Employee Benefit Plans - Schedule of Amounts Recognized in Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liability	$ 7,069	$ 6,052
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liability	7	5
Noncurrent liability	6,248	5,456
Total liabilities	6,255	5,461
Retiree Medical and  Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liability	55	24
Noncurrent liability	821	596
Total liabilities	876	620
American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liability	7,027	6,008
American Airlines, Inc. | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liability	7	5
Noncurrent liability	6,206	5,412
Total liabilities	6,213	5,417
American Airlines, Inc. | Retiree Medical and  Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liability	55	24
Noncurrent liability	821	596
Total liabilities	$ 876	$ 620