Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2019	Sep. 30, 2018	Aug. 31, 2019	Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	$ 1,223,156	$ 1,458,977	$ 3,928,539	$ 3,863,914
Reclassification for the period, net of tax			542,092	14,193
Net unrealized losses on available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification for the period, tax			(545,054)	37
Net unrealized foreign exchange losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification for the period, tax			0	(16)
Net unrealized gains (losses) on instrument specific credit risk
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification for the period, tax			(166)	126
Net unrealized gains on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification for the period, tax			161	0
Amortization of defined benefit pension plan actuarial gains (losses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification for the period, net of tax			(1,063)	(1,398)
Reclassification for the period, tax			(361)	(508)
Other pension
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification for the period, net of tax			0	(5,344)
Reclassification for the period, tax			0	0
Reclassification out of Accumulated Other Comprehensive Income | Net unrealized foreign exchange losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other revenues and Selling, general and other expenses			0	20,459
Other
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	169,248	289,387	351,544	419,888
Other | Reclassification out of Accumulated Other Comprehensive Income | Net unrealized losses on available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues and income tax provision (benefit)			543,178	105
Other | Reclassification out of Accumulated Other Comprehensive Income | Net unrealized gains on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues			470	0
Principal transactions
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	$ (20,920)	$ 116,204	465,451	315,622
Principal transactions | Reclassification out of Accumulated Other Comprehensive Income | Net unrealized gains (losses) on instrument specific credit risk
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues			$ (493)	$ 371