Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Property leases
Operating Leases
Within 1 year	$ 766
Between 1 and 2 years	579
Between 2 and 3 years	513
Between 3 and 4 years	415
Between 4 and 5 years	311
Thereafter	1,221
Total lease payments	3,805
Less: Imputed interest	(693)
Total	3,112	$ 2,693
Buses and support vehicles
Operating Leases
Within 1 year	60
Between 1 and 2 years	10
Between 2 and 3 years	3
Between 3 and 4 years	1
Between 4 and 5 years	1
Thereafter	0
Total lease payments	75
Less: Imputed interest	(2)
Total	73	119
Finance Leases
Within 1 year	75
Between 1 and 2 years	0
Between 2 and 3 years	0
Between 3 and 4 years	61
Between 4 and 5 years	7
Thereafter	0
Total lease payments	143
Less: Imputed interest	0
Total	$ 143	$ 172