Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statements of Comprehensive Income (Loss)
Net income (loss)	$ 180	$ 569	$ 250
Unrealized gains (losses) on available-for-sale securities: [Abstract]
Unrealized gains (losses) arising during the period	(80)	254	(213)
Provision (benefit) for income taxes	(27)	83	(76)
Total	(53)	171	(137)
Reclassification adjustments for (gains) losses included in net income (loss)	(7)	15	(13)
Provision (benefit) for income taxes	(3)	6	(5)
Total	(4)	9	(8)
Available-for-sale securities with other-than-temporary impairments: [Abstract]
Other-than-temporary impairments and unrealized gains (losses) arising during the period	(3)	(85)	15
Provision (benefit) for income taxes	(1)	(31)	6
Total	(2)	(54)	9
Reclassification adjustments for (gains) losses included in net income (loss)	4	6	(5)
Provision (benefit) for income taxes	1	2	(2)
Total	3	4	(3)
Foreign currency translation: [Abstract]
Foreign currency translation gains (losses)	(40)	(40)	3
Provision (benefit) for income taxes	(14)	(13)	1
Total	(26)	(27)	2
Reclassification adjustments for (gains) losses included in net income (loss)	0	4	(5)
Provision (benefit) for income taxes	0	0	0
Total	0	4	(5)
Total other comprehensive income (loss)	(82)	107	(142)
Comprehensive income (loss)	$ 98	$ 676	$ 108