Deposits - Time Certificate Denominations and Overdrawn Accounts (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Deposits. | ||
| Time certificates of deposit in denominations of $250,000 or more, in the aggregate | $ 1,400.0 | $ 1,500.0 |
| Overdrawn deposit accounts classified as loans | $ 2.8 | $ 3.2 |