REVENUE RECOGNITION - Passenger Revenue (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Operating revenue	$ 58,048	$ 50,582	$ 29,899
Passenger
Disaggregation of Revenue [Line Items]
Operating revenue	48,909	40,218	22,519
Ticket
Disaggregation of Revenue [Line Items]
Operating revenue	43,596	35,626	19,339
Loyalty travel awards
Disaggregation of Revenue [Line Items]
Operating revenue	3,462	2,898	1,786
Travel-related services
Disaggregation of Revenue [Line Items]
Operating revenue	$ 1,851	$ 1,694	$ 1,394

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details