Employee Benefit Plans - Components of Net Periodic Benefit Cost (Income) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined benefit plans:
Service cost	$ 2	$ 2	$ 2
Interest cost	721	749	737
Expected return on assets	(790)	(750)	(851)
Settlements	1	0	1
Prior service cost (benefit)	28	28	28
Unrecognized net loss (gain)	144	126	112
Net periodic benefit cost (income)	106	155	29
Defined contribution plan cost	851	766	662
Total cost (income)	957	921	691
Retiree Medical And Other Postretirement Benefits [Member]
Defined benefit plans:
Service cost	4	3	3
Interest cost	39	47	50
Expected return on assets	(21)	(20)	(19)
Settlements	0	0	0
Prior service cost (benefit)	(237)	(240)	(243)
Unrecognized net loss (gain)	(23)	(17)	(9)
Net periodic benefit cost (income)	(238)	(227)	(218)
Total cost (income)	(238)	(227)	(218)
American Airlines, Inc. [Member] | Pension Benefits [Member]
Defined benefit plans:
Service cost	2	2	1
Interest cost	717	746	733
Expected return on assets	(786)	(747)	(848)
Settlements	1	0	1
Prior service cost (benefit)	28	28	28
Unrecognized net loss (gain)	144	125	111
Net periodic benefit cost (income)	106	154	26
Defined contribution plan cost	844	761	657
Total cost (income)	950	915	683
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member]
Defined benefit plans:
Service cost	4	3	3
Interest cost	39	47	50
Expected return on assets	(21)	(20)	(19)
Settlements			0
Prior service cost (benefit)	(237)	(240)	(243)
Unrecognized net loss (gain)	(23)	(16)	(9)
Net periodic benefit cost (income)	(238)	(226)	(218)
Total cost (income)	$ (238)	$ (226)	$ (218)