v3.10.0.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Jan. 31, 2019
Jun. 30, 2018
Document Documentand Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Trading Symbol TGNA    
Entity Registrant Name TEGNA INC    
Entity Central Index Key 0000039899    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Large Accelerated Filer    
Entity Shell Company false    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Common Stock, Shares Outstanding   215,801,306  
Entity Public Float     $ 2,329,631,130