Derivative Instruments (Impact of Derivative Instruments on Borrowing Costs) (Details)	Mar. 31, 2018
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.27%)
Virgin Media [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.21%)
Telenet [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.33%)
Unitymedia [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.62%)
UPC Holding [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	0.15%