Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 239	$ 197	$ 417	$ 342
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(25)	(18)	9	(85)
Cash flow hedge adjustments	7	9	(16)	21
Postretirement benefits adjustments	3	4	6	7
Net other comprehensive income (loss)	(15)	(5)	(1)	(57)
Comprehensive income	$ 224	$ 192	$ 416	$ 285

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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