Accumulated Other Comprehensive Income (Details Of The Reclassification From AOCI) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 84	$ 63	$ 78
Income (loss) before income taxes	(339)	289	641
Provision (benefit) for income taxes	(1)	109	72
Net income (loss)	(338)	180	569
Amounts reclassified from AOCI [Member]
Net income (loss)	(1)	1	(17)
Unrealized gains (losses) on AFS, net [Member] | Amounts reclassified from AOCI [Member]
Net gains (losses) on financial instruments at fair value and foreign exchange	7	11	(17)
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)	(4)	(4)	0
Net investment income	(6)	(4)	(4)
Income (loss) before income taxes	(3)	3	(21)
Provision (benefit) for income taxes	(2)	2	(8)
Net income (loss)	(1)	1	(13)
Foreign currency translation, net [Member] | Amounts reclassified from AOCI [Member]
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 0	$ 0	$ (4)