Restructuring Charges and Other Costs Associated with Acquisitions and Cost-Reduction/Productivity Initiatives - Restructuring Accruals (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Restructuring Reserve [Roll Forward]
Balance, beginning	[1]			$ 933
Provision	[2]	$ (4)	$ 83	392	$ (50)
Utilization and other	[3]			(479)
Balance, ending	[4]	847		847
Employee Termination Costs [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning	[1]			887
Provision				357
Utilization and other	[3]			(411)
Balance, ending	[4]	832		832
Asset Impairment Charges [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning	[1]			0
Provision				45
Utilization and other	[3]			(45)
Balance, ending	[4]	0		0
Exit Costs [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning	[1]			46
Provision				(9)
Utilization and other	[3]			(23)
Balance, ending	[4]	$ 14		$ 14

[1] Included in Other current liabilities ($714 million) and Other noncurrent liabilities ($219 million).

[2] In the first nine months of 2020, restructuring charges mainly represent employee termination costs associated with our Transforming to a More Focused Company cost-reduction program. In the third quarter of 2019, restructuring charges mainly represented employee termination costs associated with cost-reduction and productivity initiatives as well as our acquisition of Array. In the first nine months of 2019, restructuring credits mostly represented the reversal of certain accruals related to our acquisition of Wyeth upon the effective favorable settlement of an IRS audit for multiple tax years, partially offset by employee termination costs associated with cost-reduction and productivity initiatives, as well as our acquisition of Array. 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 third quarter of 2020, Biopharma ($6 million charge); Upjohn ($3 million credit); and Other ($7 million credit). •For the first nine months of 2020, Biopharma ($3 million credit); Upjohn ($10 million charge); and Other ($386 million charge). The restructuring activities for 2019 are associated with the following: •For the third quarter of 2019, Biopharma ($10 million charge); Upjohn ($6 million credit); and Other ($79 million charge). •For the first nine months of 2019, Biopharma ($38 million credit); Upjohn ($27 million credit); and Other ($15 million charge). 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 first nine months of 2020, restructuring costs identified as Other primarily relate to corporate enabling functions.

[3] Includes adjustments for foreign currency translation.

[4] Included in Other current liabilities ($607 million) and Other noncurrent liabilities ($240 million).