v3.26.1
Pension and Other Employee Benefit Plans (Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost) (Detail)
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Weighted-average assumptions used to determine benefit obligations at fiscal year end:      
Discount rates 2.49% 1.67% 1.00%
Rates of increase in future compensation levels 2.00% 2.00% 2.00%
Interest credit rates 5.20% 4.79% 4.52%
Weighted-average assumptions used to determine net periodic benefit cost during the year:      
Discount rates 1.67% 1.00% 0.82%
Rates of increase in future compensation levels 2.00% 2.00% 2.00%
Expected rates of return on plan assets 1.83% 1.61% 1.66%
Interest credit rates 4.79% 4.52% 4.45%