Restructuring Charges and Other Costs Associated with Acquisitions and Cost-Reduction/Productivity Initiatives - Footnotes (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)	[1]	$ 340	$ (144)	$ 396	$ (134)
Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)		352	(74)	393	(63)
Biopharma [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)		(12)	(62)	(9)	(48)
Upjohn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)		$ (1)	$ (9)	$ 12	$ (22)

[1] In the second quarter and first six months of 2020, restructuring charges mainly represent employee termination costs associated with our Transforming to a More Focused Company cost reduction program. In the second quarter and first six months of 2019, restructuring credits mostly represent the reversal of certain accruals related to our acquisition of Wyeth upon the effective favorable settlement of an IRS audit for multiple tax years. See Notes to Consolidated Financial Statements––Note 5D. Tax Matters: Tax Contingencies in our 2019 Financial Report. The restructuring activities for 2020 are associated with the following: • For the second quarter of 2020, Biopharma ($12 million credit); Upjohn ($1 million credit); and Other ($352 million charge). • For the first six months of 2020, Biopharma ($9 million credit); Upjohn ($12 million charge); and Other ($393 million charge). The restructuring activities for 2019 are associated with the following: • For the second quarter of 2019, Biopharma ($62 million credit); Upjohn ($9 million credit); and Other ($74 million credit). • For the first six months of 2019, Biopharma ($48 million credit); Upjohn ($22 million credit); and Other ($63 million credit). Restructuring costs identified as Other are for restructuring activities associated with corporate enabling functions, WRDM, GPD and other manufacturing and commercial operations, as applicable. For the second quarter and first six months of 2020, restructuring costs identified as Other primarily relate to corporate enabling functions.