Accumulated Other Comprehensive Income (Changes In The Components Of AOCI) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Beginning balance	$ 21	$ (86)	$ 56
Other comprehensive income (loss) before reclassification	(81)	90	(126)
Amounts reclassified from AOCI	(1)	17	(16)
Total other comprehensive income (loss)	(82)	107	(142)
Ending balance	(61)	21	(86)
Unrealized gains (losses) on AFS, net [Member]
Beginning balance	34	(96)	43
Other comprehensive income (loss) before reclassification	(55)	117	(128)
Amounts reclassified from AOCI	(1)	13	(11)
Total other comprehensive income (loss)	(56)	130	(139)
Ending balance	(22)	34	(96)
Foreign currency translation, net [Member]
Beginning balance	(13)	10	13
Other comprehensive income (loss) before reclassification	(26)	(27)	2
Amounts reclassified from AOCI	0	4	(5)
Total other comprehensive income (loss)	(26)	(23)	(3)
Ending balance	$ (39)	$ (13)	$ 10