v3.10.0.1
Equity (Narrative) (Details)
$ / shares in Units, € in Millions
 1 Months Ended
Oct. 04, 2018
EUR (€)
Oct. 04, 2018
USD ($)
Aug. 31, 2018
EUR (€)
Dec. 31, 2018
USD ($)
class
$ / shares
shares
Dec. 31, 2017
$ / shares
shares
Jul. 01, 2015
vote
Class of Stock [Line Items]            
Share capital authorized, aggregate nominal amount | $       $ 20,000,000.0    
Minimum number of classes or series of stock which may be authorized | class       1    
Dividends € 351.6 $ 404,800,000        
Telenet            
Class of Stock [Line Items]            
Dividends | €     € 600.0      
Options | Telenet            
Class of Stock [Line Items]            
Awards outstanding (in shares)       4,494,002    
Class A            
Class of Stock [Line Items]            
Common stock, nominal value (in dollars per share) | $ / shares       $ 0.01 $ 0.01  
Number of votes allowed per class of stock (in votes) | vote           10
Number of ordinary shares convertible to certain class of ordinary shares (in shares)       1    
Class A | Options            
Class of Stock [Line Items]            
Awards outstanding (in shares)       580,254 580,481  
Class A | PSUs, PGUs, RSUs            
Class of Stock [Line Items]            
Common reserved for issuance (in shares)       3,487,018    
Class B            
Class of Stock [Line Items]            
Common stock, nominal value (in dollars per share) | $ / shares       $ 0.01 $ 0.01  
Number of votes allowed per class of stock (in votes) | vote           1
Common reserved for issuance (in shares)       11,099,593    
Class C            
Class of Stock [Line Items]            
Common stock, nominal value (in dollars per share) | $ / shares       $ 0.01 $ 0.01  
Class C | Options            
Class of Stock [Line Items]            
Awards outstanding (in shares)       2,667,506 2,725,566  
Class C | PSUs, PGUs, RSUs            
Class of Stock [Line Items]            
Common reserved for issuance (in shares)       6,976,788