Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	$ 624	$ 600	$ 616	$ 578
Capitalized deferred policy acquisition costs	227	212	679	640
Deferred Policy Acquisition Cost, Amortization Expense	(222)	(207)	(648)	(620)
Deferred Policy Acquisition Cost, Amortization Expense, Other	(2)	4	(20)	11
Deferred policy acquisition costs asset, end of period	627	609	627	609
Life Insurance Product Line [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	212	210	228	199
Capitalized deferred policy acquisition costs	11	11	35	34
Deferred Policy Acquisition Cost, Amortization Expense	(15)	(10)	(37)	(29)
Deferred Policy Acquisition Cost, Amortization Expense, Other	(2)	4	(20)	11
Deferred policy acquisition costs asset, end of period	206	215	206	215
Consolidated Property and Casualty Insurance Entity
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	412	390	388	379
Capitalized deferred policy acquisition costs	216	201	644	606
Deferred Policy Acquisition Cost, Amortization Expense	(207)	(197)	(611)	(591)
Deferred policy acquisition costs asset, end of period	$ 421	$ 394	$ 421	$ 394