Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 1	$ 3	$ 3
Interest cost	132	154	394	461
Expected return on assets	(269)	(253)	(813)	(757)
Special termination benefits	0	0	0	0
Settlements			0	4
Amortization of:
Prior service cost (benefit)	7	7	21	21
Unrecognized net loss (gain)	54	41	159	124
Net periodic benefit cost (income)	(75)	(50)	(236)	(144)
Retiree Medical and Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	7	5
Interest cost	8	8	23	22
Expected return on assets	(3)	(3)	(9)	(9)
Special termination benefits	0	410	139	410
Settlements			0	0
Amortization of:
Prior service cost (benefit)	(3)	(33)	(10)	(139)
Unrecognized net loss (gain)	(6)	(5)	(17)	(17)
Net periodic benefit cost (income)	(2)	379	133	272
American Airlines, Inc. | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	3	2
Interest cost	132	153	392	459
Expected return on assets	(269)	(252)	(809)	(754)
Special termination benefits	0	0	0	0
Settlements			0	4
Amortization of:
Prior service cost (benefit)	7	7	21	21
Unrecognized net loss (gain)	54	41	158	123
Net periodic benefit cost (income)	(75)	(50)	(235)	(145)
American Airlines, Inc. | Retiree Medical and Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	7	5
Interest cost	8	8	23	22
Expected return on assets	(3)	(3)	(9)	(9)
Special termination benefits	0	410	139	410
Settlements			0	0
Amortization of:
Prior service cost (benefit)	(3)	(33)	(10)	(139)
Unrecognized net loss (gain)	(6)	(5)	(17)	(17)
Net periodic benefit cost (income)	$ (2)	$ 379	$ 133	$ 272