Regulatory Capital Requirements - Schedule of Subsidiaries with Minimum Regulatory Requirements (Details) $ in Millions |
Jun. 30, 2026
USD ($)
|
|---|---|
| StoneX Financial Inc. | |
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] | |
| Actual | $ 981.8 |
| Minimum Requirement | 602.5 |
| StoneX Financial Ltd. | |
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] | |
| Actual | 600.3 |
| Minimum Requirement | 490.8 |
| Gain Capital Group, LLC | |
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] | |
| Actual | 89.3 |
| Minimum Requirement | 29.4 |
| StoneX Financial Pte. Ltd. | |
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] | |
| Actual | 148.0 |
| Minimum Requirement | 36.7 |
| StoneX Markets LLC | |
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] | |
| Actual | 261.4 |
| Minimum Requirement | $ 167.9 |