v3.25.4
Employee Benefit Plans: Plan Contributions (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year $ 1.6  
Payment for Pension Benefits 1.8 $ 2.3
Healthcare Plan    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year 4.5  
Payment for Pension and Other Postretirement Benefits 4.6 5.7
Payment for Pension Benefits 3.3 4.2
Supplemental Plans    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year 2.8  
Payment for Pension Benefits 4.5 4.1
Defined Contribution Plan, Company Retirement    
Defined Benefit Plan Disclosure [Line Items]    
Defined Contribution Plan, Employer Discretionary Contribution Amount 11.5 11.3
Defined Contribution Plan, 401K    
Defined Benefit Plan Disclosure [Line Items]    
Defined Contribution Plan, Employer Discretionary Contribution Amount $ 17.6 $ 17.7