Accumulated Other Comprehensive Income (Details Of The Reclassification From AOCI) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 38	$ (55)	$ (17)	$ 20
Income (loss) before income taxes	55	(55)	(101)	150
Provision (benefit) for income taxes	24	(20)	(28)	52
Net income (loss)	31	(35)	(73)	98
Amounts reclassified from AOCI [Member]
Net income (loss)	0	(7)	(5)	(9)
Unrealized gains (losses) on AFS, net [Member] | Amounts reclassified from AOCI [Member]
Net gains (losses) on financial instruments at fair value and foreign exchange	1	(5)	(3)	(6)
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)	0	(3)	0	(3)
Net investment income	0	(1)	(4)	(4)
Income (loss) before income taxes	1	(9)	(7)	(13)
Provision (benefit) for income taxes	1	(2)	(2)	(4)
Net income (loss)	$ 0	$ (7)	$ (5)	$ (9)