FAIR VALUE MEASUREMENTS AND FINANCIAL INSTRUMENTS - Cross-currency Swaps, Narrative (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payments or receipts in settlement of cross-currency swaps	$ 11,000,000
Net Investment Hedging | Cross-currency swaps | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate notional amounts		$ 1,250,000,000
Derivative asset, fair value	42,000,000
Net Investment Hedging | Cross-currency swaps | Designated as Hedging Instrument | Other Noncurrent Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, fair value	34,000,000
Net Investment Hedging | Cross-currency swaps | Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, fair value	$ 8,000,000