v3.25.2
Fair Value Measurements - Fair Value, Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: $ 88.3  
U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 48.9  
Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 39.4  
Recurring    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Equity securities 39.8 $ 130.9
Redeemable noncontrolling interests 55.1 56.5
Recurring | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 48.9  
Recurring | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 39.4  
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Equity securities 18.7 4.2
Redeemable noncontrolling interests 0.0 0.0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 48.9  
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 0.0  
Recurring | Significant Other Observable Inputs (Level 2)    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Equity securities 21.1 126.7
Redeemable noncontrolling interests 0.0 0.0
Recurring | Significant Other Observable Inputs (Level 2) | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 0.0  
Recurring | Significant Other Observable Inputs (Level 2) | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 39.4  
Recurring | Significant Unobservable Inputs (Level 3)    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Equity securities 0.0 0.0
Redeemable noncontrolling interests 55.1 $ 56.5
Recurring | Significant Unobservable Inputs (Level 3) | U.S. government and agency securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: 0.0  
Recurring | Significant Unobservable Inputs (Level 3) | Corporate bonds and notes    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]    
Available for sale debt securities: $ 0.0