REVENUE RECOGNITION - Variable Consideration Provisions (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	$ 2,546
Current period provision	4,468
Payments and credits	(4,514)
Reserve ending balance	2,500
Discounts and Allowances
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	167
Current period provision	643
Payments and credits	(632)
Reserve ending balance	178
Returns
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	863
Current period provision	209
Payments and credits	(264)
Reserve ending balance	808
Rebates
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	1,094
Current period provision	1,976
Payments and credits	(1,939)
Reserve ending balance	1,131
Chargebacks
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	274
Current period provision	1,462
Payments and credits	(1,512)
Reserve ending balance	224
Distribution Fees
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Reserve beginning balance	148
Current period provision	178
Payments and credits	(167)
Reserve ending balance	$ 159