Segment Reporting - Net Revenues, Expenses and Total Assets by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 747,802	$ 777,159	$ 901,851	$ 685,718	$ 761,958	$ 777,615	$ 822,557	$ 821,246	$ 3,112,530	$ 3,183,376	$ 3,198,109
Non-interest expenses									2,787,861	2,773,709	2,693,185
Earnings before income taxes	23,871	$ 83,075	$ 155,138	$ 62,585	77,963	$ 87,101	$ 121,865	$ 122,738	324,669	409,667	504,924
Total assets	43,516,115				41,168,773				43,516,115	41,168,773
Investment Banking and Capital Markets
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									3,036,000	3,184,400	3,169,900
Non-interest expenses									2,688,900	2,719,500	2,634,200
Earnings before income taxes									347,100	464,900	535,700
Total assets	40,565,800				38,700,700				40,565,800	38,700,700
Asset Management
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									76,500	(1,000)	28,200
Non-interest expenses									98,900	54,200	59,000
Earnings before income taxes									(22,400)	(55,200)	$ (30,800)
Total assets	$ 2,950,300				$ 2,468,100				$ 2,950,300	$ 2,468,100