Derivative Instruments (Interest Rate Swap Contracts, Options and Basis Swaps) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Interest Rate Swaption 1 | Virgin Media
Derivative [Line Items]
Notional amount	$ 7,085.7
Weighted average remaining life	1 year
Weighted average strike rate	2.40%
Interest Rate Swaption 2 | Virgin Media
Derivative [Line Items]
Notional amount	$ 482.7
Weighted average remaining life	18 days
Weighted average strike rate	1.96%
Basis Swaps | Virgin Media
Derivative [Line Items]
Weighted average remaining life	15 days
Basis Swaps | Telenet
Derivative [Line Items]
Weighted average remaining life	15 days
Notional amount due from counterparty | Interest Rate Swap | Virgin Media
Derivative [Line Items]
Notional amount	$ 21,715.5
Weighted average remaining life	2 years 8 months 12 days
Notional amount due from counterparty | Interest Rate Swap | UPC Holding
Derivative [Line Items]
Notional amount	$ 7,237.1
Weighted average remaining life	3 years 6 months
Notional amount due from counterparty | Interest Rate Swap | Telenet
Derivative [Line Items]
Notional amount	$ 3,239.1
Weighted average remaining life	5 years 2 months 12 days
Notional amount due from counterparty | Basis Swaps | Virgin Media
Derivative [Line Items]
Notional amount	$ 4,493.7
Notional amount due from counterparty | Basis Swaps | Telenet
Derivative [Line Items]
Notional amount	2,295.0
Notional amount due to counterparty | Interest Rate Swap | Virgin Media
Derivative [Line Items]
Notional amount	$ 11,542.6
Weighted average remaining life	4 years 4 months 24 days
Notional amount due to counterparty | Interest Rate Swap | UPC Holding
Derivative [Line Items]
Notional amount	$ 5,312.1
Weighted average remaining life	5 years 10 months 24 days
Notional amount due to counterparty | Interest Rate Swap | Telenet
Derivative [Line Items]
Notional amount	$ 1,602.4
Weighted average remaining life	3 years 8 months 12 days