CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income before allocation to noncontrolling interests	[1],[2],[3],[4]	$ 3,410	$ 3,889
Foreign currency translation adjustments, net	[2],[5]	(1,272)	324
Reclassification adjustments	[2]	0	2
Other comprehensive income (loss), foreign currency transaction and translation adjustment, before tax	[2]	(1,272)	326
Unrealized holding gains/(losses) on derivative financial instruments, net	[2]	(501)	267
Reclassification adjustments for (gains)/losses included in net income	[2],[6]	19	(263)
Other comprehensive income (loss), derivatives qualifying as hedges, before tax, total	[2]	(482)	4
Unrealized holding gains/(losses) on available-for-sale securities, net	[2]	(51)	40
Reclassification adjustments for losses included in net income	[2],[6]	15	11
Other comprehensive income (loss), available-for-sale securities, before tax, total	[2]	(36)	51
Benefit plans: actuarial losses, net	[2]	(166)	0
Reclassification adjustments related to amortization	[2]	66	60
Reclassification adjustments related to settlements, net	[2]	53	0
Other	[2]	16	(23)
Defined benefit plan, amounts recognized in other comprehensive income (loss), net gain (loss), before tax, total	[2]	(31)	37
Reclassification adjustments related to amortization of prior service costs and other, net	[2]	(45)	(46)
Other	[2]	(1)	0
Defined benefit plan, amounts recognized in other comprehensive income (loss), net prior service cost, before tax	[2]	(45)	(46)
Other comprehensive income/(loss), before tax	[2]	(1,867)	372
Tax provision/(benefit) on other comprehensive income/(loss)	[2]	(377)	25
Other comprehensive income/(loss) before allocation to noncontrolling interests	[2],[3]	(1,490)	348
Comprehensive income before allocation to noncontrolling interests	[2]	1,920	4,237
Less: Comprehensive income attributable to noncontrolling interests	[2]	9	1
Comprehensive income attributable to Pfizer Inc.	[2]	$ 1,911	$ 4,236

[1] Amounts may not add due to rounding.

[2] Amounts may not add due to rounding.

[3] Amounts may not add due to rounding.

[4] Amounts may not add due to rounding.

[5] Amounts in the first quarter of 2020 include a loss of approximately $1.6 billion pre-tax ($1.2 billion after-tax) related to foreign currency translation adjustments attributable to our equity method investment in the GSK Consumer Healthcare joint venture (see Note 2B), partially offset by the results of our net investment hedging program.

[6] Reclassified into Other (income)/deductions—net and Cost of sales in the condensed consolidated statements of income. For additional information on amounts reclassified into Other (income)/deductions—net and Cost of sales, see Note 7E. Financial Instruments: Derivative Financial Instruments and Hedging Activities.