v3.25.2
Fair Value Measurements: Other Fair Value Measurements (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Carrying Amount    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, including current maturities $ 4,252.4 $ 4,250.2
Fair Value    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, including current maturities $ 4,101.2 $ 4,059.1