Restructuring Charges and Other Costs Associated with Acquisitions and Cost-Reduction/Productivity Initiatives (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Restructuring charges/(credits):
Employee terminations		$ (15)	$ 82	$ 357	$ (86)
Asset impairments		22	3	45	3
Exit costs/(credits)		(11)	(1)	(9)	33
Restructuring charges/(credits)	[1]	(4)	83	392	(50)
Transaction costs	[2]	0	65	14	65
Integration costs and other	[3]	7	217	29	281
Restructuring charges and certain acquisition-related costs		4	365	435	295
Additional depreciation––asset restructuring recorded in our condensed consolidated statements of income	[4]	4	6	10	29
Implementation costs recorded in our condensed consolidated statements of income as follows:
Implementation costs	[5]	48	40	148	109
Total costs associated with acquisitions and cost-reduction/productivity initiatives		56	420	621	452
Other (income)/deductions––net [Member]
Restructuring charges/(credits):
Net periodic benefit costs recorded in Other (income)/deductions––net		0	9	29	19
Cost of sales [Member]
Restructuring charges/(credits):
Additional depreciation––asset restructuring recorded in our condensed consolidated statements of income	[4]	4	6	14	21
Implementation costs recorded in our condensed consolidated statements of income as follows:
Implementation costs	[5]	11	14	32	45
Selling, informational and administrative expenses [Member]
Restructuring charges/(credits):
Additional depreciation––asset restructuring recorded in our condensed consolidated statements of income	[4]	0	0	0	2
Implementation costs recorded in our condensed consolidated statements of income as follows:
Implementation costs	[5]	36	23	114	48
Research and development expenses [Member]
Restructuring charges/(credits):
Additional depreciation––asset restructuring recorded in our condensed consolidated statements of income	[4]	0	0	(3)	6
Implementation costs recorded in our condensed consolidated statements of income as follows:
Implementation costs	[5]	$ 1	$ 3	$ 2	$ 16

[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.

[2] Transaction costs represent external costs for banking, legal, accounting and other similar services.

[3] Integration costs and other represent external, incremental costs directly related to integrating acquired businesses, such as expenditures for consulting and the integration of systems and processes, and certain other qualifying costs. In the third quarter and first nine months of 2020, integration costs and other were mostly related to our acquisition of Array. In the third quarter and first nine months of 2019, integration costs and other primarily included $157 million in payments to Array employees for the fair value of previously unvested stock options that was recognized as post-closing compensation expense. See Notes to Consolidated Financial Statements––Note 2A. Acquisitions, Divestitures, Equity-Method Investments and Assets and Liabilities Held for Sale, Licensing Arrangements and Research and Development and Collaborative Arrangements: Acquisitions in our 2019 Financial Report.

[4] Additional depreciation––asset restructuring represents the impact of changes in the estimated useful lives of assets involved in restructuring actions.

[5] Implementation costs represent external, incremental costs directly related to implementing our non-acquisition-related cost-reduction/productivity initiatives.