| **Risk/Return Summary - FidelitySeriesInternationalFunds-ComboPRO - FidelitySeriesInternationalFunds-ComboPRO - Fidelity Series Emerging Markets Opportunities Fund** | Dec. 30, 2024                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
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| Risk Lose Money [Text]                                                                                                                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       |               You could lose money by investing in the fund.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Risk Not Insured Depository Institution [Text]                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       | An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency             .                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| ForeignAndEmergingMarketsRiskMember                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       | Foreign and Emerging Markets Risk.            Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.      The extent of economic development; political stability; market depth, infrastructure, and capitalization; and regulatory oversight can be less than in more developed markets. Emerging markets typically have less established legal, accounting and financial reporting systems than those in more developed markets, which may reduce the scope or quality of financial information available to investors.      Emerging markets can be subject to greater social, economic, regulatory, and political uncertainties and can be extremely volatile.      Foreign exchange rates also can be extremely volatile.                                                                                                |
| IssuerSpecificChangesMember                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       | Issuer-Specific Changes.            The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| StockMarketVolatilityMember                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       | Stock Market Volatility.            Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| GeographicExposureToChinaMember                                                                                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       | Geographic Exposure to China.            Because the fund invests a meaningful portion of its assets in China, the fund's performance is expected to be closely tied to social, political, and economic conditions in China and to be more volatile than the performance of more geographically diversified funds. The fund may obtain exposure to companies based or operated in China by investing through legal structures known as variable interest entities (VIEs). Instead of directly owning the equity securities of a Chinese company, a VIE enters into service and other contracts with the Chinese company. Although the VIE has no equity ownership of the Chinese company, the contractual arrangements permit the VIE to consolidate the Chinese company into its financial statements. Intervention by the Chinese government with respect to VIEs could significantly affect the Chinese company's performance and the enforceability of the VIE's contractual arrangements with the Chinese company. |
| GeographicExposureToAsiaMember                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| **Prospectus Line Items**                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Risk Text Block                                                                                                                                                       | Geographic Exposure to Asia.            Because the fund invests a meaningful portion of its assets in Asia, the fund's performance is expected to be closely tied to social, political, and economic conditions within Asia and to be more volatile than the performance of more geographically diversified funds.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |

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