| Document and Entity Information Document and Entity Information | Jan. 21, 2021 |
| Document and Entity Information | |
| Document type | 8-K |
| Document period end date | Jan. 21, 2021 |
| Registrant name | Travelers Companies, Inc. |
| Entity incorporation, state | MN |
| Entity file number | 001-10898 |
| Entity tax identification number | 41-0518860 |
| Entity address, address line one | 485 Lexington Avenue |
| Entity address, city | New York |
| Entity address, state | NY |
| Entity address, postal zip code | 10017 |
| City area code | 917 |
| Local phone number | 778-6000 |
| Written communications | false |
| Soliciting material | false |
| Pre-commencement communications pursuant to Rule 14d-2(b) | false |
| Pre-commencement communications pursuant to Rule 13e-4(c) | false |
| Title of 12(b) security | Common stock, without par value |
| Trading symbol | TRV |
| Security exchange name | NYSE |
| Entity emerging growth company | false |
| Central index key | 0000086312 |
| Amendment flag | false |
