Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	$ 637	$ 616
Capitalized deferred policy acquisition costs	239	222
Deferred Policy Acquisition Cost, Amortization Expense	(214)	(212)
Deferred Policy Acquisition Cost, Amortization Expense, Other	(2)	(8)
Deferred policy acquisition costs asset, end of period	660	618
Life Insurance Product Line [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	229	228
Capitalized deferred policy acquisition costs	13	12
Deferred Policy Acquisition Cost, Amortization Expense	(8)	(11)
Deferred Policy Acquisition Cost, Amortization Expense, Other	(2)	(8)
Deferred policy acquisition costs asset, end of period	232	221
Consolidated Property and Casualty Insurance Entity
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	408	388
Capitalized deferred policy acquisition costs	226	210
Deferred Policy Acquisition Cost, Amortization Expense	(206)	(201)
Deferred policy acquisition costs asset, end of period	$ 428	$ 397