Derivative Financial Instruments - External Credit Ratings of Underlyings or Referenced Assets (Details) - USD ($) $ in Millions	Feb. 28, 2022	Nov. 30, 2021
Index credit default swaps
Derivative [Line Items]
Derivative notional amount	$ 3,937.2	$ 3,910.8
Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	0.2	17.8
Investment Grade | Index credit default swaps
Derivative [Line Items]
Derivative notional amount	2,674.4	2,612.0
Investment Grade | Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	0.0	0.0
Non-investment Grade | Index credit default swaps
Derivative [Line Items]
Derivative notional amount	1,262.8	1,298.8
Non-investment Grade | Single name credit default swaps
Derivative [Line Items]
Derivative notional amount	0.0	17.6
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