Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Aug. 31, 2011	Nov. 30, 2010
ASSETS
Cash and cash equivalents	$ 2,014,950	$ 2,188,998
Financial instruments owned, at fair value, including securities pledged of $14,035,813 and $12,338,728 in 2011 and 2010, respectively:
Corporate equity securities	1,676,598	1,565,793
Corporate debt securities	4,213,249	3,630,616
Mortgage- and asset-backed securities	4,787,608	4,921,565
Loans and other receivables	528,681	434,573
Derivatives	916,142	119,268
Investments, at fair value	116,833	77,784
Total financial instruments owned, at fair value	18,139,946	15,941,572
Receivables:
Receivables from brokers and dealers	3,743,143	2,550,234
Fees	1,319,664	1,328,365
Other assets	816,573	601,799
Total assets	45,125,243	36,726,543
Financial instruments sold, not yet purchased, at fair value:
Corporate equity securities	1,736,221	1,638,372
Corporate debt securities	2,472,045	2,375,925
Government, federal agency and other sovereign obligations	15,605	0
Derivatives	595,942	59,552
Total financial instruments sold, not yet purchased, at fair value	10,320,161	9,109,799
Payables:
Brokers, dealers and clearing organizations	2,754,164	1,885,357
Accrued expenses and other liabilities	1,164,164	1,142,850
Carrying amount of mandatorily redeemable preferred interests of consolidated subsidiaries	313,095	315,885
Total liabilities	41,633,555	33,915,578
STOCKHOLDERS' EQUITY
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	203,525,528	200,301,656
Treasury stock, at cost	3,211,223	28,607,510
Variable Interest Entity, Primary Beneficiary [Member]
ASSETS
Cash and cash equivalents	283,968	202,565
Financial instruments owned, at fair value, including securities pledged of $14,035,813 and $12,338,728 in 2011 and 2010, respectively:
Securities pledged to creditors	14,035,813	12,338,728
Corporate equity securities	79,927	120,606
Corporate debt securities	300,652	462,462
Mortgage- and asset-backed securities	38,629	43,355
Loans and other receivables	372,105	362,465
Derivatives	5,147	7,579
Investments, at fair value	1,621	15,612
Total financial instruments owned, at fair value	798,081	1,012,079
Receivables:
Receivables from brokers and dealers	177,793	195,485
Fees	6,763	127
Other assets	446	370
Total assets	1,267,051	1,410,626
Financial instruments sold, not yet purchased, at fair value:
Corporate equity securities	19,341	2,708
Corporate debt securities	202,037	443,100
Loans	142,645	150,100
Derivatives	1,241	136
Total financial instruments sold, not yet purchased, at fair value	380,869	596,044
Payables:
Brokers, dealers and clearing organizations	134,477	157,134
Accrued expenses and other liabilities	7,411	94,402
Carrying amount of mandatorily redeemable preferred interests of consolidated subsidiaries	313,095	315,885
Total liabilities	$ 835,852	$ 1,163,465