Derivative Instruments (Interest Rate Swap Contracts and Options) (Details) $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($)
Interest Rate Swaption 1 \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 6,203.3
Weighted average remaining life	1 year 2 months 12 days
Weighted average strike rate	2.47%
Interest Rate Swaption 2 \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 597.9
Weighted average remaining life	1 year 1 month 6 days
Weighted average strike rate	2.08%
Interest Rate Swaption \| UPC Holding
Derivative [Line Items]
Notional amount of derivative	$ 1,349.5
Weighted average remaining life	9 days
Weighted average strike rate	1.22%
Notional amount due from counterparty \| Interest Rate Swap \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 19,373.0
Weighted average remaining life	3 years 4 months 24 days
Notional amount due from counterparty \| Interest Rate Swap \| UPC Holding
Derivative [Line Items]
Notional amount of derivative	$ 5,843.8
Weighted average remaining life	4 years 9 months 18 days
Notional amount due from counterparty \| Interest Rate Swap \| Telenet
Derivative [Line Items]
Notional amount of derivative	$ 3,904.6
Weighted average remaining life	5 years 6 months
Notional amount due to counterparty \| Interest Rate Swap \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 11,658.4
Weighted average remaining life	5 years 4 months 24 days
Notional amount due to counterparty \| Interest Rate Swap \| UPC Holding
Derivative [Line Items]
Notional amount of derivative	$ 4,028.5
Weighted average remaining life	7 years 1 month 6 days
Notional amount due to counterparty \| Interest Rate Swap \| Telenet
Derivative [Line Items]
Notional amount of derivative	$ 1,657.3
Weighted average remaining life	5 years
Maximum \| Interest Rate Swaption
Derivative [Line Items]
Weighted average remaining life	3 years

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Average fixed interest rate that will be received or paid upon exercise of a group of interest rate swaption contracts.

+ References

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- Definition

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+ References

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