Derivative Financial Instruments (Details 3) (USD $) In Thousands	Aug. 31, 2011
Counterparty credit quality:
Fair value of OTC derivatives assets, Counterparty credit quality, A or higher	$ 439,724
Fair value of OTC derivatives assets, Counterparty credit quality, B to BBB	185,906
Fair value of OTC derivative assets, Counterparty credit quality, Lower than B	6,982
Fair Value of Over the Counter Derivatives Assets Counterparty credit quality Unrated	7,787
Fair Value of Over the Counter Derivatives Assets Counterparty credit quality	$ 640,399

Derivative Fair Value of Derivative Asset Counterparty Credit Quality.

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Fair value of over the counter derivatives assets, counterparty credit quality.

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Fair value of over counter derivatives assets counterparty credit quality B to BBB.

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credit

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Fair value of Over The Counter derivatives assets, counterparty credit quality, A or higher.

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Fair value of over the counter derivatives assets, counterparty credit quality, unrated.

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