Operating Leases - Aircraft (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) lease transaction aircraft	Jun. 30, 2023 USD ($) transaction aircraft lease	Jun. 30, 2024 USD ($) lease transaction engine aircraft	Jun. 30, 2023 USD ($) lease aircraft transaction
Lessee, Lease, Description [Line Items]
Gains recognized on sale-leaseback transactions | $			$ 148	$ 57
Aircraft
Lessee, Lease, Description [Line Items]
Number of leases	148		148
Aircraft | Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	8 months		8 months
Aircraft | Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	12 years		12 years
Aircraft Engine
Lessee, Lease, Description [Line Items]
Number of leases	33		33
Number of engines dependent on usage-based metrics | engine			10
Aircraft Engine | Aircraft Sale Leaseback
Lessee, Lease, Description [Line Items]
Number of sale-leaseback transactions | transaction	2	1	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 | $	$ 77	$ 17	$ 148	$ 57
A320neo
Lessee, Lease, Description [Line Items]
Number of leases in period	0	2	0	5
A320neo | Aircraft | Aircraft Sale Leaseback
Lessee, Lease, Description [Line Items]
Number of sale-leaseback transactions | aircraft	6	1	12	4