Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2022		Apr. 30, 2021	Apr. 30, 2020
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 7		$ 11	$ 7
Additions Charged to Costs and Expenses	7		0	4
Additions Charged to Other Accounts	0		0	0
Deductions	1	[1]	4	0	[1]
Balance at End of Period	13		7	11
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	20		22	25
Additions Charged to Costs and Expenses	8		10	2
Additions Charged to Other Accounts	0		0	0
Deductions	1		12	5
Balance at End of Period	$ 27		$ 20	$ 22

[1] Doubtful accounts written off, net of recoveries.