Loans, Leases and Allowance for Credit Losses - Summary of Recorded Investment in Nonaccrual Loans and Loans Past Due 90 Days Still Accruing Interest by Loan Class (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	$ 247	$ 151
Nonaccrual with an Allowance for Credit Loss	229	122
Total Nonaccrual	476	273
Loans Past Due 90 Days or More and Still Accruing	326	441
Municipal & nonprofit
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	0	0
Nonaccrual with an Allowance for Credit Loss	5	6
Total Nonaccrual	5	6
Loans Past Due 90 Days or More and Still Accruing	0	0
Tech & innovation
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	3	23
Nonaccrual with an Allowance for Credit Loss	57	10
Total Nonaccrual	60	33
Loans Past Due 90 Days or More and Still Accruing	0	0
Other commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	11	19
Nonaccrual with an Allowance for Credit Loss	6	34
Total Nonaccrual	17	53
Loans Past Due 90 Days or More and Still Accruing	0	0
CRE - owner occupied
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	5	8
Nonaccrual with an Allowance for Credit Loss	0	1
Total Nonaccrual	5	9
Loans Past Due 90 Days or More and Still Accruing	0	0
Other CRE - non-owner occupied
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	172	82
Nonaccrual with an Allowance for Credit Loss	71	1
Total Nonaccrual	243	83
Loans Past Due 90 Days or More and Still Accruing	0	0
Residential
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	0	0
Nonaccrual with an Allowance for Credit Loss	88	70
Total Nonaccrual	88	70
Loans Past Due 90 Days or More and Still Accruing	0	0
Mortgage Loans in Process of Foreclosure, Amount	99
Residential - EBO
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	0	0
Nonaccrual with an Allowance for Credit Loss	0	0
Total Nonaccrual	0	0
Loans Past Due 90 Days or More and Still Accruing	326	399
Hotel franchise finance
Financing Receivable, Nonaccrual [Line Items]
Total Nonaccrual	0	0
Construction and land development
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	55	19
Nonaccrual with an Allowance for Credit Loss	1	0
Total Nonaccrual	56	19
Loans Past Due 90 Days or More and Still Accruing	0	42
Equity fund resources
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	0
Nonaccrual with an Allowance for Credit Loss	1
Total Nonaccrual	1	0
Loans Past Due 90 Days or More and Still Accruing	0
Other
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual with No Allowance for Credit Loss	1
Nonaccrual with an Allowance for Credit Loss	0
Total Nonaccrual	1	$ 0
Loans Past Due 90 Days or More and Still Accruing	$ 0