other comprehensive income/(loss) before allocation to noncontrolling interests		647	(1,441)
Comprehensive income/(loss) before allocation to noncontrolling interests		5,533	1,923
Less: Comprehensive income/(loss) attributable to noncontrolling interests		10	9
Comprehensive income/(loss) attributable to Pfizer Inc.		$ 5,523	$ 1,914

[1] Reclassified into Other (income)/deductions—net and Cost of sales. See Note 7E.

[2] Reclassified into Other (income)/deductions—net.