Derivative Instruments (Impact of Derivative Instruments on Borrowing Costs) (Details)	Jun. 30, 2017
Virgin Media [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	0.07%
Telenet [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.34%)
Unitymedia [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.27%)
UPC Holding [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	0.33%
CWC [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	0.47%
VTR Finance [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.52%)
Liberty Puerto Rico [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	0.86%
Liberty Global Group [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	(0.03%)
LiLAC Group [Member]
Derivative [Line Items]
Impact of derivative instruments on borrowing costs	0.30%