Investments (Details 6) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	$ 233		$ 236		$ 128
Realized - impairments	(12)		(26)		(52)
Fixed maturities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	36		55		68
Realized - impairments	(5)		(9)		(57)
Change in unrealized	(945)		790		407
Equity securities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	196		192		88
Realized - impairments	(5)		(24)		(6)
Change in unrealized	31		(23)		(48)
Mortgage Loans and Other Investments [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	2		(3)		(24)
Realized - impairments	(5)		0		(5)
Change in unrealized	0		0		0
Other [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(1)	[1]	(8)	[1]	(4)	[1]
Realized - impairments	3	[1]	7	[1]	16	[1]
Change in unrealized	504	[1]	(379)	[1]	(218)	[1]
Tax Effects [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(82)		(83)		(45)
Realized - impairments	4		9		18
Change in unrealized	144		(136)		(49)
Noncontrolling Interests [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(2)		(2)		(2)
Realized - impairments	0		0		1
Change in unrealized	6		(7)		(5)
Marketable Securities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	149		151		81
Realized - impairments	(8)		(17)		(33)
Change in unrealized	$ (260)		$ 245		$ 87

[1] Primarily adjustments to deferred policy acquisition costs and reserves related to annuities and long-term care business.