Revenue Recognition - Passenger Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Operating revenue	$ 13,824	$ 7,126	$ 23,173	$ 11,276
Passenger
Disaggregation of Revenue [Line Items]
Operating revenue	10,958	5,339	17,865	8,087
Ticket
Disaggregation of Revenue [Line Items]
Operating revenue	9,773	4,553	15,759	6,830
Loyalty travel awards
Disaggregation of Revenue [Line Items]
Operating revenue	744	428	1,287	669
Travel-related services
Disaggregation of Revenue [Line Items]
Operating revenue	$ 441	$ 358	$ 819	$ 588