Accumulated Other Comprehensive Income (Changes In The Components Of AOCI) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Beginning balance	$ (2)
Other comprehensive income (loss) before reclassifications	94
Amounts reclassified from AOCI	(1)
Total other comprehensive income (loss)	93	$ 86
Ending balance	91
Unrealized gains (losses) on AFS, net [Member]
Beginning balance	112
Other comprehensive income (loss) before reclassifications	48
Amounts reclassified from AOCI	(3)
Total other comprehensive income (loss)	45
Ending balance	157
Foreign currency translation, net [Member]
Beginning balance	(7)
Other comprehensive income (loss) before reclassifications	0
Amounts reclassified from AOCI	0
Total other comprehensive income (loss)	0
Ending balance	(7)
Instrument-specific credit risk of liabilities measured at fair value, net [Member]
Beginning balance	(107)
Other comprehensive income (loss) before reclassifications	46
Amounts reclassified from AOCI	2
Total other comprehensive income (loss)	48
Ending balance	$ (59)