REVENUE RECOGNITION - Variable Consideration Provisions (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	$ 1,813	$ 2,050
Current period provisions	4,062	3,697
Payments and credits	(3,924)	(3,845)
Reserve ending balance	1,951	1,902
Discounts and Allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	190	182
Current period provisions	472	457
Payments and credits	(448)	(454)
Reserve ending balance	214	185
Returns
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	575	691
Current period provisions	94	71
Payments and credits	(167)	(185)
Reserve ending balance	502	577
Rebates
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	779	927
Current period provisions	1,842	1,587
Payments and credits	(1,619)	(1,605)
Reserve ending balance	1,002	909
Chargebacks
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	184	168
Current period provisions	1,487	1,433
Payments and credits	(1,524)	(1,451)
Reserve ending balance	147	150
Distribution Fees
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	85	82
Current period provisions	167	149
Payments and credits	(166)	(150)
Reserve ending balance	$ 86	$ 81