| Cover Page | Dec. 11, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Dec. 11, 2019 |
| Entity Registrant Name | PROGRESSIVE CORP/OH/ |
| Entity Incorporation, State or Country Code | OH |
| Entity File Number | 001-09518 |
| Entity Tax Identification Number | 34-0963169 |
| Entity Address, Address Line One | 6300 Wilson Mills Road, |
| Entity Address, City or Town | Mayfield Village, |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 44143 |
| City Area Code | 440 |
| Local Phone Number | 461-5000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $1.00 Par Value |
| Trading Symbol | PGR |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0000080661 |
