Other Financial Data - Components of Fixed Assets, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Fixed Assets, net [Line Items]
Fixed assets, gross	$ 2,347	$ 2,146
Less: Accumulated depreciation	1,645	1,509
Fixed assets, net	702	637
Depreciation of fixed assets	188	183	$ 167
Software
Fixed Assets, net [Line Items]
Fixed assets, gross	1,013	981
Leasehold improvements
Fixed Assets, net [Line Items]
Fixed assets, gross	491	437
Furniture, fixtures and equipment
Fixed Assets, net [Line Items]
Fixed assets, gross	271	297
Computer equipment
Fixed Assets, net [Line Items]
Fixed assets, gross	327	271
Construction in progress
Fixed Assets, net [Line Items]
Fixed assets, gross	199	133
Other
Fixed Assets, net [Line Items]
Fixed assets, gross	$ 46	$ 27