Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 182	$ 190	$ 524	$ 545
Other comprehensive income (loss), net of tax:
Currency translation adjustments	(25)	(30)	(110)	(58)
Cash flow hedge adjustments	(7)	8	14	20
Postretirement benefits adjustments	6	5	13	15
Net other comprehensive income (loss)	(26)	(17)	(83)	(23)
Comprehensive income	$ 156	$ 173	$ 441	$ 522

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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