Investments (Details 11) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Other details of unrealized loss
Unrealized losses related to securities with unrealized loss position less than 20% of cost or amortized cost	$ 837		$ 837
Unrealized losses related to securities with unrealized loss position greater than 20% of cost or amortized cost	1,310		1,310
Limited partnership impairment
Limited partnership interests	4,407		4,407		3,816
Write-downs of limited partnership	197	99	435	637
Equity-method limited partnership interests
Limited partnership impairment
Limited partnership interests	2,960		2,960		2,470
Write-downs of limited partnership				1
Cost-method limited partnership interests
Limited partnership impairment
Limited partnership interests	1,450		1,450		1,350
Write-downs of limited partnership	2	10	4	41
Fixed income securities
Limited partnership impairment
Write-downs of limited partnership	80	72	268	494
Investment grade fixed income securities
Other details of unrealized loss
Unrealized losses related to securities with unrealized loss position less than 20% of cost or amortized cost	422		422
Unrealized losses related to securities with unrealized loss position greater than 20% of cost or amortized cost	488		488
Below investment grade fixed income securities
Other details of unrealized loss
Unrealized losses related to securities with unrealized loss position less than 20% of cost or amortized cost	415		415
Unrealized losses related to securities with unrealized loss position greater than 20% of cost or amortized cost	668		668
Unrealized losses related to securities with unrealized loss position greater than 20% of cost or amortized cost, unrealized loss position of 12 or more consecutive months	512		512
Equity securities
Other details of unrealized loss
Unrealized losses related to securities with unrealized loss position greater than 20% of cost or amortized cost	159		159
Limited partnership impairment
Write-downs of limited partnership	$ 81	$ 14	$ 114	$ 51