Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 1
Interest cost	131	153
Expected return on assets	(272)	(252)
Special termination benefits	0	0
Amortization of:
Prior service cost (benefit)	7	7
Unrecognized net loss (gain)	53	41
Net periodic benefit cost (income)	(80)	(50)
Retiree Medical and Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1
Interest cost	6	7
Expected return on assets	(3)	(4)
Special termination benefits	139	0
Amortization of:
Prior service cost (benefit)	(3)	(54)
Unrecognized net loss (gain)	(6)	(6)
Net periodic benefit cost (income)	135	(56)
American Airlines, Inc. | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	130	152
Expected return on assets	(270)	(251)
Special termination benefits	0	0
Amortization of:
Prior service cost (benefit)	7	7
Unrecognized net loss (gain)	52	41
Net periodic benefit cost (income)	(80)	(50)
American Airlines, Inc. | Retiree Medical and Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1
Interest cost	6	7
Expected return on assets	(3)	(4)
Special termination benefits	139	0
Amortization of:
Prior service cost (benefit)	(3)	(54)
Unrecognized net loss (gain)	(6)	(6)
Net periodic benefit cost (income)	$ 135	$ (56)