Variable Interest Entities (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	May 31, 2020	Nov. 30, 2019	May 31, 2019	Nov. 30, 2018
Variable Interest Entity [Line Items]
Assets	$ 50,283,215	$ 49,460,234
Investment in associated company	1,559,793	1,652,957	$ 2,415,894	$ 2,417,332
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	1,295,500	1,107,900
Investment in FXCM
Variable Interest Entity [Line Items]
Fair value of senior secured term loan receivable	53,800
Investment in associated company	76,200
Senior secured term loan receivable and investments in associated companies	130,000
Related party private equity vehicles | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	16,600	23,000
Other investment vehicles
Variable Interest Entity [Line Items]
Carrying amount of equity investment	877,600	574,000
Unfunded equity commitment related to investments	191,500	192,100
Other investment vehicles | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	877,600	574,000
Agency mortgage-backed securities | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	2,004,200	1,453,500
Non agency mortgage- and asset-backed securities | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	140,400	134,800
JCP Entities | Related party private equity vehicles
Variable Interest Entity [Line Items]
Equity commitments	133,000	133,000
Funded equity commitments	121,900	121,700
Carrying amount of equity investment	16,600	23,000
Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Automobile loan receivables securitized	223,300
Assets	$ 709,200	$ 645,800