Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI tax, attributable to parent [Roll Forward]
Beginning balance, tax	$ (1,091)	$ (1,218)
Other comprehensive income (loss) before reclassifications, tax	236	107
Amounts reclassified from AOCI, tax	(10)	20
Net current-period other comprehensive income (loss), tax	226	127
Ending balance, tax	(865)	(1,091)	$ (1,218)
AOCI attributable to parent, net of tax [Roll Forward]
Beginning balance, net of tax	(6,331)	(5,896)
Other comprehensive income (loss) before reclassifications, net of tax	(809)	(366)
Amounts reclassified from AOCI, net of tax	37	(69)
Total other comprehensive loss, net of tax	(772)	(435)	(120)
Ending balance, net of tax	(7,103)	(6,331)	(5,896)
Pension, Retiree Medical and Other Postretirement Benefits
AOCI attributable to parent, before tax [Roll Forward]
Beginning balance, before tax	(5,238)	(4,673)
Other comprehensive income (loss) before reclassifications, before tax	(1,045)	(476)
Amounts reclassified from AOCI, before tax	47	(89)
Net current-period other comprehensive income (loss), before tax	(998)	(565)
Ending balance, before tax	(6,236)	(5,238)	(4,673)
Unrealized Gain on Investments
AOCI attributable to parent, before tax [Roll Forward]
Beginning balance, before tax	(2)	(5)
Other comprehensive income (loss) before reclassifications, before tax	0	3
Amounts reclassified from AOCI, before tax	0	0
Net current-period other comprehensive income (loss), before tax	0	3
Ending balance, before tax	(2)	(2)	(5)
American Airlines, Inc.
AOCI tax, attributable to parent [Roll Forward]
Beginning balance, tax	(1,203)	(1,329)
Other comprehensive income (loss) before reclassifications, tax	236	106
Amounts reclassified from AOCI, tax	(10)	20
Net current-period other comprehensive income (loss), tax	226	126
Ending balance, tax	(977)	(1,203)	(1,329)
AOCI attributable to parent, net of tax [Roll Forward]
Beginning balance, net of tax	(6,423)	(5,992)
Other comprehensive income (loss) before reclassifications, net of tax	(807)	(362)
Amounts reclassified from AOCI, net of tax	36	(69)
Total other comprehensive loss, net of tax	(771)	(431)	(119)
Ending balance, net of tax	(7,194)	(6,423)	(5,992)
American Airlines, Inc. | Pension, Retiree Medical and Other Postretirement Benefits
AOCI attributable to parent, before tax [Roll Forward]
Beginning balance, before tax	(5,218)	(4,658)
Other comprehensive income (loss) before reclassifications, before tax	(1,043)	(471)
Amounts reclassified from AOCI, before tax	46	(89)
Net current-period other comprehensive income (loss), before tax	(997)	(560)
Ending balance, before tax	(6,215)	(5,218)	(4,658)
American Airlines, Inc. | Unrealized Gain on Investments
AOCI attributable to parent, before tax [Roll Forward]
Beginning balance, before tax	(2)	(5)
Other comprehensive income (loss) before reclassifications, before tax	0	3
Amounts reclassified from AOCI, before tax	0	0
Net current-period other comprehensive income (loss), before tax	0	3
Ending balance, before tax	$ (2)	$ (2)	$ (5)