Investments and Derivative Instruments (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013	Jun. 30, 2012
Other-Than-Temporary Impairment Losses
Balance as of beginning of period	$ (706)		$ (1,233)		$ (813)	$ (1,319)
Additions for credit impairments recognized on securities not previously impaired	(3)	[1]	(4)	[1]	(8)	(17)
Additions for credit impairments recognized on securities previously impaired	0	[1]	(5)	[1]	0	(8)
Securities that matured or were sold during the period	7		82		118	183
Securities due to an increase in expected cash flows	3		2		4	3
Balance as of end of period	$ (699)		$ (1,158)		$ (699)	$ (1,158)

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