Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	$ 834	$ 786	$ 774	$ 738
Capitalized deferred policy acquisition costs	272	271	873	836
Amortized deferred policy acquisition costs	(286)	(270)	(827)	(767)
Shadow deferred policy acquisition costs	(3)	(4)	(3)	(24)
Deferred policy acquisition costs asset, end of period	817	783	817	783
Consolidated Property and Casualty Insurance Entity
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	567	526	512	464
Capitalized deferred policy acquisition costs	258	256	830	790
Amortized deferred policy acquisition costs	(274)	(257)	(791)	(729)
Deferred policy acquisition costs asset, end of period	551	525	551	525
Life Insurance Segment
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	267	260	262	274
Capitalized deferred policy acquisition costs	14	15	43	46
Amortized deferred policy acquisition costs	(12)	(13)	(36)	(38)
Shadow deferred policy acquisition costs	(3)	(4)	(3)	(24)
Deferred policy acquisition costs asset, end of period	$ 266	$ 258	$ 266	$ 258