Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended
		Jul. 31, 2017	Jul. 31, 2016
Before Tax:
Net other comprehensive income (loss)		$ (5)	$ (44)
Tax Effect:
Net other comprehensive income (loss)		19	(8)
Net of Tax:
Net other comprehensive income (loss)		14	(52)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Before Tax:
Net gain (loss)		28	(68)
Reclassification to earnings		0	0
Net other comprehensive income (loss)		28	(68)
Tax Effect:
Net gain (loss)		6	1
Reclassification to earnings		0	0
Net other comprehensive income (loss)		6	1
Net of Tax:
Net gain (loss)		34	(67)
Reclassification to earnings		0	0
Net other comprehensive income (loss)		34	(67)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Before Tax:
Net gain (loss)		(36)	29
Reclassification to earnings	[1]	(2)	(10)
Net other comprehensive income (loss)		(38)	19
Tax Effect:
Net gain (loss)		14	(11)
Reclassification to earnings	[1]	1	4
Net other comprehensive income (loss)		15	(7)
Net of Tax:
Net gain (loss)		(22)	18
Reclassification to earnings	[1]	(1)	(6)
Net other comprehensive income (loss)		(23)	12
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Before Tax:
Net gain (loss)		1	0
Reclassification to earnings	[2]	4	5
Net other comprehensive income (loss)		5	5
Tax Effect:
Net gain (loss)		0	0
Reclassification to earnings	[2]	(2)	(2)
Net other comprehensive income (loss)		(2)	(2)
Net of Tax:
Net gain (loss)		1	0
Reclassification to earnings	[2]	2	3
Net other comprehensive income (loss)		$ 3	$ 3

[1] Pre-tax amount is classified as net sales in the accompanying consolidated statements of operations.

[2] Pre-tax amount is a component of pension and other postretirement benefit expense (as shown in Note 7, except for amounts related to non-U.S. benefit plans, about which no information is presented in Note 7 due to immateriality).