Property and Equipment, net - Schedule of Property and Equipment Net (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,280	$ 2,033
Less: Accumulated depreciation and amortization	(1,561)	(1,439)
Property and equipment, net	719	594
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	61	59
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	574	507
Capitalized software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	957	906
Furniture, fixtures & equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	440	382
Projects in process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	154	89
Buses and support vehicles
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 94	$ 90