Pension and Other Postretirement Benefits (Savings Plans) (Details) - USD ($) $ in Millions	12 Months Ended
Apr. 30, 2024	Apr. 30, 2023	Apr. 30, 2022
Retirement Benefits [Abstract]
Expense for matching contributions	$ 14	$ 14	$ 13

Amount of cost for defined contribution plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration