v3.25.1
Pension and Other Postretirement Benefits (Change in Benefit Obligation) (Details) - USD ($)
$ in Millions
12 Months Ended
Apr. 30, 2025
Apr. 30, 2024
Apr. 30, 2023
Pension Benefits [Member]      
Changes in present value of pension and other postretirement benefits      
Obligation at beginning of year $ 679 $ 731  
Service cost 16 18 $ 20
Interest cost 35 34 32
Net actuarial loss (gain)1 [1] 5 (61)  
Plan amendments 0 1  
Retiree contributions 0 0  
Benefits paid (52) (44)  
Special termination benefits 0 0  
Obligation at end of year 683 679 731
Medical and Life Insurance Benefits [Member]      
Changes in present value of pension and other postretirement benefits      
Obligation at beginning of year 36 40  
Service cost 0 0 1
Interest cost 2 2 1
Net actuarial loss (gain)1 [1] 3 (3)  
Plan amendments 0 0  
Retiree contributions 2 3  
Benefits paid (5) (6)  
Special termination benefits 1 0  
Obligation at end of year $ 39 $ 36 $ 40
[1] The net actuarial loss (gain) during each year was primarily attributable to changes in discount rates