Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Statements of Comprehensive Income (Loss)
Net income (loss)	$ (98)	$ (72)
Unrealized gains (losses) on available-for-sale securities: [Abstract]
Unrealized gains (losses) arising during the period	(43)	(40)
Provision (benefit) for income taxes	5	(6)
Total	(48)	(34)
Reclassification adjustments for (gains) losses included in net income (loss)	(1)	(2)
Provision (benefit) for income taxes	0	(1)
Total	(1)	(1)
Available-for-sale securities with other-than-temporary impairments: [Abstract]
Other-than-temporary impairments and unrealized gains (losses) arising during the period	6	13
Provision (benefit) for income taxes	0	5
Total	6	8
Reclassification adjustments for (gains) losses included in net income (loss)	1	2
Provision (benefit) for income taxes	0	1
Total	1	1
Foreign currency translation: [Abstract]
Foreign currency translation gains (losses)	1	144
Provision (benefit) for income taxes	0	21
Total	1	123
Instrument-specific credit risk of liabilities measured at fair value: [Abstract]
Unrealized gains (losses) arising during the period	(14)	0
Total other comprehensive income (loss)	(55)	97
Comprehensive income (loss)	$ (153)	$ 25

Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities with other-than-temporary impairments and for unrealized loss realized upon the write-down of available-for-sale securities.

No definition available.