SUPPLEMENTAL FINANCIAL INFORMATION - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Line Items]
Right-of-use asset obtained in exchange for operating lease liability	$ 69	$ 42
Right-of-use asset obtained in exchange for finance lease liability		7
Property, Plant and Equipment
Property, Plant and Equipment [Line Items]
Capital expenditures incurred but not yet paid	$ 49	$ 48