Fair Value Measurements (Details 8) (Fixed Maturities, FVO [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	$ 935	$ 1,010
Corporate [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	89	108
Commercial Real Estate collateralized debt obligation [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	193	193
CMBS Credit [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	6	4
Foreign Government Debt Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	641	699
Municipals [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	1	1
RMBS [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	5	3
U.S. Government [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of assets accounted for using fair value option	$ 0	$ 2