ALLIANCES (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2021		Sep. 30, 2020		Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Alliance Statement [Line Items]
Total Revenues	$ 11,624		$ 10,540		$ 34,400	$ 31,450
Cost of products sold	2,291	[1]	2,502	[1]	7,584	8,863
Research and development	3,251		2,499		8,747	7,393
Other (income)/expense, net	(409)		(915)		(1,113)	(488)
Receivables - from alliance partners	9,245				9,245		$ 8,501
Accounts payable - to alliance partners	2,695				2,695		2,713
Collaborative Arrangement [Member]
Alliance Statement [Line Items]
Total Revenues	2,646		2,300		8,634	7,492
Cost of products sold	1,181		1,007		3,924	3,363
Research and development	10		48		753	327
Other (income)/expense, net	1		(28)		(18)	(59)
Receivables - from alliance partners	314				314		343
Accounts payable - to alliance partners	1,101				1,101		1,093
Deferred income from alliance	344				344		$ 366
Marketing, selling and administrative	(43)		(25)		(140)	(103)
Collaborative Arrangement [Member] | Eisai
Alliance Statement [Line Items]
Upfront Payments Made To Collaborative Partner					650
Consideration for contingent development and regulatory approval					2,500
Net product sales [Member]
Alliance Statement [Line Items]
Total Revenues	11,243		10,197		33,446	30,555
Net product sales [Member] | Collaborative Arrangement [Member]
Alliance Statement [Line Items]
Total Revenues	2,452		2,116		8,139	7,040
Collaborative Arrangement [Member] | Collaborative Arrangement [Member]
Alliance Statement [Line Items]
Total Revenues	$ 194		$ 184		$ 495	$ 452

[1] Excludes amortization of acquired intangible assets