Investments (Components of Net Investment Gains Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Marketable Securities, Gain (Loss) [Abstract]
Fixed maturity securities — net gains (losses) on sales and disposals	$ 176	$ 115	$ 439	$ 383
Equity securities — net gains (losses) on sales and disposals	13	14	32	39
Other net investment gains (losses):
Mortgage loans	(31)	(26)	(193)	(78)
Real estate and real estate joint ventures	(14)	263	33	257
Other limited partnership interests	(9)	(59)	(50)	(52)
Other	(19)	18	(94)	14
Subtotal	97	291	(11)	500
FVO CSEs - changes in estimated fair value subsequent to consolidation:
Commercial mortgage loans	(3)	(4)	(3)	(6)
Securities	1	0	2	0
Long-term debt — related to commercial mortgage loans	1	1	1	3
Non-investment portfolio gains (losses) (1)	161	94	549	38
Subtotal	160	91	549	35
Total net investment gains (losses)	257	382	538	535
Fixed Maturity Securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(14)	(27)	(106)	(47)
Net investment gains (losses)	162	88	333	336
Consumer
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(17)	0	(20)
Industrial
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(3)	(79)	(5)
Communications
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	(3)	0
U.S. corporate and foreign corporate securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(20)	(82)	(25)
RMBS
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(14)	(1)	(22)	(16)
ABS
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	0	(2)	0
State and political subdivision
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(6)	0	(6)
Equity securities
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	(5)	(7)	(72)	(16)
Net investment gains (losses)	8	7	(40)	23
Nonredeemable Preferred Stock [Member]
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	0	(1)	0	(1)
Common Stock
Marketable Securities, Gain (Loss) [Abstract]
Total OTTI losses recognized in earnings	$ (5)	$ (6)	$ (72)	$ (15)