Variable Interest Entities (Narrative) (Details) - USD ($) $ in Thousands		9 Months Ended
		Aug. 31, 2020	Nov. 30, 2019	Aug. 31, 2019	Nov. 30, 2018
Variable Interest Entity [Line Items]
Assets	[1]	$ 51,773,988	$ 49,460,234
Investment in associated company		1,539,356	1,652,957	$ 2,346,297	$ 2,417,332
Investment in FXCM
Variable Interest Entity [Line Items]
Fair value of senior secured term loan receivable		56,500
Investment in associated company		80,300
Senior secured term loan receivable and investments in associated companies		136,800
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets		1,247,200	1,107,900
Related party private equity vehicles | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets		18,600	23,000
Other investment vehicles
Variable Interest Entity [Line Items]
Carrying amount of equity investment		853,900	574,000
Unfunded equity commitment related to investments		199,600	192,100
Other investment vehicles | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets		853,900	574,000
Agency mortgage-backed securities | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets		1,808,600	1,453,500
Non agency mortgage- and asset-backed securities | VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets		130,800	134,800
JCP Entities | Related party private equity vehicles
Variable Interest Entity [Line Items]
Equity commitments		133,000	133,000
Funded equity commitments		122,000	121,700
Carrying amount of equity investment		18,600	23,000
Variable interest entities, primary beneficiary
Variable Interest Entity [Line Items]
Automobile loan receivables securitized		223,300
Assets		$ 637,500	$ 645,800

[1] Total assets include assets related to variable interest entities of $637.5 million and $645.8 million at August 31, 2020 and November 30, 2019, respectively, and Total liabilities include liabilities related to variable interest entities of $3,377.3 million and $3,071.1 million at August 31, 2020 and November 30, 2019, respectively. See Note 7 for additional information related to variable interest entities.