Derivative Instruments (Basis Swaps, Interest Rate Caps and Collars) (Details) $ in Millions	3 Months Ended
Mar. 31, 2021 USD ($)
Derivative [Line Items]
Floor rate	0.000
Interest Rate Caps
Derivative [Line Items]
Notional amount of derivative	$ 470.0
Interest Rate Collars
Derivative [Line Items]
Notional amount of derivative	$ 7,839.3
UPC Holding \| Basis Swaps
Derivative [Line Items]
Weighted average remaining life	4 months 24 days
Telenet \| Basis Swaps
Derivative [Line Items]
Weighted average remaining life	9 months 18 days
Notional amount due from counterparty \| UPC Holding \| Basis Swaps
Derivative [Line Items]
Notional amount of derivative	$ 3,300.0
Notional amount due from counterparty \| Telenet \| Basis Swaps
Derivative [Line Items]
Notional amount of derivative	$ 2,295.0

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

Floor rate on a foreign currency derivative for example, but not limited to, a floor or a collar.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeExchangeRateFloor1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
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=121590274&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=121590274&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=us-gaap_InterestRateCapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=lbtya_InterestRateCollarMember
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:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_BasisSwapMember
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_DueFromCounterpartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: