FINANCIAL DERIVATIVE INSTRUMENTS - Offsetting of Derivative Assets (Details) - Fuel derivative contracts - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Prepaid expenses and other current assets
Offsetting Assets
Gross amounts of recognized assets	$ 22	$ 86
Gross amounts of recognized liabilities	(4)	(15)
Net amounts of assets presented in the Balance Sheet	$ 18	$ 71
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Prepaid expenses and other current assets	Prepaid expenses and other current assets
Other assets
Offsetting Assets
Gross amounts of recognized assets	$ 108	$ 137
Gross amounts of recognized liabilities	(18)	(35)
Net amounts of assets presented in the Balance Sheet	$ 90	$ 102
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets