Loans - Summary of Nonaccrual Loans (Detail) - USD ($) $ in Millions |
Mar. 31, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | $ 3,623 | $ 3,387 |
| Total divided by gross loans at amortized cost | 1.60% | 1.60% |
| Nonaccrual loans allowance for loans losses divided by total | 64.70% | 63.40% |
| Past due | ||
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | $ 730 | $ 756 |
| Corporate | ||
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | 1,955 | 2,065 |
| Commercial real estate | ||
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | 1,213 | 1,079 |
| Residential real estate | ||
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | 80 | 85 |
| Other collateralized | ||
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | 349 | 121 |
| Other | ||
| Financing Receivable, Impaired [Line Items] | ||
| Nonaccrual loans | $ 26 | $ 37 |