Debt (Exchangeable Senior Debentures) (Details) - Charter - Exchangeable Senior Debentures - 1.75% Exchangeable Debentures	Jun. 18, 2018 $ / shares shares
Debt Instrument [Line Items]
Interest rate	1.75%
Exchangeable ratio	2.6989
Exchangeable price (in dollars per share) \| $ / shares	$ 370.52
Number of shares exchangeable (in shares) \| shares	1,288,051
Redemption price (as a percent)	100.00%

Debt Instrument, Exchangeable, Exchangeable Price

No definition available.

Name:	gliba_DebtInstrumentExchangeableExchangeablePrice
Namespace Prefix:	gliba_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Exchangeable, Exchangeable Ratio

+ References

No definition available.

+ Details

Name:	gliba_DebtInstrumentExchangeableExchangeableRatio
Namespace Prefix:	gliba_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Exchangeable, Number Of Equity Instruments

+ References

No definition available.

+ Details

Name:	gliba_DebtInstrumentExchangeableNumberOfEquityInstruments
Namespace Prefix:	gliba_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gliba_CharterCommunicationsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ExchangeableDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gliba_A1.75ExchangeableDebenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: