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. 30, 2019	Jul. 01, 2018	Jun. 30, 2019		Jul. 01, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges (income)	[1]	$ (144)	$ (24)	$ (134)	[2]	$ (33)
Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (income)		(74)	(13)	(63)		(9)
Biopharma and Upjohn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (income)			$ (10)			$ (24)
Biopharma [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (income)		(62)		(48)
Upjohn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges (income)		$ (9)		$ (22)

[1] 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 a U.S. IRS audit for multiple tax years (see Note 5B). In the three and six months ended July 1, 2018, restructuring credits were associated with cost-reduction and productivity initiatives not associated with acquisitions, as well as acquisition-related costs, primarily associated with Hospira. 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). The restructuring activities for 2018 are associated with the following: • For the second quarter of 2018, total reportable segments ($10 million credit); and Other ($13 million credit). • For the first six months of 2018, total reportable segments ($24 million credit); and Other ($9 million credit). At the beginning of fiscal 2019, we revised our operating segments and are unable to directly associate these prior-period restructuring charges with the new individual segments.

[2] Includes the reversal of certain accruals related to our acquisition of Wyeth upon the effective favorable settlement of a U.S. IRS audit for multiple tax years. See Note 5B for additional information.