Business Segments (Geographic Data) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Total revenues	$ 2,532	$ 2,101	$ 4,670	$ 4,196
Property and equipment, net	767		767		$ 728
United States
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Total revenues	1,905	1,699	3,437	3,401
Property and equipment, net	520		520		500
All other countries
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Total revenues	627	$ 402	1,233	$ 795
Property and equipment, net	$ 247		$ 247		$ 228