Loans - Schedule of Forecasted Economic Scenarios (Detail) - Forecast - United States	Dec. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Third Quarter of 2023
Schedule Of Forecasted Economic Scenarios [Line Items]
Maximum estimated unemployment rate			7.40%
Second Quarter of 2023
Schedule Of Forecasted Economic Scenarios [Line Items]
Maximum decline in gross domestic rate relative to expected rate				2.10%
U.S. unemployment rate
Schedule Of Forecasted Economic Scenarios [Line Items]
Allowance for credit losses forecast model inputs		4.10%		4.00%	3.80%
Growth in U.S. GDP
Schedule Of Forecasted Economic Scenarios [Line Items]
Allowance for credit losses forecast model inputs	1.50%	0.80%			1.50%