Accumulated Other Comprehensive Income Schedule of Other Comprehensive Income (Details) - USD ($) $ in Millions		12 Months Ended
		Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Before Tax:
Net other comprehensive income (loss)		$ (14)	$ (69)	$ (113)
Tax Effect:
Net other comprehensive income (loss)		(26)	19	1
Net of Tax:
Net other comprehensive income (loss)		(40)	(50)	(112)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Before Tax:
Net gain (loss)		(71)	(22)	(120)
Reclassification to earnings		3	0	0
Net other comprehensive income (loss)		(68)	(22)	(120)
Tax Effect:
Net gain (loss)		(4)	(1)	6
Reclassification to earnings		(1)	0	0
Net other comprehensive income (loss)		(5)	(1)	6
Net of Tax:
Net gain (loss)		(75)	(23)	(114)
Reclassification to earnings		2	0	0
Net other comprehensive income (loss)		(73)	(23)	(114)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Before Tax:
Net gain (loss)		41	30	96
Reclassification to earnings	[1]	(40)	(60)	(41)
Net other comprehensive income (loss)		1	(30)	55
Tax Effect:
Net gain (loss)		(17)	(10)	(40)
Reclassification to earnings	[1]	16	23	17
Net other comprehensive income (loss)		(1)	13	(23)
Net of Tax:
Net gain (loss)		24	20	56
Reclassification to earnings	[1]	(24)	(37)	(24)
Net other comprehensive income (loss)		0	(17)	32
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Before Tax:
Net gain (loss)		28	(47)	(70)
Reclassification to earnings	[2]	25	30	22
Net other comprehensive income (loss)		53	(17)	(48)
Tax Effect:
Net gain (loss)		(10)	19	26
Reclassification to earnings	[2]	(10)	(12)	(8)
Net other comprehensive income (loss)		(20)	7	18
Net of Tax:
Net gain (loss)		18	(28)	(44)
Reclassification to earnings	[2]	15	18	14
Net other comprehensive income (loss)		$ 33	$ (10)	$ (30)

[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 9, except for amounts related to non-U.S. benefit plans, about which no information is presented in Note 9 due to immateriality).