| Document and Entity Information - Cover | Feb. 22, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | HELIX ENERGY SOLUTIONS GROUP, INC. |
| Document Period End Date | Feb. 22, 2021 |
| Document Type | 8-K |
| Written Communications | false |
| Entity Incorporation, State or Country Code | MN |
| Entity Central Index Key | 0000866829 |
| Entity File Number | 001-32936 |
| Entity Tax Identification Number | 95-3409686 |
| City Area Code | 281 |
| Local Phone Number | 618-0400 |
| Entity Address, Address Line One | 3505 West Sam Houston Parkway North |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Houston, |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77043 |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | HLX |
| Security Exchange Name | NYSE |
| Amendment Flag | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
