Investments (Details 24) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	$ (351)	$ (1,015)	$ (484)
Fixed maturity securities - net gains (losses) on sales and disposals	253	25	215
Equity securities - net gains (losses) on sales and disposals	38	37	118
Net investment gains (losses)	(60)	(953)	(151)
Other net investment gains (losses):
Trading and other securities FVO general account securities - changes in estimated fair value	17	(2)	0
Mortgage Loans	57	175	22
Real estate and real estate joint ventures	(36)	134	(54)
Other limited partnership interests	(36)	4	(18)
Other investment portfolio gains (losses)	(151)	(7)	(6)
Subtotal - investment portfolio gains (losses)	(209)	(649)	(207)
FVO CSEs - changes in estimated fair value subsequent to consolidation:
Commercial mortgage loans	7	(84)	758
Trading securities	0	0	(78)
Long-term debt - related to commercial mortgage loans	25	97	(722)
Long-term debt - related to trading securities	(7)	(8)	48
Non-investment portfolio gains (losses)	(168)	(223)	(207)
Subtotal FVO CSEs and non-investment portfolio gains (losses)	(143)	(218)	(201)
Total net investment gains (losses)	(352)	(867)	(408)
Fixed maturity securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(317)	(955)	(470)
Net investment gains (losses)	(64)	(930)	(255)
Utility Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(61)	(10)	(3)
Finance Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(32)	(56)	(126)
Consumer Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(19)	(50)	(36)
Communications Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(19)	(41)	(16)
Transportation Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(17)	0	0
Technology Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(6)	(1)	0
Industrial Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(5)	(11)	(2)
Corporate fixed maturity securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(159)	(169)	(183)
RMBS [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(97)	(214)	(117)
CMBS [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(51)	(32)	(86)
ABS [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(9)	(54)	(84)
State and political subdivision securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(1)	0	0
Foreign government debt securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(486)	0
Equity Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(34)	(60)	(14)
Net investment gains (losses)	4	(23)	104
Non-redeemable preferred stock [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(38)	(7)
Common Stock
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	$ (34)	$ (22)	$ (7)

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