v3.26.1
Pension and Other Postretirement Benefits - Schedule of Components of Periodic Benefit Costs (Details) - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2024
Pension benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 23 $ 23  
Interest cost 55 57  
Pension benefits | Direct Plans      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 23 23 $ 27
Interest cost 55 57 61
Expected return on plan assets (52) (50) (45)
Amortization of deferred losses (gains) 9 5 12
Net periodic benefit costs 35 35 55
Postretirement benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 0 1  
Interest cost 2 2  
Postretirement benefits | Direct Plans      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 0 1 0
Interest cost 2 2 2
Expected return on plan assets 0 0 0
Amortization of deferred losses (gains) (3) (4) (4)
Net periodic benefit costs $ (1) $ (1) $ (2)