Derivative Instruments (Cross-currency Derivative Contracts) (Details) - 3 months ended Mar. 31, 2019 € 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
Derivative [Line Items]
Notional amount of derivative instruments without exchange of notional amounts at inception and maturity | $							$ 4,700.0
Virgin Media | Cross-Currency Swap 1
Derivative [Line Items]
Weighted average remaining life	3 years 9 months 18 days
Virgin Media | Cross-Currency Swap 2
Derivative [Line Items]
Weighted average remaining life	4 years 8 months 12 days
Virgin Media | Cross-Currency Swap 3
Derivative [Line Items]
Weighted average remaining life	5 years 9 months 18 days
UPC Holding | Cross-Currency Swap 4
Derivative [Line Items]
Weighted average remaining life	5 years 4 months 24 days
UPC Holding | Cross-Currency Swap 5
Derivative [Line Items]
Weighted average remaining life	6 years
UPC Holding | Cross-Currency Swap 6
Derivative [Line Items]
Weighted average remaining life	5 years 1 month 6 days
UPC Holding | Cross-Currency Swap 7
Derivative [Line Items]
Weighted average remaining life	1 year 6 months
UPC Holding | Cross-Currency Swap 8
Derivative [Line Items]
Weighted average remaining life	2 years 9 months 18 days
UPC Holding | Cross-Currency Swap 9
Derivative [Line Items]
Weighted average remaining life	2 years 6 months
UPC Holding | Cross-Currency Swap 10
Derivative [Line Items]
Weighted average remaining life	2 years 10 months 24 days
Telenet | Cross-Currency Swap 11
Derivative [Line Items]
Weighted average remaining life	6 years 3 months 18 days
Telenet | Cross-Currency Swap 12
Derivative [Line Items]
Weighted average remaining life	6 years 2 months 12 days
Notional amount due from counterparty | Virgin Media | Cross-Currency Swap 1
Derivative [Line Items]
Notional amount of derivative | $							400.0
Notional amount due from counterparty | Virgin Media | Cross-Currency Swap 2
Derivative [Line Items]
Notional amount of derivative | $							7,182.9
Notional amount due from counterparty | Virgin Media | Cross-Currency Swap 3
Derivative [Line Items]
Notional amount of derivative | £	£ 2,365.8
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 4
Derivative [Line Items]
Notional amount of derivative | $							2,420.0
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 5
Derivative [Line Items]
Notional amount of derivative | $							1,200.0
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 6
Derivative [Line Items]
Notional amount of derivative						€ 2,824.4
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 7
Derivative [Line Items]
Notional amount of derivative						299.2
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 8
Derivative [Line Items]
Notional amount of derivative						375.5
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 9
Derivative [Line Items]
Notional amount of derivative						822.9
Notional amount due from counterparty | UPC Holding | Cross-Currency Swap 10
Derivative [Line Items]
Notional amount of derivative						217.2
Notional amount due from counterparty | Telenet | Cross-Currency Swap 11
Derivative [Line Items]
Notional amount of derivative | $							3,670.0
Notional amount due from counterparty | Telenet | Cross-Currency Swap 12
Derivative [Line Items]
Notional amount of derivative						1,431.2
Notional amount due to counterparty | Virgin Media | Cross-Currency Swap 1
Derivative [Line Items]
Notional amount of derivative						339.6
Notional amount due to counterparty | Virgin Media | Cross-Currency Swap 2
Derivative [Line Items]
Notional amount of derivative | £	£ 4,759.3
Notional amount due to counterparty | Virgin Media | Cross-Currency Swap 3
Derivative [Line Items]
Notional amount of derivative | $							3,400.0
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 4
Derivative [Line Items]
Notional amount of derivative						1,999.4
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 5
Derivative [Line Items]
Notional amount of derivative | SFr			SFr 1,107.5
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 6
Derivative [Line Items]
Notional amount of derivative | SFr			SFr 3,221.2
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 7
Derivative [Line Items]
Notional amount of derivative | Kč				Kč 8,221.8
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 8
Derivative [Line Items]
Notional amount of derivative | Ft		Ft 105,911.9
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 9
Derivative [Line Items]
Notional amount of derivative | zł					zł 3,484.5
Notional amount due to counterparty | UPC Holding | Cross-Currency Swap 10
Derivative [Line Items]
Notional amount of derivative |								610.0
Notional amount due to counterparty | Telenet | Cross-Currency Swap 11
Derivative [Line Items]
Notional amount of derivative						€ 3,243.6
Notional amount due to counterparty | Telenet | Cross-Currency Swap 12
Derivative [Line Items]
Notional amount of derivative | $							$ 1,600.0