Significant Accounting Policies - Operating Revenue by Principal Geographic Region (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 44,955	$ 24,634	$ 15,355
Domestic (U.S. and Canada)
Disaggregation of Revenue [Line Items]
Total operating revenue	28,474	16,845	9,911
Atlantic (including Africa, India and Middle East destinations)
Disaggregation of Revenue [Line Items]
Total operating revenue	9,072	3,414	2,226
Pacific
Disaggregation of Revenue [Line Items]
Total operating revenue	2,927	1,507	1,706
Latin America
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 4,482	$ 2,868	$ 1,512