Other Assets (Summary of Equity Securities without Readily Determinable Fair Value) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Other Assets [Abstract]
FHLB stock	$ 571,000,000		$ 571,000,000		$ 289,000,000
FRB stock	439,000,000		439,000,000		449,000,000
Equity investments without a readily determinable fair value
Cost basis at acquisition	86,000,000		86,000,000		89,000,000
Upward adjustments	178,000,000		178,000,000		183,000,000
Downward adjustments (including impairment)	(144,000,000)		(144,000,000)		(12,000,000)
Carrying amount, equity investments without a readily determinable fair value	120,000,000		120,000,000		260,000,000
Nonmarketable equity investments	1,130,000,000		1,130,000,000		$ 998,000,000
Upward adjustments	0	$ 1,000,000	1,000,000	$ 83,000,000
Downward adjustments (including impairment)	(137,000,000)	0	(140,000,000)	(1,000,000)
Impairment of FHLB and FRB stock	$ 0	$ 0	$ 0	$ 0