Principles of Consolidation And Other Matters (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating funds related to regulatory requirements or as collateral under captive insurance arrangements	$ 295,000,000			$ 295,000,000		$ 303,000,000
Equity method investments lag period				3 months
Gain on investment income, net	(1,000,000)	$ 13,000,000		$ 27,000,000	$ 43,000,000
Loss on sale of other investments	$ (4,000,000)
Effective tax rate (as a percent)	24.60%	24.20%		24.60%	27.10%
Excess tax benefit related to share-based payments, percent	0.90%	0.90%		1.20%	0.90%
Charge related to revaluation of deferred tax assets and liabilities			$ 100,000,000
Decrease in effective tax rate due to change in U.K. corporate income tax rate, percent					3.10%
Unrecognized tax benefits	$ 107,000,000			$ 107,000,000		$ 94,000,000
Minimum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible decrease in unrecognized tax benefits	0			0
Maximum
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible decrease in unrecognized tax benefits	$ 48,000,000			$ 48,000,000