Operating Leases - Aircraft (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) engine aircraft	Jun. 30, 2022 USD ($) aircraft	Jun. 30, 2023 USD ($) engine aircraft	Jun. 30, 2022 USD ($) aircraft
Lessee, Lease, Description [Line Items]
Gains recognized on sale-leaseback transactions | $			$ 57	$ 28
Aircraft
Lessee, Lease, Description [Line Items]
Number of leases	126		126
Aircraft | Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 month		1 month
Aircraft | Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	12 years		12 years
Aircraft Engine
Lessee, Lease, Description [Line Items]
Number of leases | engine	32		32
Number of engines dependent on usage-based metrics | engine			13
Aircraft Engine | Aircraft Sale Leaseback
Lessee, Lease, Description [Line Items]
Number of sale-leaseback transactions	1	2	2	2
Aircraft Engine | Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 month		1 month
Aircraft Engine | Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	12 years		12 years
Aircraft and Aircraft Engines
Lessee, Lease, Description [Line Items]
Gains recognized on sale-leaseback transactions | $	$ 17	$ 21	$ 57	$ 28
A320neo
Lessee, Lease, Description [Line Items]
Number of leases in period	2		5
A320neo | Aircraft | Aircraft Sale Leaseback
Lessee, Lease, Description [Line Items]
Number of sale-leaseback transactions	1	3	4	5