Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Right-of-use lease assets	$ 295	$ 305
Total property and equipment	4,692	4,269
Less accumulated depreciation and amortization	(2,539)	(2,346)
Property and equipment, net	$ 2,153	1,923
Minimum
Property, Plant and Equipment [Line Items]
Right-of-use lease assets, useful life	1 year
Maximum
Property, Plant and Equipment [Line Items]
Right-of-use lease assets, useful life	30 years
Software and internally developed software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,061	1,834
Software and internally developed software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Software and internally developed software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	7 years
Computer and network equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,073	1,033
Computer and network equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Computer and network equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 180	180
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 436	389
Buildings and building improvements | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	15 years
Buildings and building improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	30 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 455	372
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	4 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	15 years
Equipment, aircraft and office furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 192	$ 156
Equipment, aircraft and office furniture | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	4 years
Equipment, aircraft and office furniture | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	12 years