Principal Components of Net Deferred Tax Balances (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Future policy benefits payable	$ 200	$ 320
Compensation and other accrued expenses	130	168
Benefits payable	267	138
Net operating loss carryforward	47	52
Deferred acquisition costs	64	57
Unearned revenues	22	21
Other	13	17
Total deferred income tax assets	743	773
Valuation allowance	(42)	(48)
Total deferred income tax assets, net of valuation allowance	701	725
Depreciable property and intangible assets	(363)	(346)
Investment securities	(37)	(168)
Prepaid expenses	(45)	(55)
Total deferred income tax liabilities	(445)	(569)
Total net deferred income tax assets	256	156
Other current assets	0	79
Other long-term assets	256	77
Total net deferred income tax assets	$ 256	$ 156