Fair Value Disclosures (Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value based on NAV	$ 36,700	$ 42,200
Derivatives	262,799	406,268
Counterparty/cash-collateral netting, Assets	(4,165,446)	(4,759,345)
Total trading assets, excluding investments at fair value based on NAV	18,256,356	19,570,321
Total available for sale securities	207,355	1,608,769
Cash and cash equivalents	3,638,648	4,276,775
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	751,084	3,444,674
Securities received as collateral	0	5,418
Derivatives	218,243	363,515
Counterparty/cash-collateral netting, Liabilities	(4,257,998)	(4,856,618)
Total trading liabilities	6,840,430	8,904,592
Other secured financings	544	30,825
Obligation to return securities received as collateral	0	5,418
U.S. government securities segregated for regulatory purposes		453,700
Money market funds		545,000
Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	1,464,604	2,009,188
Corporate debt securities	1,556,941	1,612,217
Collateralized debt obligations	1,488,121	4,557
U.S. government and federal agency securities	1,342,996	2,253,055
Sovereign obligations	117	1,791,085
Loans	769,408	870,975
Derivatives	218,243	363,515
Counterparty/cash-collateral netting, Liabilities	(4,257,998)	(4,856,618)
Transferred from Level 1 to Level 2		6,600
Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	2,977,881	3,378,297
Corporate debt securities	2,893,041	3,365,042
Collateralized debt obligations	174,236	430,868
U.S. government and federal agency securities	2,645,651	2,775,541
Municipal securities	487,141	590,849
Sovereign obligations	2,659,441	2,759,511
Loans and other receivables	1,312,333	1,556,018
Derivatives	262,799	406,268
Counterparty/cash-collateral netting, Assets	(4,165,446)	(4,759,345)
Investments at fair value	226,018	150,195
Investment in FXCM	625,689
Physical commodities		62,234
Transferred from Level 1 to Level 2		6,100
Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	73,579	89,353
Corporate debt securities	4,744	30,403
U.S. government and federal agency securities	63,945	593,773
Residential Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	2,801,333	2,962,511
Residential Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	23,240	606,683
Commercial Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	1,029,239	993,306
Commercial Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	2,374	43,401
Other Asset Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	161,554	139,681
Other Asset Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	39,473	245,156
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total trading assets, excluding investments at fair value based on NAV	6,611,880	7,859,052
Total available for sale securities	137,524	683,126
Cash and cash equivalents	3,638,648	4,276,775
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	751,084	3,444,674
Securities received as collateral		5,418
Total trading liabilities	3,754,147	5,457,377
Other secured financings	0	0
Obligation to return securities received as collateral		5,418
Level 1 [Member] \| Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	1,428,048	1,934,469
Corporate debt securities	0	0
Collateralized debt obligations	1,488,121	0
U.S. government and federal agency securities	837,614	2,253,055
Sovereign obligations	0	1,217,075
Loans	0	0
Derivatives	364	52,778
Level 1 [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	2,803,243	3,130,892
Corporate debt securities	0	0
Collateralized debt obligations	0	0
U.S. government and federal agency securities	2,555,018	2,694,268
Municipal securities	0	0
Sovereign obligations	1,251,366	1,968,747
Loans and other receivables	0	0
Derivatives	2,253	65,145
Investments at fair value	0	0
Investment in FXCM	0
Physical commodities		0
Level 1 [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	73,579	89,353
Corporate debt securities	0	0
U.S. government and federal agency securities	63,945	593,773
Level 1 [Member] \| Residential Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 1 [Member] \| Residential Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 1 [Member] \| Commercial Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 1 [Member] \| Commercial Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 1 [Member] \| Other Asset Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 1 [Member] \| Other Asset Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total trading assets, excluding investments at fair value based on NAV	14,495,857	15,962,233
Total available for sale securities	69,831	925,643
Cash and cash equivalents	0	0
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	0	0
Securities received as collateral		0
Total trading liabilities	7,314,231	8,239,570
Other secured financings	0	0
Obligation to return securities received as collateral		0
Level 2 [Member] \| Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	36,518	74,681
Corporate debt securities	1,556,941	1,611,994
Collateralized debt obligations	0	4,557
U.S. government and federal agency securities	505,382	0
Sovereign obligations	117	574,010
Loans	758,939	856,525
Derivatives	4,456,334	5,117,803
Level 2 [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	133,732	226,441
Corporate debt securities	2,867,165	3,342,276
Collateralized debt obligations	89,144	306,218
U.S. government and federal agency securities	90,633	81,273
Municipal securities	487,141	590,849
Sovereign obligations	1,407,955	790,764
Loans and other receivables	1,123,044	1,458,760
Derivatives	4,406,207	5,046,278
Investments at fair value	26,224	73,148
Investment in FXCM	0
Physical commodities		62,234
Level 2 [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	0	0
Corporate debt securities	4,744	30,403
U.S. government and federal agency securities	0	0
Level 2 [Member] \| Residential Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	2,731,070	2,879,954
Level 2 [Member] \| Residential Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	23,240	606,683
Level 2 [Member] \| Commercial Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	1,014,913	966,651
Level 2 [Member] \| Commercial Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	2,374	43,401
Level 2 [Member] \| Other Asset Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	118,629	137,387
Level 2 [Member] \| Other Asset Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	39,473	245,156
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total trading assets, excluding investments at fair value based on NAV	1,314,065	508,381
Total available for sale securities	0	0
Cash and cash equivalents	0	0
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	0	0
Securities received as collateral		0
Total trading liabilities	30,050	64,263
Other secured financings	544	30,825
Obligation to return securities received as collateral		0
Increase corporate debt obligations		33,200
Level 3 [Member] \| Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	38	38
Corporate debt securities	0	223
Collateralized debt obligations	0	0
U.S. government and federal agency securities	0	0
Sovereign obligations	0	0
Loans	10,469	14,450
Derivatives	19,543	49,552
Level 3 [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	40,906	20,964
Corporate debt securities	25,876	22,766
Collateralized debt obligations	85,092	124,650
U.S. government and federal agency securities	0	0
Municipal securities	0	0
Sovereign obligations	120	0
Loans and other receivables	189,289	97,258
Derivatives	19,785	54,190
Investments at fair value	199,794	77,047
Investment in FXCM	625,689
Physical commodities		0
Level 3 [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	0	0
Corporate debt securities	0	0
U.S. government and federal agency securities	0	0
Level 3 [Member] \| Residential Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	70,263	82,557
Level 3 [Member] \| Residential Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 3 [Member] \| Commercial Mortgage Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	14,326	26,655
Level 3 [Member] \| Commercial Mortgage Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	0	0
Level 3 [Member] \| Other Asset Backed Securities [Member] \| Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	42,925	2,294
Level 3 [Member] \| Other Asset Backed Securities [Member] \| Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, assets	$ 0	$ 0

Derivative, Fair Value of Derivative Asset, Amount Netting in Consolidated Statement of Financial Condition

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Derivative, Fair Value of Derivative Liability, Amount Netting in Consolidated Statement of Financial Condition

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- Definition

Fair value of loan obligations.

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Fair Value of Senior Secured Term Loan receivable and rights to future distributions

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- Definition

The fair value as of the balance sheet date of firm holdings in structured asset - backed securities whose value and payments are derived from portfolio of fixed income underlying assets.

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No definition available.

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The fair value as of the balance sheet date of firm holdings in corporate loans, participation certificates in GNMA project and construction loans, and escrow and trade claim receivables.

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No definition available.

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Financial Instruments, Owned, Reclassification of Investments from Corporate Debt Securities to Collateralized Debt Obligations

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No definition available.

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- Definition

Financial Instruments Owned Trading Assets, at Fair Value, Excluding Investments Based on Net Asset Value

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No definition available.

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Financial Instruments Sold Not Yet Purchased Collateralized Debt Obligations At Fair Value

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No definition available.

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Investments at Fair Value Based on Net Asset Value

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Other Secured Financings at Fair Value

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- Definition

U.S. government securities segregated for regulatory purposes

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 320
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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

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-Name Accounting Standards Codification
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- Definition

Amount of cash subject to withdrawal restrictions, restricted deposits held as compensating balances, and cash and securities segregated in compliance with regulations (such as cash deposited in a special reserve account for the exclusive benefit of customers).

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-Topic 942
-SubTopic 305
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Amount of transfers of financial instruments classified in shareholders' equity measured on a recurring basis out of level 1 of the fair value hierarchy into level 2.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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-Paragraph 2
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- Definition

The fair value as of the balance sheet date of firm holdings in fixed income or other debt securities issued by a corporation or other issuer not elsewhere specified in the taxonomy. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 320
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42546-110969

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- Definition

The fair value as of the balance sheet date of firm holdings in corporate stocks (common and preferred), stock options, warrants and any other financial instrument which represents, or provides the ability to obtain, ownership rights in a corporation. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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- Definition

The fair value as of the balance sheet date of firm holdings in all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments. Their value is derived from the values of one or more underlying assets, reference rates, or indices of asset values. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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-Paragraph 4B
-Subparagraph c
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- Definition

The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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- Definition

The fair value as of the balance sheet date of firm holdings in fixed income obligations issued by foreign governments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

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- Definition

The fair value as of the balance sheet date of firm holdings in physical commodity contracts (for example, agricultural products, metals and energy). Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

No definition available.

+ Details

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- Definition

The fair value as of the balance sheet date of firm holdings in private equity, mezzanine, venture capital, merchant banking, real estate and special situations investments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

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- Definition

The fair value as of the balance sheet date of firm holdings in fixed income obligations issued by state and local governments and authorities. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

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The fair value as of the balance sheet date of firm holdings in debt obligations issued by the US government including short-term Treasury bills, medium-term Treasury notes, and long-term Treasury bonds, as well as debt issued by agencies. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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Fair value of obligations incurred from short sales.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35711043&loc=d3e42429-110968

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Fair value of obligations arising from corporate debt obligations sold short.

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Fair value of obligations arising from corporate equity sold short.

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Fair value of obligations arising from derivatives and other contracts sold short.

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Fair value of obligations arising from foreign government debt obligations short.

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Fair value of obligations arising from US treasury and other US government and agency debt obligations sold short.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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The fair value of collateral received by the entity associated with securities borrowed that must be returned if the counterparty fulfills its obligations. It appears on the balance sheet as a liability and has a corresponding asset that appears on the balance sheet called Securities Received as Collateral.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Collateral
-URI http://asc.fasb.org/extlink&oid=6507830

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The carrying value as of the balance sheet date of the assets received as collateral against securities loaned to other broker-dealers. Borrowers of securities generally are required to provide collateral to the lenders of securities, commonly cash but sometimes other securities or standby letters of credit, with a value slightly higher than that of the securities borrowed. In instances where the entity is permitted to sell or re-pledge these securities, the entity reports the fair value of the collateral received and the related obligation to return the collateral as a liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 10
-Section 05
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=7517284&loc=d3e93645-111703

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=34720971&loc=SL6224234-111729

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