Comprehensive Income (Details) (USD $) In Thousands	3 Months Ended	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2009
Components of comprehensive income
Net income	$ 111,523	$ 102,881	$ 479,482	$ 494,138	$ 265,953
Other comprehensive (loss) income:
Foreign currency translation adjustments	(3,321)	(3,608)
Unrealized loss on available-for-sale securities	(206)	(1,397)	2,124	4,162	(4,384)
Unrealized (loss) gain on cash flow hedging derivatives, net	(12,122)	8,968
Unrealized loss on pension and other postretirement liabilities	0	(300)
Income tax benefit (expense)	4,482	(2,863)	1,015	3,971	27,745
Comprehensive income	$ 100,356	$ 103,681

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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-Appendix A

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The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.

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Amounts recognized in other comprehensive income (but not yet recognized in net periodic benefit cost), including the net gain (loss) and net prior service cost (credit) arising during the period. Also includes reclassification adjustments out of other comprehensive income as a result of being recognized as components of net periodic benefit cost for the period.

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Pre tax change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges, net of reclassifications into earnings during the period. A cash flow hedge is a hedge of the exposure to variability in the cash flows of a recognized asset or liability or a forecasted transaction that is attributable to a particular risk. Includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.

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Pre-tax adjustment that results from the process of translating subsidiary financial statements and foreign equity investments into functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains (losses). Includes gain (loss) on foreign currency forward exchange contracts. Includes foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements. Includes the gain or loss on a derivative instrument or nonderivative financial instrument that may give rise to a foreign currency transaction gain or loss under FAS 52 and that have been designated and have qualified as hedging instruments for hedges of the foreign currency exposure of a net investment in a foreign operation.

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Tax effect of the change in accumulated other comprehensive income, that is, the tax effect on items included in other comprehensive income during the period.

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Gross appreciation or the gross loss in value of the total of unsold available-for-sale securities during the period being reported (except when designated as a fair value hedge).

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