Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statements of Comprehensive Income (Loss)
Net income (loss)	$ 31	$ (35)	$ (73)	$ 98
Unrealized gains (losses) on available-for-sale securities: [Abstract]
Unrealized gains (losses) arising during the period	(20)	51	204	(35)
Provision (benefit) for income taxes	(7)	19	72	(11)
Total	(13)	32	132	(24)
Reclassification adjustments for (gains) losses included in net income (loss)	(1)	6	7	10
Provision (benefit) for income taxes	(1)	1	2	3
Total	0	5	5	7
Available-for-sale securities with other-than-temporary impairments: [Abstract]
Other-than-temporary impairments and unrealized gains (losses) arising during the period	0	(1)	7	(5)
Provision (benefit) for income taxes	0	(1)	2	(2)
Total	0	0	5	(3)
Reclassification adjustments for (gains) losses included in net income (loss)	0	3	0	3
Provision (benefit) for income taxes	0	1	0	1
Total	0	2	0	2
Foreign currency translation: [Abstract]
Foreign currency translation gains (losses)	(15)	(18)	(70)	(19)
Provision (benefit) for income taxes	(5)	(5)	(24)	(6)
Total	(10)	(13)	(46)	(13)
Total other comprehensive income (loss)	(23)	26	96	(31)
Comprehensive income (loss)	$ 8	$ (9)	$ 23	$ 67