v2.4.0.8
Investments (Narrative) (Detail) (USD $)
 3 Months Ended 9 Months Ended
Sep. 30, 2014
Security
Sep. 30, 2013
Sep. 30, 2014
Security
Sep. 30, 2013
Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]          
Non-cash exchange of securities $ 219,000,000        
Fair value of securities transferred from AFS to HTM 2,000,000,000   2,000,000,000    
Net unrealized appreciation (depreciation) included in OCI (1,000,000) 1,000,000 (6,000,000) (24,000,000)  
Net unrealized depreciation included in AOCI         4,000,000
Percentage of mortgage-backed securities represented by investments in US government agency bonds 83.00%   83.00%   83.00%
Credit losses recognized in net income for corporate securities 4,000,000 1,000,000 14,000,000 8,000,000  
Credit losses recognized in net income for mortgage-backed securities 0 0 0 0  
Number of fixed maturities in an unrealized loss position 5,799   5,799    
Total number of fixed maturities 25,735   25,735    
Largest single unrealized loss in the fixed maturities 3,000,000   3,000,000    
Number of equity securities in an unrealized loss position 64   64    
Total number of equity securities 238   238    
Largest single unrealized loss in the equity securities 1,000,000   1,000,000    
Restricted assets in fixed maturities and short-term investments 15,700,000,000   15,700,000,000   16,300,000,000
Restricted assets in cash $ 72,000,000   $ 72,000,000   $ 162,000,000
Moodys Historical Mean Recovery Rate     42.00%    
Company Assumed Recovery Rate     32.00%