Expenses Associated With Long-Duration Insurance Products - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Long Duration Insurance Products [Line Items]
Percent of consolidated premiums and services revenues related to long-duration insurance products		2.00%
Future policy benefits payable	$ 2,207,000,000	$ 2,349,000,000	$ 2,207,000,000
Benefit expense with future policy benefits payable		32,000,000	354,000,000	136,000,000
Charge related to closed block of long-term care policies	243,000,000		243,000,000	29,000,000
Amortization of deferred acquisition costs		39,000,000	55,000,000	44,000,000
Adjustment to future policy benefits assuming unrealized gains on investments realized and reinvested at current yields		123,000,000	0
Increase in future policy benefits payable	350,000,000		350,000,000
Increase in reinsurance recoverable	107,000,000		107,000,000
Deferred acquisition costs associated with our individual major medical policies	66,000,000	59,000,000	66,000,000
100% Coinsurance Agreements
Long Duration Insurance Products [Line Items]
Future policy benefits payable	215,000,000	210,000,000	215,000,000
Percentage of coinsurance agreement		100.00%
Closed Block Long Term Care Policies
Long Duration Insurance Products [Line Items]
Future policy benefits payable	1,400,000,000	1,500,000,000	1,400,000,000
Individual Major Medical Policies
Long Duration Insurance Products [Line Items]
Future policy benefits payable	$ 327,000,000	$ 297,000,000	$ 327,000,000