Fair Value Measurements (Details 7) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in fair value of assets and liabilities accounted for using the fair value option	$ (47)	$ 1	$ (95)	$ (40)
Corporate [Member] | Fixed Maturities, FVO [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in fair value of assets and liabilities accounted for using the fair value option	(4)	(1)	(13)	0
Commercial Real Estate collateralized debt obligation [Member] | Fixed Maturities, FVO [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in fair value of assets and liabilities accounted for using the fair value option	(6)	(10)	3	9
Foreign Government Debt Securities [Member] | Fixed Maturities, FVO [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in fair value of assets and liabilities accounted for using the fair value option	(37)	20	(85)	(29)
Credit Linked Notes [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in fair value of assets and liabilities accounted for using the fair value option	$ 0	$ (8)	$ 0	$ (20)