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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 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	$ 24	$ 40	$ 37	$ 43
Additions where no OTTI was previously recorded	2	1	9	5
Additions where an OTTI was previously recorded	2	0	5	3
Reductions for securities sold during the period	(11)	(3)	(34)	(13)
Balance of credit losses related to securities still held – end of period	$ 17	$ 38	$ 17	$ 38