REVENUE - Cargo and Other Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Total Operating Revenue	$ 3,766	$ 3,072	$ 10,607	$ 8,201
Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	142	80	403	216
Passenger | Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	70	43	194	107
Other Services | Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	$ 72	$ 37	$ 209	$ 109