Other Assets (Summary of Equity Securities without Readily Determinable Fair Value) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Assets [Abstract]
FHLB stock	$ 289,000,000	$ 276,000,000
FRB stock	449,000,000	449,000,000
Equity securities without a readily determinable fair value
Cost basis	89,000,000	87,000,000
Upward adjustments	183,000,000	115,000,000
Downward adjustments (including impairment)	(12,000,000)	(12,000,000)
Carrying amount, equity securities without a readily determinable fair value	260,000,000	190,000,000
Nonmarketable equity investments	998,000,000	915,000,000
Upward adjustments	88,000,000	105,000,000
Downward adjustments (including impairment)	(1,000,000)	(6,000,000)
Impairment of FHLB and FRB stock	0	0
Gain on nonmarketable equity investments, net	$ 142,000,000	$ 99,000,000	$ 9,000,000