Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	$ 751	$ 691	$ 738	$ 670
Capitalized deferred policy acquisition costs	295	266	565	511
Amortized deferred policy acquisition costs	(251)	(236)	(497)	(470)
Shadow deferred policy acquisition costs	(9)	7	(20)	17
Deferred policy acquisition costs asset, end of period	786	728	786	728
Consolidated Property and Casualty Insurance Entity
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	485	446	464	438
Capitalized deferred policy acquisition costs	280	251	534	483
Amortized deferred policy acquisition costs	(239)	(225)	(472)	(449)
Deferred policy acquisition costs asset, end of period	526	472	526	472
Life Insurance Segment
Movement Analysis of Deferred Policy Acquisition Costs
Deferred policy acquisition costs asset, beginning of period	266	245	274	232
Capitalized deferred policy acquisition costs	15	15	31	28
Amortized deferred policy acquisition costs	(12)	(11)	(25)	(21)
Shadow deferred policy acquisition costs	(9)	7	(20)	17
Deferred policy acquisition costs asset, end of period	$ 260	$ 256	$ 260	$ 256