Principles of Consolidation and Other Matters (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating funds related to regulatory requirements or as collateral under captive insurance arrangements	$ 507		$ 507		$ 486
Equity method investments lag period (in months)			3 months
Net investment income	$ 1	$ 1	$ 3	$ 6
Effective tax rate (as a percent)	27.30%	20.60%	25.80%	23.70%
Share-based payments of excess tax benefit (as a percent)	0.30%	1.00%	1.30%	1.20%
Valuation allowance		$ 48
Effective tax rate due to change in enacted income tax rate (as a percent)		4.80%		1.10%
Unrecognized tax benefits	$ 122		$ 122		$ 124
Reasonably possible decrease in unrecognized tax benefits	$ 66		$ 66

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