v3.25.4
Pension Plans and Postretirement Benefits - Plan Asset Allocations by Asset Category (Detail)
Dec. 31, 2025
Dec. 31, 2024
United States: | Pension Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Total 100.00% 100.00%
United States: | Pension Benefits | U.S. Government Securities    
Defined Benefit Plan Disclosure [Line Items]    
Total 38.00% 33.00%
United States: | Pension Benefits | Commingled and Mutual Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total 4.00% 27.00%
United States: | Pension Benefits | Real Estate    
Defined Benefit Plan Disclosure [Line Items]    
Total 14.00% 14.00%
United States: | Pension Benefits | Diversified Credit    
Defined Benefit Plan Disclosure [Line Items]    
Total 13.00% 14.00%
United States: | Pension Benefits | Fixed Income (excluding U.S. Government Securities)    
Defined Benefit Plan Disclosure [Line Items]    
Total 7.00% 6.00%
United States: | Pension Benefits | Partnerships with Security Holdings    
Defined Benefit Plan Disclosure [Line Items]    
Total 1.00% 2.00%
United States: | Pension Benefits | Cash and Accrued Items    
Defined Benefit Plan Disclosure [Line Items]    
Total 23.00% 4.00%
Canada | Other Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Total 100.00% 100.00%
Canada | Other Benefits | Fixed Income    
Defined Benefit Plan Disclosure [Line Items]    
Total 29.00% 60.00%
Canada | Other Benefits | Commingled and Mutual Funds    
Defined Benefit Plan Disclosure [Line Items]    
Total 49.00% 37.00%
Canada | Other Benefits | Cash and Other    
Defined Benefit Plan Disclosure [Line Items]    
Total 22.00% 3.00%