Other Assets (Summary of Equity Securities without Readily Determinable Fair Value) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Other Assets [Abstract]
FHLB stock	$ 407,000,000		$ 289,000,000
FRB stock	449,000,000		449,000,000
Equity securities without a readily determinable fair value
Cost basis	90,000,000		89,000,000
Upward adjustments	183,000,000		183,000,000
Downward adjustments (including impairment)	(13,000,000)		(12,000,000)
Carrying amount, equity securities without a readily determinable fair value	260,000,000		260,000,000
Nonmarketable equity investments	1,116,000,000		$ 998,000,000
Upward adjustments	1,000,000	$ 2,000,000
Downward adjustments (including impairment)	(2,000,000)	(1,000,000)
Impairment of FHLB and FRB stock	0	0
(Loss) gain on nonmarketable equity investments, net	$ (1,000,000)	$ 4,000,000