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Regulatory Requirements and Subsidiary Dividend Restrictions - Regulatory Capital Requirements (Details) | Sep. 30, 2021 USD ($)
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StoneX Financial Inc. |
Capital and Other Regulatory Requirements [Line Items] |
Cash and securities segregated under commodity exchange act regulation | $ 4,429,800,000
Secured funds | 216,500,000
Minimum regulatory requirement | 4,364,500,000
Secured funds required under commodity exchange act | 203,100,000
StoneX Financial Ltd. |
Capital and Other Regulatory Requirements [Line Items] |
Cash and securities segregated under commodity exchange act regulation | 1,071,800,000
Minimum regulatory requirement | 1,040,600,000
Gain Capital Group, LLC |
Capital and Other Regulatory Requirements [Line Items] |
Cash and securities segregated under commodity exchange act regulation | 270,700,000
Secured funds | 4,000,000
Minimum regulatory requirement | 255,600,000
Secured funds required under commodity exchange act | 2,100,000
StoneX Financial Pte. Ltd. |
Capital and Other Regulatory Requirements [Line Items] |
Cash and securities segregated under commodity exchange act regulation | 413,700,000
Minimum regulatory requirement | 395,300,000
StoneX Markets LLC |
Capital and Other Regulatory Requirements [Line Items] |
Minimum regulatory capital requirement | $ 100,000,000

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- Definition Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
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