Investment Securities (Narrative) (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Fair Value	$ 7,892,697,000	$ 4,234,854,000
Increase In Available For Sale Debt Securities	830,100,000
Interest Receivable	226,300,000	50,700,000
Debt Maturity, Held-to-Maturity, Non-Accrual	0	0
Callable [Member]
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Fair Value	2,900,000,000
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss	900,000,000
Held-to-maturity Securities [Member]
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Interest Receivable	$ 24,200,000	$ 21,200,000