v3.26.1
Retirement Benefit Obligations - Key Weighted Average Assumptions Used in Determining Benefit Plan Costs and Obligations (Detail) - Benefit Plan Costs
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Defined Benefit Plan Disclosure [Line Items]    
Discount Rate 5.45% 5.60%
Rate of Compensation Increase 3.00% 3.00%
Expected Long-term rate of return on plan assets 7.50% 7.50%