Accumulated Other Comprehensive Loss, Excluding Noncontrolling Interests (Detail) $ in Millions	9 Months Ended
	Sep. 27, 2020 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	$ 63,143
Balance, ending	65,259
Foreign currency translation loss attributable to noncontrolling interest	9
Increase in pension plan liability	1,200
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(11,640)
Other comprehensive income/(loss)	(1,036)	[1]
Balance, ending	(12,676)
Foreign Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(5,952)
Other comprehensive income/(loss)	249	[1]
Balance, ending	(5,703)
Derivative Financial Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	20
Other comprehensive income/(loss)	(546)	[1]
Balance, ending	(526)
Available-For-Sale Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(35)
Other comprehensive income/(loss)	179	[1]
Balance, ending	144
Actuarial Gains/(Losses) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	(6,257)
Other comprehensive income/(loss)	(817)	[1]
Balance, ending	(7,074)
Prior Service (Costs)/Credits and Other [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning	584
Other comprehensive income/(loss)	(102)	[1]
Balance, ending	$ 482

[1] Amounts do not include foreign currency translation adjustments attributable to noncontrolling interests of $9 million loss for the first nine months of 2020. Foreign currency translation adjustments primarily include gains from the strengthening of certain major currencies against the U.S. dollar, partially offset by net after-tax losses related to foreign currency translation adjustments and the impact of our net investment hedging program, both attributable to our equity method investment in GSK Consumer Healthcare joint venture (see Note 2B). The actuarial gains/(losses) activity mainly reflects interim U.S. Pfizer Consolidated Pension remeasurements, which resulted in an increase of $1.2 billion in the pension plan liability, primarily due to a reduction in the discount rate since December 31, 2019.