Revenue - Operating Revenue by Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 14,178	$ 12,112	$ 25,607	$ 19,678
Domestic (U.S. and Canada)
Disaggregation of Revenue [Line Items]
Total operating revenue	8,417	7,819	15,584	12,905
Atlantic (including Europe, Africa, India and Middle East destinations)
Disaggregation of Revenue [Line Items]
Total operating revenue	3,229	2,481	5,061	3,570
Latin America
Disaggregation of Revenue [Line Items]
Total operating revenue	1,273	1,195	2,589	2,104
Pacific
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 1,259	$ 617	$ 2,373	$ 1,099