Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2019	Jun. 30, 2018	May 31, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	$ 1,510,371	$ 1,243,826	$ 2,705,383	$ 2,404,937
Reclassification for the period, net of tax			542,447	14,569
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)	78
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			(708)	(919)
Reclassification for the period, tax			(241)	(339)
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	144,206	90,021	198,037	143,989
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	103
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	$ 240,189	$ 53,755	486,371	199,418
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)	$ 270