Derivative Financial Instruments (Credit Related Derivative Contracts) (Details) - USD ($)
$ in Millions
May 31, 2022
Nov. 30, 2021
Index credit default swaps    
Derivative [Line Items]    
Notional amount $ 3,327.3 $ 3,910.8
Single name credit default swaps    
Derivative [Line Items]    
Notional amount 0.2 17.8
Investment Grade | Index credit default swaps    
Derivative [Line Items]    
Notional amount 2,428.4 2,612.0
Investment Grade | Single name credit default swaps    
Derivative [Line Items]    
Notional amount 0.0 0.0
Non-investment grade | Index credit default swaps    
Derivative [Line Items]    
Notional amount 898.9 1,298.8
Non-investment grade | Single name credit default swaps    
Derivative [Line Items]    
Notional amount 0.0 17.6
Unrated | Index credit default swaps    
Derivative [Line Items]    
Notional amount 0.0 0.0
Unrated | Single name credit default swaps    
Derivative [Line Items]    
Notional amount $ 0.2 $ 0.2