| **Cover Page**                                 | Dec. 02, 2020                                                             |
|------------------------------------------------|---------------------------------------------------------------------------|
| **Entity Information [Line Items]**            |                                                                      |
| Document Type                                  | 8-K                                                                       |
| Document Period End Date                       | Dec.  02,  2020                                                           |
| Entity Registrant Name                         | GCI LIBERTY, INC                                                          |
| Entity Central Index Key                       | 0000808461                                                                |
| Amendment Flag                                 | false                                                                     |
| Entity Incorporation, State or Country Code    | DE                                                                        |
| Entity File Number                             | 001-38385                                                                 |
| Entity Tax Identification Number               | 92-0072737                                                                |
| Entity Address, Address Line One               | 12300 Liberty Blvd.                                                       |
| Entity Address, City or Town                   | Englewood                                                                 |
| Entity Address, State or Province              | CO                                                                        |
| Entity Address, Postal Zip Code                | 80112                                                                     |
| City Area Code                                 | 720                                                                       |
| Local Phone Number                             | 875-5900                                                                  |
| Written Communications                         | false                                                                     |
| Soliciting Material                            | false                                                                     |
| Pre-commencement Tender Offer                  | false                                                                     |
| Pre-commencement Issuer Tender Offer           | false                                                                     |
| Entity Emerging Growth Company                 | false                                                                     |
| Series A Common Stock                          |                                                                      |
| **Entity Information [Line Items]**            |                                                                      |
| Title of 12(b) Security                        | Series A Common Stock, par value $0.01 per share                          |
| Trading Symbol                                 | GLIBA                                                                     |
| Security Exchange Name                         | NASDAQ                                                                    |
| Series A Cumulative Redeemable Preferred Stock |                                                                      |
| **Entity Information [Line Items]**            |                                                                      |
| Title of 12(b) Security                        | Series A Cumulative Redeemable preferred stock, par value $0.01 per share |
| Trading Symbol                                 | GLIBP                                                                     |
| Security Exchange Name                         | NASDAQ                                                                    |

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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.
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