Impact of the COVID-19 Pandemic - 2020 Aircraft Retirement Decisions (Details) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020 USD ($) aircraft	Jun. 30, 2020 USD ($) aircraft	Mar. 31, 2020 USD ($) aircraft	Sep. 30, 2020 USD ($) aircraft
Aircraft retirement decisions
Number of aircraft | aircraft				383
Impairment-related charge | $				$ 4,427
717
Aircraft retirement decisions
Number of aircraft | aircraft	91
Impairment-related charge | $	$ 950
767-300ER
Aircraft retirement decisions
Number of aircraft | aircraft	49	7
Impairment-related charge | $	$ 905	$ 180
CRJ-200
Aircraft retirement decisions
Number of aircraft | aircraft	125
Impairment-related charge | $	$ 320
777
Aircraft retirement decisions
Number of aircraft | aircraft		18
Impairment-related charge | $		$ 1,440
MD-90
Aircraft retirement decisions
Number of aircraft | aircraft		26
Impairment-related charge | $		$ 330
737-700
Aircraft retirement decisions
Number of aircraft | aircraft		10
Impairment-related charge | $		$ 220
A320
Aircraft retirement decisions
Number of aircraft | aircraft		10
Impairment-related charge | $		$ 60
MD-88
Aircraft retirement decisions
Number of aircraft | aircraft			47
Impairment-related charge | $			$ 22