Deferred Policy Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	$ 1,109	$ 1,046	$ 1,013	$ 916
Capitalized deferred policy acquisition costs	365	336	1,166	1,097
Amortized deferred policy acquisition costs	(373)	(349)	(1,078)	(980)
Deferred policy acquisition costs asset, end of period	1,101	1,033	1,101	1,033
Consolidated Property And Casualty Insurance
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	771	723	682	602
Capitalized deferred policy acquisition costs	355	325	1,134	1,064
Amortized deferred policy acquisition costs	(366)	(342)	(1,056)	(960)
Deferred policy acquisition costs asset, end of period	760	706	760	706
Life Insurance Segment
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	338	323	331	314
Capitalized deferred policy acquisition costs	10	11	32	33
Amortized deferred policy acquisition costs	(7)	(7)	(22)	(20)
Deferred policy acquisition costs asset, end of period	$ 341	$ 327	$ 341	$ 327