RESTRUCTURING NARRATIVE (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019
Celgene Integration [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related charges	$ 3,000
Cash outlays	2,500
Restructuring and related charges incurred to date	$ 1,900
Workforce reduction of manufacturing, selling, administrative, and research and development personnel	1,565	125
MyoKardia Acquisition Plan [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related charges	$ 150
Operating Model 2020 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges incurred to date	$ 1,500