v3.25.2
Fair Value Measurements (Assets and Liabilities at Fair Value) (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments $ 322.0 $ 843.9
SMAs 82.8 433.1
Other investments 3,175.3 2,810.2
Total investments 3,258.1 3,243.3
Total assets 3,580.1 4,087.2
Derivative instruments: 333.2 186.4
Total liabilities 333.2 186.4
Quoted prices in active markets for identical assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
SMAs 0.0 127.0
Other investments 1,807.5 1,546.3
Total investments 1,807.5 1,673.3
Total assets 1,807.5 1,673.3
Total liabilities 0.0 0.0
Significant other observable inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 322.0 630.5
SMAs 82.8 306.1
Other investments 0.1 0.1
Total investments 82.9 306.2
Total assets 404.9 936.7
Total liabilities 333.2 186.4
Significant unobservable inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 213.4
SMAs 0.0 0.0
Other investments 1,367.7 1,263.8
Total investments 1,367.7 1,263.8
Total assets 1,367.7 1,477.2
Total liabilities 0.0 0.0
Cross-currency and interest rate derivative contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 270.1 623.2
Derivative instruments: 304.5 183.1
Cross-currency and interest rate derivative contracts | Quoted prices in active markets for identical assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
Derivative instruments: 0.0 0.0
Cross-currency and interest rate derivative contracts | Significant other observable inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 270.1 623.2
Derivative instruments: 304.5 183.1
Cross-currency and interest rate derivative contracts | Significant unobservable inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
Derivative instruments: 0.0 0.0
Equity-related derivative instruments    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 29.3 213.4
Equity-related derivative instruments | Quoted prices in active markets for identical assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
Equity-related derivative instruments | Significant other observable inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 29.3 0.0
Equity-related derivative instruments | Significant unobservable inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 213.4
Foreign currency forward and option contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 15.6 6.5
Derivative instruments: 21.8 3.3
Foreign currency forward and option contracts | Quoted prices in active markets for identical assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
Derivative instruments: 0.0 0.0
Foreign currency forward and option contracts | Significant other observable inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 15.6 6.5
Derivative instruments: 21.8 3.3
Foreign currency forward and option contracts | Significant unobservable inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
Derivative instruments: 0.0 0.0
Other    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 7.0 0.8
Derivative instruments: 6.9 0.0
Other | Quoted prices in active markets for identical assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 0.0
Derivative instruments: 0.0  
Other | Significant other observable inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 7.0 0.8
Derivative instruments: 6.9  
Other | Significant unobservable inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative instruments 0.0 $ 0.0
Derivative instruments: $ 0.0