v3.26.1
Retirement benefits - Weighted-Average Asset Allocation of Said Plan Assets for Pension Benefits (Detail) - Pension
Mar. 31, 2026
Funds managed by trust  
Weighted-average asset allocation 100.00%
Government Securities  
Funds managed by trust  
Weighted-average asset allocation 88.60%
Debenture and bonds  
Funds managed by trust  
Weighted-average asset allocation 11.40%
Other  
Funds managed by trust  
Weighted-average asset allocation 0.00%