FAIR VALUE MEASUREMENTS AND FINANCIAL INSTRUMENTS - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Liabilities:
Highly liquid investments, maturity period (in months) (or less)	3 months
Recurring basis
Assets:
Cash equivalents	$ 284	$ 197
Restricted cash	2	2
Liabilities:
Acquisition-related contingent consideration	313	339
Recurring basis | Cross-currency swaps | Net Investment Hedging | Designated as Hedging Instrument
Assets:
Cross-currency swaps	8	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	250	166
Restricted cash	2	2
Liabilities:
Acquisition-related contingent consideration	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cross-currency swaps | Net Investment Hedging | Designated as Hedging Instrument
Assets:
Cross-currency swaps	0	0
Recurring basis | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	34	31
Restricted cash	0	0
Liabilities:
Acquisition-related contingent consideration	0	0
Recurring basis | Significant Other Observable Inputs (Level 2) | Cross-currency swaps | Net Investment Hedging | Designated as Hedging Instrument
Assets:
Cross-currency swaps	8	0
Recurring basis | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Restricted cash	0	0
Liabilities:
Acquisition-related contingent consideration	313	339
Recurring basis | Significant Unobservable Inputs (Level 3) | Cross-currency swaps | Net Investment Hedging | Designated as Hedging Instrument
Assets:
Cross-currency swaps	$ 0	$ 0