v3.26.3
Investments (Investments) (Details)
€ in Millions, £ in Millions, $ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Jun. 29, 2026
USD ($)
Jun. 30, 2026
USD ($)
Mar. 31, 2026
USD ($)
Mar. 31, 2026
GBP (£)
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Sep. 30, 2026
EUR (€)
Schedule of Investments [Line Items]                
Equity         $ 3,989.9   $ 6,054.6  
Short-term investments at fair value         0.0   76.2  
Total — fair value         1,060.9   1,707.7  
Total investments         5,050.8   7,762.3  
Short-term investments         0.0   76.2  
Long-term investments         5,050.8   7,686.1  
Structured Notes                
Schedule of Investments [Line Items]                
Proceeds received from the sale and maturities of debt securities     $ 36.6          
Received cash proceeds   $ 46.3            
ITV                
Schedule of Investments [Line Items]                
Ownership interest retained after disposal     50.00% 50.00%        
VMO2 JV                
Schedule of Investments [Line Items]                
Equity         $ 3,442.9   3,756.7  
Ownership percentage         50.00%     50.00%
AE Group Sàrl (AtlasEdge JV)                
Schedule of Investments [Line Items]                
Equity         $ 365.2   388.4  
Ownership percentage         48.80%     48.80%
Nexfibre Networks Limited (nexfibre JV)                
Schedule of Investments [Line Items]                
Equity         $ 73.5   88.3  
Ownership percentage         25.00%     25.00%
VodafoneZiggo JV                
Schedule of Investments [Line Items]                
Equity         $ 0.0   1,738.6  
Ownership percentage         50.00%     50.00%
VodafoneZiggo JV | VodafoneZiggo JV Loan                
Schedule of Investments [Line Items]                
Excess of carrying amount over proportional share in investees net assets             $ 1,029.2  
Related party note receivable rate             5.55%  
VodafoneZiggo JV | VodafoneZiggo JV Receivable I                
Schedule of Investments [Line Items]                
Related party note receivable             $ 1,065.5 € 907.9
Other                
Schedule of Investments [Line Items]                
Equity         $ 108.3   82.6  
Equity securities fair value         461.4   385.2  
Televisa Univision, Inc. (Televisa Univision)                
Schedule of Investments [Line Items]                
Long-term investments at fair value         $ 299.5   299.5  
Ownership percentage         6.50%     6.50%
ITV                
Schedule of Investments [Line Items]                
Equity securities fair value         $ 84.4   208.4  
Ownership percentage         2.50%     2.50%
Proceeds from sale of equity method investments     $ 101.8 £ 76.1        
CANAL+ Polska S.A.                
Schedule of Investments [Line Items]                
Equity securities fair value         $ 82.2   81.8  
Ownership percentage         17.00%     17.00%
Lionsgate Studios Corp. (Lionsgate)                
Schedule of Investments [Line Items]                
Equity securities fair value         $ 78.8   64.2  
Ownership percentage         2.40%     2.40%
Plume Design, Inc. (Plume)                
Schedule of Investments [Line Items]                
Long-term investments at fair value         $ 54.6   64.1  
Ownership percentage         10.20%     10.20%
Warrants, fair value         $ 17.4   21.1  
EdgeConneX, Inc. (EdgeConneX)                
Schedule of Investments [Line Items]                
Equity securities fair value         0.0   $ 528.3  
Proceeds from sale of equity method investments         $ 677.8 $ 0.0    
Proceeds from sale of securities $ 604.2   $ 73.6          
EdgeConneX, Inc. (EdgeConneX) | Herndon Topco                
Schedule of Investments [Line Items]                
Disposed interest percentage     16.00% 16.00%        
AtlasEdge JV | Liberty Global                
Schedule of Investments [Line Items]                
Percentage of ownership interest         50.00%     50.00%
nexfibre JV | Liberty Global                
Schedule of Investments [Line Items]                
Percentage of ownership interest         25.00%     25.00%