Employee Benefit Plans - Schedule of Accumulated Benefit Obligations Exceeding Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 16,351	$ 18,245
Accumulated benefit obligation	16,341	18,235
Fair value of plan assets	10,023	11,364
ABO less fair value of plan assets	6,318	6,871
Retiree Medical And Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	837	1,011
Fair value of plan assets	225	295
American Airlines, Inc. [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	16,254	18,144
Accumulated benefit obligation	16,246	18,135
Fair value of plan assets	9,971	11,307
ABO less fair value of plan assets	6,275	6,828
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	837	1,010
Fair value of plan assets	$ 225	$ 295