Share-based Compensation (Awards Outstanding and Exercisable) (Details)	Sep. 30, 2020 $ / shares shares
Held by Liberty Global employees: \| Options and SARs \| Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	23,912,350
Options outstanding, weighted average exercise or base price (in dollars per shares) \| $ / shares	$ 27.19
Options exercisable (in shares)	11,650,343
Options exercisable, weighted average exercise price or base price (in dollars per shares) \| $ / shares	$ 32.33
Held by Liberty Global employees: \| Options and SARs \| Class C
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	52,501,482
Options outstanding, weighted average exercise or base price (in dollars per shares) \| $ / shares	$ 26.07
Options exercisable (in shares)	27,338,053
Options exercisable, weighted average exercise price or base price (in dollars per shares) \| $ / shares	$ 30.36
Held by Liberty Global employees: \| RSUs \| Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	2,501,418
Held by Liberty Global employees: \| RSUs \| Class B
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	0
Held by Liberty Global employees: \| RSUs \| Class C
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	4,995,466
Held by Liberty Global employees: \| PSUs \| Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	2,736,957
Held by Liberty Global employees: \| PSUs \| Class B
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	660,000
Held by Liberty Global employees: \| PSUs \| Class C
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	5,473,398
Held by former Liberty Global employees (a): \| Options and SARs \| Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	1,428,077
Options outstanding, weighted average exercise or base price (in dollars per shares) \| $ / shares	$ 34.09
Options exercisable (in shares)	1,403,436
Options exercisable, weighted average exercise price or base price (in dollars per shares) \| $ / shares	$ 34.07
Held by former Liberty Global employees (a): \| Options and SARs \| Class C
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	3,176,210
Options outstanding, weighted average exercise or base price (in dollars per shares) \| $ / shares	$ 32.22
Options exercisable (in shares)	3,126,939
Options exercisable, weighted average exercise price or base price (in dollars per shares) \| $ / shares	$ 32.18
Held by former Liberty Global employees (a): \| RSUs \| Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	880
Held by former Liberty Global employees (a): \| RSUs \| Class B
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	0
Held by former Liberty Global employees (a): \| RSUs \| Class C
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	1,748
Held by former Liberty Global employees (a): \| PSUs \| Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	24,521
Held by former Liberty Global employees (a): \| PSUs \| Class B
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	0
Held by former Liberty Global employees (a): \| PSUs \| Class C
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options outstanding (in shares)	49,034

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_TitleOfIndividualAxis=lbtya_EmployeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=lbtya_OptionsandShareAppreciationRightsSARsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=lbtya_FormerEmployeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: