Accumulated Other Comprehensive Loss, Excluding Noncontrolling Interests (Detail) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jun. 28, 2020	Jun. 28, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019	[1]		$ 63,143
Balance, June 28, 2020	[1]	$ 64,336	64,336
Foreign currency translation income (loss) attributable to noncontrolling interest			12
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019			(11,640)
Other comprehensive income/(loss)	[2]		(1,605)
Balance, June 28, 2020		(13,246)	(13,246)
Foreign Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019			(5,952)
Other comprehensive income/(loss)	[2]		(1,310)
Balance, June 28, 2020		(7,262)	(7,262)
Derivative Financial Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019			20
Other comprehensive income/(loss)	[2]		(353)
Balance, June 28, 2020		(333)	(333)
Available-For-Sale Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019			(35)
Other comprehensive income/(loss)	[2]		44
Balance, June 28, 2020		9	9
Actuarial Gains/(Losses) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019			(6,257)
Other comprehensive income/(loss)	[2]		79
Balance, June 28, 2020		(6,178)	(6,178)
Prior Service (Costs)/Credits and Other [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, December 31, 2019			584
Other comprehensive income/(loss)	[2]		(65)
Balance, June 28, 2020		518	518
GSK Consumer Healthcare [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), foreign currency transaction and translation adjustment, net of tax		$ 291	$ (902)

[1] Amounts may not add due to rounding.

[2] Amounts do not include foreign currency translation adjustments attributable to noncontrolling interests of $12 million loss for the first six months of 2020. Includes after-tax losses of approximately $902 million 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 (see Note 2B), and losses from the weakening of certain major currencies against the U.S. dollar. These losses were partially offset by the results of our net investment hedging program.