Employee Benefit Plans - Fair Values of Retiree Medical and Other Postretirement Benefit Plans Assets by Asset Category (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Mutual funds [Member] | Non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	27.00%	25.00%
Retiree Medical And Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 204	$ 225	$ 295
Retiree Medical And Other Postretirement Benefits [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	4
Retiree Medical And Other Postretirement Benefits [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	200	221
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	4
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	4
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	200	221
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	200	221
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	24.00%	30.00%
American Airlines, Inc. [Member] | Mutual funds [Member] | Non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	24.00%	30.00%
American Airlines, Inc. [Member] | Retiree Medical And Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 204	$ 225	$ 295
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	4
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	200	221
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	4
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	4
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	200	221
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	200	221
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