Document and Entity Information
3 Months Ended
Mar. 31, 2019
Document Document And Entity Information [Abstract]  
Entity Registrant Name PROGRESSIVE CORP/OH/
Entity Central Index Key 0000080661
Current Fiscal Year End Date --12-31
Entity Filer Category Large Accelerated Filer
Document Type 10-Q
Document Period End Date Mar. 31, 2019
Document Fiscal Year Focus 2019
Document Fiscal Period Focus Q1
Amendment Flag false
Entity Common Stock, Shares Outstanding 583,985,804
Trading Symbol PGR
Entity Small Business false
Entity Emerging Growth Company false