Economic Dependency and Concentration of Credit Risk (Details) - Community Financial System, Inc. 401(k) Employee Stock Ownership Plan |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Common stock of plan sponsor | ||
| Economic Dependency and Concentration of Credit Risk | ||
| Percentage of investments | 17.00% | 19.00% |
| Mutual funds | Vanguard | ||
| Economic Dependency and Concentration of Credit Risk | ||
| Percentage of investments | 48.00% | 44.00% |
| Mutual funds | JP Morgan | ||
| Economic Dependency and Concentration of Credit Risk | ||
| Percentage of investments | 10.00% | 10.00% |