| **Average Annual Total Returns - FidelitySAISustainableInternationalEquityEmergingMarketsEquityFunds-ComboPRO - FidelitySAISustainableInternationalEquityEmergingMarketsEquityFunds-ComboPRO - Fidelity SAI Sustainable Emerging Markets Equity Fund** | Dec. 30, 2024 |
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| Fidelity SAI Sustainable Emerging Markets Equity Fund | Return Before Taxes                                                                                                                                                                            |          |  |
| **Average Annual Return:**                                                                                                                                                                                                                             |          |  |
| Past 1 year                                                                                                                                                                                                                                            | 11.67%        |  |
| Since Inception                                                                                                                                                                                                                                        | (1.38%)       | [1] |
| Fidelity SAI Sustainable Emerging Markets Equity Fund | After Taxes on Distributions                                                                                                                                                                   |          |  |
| **Average Annual Return:**                                                                                                                                                                                                                             |          |  |
| Past 1 year                                                                                                                                                                                                                                            | 11.41%        |  |
| Since Inception                                                                                                                                                                                                                                        | (1.58%)       | [1] |
| Fidelity SAI Sustainable Emerging Markets Equity Fund | After Taxes on Distributions and Sales                                                                                                                                                         |          |  |
| **Average Annual Return:**                                                                                                                                                                                                                             |          |  |
| Past 1 year                                                                                                                                                                                                                                            | 7.11%         |  |
| Since Inception                                                                                                                                                                                                                                        | (1.00%)       | [1] |
| IXWRU                                                                                                                                                                                                                                                  |          |  |
| **Average Annual Return:**                                                                                                                                                                                                                             |          |  |
| Past 1 year                                                                                                                                                                                                                                            | 6.16%         |  |
| Since Inception                                                                                                                                                                                                                                        | (5.30%)       |  |
| MC041                                                                                                                                                                                                                                                  |          |  |
| **Average Annual Return:**                                                                                                                                                                                                                             |          |  |
| Past 1 year                                                                                                                                                                                                                                            | 9.86%         |  |
| Since Inception                                                                                                                                                                                                                                        | (2.17%)       |  |
|                                                                                                                                                                                                                                                        |
| [1]AFrom April 14, 2022.                                                                                                                                                                                                                               |

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Return Before Taxes.
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