Investments (Details 21) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Total OTTI losses recognized in earnings:
Net investment gains (losses)	$ (6)	$ 64	$ 40	$ (3)
Total gains (losses) on fixed maturity securities:
Other-than-temporary impairments on fixed maturity securities	(19)	(5)	(50)	(35)
Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income (loss)	6	(9)	8	(5)
Total OTTI losses recognized in earnings	(13)	(14)	(42)	(40)
Fixed maturity securities - net gains (losses) on sales and disposals	6	79	84	61
Other net investment gains (losses):
Other securities - FVO general account securities - changes in estimated fair value subsequent to purchase	(1)	0	0	0
Mortgage Loans	0	8	20	26
Real estate and real estate joint ventures	0	(1)	(3)	(1)
Other limited partnership interests	2	(2)	3	(4)
Other investment portfolio gains (losses)	2	(2)	2	(7)
Subtotal - investment portfolio gains (losses)	(3)	67	62	11
FVO consolidated securitization entities - changes in estimated fair value included in net investment gains (losses):
Commercial mortgage loans	9	(64)	8	(39)
Long-term debt - related to commercial mortgage loans	(2)	55	9	44
Other Gains Losses	0	0	0	1
Subtotal consolidated securitizations entities and other gains (losses)	7	(9)	17	6
Total net investment gains (losses)	4	58	79	17
Fixed maturity securities [Member]
Total OTTI losses recognized in earnings:
Net investment gains (losses)	(7)	65	42	21
Total gains (losses) on fixed maturity securities:
Total OTTI losses recognized in earnings	13	14	42	40
Equity Securities [Member]
Total OTTI losses recognized in earnings:
Net investment gains (losses)	$ 1	$ (1)	$ (2)	$ (24)

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