v3.3.1.900
Income Taxes (Narrative) (Details) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Mar. 31, 2014
Apr. 30, 2015
Apr. 30, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Change in valuation allowances       $ 373.4    
Net operating losses from deductions of stock based compensation excluded from recorded deferred tax assets       141.7    
Deferred tax liability, temporary difference       11,100.0    
Unrecognized tax benefits - favorable impact on effective income tax rate if ultimately recognized, net of valuation allowances       332.9    
Reasonably possible resolution of ongoing income tax examinations, reduction to unrecognized tax benefits, upper bound       230.0    
Accrued interest and penalties on tax related items       51.7    
Virgin Media [Member]            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Amount on which future tax deductions can be claimed       $ 21,600.0 $ 22,200.0  
Maximum percent of capital allowances claimed allowance       18.00%    
Continuing operations [Member]            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Change in valuation allowances related to net tax expense       $ (361.2)    
Benefit (expense) from release (accrual) of interest and penalties       $ (10.9) $ (14.0) $ (7.7)
Domestic Tax Authority [Member]            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Statutory income tax rate 23.00%   21.00%      
Domestic Tax Authority [Member] | Scenario, Forecast [Member]            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Statutory income tax rate   20.00%        
Foreign Tax Authority [Member]            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Statutory income tax rate       35.00%