Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 684us-gaap_NetIncomeLoss	$ 659us-gaap_NetIncomeLoss	$ 591us-gaap_NetIncomeLoss
Currency translation adjustments	(114)	(4)	17
Cash flow hedge adjustments	32	(4)	3
Postretirement benefits adjustments	(30)	31	(1)
Net other comprehensive income (loss)	(112)	23	19
Comprehensive income	$ 572us-gaap_ComprehensiveIncomeNetOfTax	$ 682us-gaap_ComprehensiveIncomeNetOfTax	$ 610us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans, attributable to parent entity.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss), attributable to parent entity.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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