| Document and Entity Information | Apr. 23, 2020 |
| Cover [Abstract] | |
| Entity Registrant Name | TRAVELERS COMPANIES, INC. |
| Entity Address, State or Province | NY |
| Amendment Flag | false |
| Entity Central Index Key | 0000086312 |
| Document Type | 8-K |
| Document Period End Date | Apr. 23, 2020 |
| Entity Incorporation State Country Code | MN |
| Entity File Number | 001-10898 |
| Entity Tax Identification Number | 41-0518860 |
| Entity Address, Address Line One | 485 Lexington Avenue |
| Entity Address, City or Town | New York |
| Entity Address, Postal Zip Code | 10017 |
| City Area Code | (917) |
| Local Phone Number | 778-6000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, without par value |
| Trading Symbol | TRV |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
