Employee Benefit and Stock Plans (Details) (USD $)	12 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Stock option transactions
Options outstanding at beginning of year, Options	10,160,396	8,798,613	5,711,701
Options outstanding at beginning of year, Weighted Average Exercise Price	$ 21.27	$ 24.19	$ 27.39
Granted, Options	30,000	1,716,000	3,572,237
Granted, Weighted Average Exercise Price	$ 9.08	$ 6.36	$ 18.71
Exercised, Shares	(7,494)	0	(28,281)
Exercised, Weighted Average Exercise Price	$ 13.93	$ 0.00	$ 13.00
Cancelled, Options	(77,356)	(354,217)	(457,044)
Cancelled, Weighted Average Exercise Price	$ 17.96	$ 21.47	$ 22.05
Options outstanding at end of year, Options	10,105,546	10,160,396	8,798,613
Options outstanding at end of year, Weighted Average Exercise Price	$ 21.27	$ 21.27	$ 24.19
Options exercisable at end of year, Options	8,533,224	7,142,568	6,146,605
Options exercisable at end of period, Weighted Average Exercise Price	$ 23.76	$ 26.43	$ 28.73
Options available for grant at end of year, Options	1,721,847	2,477,219	21,703
1988 Employee Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based payments award terms of Award	15 years