Investments (Net Unrealized Gains Losses on Investments by Asset Class) (Details) (USD $) In Millions	Sep. 30, 2011		Dec. 31, 2010
Net unrealized gains (losses) on investments	$ 13,838		$ 8,412
Net unrealized losses on held to maturity securities transferred from available-for-sale	125
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Net unrealized gains (losses) on investments	(102)	[1]	(262)	[1]
Securities Related to Other Than Temporary Impairments [Member] | Fixed Maturities [Member]
Net unrealized gains (losses) on investments	(1,027)		(849)
Available-for-sale Securities [Member] | Fixed Maturities [Member]
Net unrealized gains (losses) on investments	14,605		8,078
Available-for-sale Securities [Member] | Equity Securities [Member]
Net unrealized gains (losses) on investments	380		1,272
Other Long-term Investments [Member]
Net unrealized gains (losses) on investments	$ (18)	[2]	$ 173

[1] See Note 14 for more information on cash flow hedges.

[2] As of September 30, 2011, includes $125 million of net unrealized losses on held to maturity securities that were previously transferred from available for sale. Also includes net unrealized gains on certain joint ventures that are included in “Other assets.”