| **Summary of Significant Accounting Principles (Nature of Services and Products) (Details)** | 12 Months Ended |
|----------------------------------------------------------------------------------------------|-----------------|
||
| Certain Wireless Devices                                                                     |            |
| **Disaggregation of Revenue [Line Items]**                                                   |            |
| Equipment installment plan period                                                            | 24 months       |
| Trade-In Equipment                                                                           |            |
| **Disaggregation of Revenue [Line Items]**                                                   |            |
| Number of installment plan payments                                                          | 12              |

| X                                                                                                                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Equipment Installment Plan Payment Term
+ References
No definition available.
+ Details**Name:**gliba_EquipmentInstallmentPlanPaymentTerm**Namespace Prefix:**gliba_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of Installment Plan Payments required for right to trade-in handset.
+ References
No definition available.
+ Details**Name:**gliba_NumberofInstallmentPlanPayments**Namespace Prefix:**gliba_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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_DisaggregationOfRevenueLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_ProductOrServiceAxis=gliba_CertainWirelessDevicesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_ProductOrServiceAxis=gliba_TradeInEquipmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |