XML 12 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Document And Entitiy Information [Abstract]    
Document Type 10-Q  
Document period end date Sep. 30, 2018  
Amendment flag false  
Entity registrant name REINSURANCE GROUP OF AMERICA INC  
Entity central index key 0000898174  
Entity current reporting status Yes  
Current fiscal year end date --12-31  
Entity filer category Large Accelerated Filer  
Common Shares Outstanding   62,774,675
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Entity Emerging Growth Company false  
Entity Small Business false