Collateralized Transactions - Collateral Pledged (Details) - USD ($) $ in Millions	Aug. 31, 2025	Nov. 30, 2024
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	$ 2,498.0	$ 2,540.9
Repurchase Agreements	18,011.7	18,088.9
Obligation to Return Securities Received as Collateral, at Fair Value	54.2	185.6
Total	20,563.9	20,815.4
Corporate equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	1,982.5	2,059.8
Repurchase Agreements	1,643.2	1,394.2
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	3.9
Total	3,625.7	3,457.8
Corporate debt securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	448.9	416.4
Repurchase Agreements	3,252.0	4,522.5
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	3,700.9	4,938.9
Mortgage-backed and asset-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0.0	0.0
Repurchase Agreements	1,455.0	2,384.8
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	1,455.0	2,384.8
U.S. government and federal agency securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	36.7	30.9
Repurchase Agreements	8,764.4	6,837.1
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	8,801.1	6,868.0
Municipal securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	1.1	0.0
Repurchase Agreements	493.8	212.1
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	494.9	212.1
Sovereign obligations
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	28.8	33.7
Repurchase Agreements	1,857.6	1,981.0
Obligation to Return Securities Received as Collateral, at Fair Value	54.2	181.7
Total	1,940.6	2,196.4
Loans and other receivables
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0.0	0.0
Repurchase Agreements	545.7	757.4
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	$ 545.7	$ 757.4

Amount, after effect of master netting arrangement and deduction of obligation to return financial collateral not offset and financial instrument subject to master netting arrangement not offset, of derivative liability, security sold under agreement to repurchase, and security loaned. Includes liability not subject to master netting arrangement or similar agreement.

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