Variable Interest Entities (Assets And Liabilities Of Consolidated VIEs) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Cash	$ 4,261,427	$ 3,807,558	$ 2,604,066	$ 3,638,648
Financial instruments owned	15,068,942	15,286,286
Securities purchased under agreement to resell	4,468,494	3,862,488
Receivables	5,553,667	4,425,178
Loans to and investments in associated companies	2,122,479	2,125,098
Other	1,836,389	1,635,664
Total assets	45,979,997	45,071,307
Other secured financings	837,204	1,026,429
Long-term debt	8,198,419	7,380,443
Total liabilities	34,920,677	34,305,849
Noncontrolling interests	193,588	175,549
Securitization Vehicles [Member]
Variable Interest Entity [Line Items]
Cash	6,700	18,400
Financial instruments owned	52,800	86,600
Securities purchased under agreement to resell	570,200	733,500
Receivables	246,600	277,700
Loans to and investments in associated companies	0	0
Other	15,600	14,500
Total assets	891,900	1,130,700
Other secured financings	856,500	1,083,800
Long-term debt	0	24,100
Other	35,000	22,300
Total liabilities	891,500	1,130,200
Noncontrolling interests	0	0
Real Estate Investment Vehicles [Member]
Variable Interest Entity [Line Items]
Cash	2,700	2,200
Financial instruments owned	0	0
Securities purchased under agreement to resell	0	0
Receivables	312,000	296,900
Loans to and investments in associated companies	120,000	108,700
Other	11,000	10,800
Total assets	445,700	418,600
Other secured financings	0	0
Long-term debt	258,100	243,900
Other	8,200	11,700
Total liabilities	266,300	255,600
Noncontrolling interests	107,500	98,700
Jefferies [Member]
Variable Interest Entity [Line Items]
Secured financings eliminated in consolidation	$ 19,500	$ 57,600