Collateralized Transactions - Collateral Pledged (Details) - USD ($) $ in Millions	Feb. 28, 2026	Nov. 30, 2025
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	$ 2,690.4	$ 2,540.8
Repurchase Agreements	15,831.0	18,261.2
Obligation to Return Securities Received as Collateral, at Fair Value	393.9	200.5
Total	18,915.3	21,002.5
Corporate equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	1,954.8	1,875.2
Repurchase Agreements	1,604.3	1,028.6
Obligation to Return Securities Received as Collateral, at Fair Value	168.4	0.0
Total	3,727.5	2,903.8
Corporate debt securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	594.4	589.7
Repurchase Agreements	3,465.1	3,271.5
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	4,059.5	3,861.2
Mortgage-backed and asset-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	89.0	0.0
Repurchase Agreements	2,208.7	2,062.6
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	2,297.7	2,062.6
U.S. government and federal agency securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	22.1	21.6
Repurchase Agreements	6,057.8	9,183.1
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	6,079.9	9,204.7
Municipal securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	0.0	0.0
Repurchase Agreements	421.7	422.3
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	421.7	422.3
Sovereign obligations
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Lending Arrangements	30.1	54.3
Repurchase Agreements	1,666.5	1,487.7
Obligation to Return Securities Received as Collateral, at Fair Value	225.5	200.5
Total	1,922.1	1,742.5
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	406.9	805.4
Obligation to Return Securities Received as Collateral, at Fair Value	0.0	0.0
Total	$ 406.9	$ 805.4

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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