Accumulated Other Comprehensive Income (Changes In The Components Of AOCI) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Beginning balance			$ (2)
Other comprehensive income (loss) before reclassifications			136
Amounts reclassified from AOCI			(5)
Total other comprehensive income (loss)	$ 38	$ 107	131	$ 193
Ending balance	129		129
Unrealized gains (losses) on AFS, net [Member]
Beginning balance			112
Other comprehensive income (loss) before reclassifications			88
Amounts reclassified from AOCI			(8)
Total other comprehensive income (loss)			80
Ending balance	192		192
Foreign currency translation, net [Member]
Beginning balance			(7)
Other comprehensive income (loss) before reclassifications			(1)
Amounts reclassified from AOCI			0
Total other comprehensive income (loss)			(1)
Ending balance	(8)		(8)
Instrument-specific credit risk of liabilities measured at fair value, net [Member]
Beginning balance			(107)
Other comprehensive income (loss) before reclassifications			49
Amounts reclassified from AOCI			3
Total other comprehensive income (loss)			52
Ending balance	$ (55)		$ (55)