v3.3.1.900
Investments (Details)
£ / shares in Units, $ / shares in Units, € in Millions, £ in Millions, $ in Millions
1 Months Ended 12 Months Ended
Sep. 30, 2014
EUR (€)
Sep. 30, 2014
USD ($)
Dec. 31, 2013
USD ($)
shares
Dec. 31, 2014
shares
Jul. 17, 2014
USD ($)
$ / shares
shares
Jul. 17, 2014
GBP (£)
£ / shares
shares
All3Media [Member]            
Schedule of Investments [Line Items]            
Business acquisition, cash consideration € 90.0 $ 147.2        
DLG [Member] | All3Media [Member]            
Schedule of Investments [Line Items]            
Percentage of equity, percentage of shares acquired 100.00% 100.00%        
Ziggo [Member]            
Schedule of Investments [Line Items]            
Number of common stock shares owned (in shares)     57,000,738      
Percent of investment owned (less than 5% for Sumitomo)     28.50%      
Shares not pledged as collateral (in shares)     4,743,738      
Cash dividends from investment | $     $ 78.4      
ITV [Member]            
Schedule of Investments [Line Items]            
Number of common stock shares owned (in shares)         259,820,065 259,820,065
Percent of investment owned (less than 5% for Sumitomo) 6.40% 6.40%        
Share price (in GBP/USD per share) | (per share)         $ 3.14 £ 1.85
Cost method investments         $ 816.3 £ 480.7
DLG Acquisition Limited [Member]            
Schedule of Investments [Line Items]            
Percent of investment owned (less than 5% for Sumitomo)       50.00%    
Sumitomo [Member]            
Schedule of Investments [Line Items]            
Number of common stock shares owned (in shares)     45,652,043 45,652,043    
Percent of investment owned (less than 5% for Sumitomo)       5.00%    
ITI Neovision S.A. (ITI Neovision) (formerly Canal Cyfrowy S.A.) [Member]            
Schedule of Investments [Line Items]            
Percentage of equity, percentage of shares acquired       17.00%