Fair Value Disclosures (Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value) (Details) (USD $)	Jun. 30, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	$ 192,766,000
Derivatives	(2,039,660,000)	[1]
Total trading assets	15,270,288,000		1,077,172,000
Total available for sale securities	2,664,101,000		3,356,992,000
Cash and cash equivalents	3,553,645,000		145,960,000
Investments in managed funds	55,141,000
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	3,056,141,000	[2]
Securities received as collateral	36,202,000
Derivatives	199,717,000
Derivatives	(2,215,626,000)	[1]
Total trading liabilities	6,771,793,000
Other secured financings	32,294,000
Obligation to return securities received as collateral	36,202,000
US government and Federal agency securities segregated for regulatory purposes	284,300,000
Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	1,645,717,000
Corporate debt securities	1,315,930,000
U.S. government and federal agency securities	762,107,000
Sovereign obligations	1,472,250,000
Loans	1,018,939,000
Derivatives	199,717,000
Physical commodities	174,906,000
Total trading liabilities	6,771,793,000
Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	1,914,731,000
Corporate debt securities	3,078,196,000
Collateralized debt obligations	243,089,000
U.S. government and federal agency securities	966,901,000
Municipal securities	621,440,000
Sovereign obligations	2,062,352,000
Loans and other receivables	1,644,613,000
Derivatives	192,766,000
Investments at fair value	77,433,000
Investment in associated companies carried at fair value			1,077,172,000
Physical commodities	149,175,000
Total trading assets	15,270,288,000
Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	335,765,000		934,823,000
Corporate debt securities	39,487,000		16,648,000
U.S. government and federal agency securities	1,453,219,000		1,663,512,000
Other	97,000		884,000
Total available for sale securities	2,664,101,000		3,356,992,000
Residential Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, liabilities	179,270,000
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	3,584,713,000
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	637,699,000		601,456,000
Commercial Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, liabilities	2,957,000
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	689,923,000
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	76,435,000		59,113,000
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	44,956,000
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	121,399,000		80,556,000
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	3,553,645,000	[3]	145,960,000	[3]
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	3,056,141,000	[2],[3]
Securities received as collateral	36,202,000	[3]
Obligation to return securities received as collateral	36,202,000	[3]
Level 1 [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	1,608,517,000	[3]
U.S. government and federal agency securities	762,107,000	[3]
Sovereign obligations	672,691,000	[3]
Derivatives	624,205,000	[3]
Total trading liabilities	3,667,520,000	[3]
Level 1 [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	1,788,659,000	[3]
U.S. government and federal agency securities	811,279,000	[3]
Sovereign obligations	931,923,000	[3]
Derivatives	599,947,000	[3]
Investment in associated companies carried at fair value			1,077,172,000	[3]
Total trading assets	4,131,808,000	[3]
Level 1 [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	335,765,000	[3]	934,823,000	[3]
U.S. government and federal agency securities	1,453,219,000	[3]	1,657,022,000	[3]
Total available for sale securities	1,788,984,000	[3]	2,591,845,000	[3]
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other secured financings	30,000,000	[3]
Level 2 [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	37,162,000	[3]
Corporate debt securities	1,315,930,000	[3]
Sovereign obligations	799,559,000	[3]
Loans	1,003,727,000	[3]
Derivatives	1,771,907,000	[3]
Physical commodities	174,906,000	[3]
Total trading liabilities	5,285,418,000	[3]
Level 2 [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	106,495,000	[3]
Corporate debt securities	3,059,581,000	[3]
Collateralized debt obligations	197,965,000	[3]
U.S. government and federal agency securities	155,622,000	[3]
Municipal securities	621,440,000	[3]
Sovereign obligations	1,130,429,000	[3]
Loans and other receivables	1,527,117,000	[3]
Derivatives	1,624,047,000	[3]
Investments at fair value	1,069,000	[3]
Physical commodities	149,175,000	[3]
Total trading assets	12,731,254,000	[3]
Level 2 [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate debt securities	39,487,000	[3]	16,648,000	[3]
U.S. government and federal agency securities			6,490,000	[3]
Other	97,000	[3]	884,000	[3]
Total available for sale securities	875,117,000	[3]	765,147,000	[3]
Level 2 [Member] | Residential Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, liabilities	179,270,000	[3]
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	3,440,947,000	[3]
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	637,699,000	[3]	601,456,000	[3]
Level 2 [Member] | Commercial Mortgage-Backed Securities [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage- and asset-backed securities, liabilities	2,957,000	[3]
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	673,855,000	[3]
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	76,435,000	[3]	59,113,000	[3]
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	43,512,000	[3]
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	121,399,000	[3]	80,556,000	[3]
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in managed funds	55,141,000
Other secured financings	2,294,000
Level 3 [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	38,000
Loans	15,212,000
Derivatives	19,231,000
Total trading liabilities	34,481,000
Level 3 [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate equity securities	19,577,000
Corporate debt securities	18,615,000
Collateralized debt obligations	45,124,000
Loans and other receivables	117,496,000
Derivatives	8,432,000
Investments at fair value	76,364,000
Total trading assets	446,886,000
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	143,766,000
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	16,068,000
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	1,444,000
Counterparty and Cash Collateral Netting [Member] | Trading Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	(2,215,626,000)	[4]
Total trading liabilities	(2,215,626,000)	[4]
Counterparty and Cash Collateral Netting [Member] | Trading Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	(2,039,660,000)	[4]
Total trading assets	$ (2,039,660,000)	[4]

[1] Netting is applied by counterparty when a legal right of offset exists under an enforceable master netting agreement, as permitted under GAAP. Further, for derivative assets and liabilities, netting is inclusive of cash paid or received as collateral under credit support agreements pursuant to the master netting agreement.

[2] Securities comprise U.S. government securities segregated for regulatory purposes with a fair value of $284.3 million.

[3] There were no transfers between Level 1 and Level 2 during 2013 or 2012.

[4] Represents counterparty and cash collateral netting across the levels of the fair value hierarchy for positions with the same counterparty.