Derivative Instruments (Basis Swaps, Interest Rate Caps and Collars) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)
Interest Rate Caps
Derivative [Line Items]
Notional amount of derivative	$ 245.8
Interest Rate Collars
Derivative [Line Items]
Notional amount of derivative	$ 618.7
Virgin Media | Basis Swaps
Derivative [Line Items]
Weighted average remaining life	9 months 18 days
Telenet | Basis Swaps
Derivative [Line Items]
Weighted average remaining life	9 months 18 days
Notional amount due from counterparty | Virgin Media | Basis Swaps
Derivative [Line Items]
Notional amount of derivative	$ 4,506.1
Notional amount due from counterparty | Telenet | Basis Swaps
Derivative [Line Items]
Notional amount of derivative	$ 2,075.0