Investments (Components of Net Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	$ (9)	$ (13)	$ (23)	$ (48)
Fixed maturity securities - net gains (losses) on sales and disposals	(50)	6	33	84
Equity securities - net gains (losses) on sales and disposals	(2)	1	4	4
Net investment gains (losses)	(61)	(6)	14	40
Other net investment gains (losses):
FVO securities - FVO general account securities - changes in estimated fair value	0	(1)	0	0
Mortgage Loans	(1)	0	0	20
Real estate and real estate joint ventures	0	0	0	(3)
Other limited partnership interests	0	2	1	3
Other investment portfolio gains (losses)	1	2	2	2
Subtotal - investment portfolio gains (losses)	(61)	(3)	17	62
FVO CSEs - changes in estimated fair value:
Commercial mortgage loans	(14)	9	(50)	8
Long-term debt - related to commercial mortgage loans	18	(2)	68	9
Non-investment portfolio gains (losses)	6	0	(4)	0
Subtotal FVO CSEs and non-investment portfolio gains (losses)	10	7	14	17
Total net investment gains (losses)	(51)	4	31	79
Fixed maturity securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(9)	(13)	(20)	(42)
Net investment gains (losses)	(59)	(7)	13	42
Finance Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	(3)	(7)
Utility Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	0	(3)
Communications Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	0	(2)
Industrial Domestic Corporate Debt Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	0	(1)
Other Industries [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(3)	(10)	(3)	(16)
Corporate fixed maturity securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(3)	(10)	(6)	(29)
RMBS [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(6)	(3)	(14)	(13)
Equity Securities [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	(3)	(6)
Net investment gains (losses)	(2)	1	1	(2)
Non-redeemable preferred stock [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	(3)	0
Common Stock [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	$ 0	$ 0	$ 0	$ (6)