Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 208	$ 206	$ 358	$ 349
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(30)	7	(46)	(5)
Cash flow hedge adjustments	22	(10)	27	(4)
Postretirement benefits adjustments	12	14	16	19
Net other comprehensive income (loss)	4	11	(3)	10
Comprehensive income	$ 212	$ 217	$ 355	$ 359

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.

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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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