Invested Assets and Related Income - Sources of Net Investment Income (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gross investment income	$ 1,465	$ 1,556	$ 1,644
Investment Expenses	49	38	39
Net Investment income	1,416	1,518	1,605
Fixed Maturities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gross investment income	1,380	1,465	1,549
Equity Securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gross investment income	38	40	34
Short Term Investments [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gross investment income	16	18	16
Other [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gross investment income	$ 31	$ 33	$ 45