PENSION AND POSTRETIREMENT BENEFIT PLANS (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Net periodic benefit cost/(credit)	$ 0			$ 1,537	$ (6)	$ 1,607
Pension and postretirement	871		$ 725		871
Defined contribution plan expense	70			50	220	140
Pension Assets Transfer		$ 381
Reversion excise tax	0	$ 76		0	76	0
Payment for Pension Benefits			200	1,300
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement				1,500
Bristol-Myers Squibb Retirement Income Plan [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Benefit Obligation				2,400		2,400
Pension Benefits [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Service cost - benefits earned during the period	12			6	36	18
Interest cost on projected benefit obligation	11			20	30	101
Expected return on plan assets	(26)			(39)	(73)	(173)
Amortization of prior service credits	(1)			(1)	(3)	(3)
Amortization of net actuarial (gain)/loss	12			14	33	49
Curtailment and settlements	3			1,550	7	1,643
Net periodic benefit cost/(credit)	11			$ 1,550	30	$ 1,635
Pension and postretirement	$ 588		$ 569		$ 588