v3.26.1
Benefit Plans (Fair value of our pension benefits plan assets) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Defined Benefit Plan Disclosure [Line Items]      
Other Investments $ 7.8 $ 6.9 $ 6.1
Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Cash and Cash Equivalents, Fair Value Disclosure 439.6 171.7  
Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Cash and Cash Equivalents, Fair Value Disclosure 0.0 0.0  
Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Cash and Cash Equivalents, Fair Value Disclosure 0.0 0.0  
Other Defined Benefit Pension Plans [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Insurance Contract 7.8 6.9  
Trading Securities, Cost 31.3 39.8  
Cash and Cash Equivalents, Fair Value Disclosure 0.9 0.4  
Other Investments 9.1 9.9  
Defined Benefit Plan, Plan Assets, Amount 112.8 109.3 $ 113.9
Debt Securities, Trading 63.8 52.3  
Other Defined Benefit Pension Plans [Member] | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Insurance Contract 0.0 0.0  
Cash and Cash Equivalents, Fair Value Disclosure 0.9 0.4  
Other Investments 0.0 0.0  
Defined Benefit Plan, Plan Assets, Amount 0.9 0.4  
Other Defined Benefit Pension Plans [Member] | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Insurance Contract 0.0 0.0  
Cash and Cash Equivalents, Fair Value Disclosure 0.0 0.0  
Other Investments 9.1 9.9  
Defined Benefit Plan, Plan Assets, Amount 9.1 9.9  
Other Defined Benefit Pension Plans [Member] | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Insurance Contract 7.8 6.9  
Cash and Cash Equivalents, Fair Value Disclosure 0.0 0.0  
Other Investments 0.0 0.0  
Defined Benefit Plan, Plan Assets, Amount $ 7.8 $ 6.9