Fair Value Measurements (Fair Value And Maximum Future Funding Commitments Related To Investments) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fair Value
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]
Financial	$ 256	$ 225
Real estate	322	292
Distressed	180	192
Mezzanine	276	284
Traditional	813	711
Vintage	13	14
Investment funds	428	395
Total of alternative investments	2,288	2,113
Maximum Future Funding Commitments
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]
Financial	129	111
Real estate	92	62
Distressed	230	152
Mezzanine	252	279
Traditional	456	587
Vintage
Investment funds
Total of alternative investments	$ 1,159	$ 1,191
Expected Liquidation Period Lower Range
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]
Liquidation period for financial alternative investments	5 years	5 years
Liquidation period for real estate alternative investments	3 years	3 years
Liquidation period for distressed alternative investments	6 years	6 years
Liquidation period for mezzanine alternative investments	6 years	6 years
Liquidation period for traditional alternative investments	3 years	3 years
Liquidation period for vintage alternative investments	1 year	1 year
Expected Liquidation Period Upper Range
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]
Liquidation period for financial alternative investments	9 years	9 years
Liquidation period for real estate alternative investments	9 years	9 years
Liquidation period for distressed alternative investments	9 years	9 years
Liquidation period for mezzanine alternative investments	9 years	9 years
Liquidation period for traditional alternative investments	8 years	8 years
Liquidation period for vintage alternative investments	3 years	3 years