INVESTMENTS - Equity Investments Ownership Interest and Carrying Value (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Equity Investments
Equity investments	$ 3,457	$ 2,128
Air France-KLM
Equity Investments
Ownership Interest	3.00%	3.00%
Carrying Value	$ 110	$ 97
China Eastern
Equity Investments
Ownership Interest	2.00%	2.00%
Carrying Value	$ 134	$ 189
CLEAR
Equity Investments
Ownership Interest	6.00%	5.00%
Carrying Value	$ 171	$ 227
Hanjin-KAL
Equity Investments
Ownership Interest	15.00%	15.00%
Carrying Value	$ 561	$ 296
Hanjin-KAL | Common and Preferred Shares
Equity Investments
Ownership Interest	14.80%
Hanjin-KAL | Common Stock
Equity Investments
Ownership Interest	14.90%
LATAM
Equity Investments
Ownership Interest	10.00%	10.00%
Carrying Value	$ 658	$ 403
Wheels Up
Equity Investments
Ownership Interest	38.00%	21.00%
Carrying Value	$ 903	$ 54
Other investments
Equity Investments
Carrying Value	$ 337	$ 285
Grupo Aeroméxico
Equity Investments
Ownership Interest	20.00%	20.00%
Carrying Value	$ 421	$ 412
Unifi Aviation
Equity Investments
Ownership Interest	49.00%	49.00%
Carrying Value	$ 162	$ 165