Investments (Details 6) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	$ (25)	$ (9)	$ (41)	$ (51)
Portion of loss recognized in other comprehensive income	8	(4)	(2)	(4)
Net other-than-temporary impairment losses recognized in earnings	(17)	(13)	(43)	(55)
Fixed income securities
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(13)	(5)	(39)	(51)
Portion of loss recognized in other comprehensive income	8	(4)	(2)	(4)
Net other-than-temporary impairment losses recognized in earnings	(5)	(9)	(41)	(55)
Municipal
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses			(8)
Net other-than-temporary impairment losses recognized in earnings			(8)
ABS
Other-than-temporary impairment losses by asset type
Portion of loss recognized in other comprehensive income			(1)
Net other-than-temporary impairment losses recognized in earnings			(1)
Corporate
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses				(14)
Portion of loss recognized in other comprehensive income		(2)		(2)
Net other-than-temporary impairment losses recognized in earnings		(2)		(16)
RMBS
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(5)	(1)	(4)	(18)
Portion of loss recognized in other comprehensive income	4	(5)	3	(8)
Net other-than-temporary impairment losses recognized in earnings	(1)	(6)	(1)	(26)
CMBS
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(8)	(4)	(27)	(19)
Portion of loss recognized in other comprehensive income	4	3	(4)	6
Net other-than-temporary impairment losses recognized in earnings	(4)	(1)	(31)	(13)
Mortgage loans
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(6)	(1)	11	3
Net other-than-temporary impairment losses recognized in earnings	(6)	(1)	11	3
Equity securities
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(4)	(1)	(5)	(1)
Net other-than-temporary impairment losses recognized in earnings	(4)	(1)	(5)	(1)
Limited partnership interests
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(1)		(5)	(2)
Net other-than-temporary impairment losses recognized in earnings	(1)		(5)	(2)
Other
Other-than-temporary impairment losses by asset type
Total other-than-temporary impairment losses	(1)	(2)	(3)
Net other-than-temporary impairment losses recognized in earnings	$ (1)	$ (2)	$ (3)