Securities and Commodity Financing Transactions - Netting of Securities Purchased Under Agreements (Details) - USD ($) $ in Millions |
Mar. 31, 2025 |
Sep. 30, 2024 |
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| Broker-Dealer [Abstract] | ||
| Securities purchased under agreements to resell, gross | $ 19,826.2 | $ 13,148.1 |
| Securities purchased under agreements to resell, offset | (12,908.6) | (7,946.6) |
| Securities purchased under agreements to resell, net | 6,917.6 | 5,201.5 |
| Securities borrowed, gross | 1,803.9 | 1,662.3 |
| Securities borrowed, offset | 0.0 | 0.0 |
| Securities borrowed, net | 1,803.9 | 1,662.3 |
| Securities sold under agreements to repurchase, gross | 24,045.9 | 16,527.9 |
| Securities sold under agreements to repurchase, offset | (12,908.6) | (7,946.6) |
| Securities sold under agreements to repurchase, net | 11,137.3 | 8,581.3 |
| Securities loaned, gross | 1,509.9 | 1,615.9 |
| Securities loaned, offset | 0.0 | 0.0 |
| Securities loaned, net | $ 1,509.9 | $ 1,615.9 |
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- References No definition available.
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- Definition Amount, after the effects of master netting arrangements, of securities borrowed from entities in exchange for collateral. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, before effects of master netting arrangements, of securities borrowed from entities in exchange for collateral. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of liability associated with securities borrowed from entities in exchange for collateral. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount, after the effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount, before effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, after the effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes purchases of participations in pools of securities that are subject to a resale agreement, assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Amount, before effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of liability associated with funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of asset associated with funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, after effect of master netting arrangement, of security loaned to entity in exchange for collateral. Includes financial instrument subject to master netting arrangement not elected or qualified to offset. Excludes security loaned not subject to master netting arrangement or similar agreement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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