Fair Value Disclosures - Analysis of Level 3 Assets and Liabilities Narrative (Details) - USD ($) $ in Thousands	11 Months Ended	12 Months Ended
	Nov. 30, 2018	Nov. 30, 2020	Nov. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3	$ 57,800	$ 88,000	$ 68,600
Transfers of assets from Level 3 to Level 2	12,300	24,700	26,700
Transfers of liabilities from Level 2 to Level 3		1,900
Fair value, measurement with unobservable inputs reconciliation, liability, transfers out of level 3		143,400
Net gains (losses) on Level 3 assets (realized and unrealized)	79,200	(51,600)	(217,000)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	33,600	(82,100)	44,500
Loans and other receivables
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3		10,900	27,400
Transfers of assets from Level 3 to Level 2		7,100	8,600
Net gains (losses) on Level 3 assets (realized and unrealized)	(5,137)	(12,341)	(4,507)
Other asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3		23,000	12,100
Transfers of assets from Level 3 to Level 2		6,800	2,600
Net gains (losses) on Level 3 assets (realized and unrealized)	(9,934)	(3,848)	433
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3		18,000	8,900
Transfers of assets from Level 3 to Level 2	3,600	3,000
Net gains (losses) on Level 3 assets (realized and unrealized)	(439)	83	(4,860)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	0	268	381
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3	16,300		5,600
Net gains (losses) on Level 3 assets (realized and unrealized)	(2,186)	(827)	(2,888)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	105	0	(35)
CDOs and CLOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3	17,300		3,000
Transfers of assets from Level 3 to Level 2			8,800
Net gains (losses) on Level 3 assets (realized and unrealized)	(16,258)	(3,821)	(514)
Corporate equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3		32,500
Transfers of assets from Level 3 to Level 2	2,900	5,100	6,000
Net gains (losses) on Level 3 assets (realized and unrealized)	24,914	(4,086)	(11,407)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	0	(456)	2,649
Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of liabilities from Level 2 to Level 3			57,200
Fair value, measurement with unobservable inputs reconciliation, liability, transfers out of level 3		60,800	14,300
Net gains (losses) on Level 3 liabilities (realized and unrealized)	3,237	40	21,452
Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of liabilities from Level 2 to Level 3	146,200
Net gains (losses) on Level 3 liabilities (realized and unrealized)	30,347	(84,930)	18,662
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3	15,300
Transfers of assets from Level 3 to Level 2	4,600
Net gains (losses) on Level 3 assets (realized and unrealized)	(6,970)	(934)	(1,669)
Investments at fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3			10,200
Net gains (losses) on Level 3 assets (realized and unrealized)	76,636	(31,666)	(183,480)
Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of liabilities from Level 2 to Level 3		1,800
Net gains (losses) on Level 3 liabilities (realized and unrealized)	$ (84)	520	1,382
Loans to and investments in associated companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of assets from Level 2 to Level 3		34,700
Net gains (losses) on Level 3 assets (realized and unrealized)		5,497
Structured notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of liabilities from Level 2 to Level 3			22,600
Fair value, measurement with unobservable inputs reconciliation, liability, transfers out of level 3		$ 80,600	$ 61,700