Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended						9 Months Ended
		Jan. 31, 2022	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Jan. 31, 2022	Jan. 31, 2021
Before Tax:
Net other comprehensive income (loss)		$ 4			$ 2			$ 30	$ 26
Tax Effect:
Net other comprehensive income (loss)		(10)			17			(26)	32
Net of Tax:
Net other comprehensive income (loss)		(6)	$ 2	$ 8	19	$ 15	$ 24	4	58
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Before Tax:
Net gain (loss)		(23)			39			(40)	97
Reclassification to earnings		0			0			0	0
Net other comprehensive income (loss)		(23)			39			(40)	97
Tax Effect:
Net gain (loss)		(4)			8			(9)	16
Reclassification to earnings		0			0			0	0
Net other comprehensive income (loss)		(4)			8			(9)	16
Net of Tax:
Net gain (loss)		(27)			47			(49)	113
Reclassification to earnings		0			0			0	0
Net other comprehensive income (loss)		(27)			47			(49)	113
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Before Tax:
Net gain (loss)		23			(39)			53	(73)
Reclassification to earnings	[1]	(2)			(4)			(1)	(21)
Net other comprehensive income (loss)		21			(43)			52	(94)
Tax Effect:
Net gain (loss)		(5)			9			(12)	17
Reclassification to earnings	[1]	0			1			0	5
Net other comprehensive income (loss)		(5)			10			(12)	22
Net of Tax:
Net gain (loss)		18			(30)			41	(56)
Reclassification to earnings	[1]	(2)			(3)			(1)	(16)
Net other comprehensive income (loss)		16			(33)			40	(72)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Before Tax:
Net gain (loss)		0			0			(1)	0
Reclassification to earnings	[2]	6			6			19	23
Net other comprehensive income (loss)		6			6			18	23
Tax Effect:
Net gain (loss)		0			0			0	0
Reclassification to earnings	[2]	(1)			(1)			(5)	(6)
Net other comprehensive income (loss)		(1)			(1)			(5)	(6)
Net of Tax:
Net gain (loss)		0			0			(1)	0
Reclassification to earnings	[2]	5			5			14	17
Net other comprehensive income (loss)		$ 5			$ 5			$ 13	17
Gain on sale of business [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Before Tax:
Reclassification to earnings									$ 4

[1] Pre-tax amount for each period is classified as sales in the accompanying condensed consolidated statements of operations.

[2] For the nine months ended January 31, 2021, $4 of the pre-tax amount of $23 is classified in gain on sale of business in the accompanying condensed consolidated statements of operations. Otherwise, the pre-tax amount for each period is classified as non-operating postretirement expense.