Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 129	$ 355	$ 627	$ 556
Unrealized holding gains (losses) arising during the period on:
Investments with no other-than-temporary impairment, net of tax provision (benefit) of $17, $4, $(36) and $74	41	(5)	(77)	164
Investments with other-than-temporary impairment, net of tax provision (benefit) of $(9), $1, $(12) and $(4)	(15)	1	(23)	(8)
Unrealized holding gains (losses) arising during the period, net of tax	26	(4)	(100)	156
Less: reclassification adjustment for gains (losses) included in net income (loss), net of tax provision (benefit) of $(6), $(5), $(4) and $(9)	(12)	(10)	(7)	(19)
Change in net unrealized gains on investments	38	6	(93)	175
Other, net of tax provision	(4)	(5)	(4)	(2)
Other comprehensive income (loss)	34	1	(97)	173
Comprehensive income (loss)	$ 163	$ 356	$ 530	$ 729