Revenue Recognition - Significant Contract Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Contract balances, liability	$ 15,645	$ 13,952
Loyalty program liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	9,195	9,195
Air traffic liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	6,450	4,757
American Airlines, Inc.
Disaggregation of Revenue [Line Items]
Contract balances, liability	15,645	13,952
American Airlines, Inc. | Loyalty program liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	9,195	9,195
American Airlines, Inc. | Air traffic liability
Disaggregation of Revenue [Line Items]
Contract balances, liability	$ 6,450	$ 4,757