Accumulated Other Comprehensive Income (Changes In The Components Of AOCI) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Beginning balance			$ (156)
Other comprehensive income (loss) before reclassification			107
Amounts reclassified from AOCI			6
Total other comprehensive income (loss)	$ (39)	$ 49	113	$ (20)
Ending balance	(43)		(43)
Unrealized gains (losses) on AFS, net [Member]
Beginning balance			(39)
Other comprehensive income (loss) before reclassification			133
Amounts reclassified from AOCI			(20)
Total other comprehensive income (loss)			113
Ending balance	74		74
Foreign currency translation, net [Member]
Beginning balance			(7)
Other comprehensive income (loss) before reclassification			1
Amounts reclassified from AOCI			0
Total other comprehensive income (loss)			1
Ending balance	(6)		(6)
Instrument-specific credit risk of liabilities measured at fair value, net [Member]
Beginning balance			(110)
Other comprehensive income (loss) before reclassification			(27)
Amounts reclassified from AOCI			26
Total other comprehensive income (loss)			(1)
Ending balance	$ (111)		$ (111)