v3.26.1
Derivative Financial Instruments - Notional Amounts and Credit Exposure (Details) - USD ($)
$ in Millions
6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Derivative Financial Instruments, exposure    
Cash and securities posted under collateral arrangements associated with derivative credit support agreements and Futures Commission Merchant agreements $ 414.4 $ 491.1
Aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position 516.3 546.9
Collateral and initial margin posted supporting derivatives with credit-risk-related contingent features that were in a liability position 414.4 491.1
Additional collateral required to be posted if derivative credit-risk-related contingent features were triggered 118.9  
Cash collateral received associated with derivative credit support annex agreements and Futures Commission Merchant agreements 1,225.0 787.6
Notional amount 114,408.1 107,309.8
Gross credit exposure 1,760.4 1,232.0
Less: collateral received 1,441.1 923.7
Net credit exposure 319.3 308.3
Interest rate options    
Derivative Financial Instruments, exposure    
Notional amount 4,528.0 3,578.0
Gross credit exposure 11.2 4.0
Interest rate swaps    
Derivative Financial Instruments, exposure    
Cash exchanged under contract 0.0  
Principal payments made under contract 0.0  
Notional amount 63,019.9 60,267.1
Gross credit exposure 7.9 13.2
Interest rate futures    
Derivative Financial Instruments, exposure    
Notional amount 2,504.7 1,994.7
Interest rate forwards    
Derivative Financial Instruments, exposure    
Notional amount 1,837.0 1,687.0
Gross credit exposure 2.6 1.1
Currency swaps    
Derivative Financial Instruments, exposure    
Notional amount 4,205.4 3,538.7
Gross credit exposure 233.1 190.0
Currency forwards    
Derivative Financial Instruments, exposure    
Notional amount 1,177.4 914.6
Gross credit exposure 29.2 30.0
Equity options    
Derivative Financial Instruments, exposure    
Notional amount 8,523.5 7,449.3
Gross credit exposure 1,441.1 971.5
Total return swaps    
Derivative Financial Instruments, exposure    
Gross credit exposure 26.3 18.8
Total return swaps | Equity contracts    
Derivative Financial Instruments, exposure    
Gross credit exposure 6.4  
Equity futures    
Derivative Financial Instruments, exposure    
Notional amount 2,135.5 1,699.1
Equity total return swaps | Equity contracts    
Derivative Financial Instruments, exposure    
Notional amount 829.9 499.6
Credit default swaps    
Derivative Financial Instruments, exposure    
Notional amount 611.9 531.0
Credit default swaps | Credit contracts    
Derivative Financial Instruments, exposure    
Gross credit exposure 2.6 3.4
Credit total return swaps | Credit contracts    
Derivative Financial Instruments, exposure    
Notional amount 500.0 500.0
Embedded derivative financial instruments    
Derivative Financial Instruments, exposure    
Notional amount $ 24,534.9 $ 24,650.7