REVENUE - Cargo and Other Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Total Operating Revenue	$ 3,704	$ 2,897	$ 6,841	$ 5,129
Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	139	72	261	136
Passenger | Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	67	36	124	64
Other Services | Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	$ 72	$ 36	$ 137	$ 72