FINANCIAL INSTRUMENTS - Balance sheet (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Designated as Hedging Instrument | Foreign currency | Prepayments and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	$ 1	$ 0
Designated as Hedging Instrument | Foreign currency | Other non-current assets
Derivatives, Fair Value [Line Items]
Derivative assets	0	0
Designated as Hedging Instrument | Foreign currency | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	4	1
Designated as Hedging Instrument | Foreign currency | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	0
Designated as Hedging Instrument | Cross-currency swaps | Other non-current assets | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	0	3
Designated as Hedging Instrument | Cross-currency swaps | Other non-current liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	161	8
Not Designated as Hedging Instrument | Foreign currency | Prepayments and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	4	0
Not Designated as Hedging Instrument | Foreign currency | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 1	$ 0