Employee Benefit Plans - Schedule of Changes in Projected Benefit Obligations (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2012
Reconciliation of benefit obligation:
Plan amendments (4)	$ (313)					$ (1,900)
Pension Benefits
Reconciliation of benefit obligation:
Benefit obligation at beginning of period			$ 18,358	$ 16,378
Service cost			2	2	$ 3
Interest cost			615	703	674
Actuarial (gain) loss			1,613	1,965
Special termination benefits			0	0	0
Plan amendments (4)			0	0
Settlements			(36)	(2)
Benefit payments			(740)	(689)
Other			0	1
Benefit obligation at end of period	19,812		19,812	18,358	16,378
Retiree Medical and  Other Postretirement Benefits
Reconciliation of benefit obligation:
Benefit obligation at beginning of period			824	837
Service cost			8	3	5
Interest cost			30	33	35
Actuarial (gain) loss			46	20
Special termination benefits		$ 410	410	0	0
Plan amendments (4)			(195)	0
Settlements			0	0
Benefit payments			(77)	(74)
Other			0	5
Benefit obligation at end of period	1,046		1,046	824	837
American Airlines, Inc.
Reconciliation of benefit obligation:
Plan amendments (4)	(313)					$ (1,900)
American Airlines, Inc. | Pension Benefits
Reconciliation of benefit obligation:
Benefit obligation at beginning of period			18,246	16,282
Service cost			2	2	2
Interest cost			611	699	670
Actuarial (gain) loss			1,603	1,951
Special termination benefits			0	0	0
Plan amendments (4)			0	0
Settlements			(36)	(2)
Benefit payments			(736)	(686)
Other			0	0
Benefit obligation at end of period	19,690		19,690	18,246	16,282
American Airlines, Inc. | Retiree Medical and  Other Postretirement Benefits
Reconciliation of benefit obligation:
Benefit obligation at beginning of period			824	837
Service cost			8	3	5
Interest cost			30	33	35
Actuarial (gain) loss			46	20
Special termination benefits		$ 410	410	0	0
Plan amendments (4)			(195)	0
Settlements			0	0
Benefit payments			(77)	(74)
Other			0	5
Benefit obligation at end of period	$ 1,046		$ 1,046	$ 824	$ 837