Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement of Other Comprehensive Income [Abstract]
Net income (loss)	$ (144)	$ (483)
Investments with no other-than-temporary impairment, net of tax provision (benefit) of $(19) and $19	(50)	42
Investments with other-than-temporary impairment, net of tax provision (benefit) of $(8) and $(7)	(16)	(14)
Unrealized holding gains (losses) arising during the period, net of tax	(66)	28
Less: reclassification adjustment for gains (losses) included in net income (loss), net of tax provision (benefit) of $(2) and $(1)	(3)	(1)
Change in net unrealized gains on investments	(63)	29
Other, net of tax provision	(5)	2
Other comprehensive income (loss)	(68)	31
Comprehensive income (loss)	$ (212)	$ (452)