REVENUE - Cargo and Other Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Total Operating Revenue	$ 3,137	$ 2,232
Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	122	64
Passenger | Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	57	28
Other Services | Cargo and other revenue
Disaggregation of Revenue [Line Items]
Total Operating Revenue	$ 65	$ 36