Investment Securities (Narrative) (Detail)	3 Months Ended
	Mar. 31, 2023 USD ($) security	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Investments, Debt and Equity Securities [Abstract]
Equity securities without readily determinable fair value	$ 52,500,000
Upward adjustments of equity securities without readily determinable fair values	0	$ 0
Downward adjustments of equity securities without readily determinable fair values	0	0
Impairment of equity securities without readily determinable fair values	0	571,000
Pledged securities	$ 5,700,000,000	$ 2,500,000,000	$ 2,800,000,000
Number of securities by a single non-government sponsored issuer exceeding 10% of shareholders' equity | security	0