INVESTMENTS - Equity Investments Ownership Interest and Carrying Value (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Equity Investments
Equity investments	$ 2,291	$ 2,128
Air France-KLM
Equity Investments
Ownership interest (percent)	3.00%	3.00%
Carrying value	$ 92	$ 97
China Eastern
Equity Investments
Ownership interest (percent)	2.00%	2.00%
Carrying value	$ 159	$ 189
CLEAR
Equity Investments
Ownership interest (percent)	5.00%	5.00%
Carrying value	$ 158	$ 227
Hanjin-KAL
Equity Investments
Ownership interest (percent)	15.00%	15.00%
Carrying value	$ 313	$ 296
Hanjin-KAL | Common and Preferred Shares
Equity Investments
Ownership interest (percent)	14.80%
Hanjin-KAL | Common Stock
Equity Investments
Ownership interest (percent)	14.90%
LATAM
Equity Investments
Ownership interest (percent)	10.00%	10.00%
Carrying value	$ 548	$ 403
Wheels Up
Equity Investments
Ownership interest (percent)	39.00%	21.00%
Carrying value	$ 59	$ 54
Other investments
Equity Investments
Carrying value	$ 329	$ 285
Grupo Aeromexico
Equity Investments
Ownership interest (percent)	20.00%	20.00%
Carrying value	$ 459	$ 412
Unifi Aviation
Equity Investments
Ownership interest (percent)	49.00%	49.00%
Carrying value	$ 174	$ 165