Investments (Schedule of Details Of The Amount Of Credit Losses Of OTTI Recognized In Net Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Amortized Cost	$ 958	$ 976
Gross Unrealized Gains	37	27
Gross Unrealized Losses and OTTI	128	154
Fair Value	867	849
OTTI in Credit Losses	437	424	410	390
Corporate Bonds [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Amortized Cost	290	299
Gross Unrealized Gains	9	4
Gross Unrealized Losses and OTTI	86	98
Fair Value	213	205
OTTI in Credit Losses	108	104
RMBS [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Amortized Cost	630	636
Gross Unrealized Gains	25	22
Gross Unrealized Losses and OTTI	28	40
Fair Value	627	618
OTTI in Credit Losses	234	227
CMBS [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Amortized Cost	38	41
Gross Unrealized Gains	3	1
Gross Unrealized Losses and OTTI	14	16
Fair Value	27	26
OTTI in Credit Losses	$ 95	$ 93