Investments (Components Of Other-Than-Temporary Impairment ("OTTI") Losses Recognized In Earnings By Asset Type) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	$ 216	$ 232	$ 1,352
Corporate And Other Bonds [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	95	68	357
States, Municipalities And Political Subdivisions [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings		62	79
Residential Mortgage-Backed [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	105	71	461
Commercial Mortgage-Backed [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings		3	193
Other Asset-Backed [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	6	3	31
Asset-Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	111	77	685
Redeemable Preferred Stock [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings			9
Fixed Maturity Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	206	207	1,130
Common Stock [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	8	11	5
Preferred Stock [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	1	14	217
Short Term Investments [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	1
Equity Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	$ 9	$ 25	$ 222