Other (Income)/Deductions - Net - Footnotes (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Loss Contingencies [Line Items]
Proceeds from legal dispute			$ 82		$ 82
Unrealized gain (loss) on equity securities	[1]	$ 733	31	$ 459	137
Other asset impairments					20
Insurance Recoveries			(25)		(50)
Change in fair value of contingent consideration			81
Allogene [Member]
Loss Contingencies [Line Items]
Unrealized gain (loss) on equity securities		508		374
BioNTech SE [Member]
Loss Contingencies [Line Items]
Unrealized gain (loss) on equity securities		61		127
Cortexyme, Inc. [Member]
Loss Contingencies [Line Items]
Unrealized gain (loss) on equity securities					104
ViiV [Member]
Loss Contingencies [Line Items]
Dividend income		76	$ 76	153	140
Puma Technologies [Member] | Collaborative Arrangement [Member]
Loss Contingencies [Line Items]
Milestone payment received		40		40
Eli Lilly & Company [Member] | Collaborative Arrangement [Member]
Loss Contingencies [Line Items]
Milestone payment received		30		30
Mylan [Member] | Collaborative Arrangement [Member]
Loss Contingencies [Line Items]
Milestone payment received					68
Disposed of by Sale [Member] | CK1 assets sold to Biogen, Inc [Member]
Loss Contingencies [Line Items]
Consideration transferred		75		75
Biopharma [Member] | Operating Segments [Member] | Developed Technology Rights [Member] | King [Member]
Loss Contingencies [Line Items]
Intangible asset impairment charge					40
Biopharma [Member] | Operating Segments [Member] | Developed Technology Rights [Member] | Anacor [Member]
Loss Contingencies [Line Items]
Intangible asset impairment charge					10
Gene Therapies [Member] | WRDM [Member] | In Process Research and Development [Member]
Loss Contingencies [Line Items]
Intangible asset impairment charge					$ 90
ViiV [Member]
Loss Contingencies [Line Items]
Change in fair value of contingent consideration		$ 86		$ 99

[1]   Included in net unrealized gains are observable price changes on equity securities without readily determinable fair values. Since January 1, 2018, there were cumulative impairments and downward adjustments of $67 million and upward adjustments of $66 million. Impairments, downward and upward adjustments were not significant in the second quarter and the first six months of 2020 and 2019.