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Document And Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2017
Jan. 31, 2018
Jun. 30, 2017
Entity Registrant Name United States Cellular Corporation    
Entity Central Index Key 0000821130    
Document Type 10-K    
Document Period End Date Dec. 31, 2017    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Accelerated Filer    
Entity Public Float     $ 540,716,391
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY    
Trading Symbol USM    
Common Shares      
Entity Common Stock, Shares Outstanding   52,122,000  
Series A Common Shares      
Entity Common Stock, Shares Outstanding   33,006,000