Fair Value Accounting - Schedule of Assets Measured at Fair Value on a Non-Recurring Basis (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Collateral dependent loans, valuation allowance | $ 33 | $ 32 |
| Level 1 | Fair Value, Measurements, Nonrecurring Basis | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Collateral dependent loans | 0 | 0 |
| Other real estate | 0 | 0 |
| Level 2 | Fair Value, Measurements, Nonrecurring Basis | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Collateral dependent loans | 0 | 0 |
| Other real estate | 0 | 0 |
| Level 3 | Fair Value, Measurements, Nonrecurring Basis | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Collateral dependent loans | 106 | 80 |
| Other real estate | $ 30 | $ 8 |