| Document and Entity Information | Aug. 29, 2024 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 29, 2024 |
| Entity Registrant Name | TORTOISEECOFIN ACQUISITION CORP. III |
| Entity Incorporation State Country Code | E9 |
| Entity File Number | 001-40633 |
| Entity Tax Identification Number | 98-1583266 |
| Entity Address Address Line 1 | 195 US HWY 50 |
| Entity Address Address Line 2 | Suite 309 |
| Entity Address City Or Town | Zephyr Cove |
| Entity Address State Or Province | NV |
| Entity Address Postal Zip Code | 89448 |
| City Area Code | 239 |
| Local Phone Number | 288-2275 |
| Written Communications | true |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001847112 |
| Capital Units [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Units, each consisting of one share of Class A Ordinary Share, $0.0001 par value, and one-fourth of one redeemable warrant |
| Trading Symbol | TRTUF |
| Security Exchange Name | NONE |
| Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Redeemable warrants included as part of the units, each whole warrant exercisable for one Class A Ordinary Share at an exercise price of $11.50 |
| Trading Symbol | TRTWF |
| Security Exchange Name | NONE |
| Capital Unit Class A [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A Ordinary Shares included as part of the units |
| Trading Symbol | TRTLF |
| Security Exchange Name | NONE |
