Intangible Assets and Goodwill (Schedule of Components of Intangible Assets) (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Intangible Assets [Line Items] | ||
| Assigned Value | $ 4,833.3 | $ 4,839.4 |
| Accumulated Amortization | (2,843.2) | (2,678.7) |
| Net Book Value | 1,990.1 | 2,160.7 |
| Total intangible assets – other, net | 2,440.1 | 2,610.7 |
| Trading products | 17,175.3 | 17,175.3 |
| Trade names | ||
| Intangible Assets [Line Items] | ||
| Trade names | 450.0 | 450.0 |
| Clearing firm, market data and other customer relationships | ||
| Intangible Assets [Line Items] | ||
| Assigned Value | 4,697.1 | 4,703.0 |
| Accumulated Amortization | (2,716.6) | (2,557.5) |
| Net Book Value | 1,980.5 | 2,145.5 |
| Technology-related intellectual property | ||
| Intangible Assets [Line Items] | ||
| Assigned Value | 62.5 | 62.5 |
| Accumulated Amortization | (62.5) | (62.5) |
| Net Book Value | 0.0 | 0.0 |
| Other | ||
| Intangible Assets [Line Items] | ||
| Assigned Value | 73.7 | 73.9 |
| Accumulated Amortization | (64.1) | (58.7) |
| Net Book Value | $ 9.6 | $ 15.2 |
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- Definition Intangible assets, Trading Products No definition available.
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- Definition Amount of accumulated amortization of finite-lived intangible asset. Excludes goodwill and capitalized cost for software to be sold, leased, or marketed. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount, before accumulated amortization, of finite-lived intangible asset. Excludes goodwill and capitalized cost for software to be sold, leased, or marketed. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount, after accumulated amortization, of finite-lived intangible asset. Excludes goodwill and capitalized cost for software to be sold, leased, or marketed. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of indefinite-lived intangible asset. Excludes goodwill. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount after impairment of indefinite-lived intangible assets classified as other. Excludes financial assets and goodwill. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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