Derivative Instruments (Interest Rate Swap Contracts and Options) (Details) $ in Millions	6 Months Ended
Jun. 30, 2019 USD ($)
Interest Rate Swaption 1 \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 6,782.2
Weighted average remaining life	1 year 6 months
Weighted average strike rate	2.40%
Interest Rate Swaption 2 \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 488.3
Weighted average remaining life	1 year 1 month 6 days
Weighted average strike rate	1.96%
Notional amount due from counterparty \| Interest Rate Swap \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 20,883.1
Weighted average remaining life	3 years 2 months 12 days
Notional amount due from counterparty \| Interest Rate Swap \| UPC Holding
Derivative [Line Items]
Notional amount of derivative	$ 8,478.5
Weighted average remaining life	3 years 10 months 24 days
Notional amount due from counterparty \| Interest Rate Swap \| Telenet
Derivative [Line Items]
Notional amount of derivative	$ 3,821.9
Weighted average remaining life	4 years 8 months 12 days
Notional amount due to counterparty \| Interest Rate Swap \| Virgin Media
Derivative [Line Items]
Notional amount of derivative	$ 11,576.0
Weighted average remaining life	4 years 10 months 24 days
Notional amount due to counterparty \| Interest Rate Swap \| UPC Holding
Derivative [Line Items]
Notional amount of derivative	$ 5,303.1
Weighted average remaining life	6 years 4 months 24 days
Notional amount due to counterparty \| Interest Rate Swap \| Telenet
Derivative [Line Items]
Notional amount of derivative	$ 1,620.9
Weighted average remaining life	4 years 2 months 12 days
Maximum \| Interest Rate Swaption
Derivative [Line Items]
Weighted average remaining life	3 years

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.

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageRemainingMaturity1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageSwaptionInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=lbtya_InterestRateSwaption1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=lbtya_VirginMediaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=lbtya_InterestRateSwaption2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=lbtya_DueFromCounterpartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=lbtya_UpcHoldingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=lbtya_TelenetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=lbtya_DueToCounterpartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwaptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: