FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of assets (liabilities) measured at fair value on a recurring basis

Assets/(Liabilities) Measured at Fair Value on a Recurring Basis

(in millions)	March 31, 2023		Level 1		Level 2		Level 3
Cash equivalents	$	2,231	$	2,231	$	—	$	—
Restricted cash equivalents	213		213		—		—
Short-term investments
U.S. Government securities	1,501		162		1,339		—
Corporate obligations	1,756		—		1,756		—
Asset-backed securities	37		—		37		—
Other fixed income securities	102		—		102		—
Long-term investments	1,572		1,424		38		110
Fuel hedge contracts	(6)		—		(6)		—

(in millions)	December 31, 2022		Level 1		Level 2		Level 3
Cash equivalents	$	2,021	$	2,021	$	—	$	—
Restricted cash equivalents	206		206		—		—
Short-term investments
U.S. Government securities	1,587		122		1,465		—
Corporate obligations	1,614		—		1,614		—
Other fixed income securities	67		—		67		—
Long-term investments	1,450		1,305		38		107
Fuel hedge contracts	(47)		—		(47)		—