Acquisitions, Divestitures, Equity-Method Investments, Licensing Arrangements and Collaborative Arrangements - Summarized Financial Information of Equity Method Investee (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Sep. 29, 2019	Dec. 31, 2020	Sep. 27, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Method Investment, Summarized Financial Information, Balance Sheet [Abstract]
Current assets		$ 35,067		$ 32,803
Total assets		154,229		167,594
Current liabilities		25,920		37,304
Total liabilities		90,756		104,148
Total net equity/(deficit) attributable to shareholders		63,238		63,143
Equity attributable to noncontrolling interests		235		303
Total equity		63,473		63,447	$ 63,758	$ 71,656
Equity Method Investment, Summarized Financial Information [Abstract]
Income from continuing operations		7,021		10,867	3,861
Net income		9,652		16,302	11,188
Income attributable to shareholders		9,616		16,273	11,153
Consumer Healthcare JV [Member]
Equity Method Investment, Summarized Financial Information, Balance Sheet [Abstract]
Current assets	$ 7,505		$ 6,614
Noncurrent assets	38,575		38,361
Total assets	46,081		44,975
Current liabilities	5,241		5,246
Noncurrent liabilities	5,536		5,330
Total liabilities	10,776		10,576
Total net equity/(deficit) attributable to shareholders	35,199		34,154
Equity attributable to noncontrolling interests	105		245
Total equity	35,304		34,400
Equity Method Investment, Summarized Financial Information [Abstract]
Net sales	2,161		12,720
Cost of sales	(803)		(5,439)
Gross profit	1,358		7,281
Income from continuing operations	152		1,350
Net income	152		1,350
Income attributable to shareholders	$ 148		$ 1,307
ViiV [Member] | ViiV [Member]
Equity Method Investment, Summarized Financial Information, Balance Sheet [Abstract]
Current assets		3,283		3,839
Noncurrent assets		3,381		3,437
Total assets		6,664		7,276
Current liabilities		3,028		2,904
Noncurrent liabilities		6,370		5,860
Total liabilities		9,398		8,765
Total net equity/(deficit) attributable to shareholders		(2,734)		(1,489)
Equity Method Investment, Summarized Financial Information [Abstract]
Net sales		6,224		6,139	6,219
Cost of sales		(574)		(516)	(462)
Gross profit		5,650		5,623	5,757
Income from continuing operations		2,012		3,398	2,154
Net income		2,012		3,398	2,154
Income attributable to shareholders		$ 2,012		$ 3,398	$ 2,154