Derivative Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Feb. 29, 2012	Feb. 28, 2011
Unrealized and realized gains and (losses) on derivative contracts
Unrealized and realized gains and (losses)	$ (39,733)	$ (41,044)
Interest rate contracts [Member]
Unrealized and realized gains and (losses) on derivative contracts
Unrealized and realized gains and (losses)	(16,235)	6,808
Foreign exchange contracts [Member]
Unrealized and realized gains and (losses) on derivative contracts
Unrealized and realized gains and (losses)	1,161	(5,025)
Equity contracts [Member]
Unrealized and realized gains and (losses) on derivative contracts
Unrealized and realized gains and (losses)	(30,112)	(60,917)
Commodity contracts [Member]
Unrealized and realized gains and (losses) on derivative contracts
Unrealized and realized gains and (losses)	20,680	20,531
Credit contracts [Member]
Unrealized and realized gains and (losses) on derivative contracts
Unrealized and realized gains and (losses)	$ (15,227)	$ (2,441)