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Loans and Leases and the Allowance for Credit Losses - Loan and Leases Considered Nonaccrual and Interest Income Recognized on Loans (Detail) - USD ($) $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2024 | Mar. 31, 2023 | Jan. 01, 2024 | Jan. 01, 2023
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | $ 1,232 | $ 986 |  |
Amortized Cost without Allowance | 1,070 | 1,571 |  |
Total | 2,302 | 2,557 |  |
Amortized Cost |  |  | $ 2,166 | $ 2,439
Interest Income Recognized | 13 | 17 |  |
Commercial and Industrial [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 590 | 227 |  |
Amortized Cost without Allowance | 274 | 342 |  |
Total | 864 | 569 |  |
Amortized Cost |  |  | 670 | 504
Interest Income Recognized | 2 | 3 |  |
Commercial [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 379 | 364 |  |
Amortized Cost without Allowance | 476 | 966 |  |
Total | 855 | 1,330 |  |
Amortized Cost |  |  | 869 | 1,240
Interest Income Recognized | 6 | 5 |  |
Residential Builder and Developer [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 3 | 3 |  |
Total | 3 | 3 |  |
Amortized Cost |  |  | 3 | 1
Other Commercial Construction [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 33 | 94 |  |
Amortized Cost without Allowance | 108 | 49 |  |
Total | 141 | 143 |  |
Amortized Cost |  |  | 171 | 125
Interest Income Recognized |  | 2 |  |
Residential [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 82 | 125 |  |
Amortized Cost without Allowance | 120 | 129 |  |
Total | 202 | 254 |  |
Amortized Cost |  |  | 215 | 272
Interest Income Recognized | 3 | 5 |  |
Residential Limited Documentation [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 18 | 40 |  |
Amortized Cost without Allowance | 35 | 29 |  |
Total | 53 | 69 |  |
Amortized Cost |  |  | 55 | 78
Interest Income Recognized | 1 |  |  |
Home Equity Lines and Loans [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 48 | 39 |  |
Amortized Cost without Allowance | 39 | 42 |  |
Total | 87 | 81 |  |
Amortized Cost |  |  | 81 | 85
Interest Income Recognized | 1 | 2 |  |
Recreational Finance [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 18 | 24 |  |
Amortized Cost without Allowance | 12 | 10 |  |
Total | 30 | 34 |  |
Amortized Cost |  |  | 36 | 45
Automobile [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 7 | 23 |  |
Amortized Cost without Allowance | 6 | 4 |  |
Total | 13 | 27 |  |
Amortized Cost |  |  | 14 | 40
Other [Member] |  |  |  |
Financing Receivable, Impaired [Line Items] |  |  |  |
Amortized Cost with Allowance | 54 | 47 |  |
Total | $ 54 | $ 47 |  |
Amortized Cost |  |  | $ 52 | $ 49

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