Investments (Fixed Maturities Proceeds)(Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Fixed maturity and equity security impairments
Net writedowns for other-than-temporary impairment losses on fixed maturities recognized in earnings	$ 33	[1]	$ 93	[1]	$ 103	[1]	$ 205	[1]
Writedowns for impairments on equity securities	1		41		8		90
Equity Securities [Member]
Available For Sale
Gross investment gains from sales	124		92		231		214
Available-for-sale Securities, Gross Realized Losses	(29)		(75)		(52)		(161)
Equity securities, available for sale
Proceeds From Sale Of Available For Sale Securities Equity Including Not Settled	1,137		1,068		2,185		2,150
Fixed Maturities, Available For Sale [Member]
Available For Sale
Proceeds from sales	8,139		3,795		14,634		9,458
Proceeds from maturities/repayments	6,705		5,296		12,444		10,285
Gross investment gains from sales	413		141		642		268
Available-for-sale Securities, Gross Realized Losses	(88)		(80)		(194)		(158)
Fixed Maturities, Held To Maturity [Member]
Fixed maturities, held to maturity
Proceeds from maturities/repayments	148		124		273		247
Gross investment gains from prepayments	$ 0		$ 0		$ 0		$ 0

[1] Excludes the portion of other-than-temporary impairments recorded in “Other comprehensive income (loss),” representing any difference between the fair value of the impaired debt security and the net present value of its projected future cash flows at the time of impairment.