Pension and Other Postretirement Benefits (Assumptions and SensItivity) (Details)	12 Months Ended
	Apr. 30, 2024	Apr. 30, 2023	Apr. 30, 2022
Pension Benefits [Member]
Assumptions used in computing benefit plan obligations
Discount rate (percent)	5.70%	4.91%
Rate of salary increase (percent)	4.00%	4.00%
Interest crediting rate (percent)	4.79%	3.69%
Assumptions used in computing benefit plan expense
Discount rate for service cost (percent)	4.98%	4.52%	3.36%
Discount rate for interest cost (percent)	4.79%	4.12%	2.34%
Rate of salary increase (percent)	4.00%	4.00%	4.00%
Interest crediting rate (percent)	3.69%	3.06%	3.06%
Expected return on plan assets (percent)	6.50%	6.25%	6.25%
Medical and Life Insurance Benefits [Member]
Assumptions used in computing benefit plan obligations
Discount rate (percent)	5.66%	4.86%
Assumptions used in computing benefit plan expense
Discount rate for service cost (percent)	5.02%	4.50%	3.49%
Discount rate for interest cost (percent)	4.78%	3.96%	2.27%
Assumed health care cost trend rates
Health care cost trend rate assumed for next year (percent)	7.13%	7.23%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) (percent)	4.50%	4.50%