COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	3 Months Ended		12 Months Ended	40 Months Ended
	Dec. 31, 2022 USD ($) aircraft	Jun. 30, 2021 USD ($)	Dec. 31, 2022 USD ($) aircraft	Dec. 31, 2020 USD ($)	Mar. 31, 2022 gate	Dec. 31, 2021 USD ($)
Payment Guarantee
Other Commitments [Line Items]
Principal amount of guarantee	$ 70		$ 70
Net present value of future principal and interest payments	77		77			$ 89
William P. Hobby Airport
Other Commitments [Line Items]
New airport gates | gate					7
New airport gates for domestic use | gate					6
New common-use airport gates | gate					1
Projected airport improvement costs	250		250
New airport gates available to lease | gate					6
Los Angeles World Airports
Other Commitments [Line Items]
Payments for airport projects				$ 410
Decrease in operating lease liability		$ (365)
Los Angeles World Airports | Leaseholds and Leasehold Improvements
Other Commitments [Line Items]
Construction payments		$ 365
Aircraft
Other Commitments [Line Items]
Committed expenditures, year one	3,200		3,200
Committed expenditures, year two	1,200		1,200
Committed expenditures, year three	953		953
Committed expenditures, year four	1,400		1,400
Committed expenditures, year five	1,100		1,100
Committed expenditures, year six and beyond	$ 5,800		$ 5,800
737 MAX 8
Other Commitments [Line Items]
Number of aircraft orders | aircraft			235
Options - 737MAX (in units) | aircraft	147		147
737 MAX 8 | Aircraft
Other Commitments [Line Items]
Number of aircraft orders | aircraft			90
Committed expenditures, year one	$ 2,300		$ 2,300
737 MAX 7
Other Commitments [Line Items]
Number of aircraft orders | aircraft			182
Options exercised | aircraft	10
737 MAX 7 | Aircraft
Other Commitments [Line Items]
Number of aircraft orders | aircraft			46
Committed expenditures, year one	$ 956		$ 956
Committed expenditures, year two	$ 1,400		$ 1,400