v3.20.2
Segment, Geographic and Other Revenue Information - Footnotes (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 27, 2020
Sep. 29, 2019
Sep. 27, 2020
Sep. 29, 2019
Segment Reporting Information [Line Items]        
Intangible asset impairment charge     $ 900  
Gain on completion of Consumer Healthcare JV transaction $ 0 $ 8,087 6 $ 8,087
IPR&D [Member]        
Segment Reporting Information [Line Items]        
Intangible asset impairment charge [1]     900  
Operating Segments [Member] | IPR&D [Member] | Biopharma [Member]        
Segment Reporting Information [Line Items]        
Intangible asset impairment charge 900   900  
ViiV [Member]        
Segment Reporting Information [Line Items]        
Dividend income $ 44 43 $ 196 $ 184
GSK Consumer Healthcare [Member]        
Segment Reporting Information [Line Items]        
Gain on completion of Consumer Healthcare JV transaction   $ 8,100    
[1] Reflects intangible assets written down to fair value in the first nine months of 2020. Fair value was determined using the income approach, specifically the multi-period excess earnings method, also known as the discounted cash flow method. We started with a forecast of all the expected net cash flows associated with the asset and then applied an asset-specific discount rate to arrive at a net present value amount. Some of the more significant estimates and assumptions inherent in this approach include: the amount and timing of the projected net cash flows, which includes the expected impact of competitive, legal and/or regulatory forces on the product; the discount rate, which seeks to reflect the various risks inherent in the projected cash flows; and the tax rate, which seeks to incorporate the geographic diversity of the projected cash flows.