Employee Benefit Plans - Fair Values of Retiree Medical and Other Postretirement Benefit Plans Assets by Asset Category (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Mutual funds [Member] | non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	25.00%	27.00%
Retiree Medical And Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 225	$ 295	$ 266
Retiree Medical And Other Postretirement Benefits [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
Retiree Medical And Other Postretirement Benefits [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	290
Retiree Medical And Other Postretirement Benefits [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	290
Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	290
Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0
Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds [Member] | non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%	30.00%
American Airlines, Inc. [Member] | Mutual funds [Member] | non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%	30.00%
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 225	$ 295	$ 266
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	290
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Money market funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	290
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221	290
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member] | Mutual funds - AAL Class [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0