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Total costs of sales and operating expenses for the period.

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REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Deferred Revenue Arrangement [Line Items]
Receivable	$ 370		$ 370		$ 383
Costs and Expenses	2,575	$ 2,501	4,973	$ 4,883
Mileage Plan Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Contract liability revenue recognized			613	602
Receivable	87		87		$ 102
Mileage Plan Revenue [Member] \| Mileage plan other revenue [Member]
Deferred Revenue Arrangement [Line Items]
Contract liability revenue recognized			(67)	(52)
Passenger Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Contract liability revenue recognized	$ 150	$ 103	$ 717	$ 588