Collateralized Transactions (Contractual Maturity) (Details) - USD ($) $ in Thousands	Aug. 31, 2020	Nov. 30, 2019
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending arrangements	$ 1,929,737	$ 1,525,140
Repurchase agreements	19,837,038	18,756,917
Obligation to return securities received as collateral, at fair value	4,413	9,500
Total	21,771,188	20,291,557
Overnight and Continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending arrangements	630,163	694,821
Repurchase agreements	10,606,433	6,614,026
Obligation to return securities received as collateral, at fair value	4,413	0
Total	11,241,009	7,308,847
Up to 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending arrangements	0	0
Repurchase agreements	1,695,229	1,556,260
Obligation to return securities received as collateral, at fair value	0	0
Total	1,695,229	1,556,260
31 to 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending arrangements	553,062	672,969
Repurchase agreements	4,243,474	8,988,528
Obligation to return securities received as collateral, at fair value	0	9,500
Total	4,796,536	9,670,997
Greater than 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending arrangements	746,512	157,350
Repurchase agreements	3,291,902	1,598,103
Obligation to return securities received as collateral, at fair value	0	0
Total	$ 4,038,414	$ 1,755,453