XML 21 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document and Entity Information - USD ($)
$ / shares in Units, $ in Billions
12 Months Ended
Dec. 31, 2018
Jan. 31, 2019
Jun. 30, 2018
Dec. 31, 2017
Document Document And Entity Information [Abstract]        
Document Type 10-K      
Document Fiscal Period Focus FY      
Document Fiscal Year Focus 2018      
Document Period End Date Dec. 31, 2018      
Current Fiscal Year End Date --12-31      
Registrant Name CIGNA Corporation      
Central Index Key 0001739940      
Common stock, par value per share $ 0.01     $ 0.25
Trading Symbol CI      
Well Known Seasoned Issuer Yes      
Voluntary Filers No      
Current Reporting Status Yes      
Filer Category Large Accelerated Filer      
Smaller reporting company false      
Emerging growth company false      
Shell company false      
Common Stock outstanding   380,058,967    
Public float     $ 41.2  
Amendment Flag false