Investments (Components of Net Investment Gains Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Marketable Securities, Gain (Loss) [Abstract]
Fixed maturity securities — net gains (losses) on sales and disposals	$ 115	$ 184	$ 383	$ 349
Equity securities — net gains (losses) on sales and disposals	14	15	39	99
Other net investment gains (losses):
FVO and trading securities — FVO general account securities	0	0	0	8
Mortgage loans	(26)	(30)	(78)	(25)
Real estate and real estate joint ventures	263	86	257	150
Other limited partnership interests	(59)	(14)	(52)	(52)
Other investment portfolio gains (losses)	18	(20)	14	(26)
Subtotal — investment portfolio gains (losses)	291	189	500	412
FVO CSEs - changes in estimated fair value subsequent to consolidation:
Commercial mortgage loans	(4)	1	(6)	(14)
Long-term debt — related to commercial mortgage loans	1	3	3	21
Long-term debt — related to securities	0	(1)	0	(1)
Non-investment portfolio gains (losses)	94	(83)	38	(845)
Subtotal FVO CSEs and non-investment portfolio gains (losses)	91	(80)	35	(839)
Total net investment gains (losses)	382	109	535	(427)
Fixed Maturity Securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(27)	(31)	(47)	(56)
Net investment gains (losses)	88	153	336	293
Consumer
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(17)	0	(20)	(7)
Transportation
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	0	(2)
Industrial
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(3)	0	(5)	0
Corporate fixed maturity securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(20)	0	(25)	(9)
RMBS
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(1)	(18)	(16)	(27)
ABS
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	0	(7)
CMBS
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(13)	0	(13)
State and political subdivision
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(6)	0	(6)	0
Equity securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(7)	(1)	(16)	(35)
Net investment gains (losses)	7	14	23	64
Non-redeemable preferred stock
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(1)	0	(1)	(23)
Common Stock
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	$ (6)	$ (1)	$ (15)	$ (12)