Principles of Consolidation and Other Matters (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating funds related to regulatory requirements or as collateral under captive insurance arrangements	$ 542		$ 542		$ 455
Equity method investments lag period (in months)			3 months
Net investment income	$ 15	$ 1	$ 27	$ 3
Effective tax rate (as a percent)	25.10%	27.30%	24.20%	25.80%
Share-based payments of excess tax benefit (as a percent)	0.30%	0.30%	1.00%	1.30%
Unrecognized tax benefits	$ 113		$ 113		$ 112
Reasonably possible decrease in unrecognized tax benefits	$ 69		$ 69

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Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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Amount of realized and unrealized gain (loss) on investment.

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Amount of cash restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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Amount of unrecognized tax benefits.

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