Investments (Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which Portion Of Other-Than-Temporary Impairment Was Recognized In Other Comprehensive Income) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments, Debt and Equity Securities [Abstract]
Document Fiscal Year Focus			2013
Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which Portion Of Other-Than-Temporary Impairment Was Recognized In Other Comprehensive Income [Roll Forward]
Balance of credit losses related to securities still held – beginning of period	$ 40	$ 47	$ 43	$ 74
Additions where no OTTI was previously recorded	1	1	5	3
Additions where an OTTI was previously recorded	0	6	3	11
Reductions for securities sold during the period	(3)	(4)	(13)	(38)
Balance of credit losses related to securities still held – end of period	$ 38	$ 50	$ 38	$ 50