Restructuring Charges and Other Costs Associated with Acquisitions and Cost-Reduction/Productivity Initiatives - Footnotes (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)	[1]	$ (4)	$ 83	$ 392	$ (50)
Array [Member]
Restructuring Cost and Reserve [Line Items]
Post-closing compensation expense for payments to Array employees for fair value of previously unvested stock options			157		157
Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)		(7)	79	386	15
Biopharma [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)		6	10	(3)	(38)
Upjohn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charge (credit)		$ (3)	$ (6)	$ 10	$ (27)

[1] 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.