Expenses Associated With Long-Duration Insurance Products - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Long Duration Insurance Products [Line Items]
Percent of consolidated premiums and services revenues related to long-duration insurance products	1.00%
Future policy benefits payable	$ 2,151,000,000	$ 2,349,000,000
Benefit expense with future policy benefits payable	(80,000,000)	32,000,000	$ 354,000,000
Amortization of deferred acquisition costs	63,000,000	39,000,000	55,000,000
Adjustment to future policy benefits assuming unrealized gains on investments realized and reinvested at current yields	0	123,000,000
Increase in future policy benefits payable			350,000,000
Increase in reinsurance recoverable			107,000,000
Deferred acquisition costs associated with our individual major medical policies	26,000,000	59,000,000
100% Coinsurance Agreements
Long Duration Insurance Products [Line Items]
Future policy benefits payable	$ 205,000,000	210,000,000
Percentage of coinsurance agreement	100.00%
Closed Block Long Term Care Policies
Long Duration Insurance Products [Line Items]
Future policy benefits payable	$ 1,500,000,000	1,500,000,000	$ 243,000,000
Individual Major Medical Policies
Long Duration Insurance Products [Line Items]
Future policy benefits payable	$ 180,000,000	$ 297,000,000