REVENUE RECOGNITION - Variable Consideration Provisions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	$ 1,813	$ 2,050
Current period provisions	1,300	1,337
Payments and credits	(1,222)	(1,392)
Reserve ending balance	1,891	1,995
Discounts and Allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	190	182
Current period provisions	147	156
Payments and credits	(160)	(167)
Reserve ending balance	177	171
Returns
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	575	691
Current period provisions	34	42
Payments and credits	(56)	(75)
Reserve ending balance	553	658
Rebates
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	779	927
Current period provisions	602	602
Payments and credits	(457)	(588)
Reserve ending balance	924	941
Chargebacks
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	184	168
Current period provisions	462	484
Payments and credits	(483)	(501)
Reserve ending balance	163	151
Distribution Fees
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	85	82
Current period provisions	55	53
Payments and credits	(66)	(61)
Reserve ending balance	$ 74	$ 74