Investments and Derivative Instruments (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Investments and Derivative Instruments [Abstract]
Document Period End Date					Sep. 30, 2012
Other-Than-Temporary Impairment Losses
Balance as of beginning of period	$ (1,407)		$ (1,933)		$ (1,676)		$ (2,072)
Additions for credit impairments recognized on securities not previously impaired	(5)	[1]	(4)	[1]	(21)	[1]	(40)	[1]
Additions for credit impairments recognized on securities previously impaired	(9)	[1]	(38)	[1]	(19)	[1]	(63)	[1]
Securities that matured or were sold during the period	104		157		392		349
Securities due to an increase in expected cash flows	2		4		9		12
Balance as of end of period	$ (1,315)		$ (1,814)		$ (1,315)		$ (1,814)

[1] These additions are included in the net OTTI losses recognized in earnings in the Condensed Consolidated Statements of Operations.