Derivative Financial Instruments - External Credit Ratings of Underlyings or Referenced Assets (Details) - USD ($) $ in Millions	May 31, 2021	Nov. 30, 2020
Index credit default swaps
Derivative [Line Items]
Derivative notional amount	$ 233.2	$ 324.8
Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	88.2	6.4
Investment Grade | Index credit default swaps
Derivative [Line Items]
Derivative notional amount	163.2	62.0
Investment Grade | Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	81.8	0.0
Non-investment Grade | Index credit default swaps
Derivative [Line Items]
Derivative notional amount	70.0	262.8
Non-investment Grade | Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	6.2	6.2
Unrated | Index credit default swaps
Derivative [Line Items]
Derivative notional amount	0.0	0.0
Unrated | Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	$ 0.2	$ 0.2