Derivative Instruments (Cross-currency Derivative Contracts) (Details) - 3 months ended Mar. 31, 2018 € in Millions, £ in Millions, zł in Millions, SFr in Millions, Kč in Millions, Ft in Millions, $ in Millions, in Millions	GBP (£)	HUF (Ft)	CHF (SFr)	CZK (Kč)	PLN (zł)	EUR (€)	USD ($)	RON ( )
Virgin Media [Member]
Derivative [Line Items]
Notional amount of derivative instruments without exchange of notional amounts at inception and maturity | $							$ 3,800.0
Virgin Media [Member] | Cross-Currency Swap 1 [Member]
Derivative [Line Items]
Weighted average remaining life	4 years 9 months 18 days
Virgin Media [Member] | Cross-Currency Swap 2 [Member]
Derivative [Line Items]
Weighted average remaining life	5 years 6 months
Virgin Media [Member] | Cross-Currency Swap 3 [Member]
Derivative [Line Items]
Weighted average remaining life	6 years 9 months 18 days
UPC Holding [Member] | Cross-Currency Swap 4 [Member]
Derivative [Line Items]
Weighted average remaining life	6 years 6 months
UPC Holding [Member] | Cross-Currency Swap 5 [Member]
Derivative [Line Items]
Weighted average remaining life	7 years
UPC Holding [Member] | Cross-Currency Swap 6 [Member]
Derivative [Line Items]
Weighted average remaining life	5 years 8 months 12 days
UPC Holding [Member] | Cross-Currency Swap 7 [Member]
Derivative [Line Items]
Weighted average remaining life	2 years 3 months 18 days
UPC Holding [Member] | Cross-Currency Swap 8 [Member]
Derivative [Line Items]
Weighted average remaining life	3 years 9 months 18 days
UPC Holding [Member] | Cross-Currency Swap 9 [Member]
Derivative [Line Items]
Weighted average remaining life	3 years 6 months
UPC Holding [Member] | Cross-Currency Swap 10 [Member]
Derivative [Line Items]
Weighted average remaining life	3 years 10 months 24 days
Unitymedia [Member] | Cross-Currency Swap 11 [Member]
Derivative [Line Items]
Weighted average remaining life	6 years 3 months 18 days
Telenet [Member] | Cross-Currency Swap 12 [Member]
Derivative [Line Items]
Weighted average remaining life	7 years 1 month 6 days
Due From Counterparty [Member] | Virgin Media [Member] | Cross-Currency Swap 1 [Member]
Derivative [Line Items]
Notional amount of derivative | $							400.0
Due From Counterparty [Member] | Virgin Media [Member] | Cross-Currency Swap 2 [Member]
Derivative [Line Items]
Notional amount of derivative | $							8,933.0
Due From Counterparty [Member] | Virgin Media [Member] | Cross-Currency Swap 3 [Member]
Derivative [Line Items]
Notional amount of derivative | £	£ 2,396.1
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 4 [Member]
Derivative [Line Items]
Notional amount of derivative | $							2,765.0
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 5 [Member]
Derivative [Line Items]
Notional amount of derivative | $							1,200.0
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 6 [Member]
Derivative [Line Items]
Notional amount of derivative						€ 2,521.2
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 7 [Member]
Derivative [Line Items]
Notional amount of derivative						418.5
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 8 [Member]
Derivative [Line Items]
Notional amount of derivative						488.0
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 9 [Member]
Derivative [Line Items]
Notional amount of derivative						851.6
Due From Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 10 [Member]
Derivative [Line Items]
Notional amount of derivative						225.9
Due From Counterparty [Member] | Unitymedia [Member] | Cross-Currency Swap 11 [Member]
Derivative [Line Items]
Notional amount of derivative | $							3,155.0
Due From Counterparty [Member] | Telenet [Member] | Cross-Currency Swap 12 [Member]
Derivative [Line Items]
Notional amount of derivative | $							3,195.0
Due To Counterparty [Member] | Virgin Media [Member] | Cross-Currency Swap 1 [Member]
Derivative [Line Items]
Notional amount of derivative						339.6
Due To Counterparty [Member] | Virgin Media [Member] | Cross-Currency Swap 2 [Member]
Derivative [Line Items]
Notional amount of derivative | £	£ 5,844.3
Due To Counterparty [Member] | Virgin Media [Member] | Cross-Currency Swap 3 [Member]
Derivative [Line Items]
Notional amount of derivative | $							$ 3,450.0
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 4 [Member]
Derivative [Line Items]
Notional amount of derivative						2,276.7
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 5 [Member]
Derivative [Line Items]
Notional amount of derivative | SFr			SFr 1,107.5
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 6 [Member]
Derivative [Line Items]
Notional amount of derivative | SFr			SFr 2,901.0
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 7 [Member]
Derivative [Line Items]
Notional amount of derivative | Kč				Kč 11,521.8
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 8 [Member]
Derivative [Line Items]
Notional amount of derivative | Ft		Ft 138,437.5
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 9 [Member]
Derivative [Line Items]
Notional amount of derivative | zł					zł 3,604.5
Due To Counterparty [Member] | UPC Holding [Member] | Cross-Currency Swap 10 [Member]
Derivative [Line Items]
Notional amount of derivative |								650.0
Due To Counterparty [Member] | Unitymedia [Member] | Cross-Currency Swap 11 [Member]
Derivative [Line Items]
Notional amount of derivative						2,603.5
Due To Counterparty [Member] | Telenet [Member] | Cross-Currency Swap 12 [Member]
Derivative [Line Items]
Notional amount of derivative						€ 2,834.1