Accumulated Other Comprehensive Income (Changes In The Components Of AOCI) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Beginning balance			$ (2)
Other comprehensive income (loss) before reclassifications			144
Amounts reclassified from AOCI			(12)
Total other comprehensive income (loss)	$ 1	$ (51)	132	$ 142
Ending balance	130		130
Unrealized gains (losses) on AFS, net [Member]
Beginning balance			112
Other comprehensive income (loss) before reclassifications			93
Amounts reclassified from AOCI			(17)
Total other comprehensive income (loss)			76
Ending balance	188		188
Foreign currency translation, net [Member]
Beginning balance			(7)
Other comprehensive income (loss) before reclassifications			(3)
Amounts reclassified from AOCI			0
Total other comprehensive income (loss)			(3)
Ending balance	(10)		(10)
Instrument-specific credit risk of liabilities measured at fair value, net [Member]
Beginning balance			(107)
Other comprehensive income (loss) before reclassifications			54
Amounts reclassified from AOCI			5
Total other comprehensive income (loss)			59
Ending balance	$ (48)		$ (48)