Accumulated Other Comprehensive Income (Changes In The Components Of AOCI) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Beginning balance			$ 115
Other comprehensive income (loss) before reclassifications			(28)
Amounts reclassified from AOCI			16
Total other comprehensive income (loss)	$ 64	$ 38	(12)	$ 131
Ending balance	103		103
Unrealized gains (losses) on AFS, net [Member]
Beginning balance			176
Other comprehensive income (loss) before reclassifications			(32)
Amounts reclassified from AOCI			(8)
Total other comprehensive income (loss)			(40)
Ending balance	136		136
Foreign currency translation, net [Member]
Beginning balance			(10)
Other comprehensive income (loss) before reclassifications			3
Amounts reclassified from AOCI			0
Total other comprehensive income (loss)			3
Ending balance	(7)		(7)
Instrument-specific credit risk of liabilities measured at fair value, net [Member]
Beginning balance			(51)
Other comprehensive income (loss) before reclassifications			1
Amounts reclassified from AOCI			24
Total other comprehensive income (loss)			25
Ending balance	$ (26)		$ (26)