Commitments and Contingencies - Summary of Contractual Amounts for Unfunded Commitments and Letters of Credit (Detail) - USD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Other Commitments [Line Items] | ||
| Total amount | $ 14,826 | $ 14,568 |
| Commitments to extend credit | ||
| Other Commitments [Line Items] | ||
| Unsecured loan commitments | 1,063 | 860 |
| Total amount | 13,612 | 13,546 |
| Credit card guarantees | ||
| Other Commitments [Line Items] | ||
| Total amount | 702 | 585 |
| Standby letters of credit | ||
| Other Commitments [Line Items] | ||
| Unsecured letters of credit | 2 | 2 |
| Total amount | $ 512 | $ 437 |