v3.10.0.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Jan. 31, 2019
Jun. 29, 2018
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Amendment Flag false    
Entity Registrant Name GCI LIBERTY, INC.    
Entity Central Index Key 0000808461    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Well-known Seasoned Issuer Yes    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Entity Public Float     $ 4,740,308,542
Series A common stock      
Entity Common Stock Shares Outstanding   101,128,246  
Series B common stock      
Entity Common Stock Shares Outstanding   4,441,109