Revenue Recognition - Significant Contract Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Contract balances, liability	$ 14,976	$ 13,952
Loyalty program liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	9,378	9,195
Air traffic liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	5,598	4,757
American Airlines, Inc.
Disaggregation of Revenue [Line Items]
Contract balances, liability	14,976	13,952
American Airlines, Inc. | Loyalty program liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	9,378	9,195
American Airlines, Inc. | Air traffic liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	$ 5,598	$ 4,757