Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Property and casualty claim and claim adjustment expense reserves	$ 125	$ 178
Unearned premium reserves	206	230
Receivables	26	30
Employee benefits	407	419
Life settlement contracts	56	48
Deferred retroactive reinsurance benefit	117	84
Net operating loss carryforwards	178	245
Tax credit carryforwards	289	131
Basis differential in investment in subsidiary	17	19
Other	246	282
Total deferred tax assets	1,667	1,666
Valuation allowance	(210)	(147)
Net deferred tax assets	1,457	1,519
Deferred tax liabilities:
Deferred acquisition costs	(120)	(117)
Net unrealized gains	(295)	(166)
Property, plant and equipment	(1,019)	(998)
Basis differential in investment in subsidiary	(409)	(428)
Other liabilities	(235)	(173)
Total deferred tax liabilities	(2,078)	(1,882)
Net deferred tax liabilities	$ (621)	$ (363)