Investments (Sales or Disposals and Impairments of Fixed Maturity and Equity Securities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Components of Sales or Disposals of Fixed Maturity and Equity Securities
Proceeds	$ 19,636	$ 19,519
Gross investment gains	508	335
Gross investment losses	(145)	(336)
Total OTTI losses recognized in earnings:
Credit-related	(42)	(73)
Other	(39)	(75)
Total OTTI losses recognized in earnings	(81)	(148)
Net investment gains (losses)	282	(149)
Fixed maturity securities [Member]
Components of Sales or Disposals of Fixed Maturity and Equity Securities
Proceeds	19,550	19,394
Gross investment gains	500	325
Gross investment losses	(131)	(332)
Total OTTI losses recognized in earnings:
Credit-related	(42)	(73)
Other	(18)	(60)
Total OTTI losses recognized in earnings	(60)	(133)
Net investment gains (losses)	309	(140)
Equity Securities [Member]
Components of Sales or Disposals of Fixed Maturity and Equity Securities
Proceeds	86	125
Gross investment gains	8	10
Gross investment losses	(14)	(4)
Total OTTI losses recognized in earnings:
Credit-related	0	0
Other	(21)	(15)
Total OTTI losses recognized in earnings	(21)	(15)
Net investment gains (losses)	$ (27)	$ (9)