FAIR VALUE MEASUREMENTS AND FINANCIAL INSTRUMENTS - Assets and Liabilities Measured on a Non-Recurring Basis and Fair Value of Long-term Debt, Narrative (Details) - Nonrecurring adjustment - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-current assets held for sale	$ 0	$ 39
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-current assets held for sale	0	0
Fair value of long-term debt	$ 25,258	$ 27,520