REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Allowance for credit loss	$ 16	$ 10
Liability, current	22	10
Deferred income	55	49
Receivable allowance for credit loss	8
Customer incentive payments	43	37
Customer incentive payments	$ 166	180
Minimum
Revenue from External Customer [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction (in years)	3 years
Maximum
Revenue from External Customer [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction (in years)	7 years
Accounts payable and accrued expenses
Revenue from External Customer [Line Items]
Liability, current	$ 22	10
Other non-current liabilities
Revenue from External Customer [Line Items]
Deferred income	6	12
Prepayments and other current assets
Revenue from External Customer [Line Items]
Customer incentive payments	43	37
Other non-current assets
Revenue from External Customer [Line Items]
Customer incentive payments	$ 166	$ 180