DERIVATIVE INSTRUMENTS - FAIR VALUE OF HEDGE POSITIONS (Details) gallons in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) gallons	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Payments for (Proceeds from) Hedge, Investing Activities	$ (38)	$ 14	$ 19
Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	$ (6)
Fuel hedge contracts [Member] | Derivative Instruments Not Designated as Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | gallons	425
Interest rate swaps agreements [Member] | Secured Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 469