Risk/Return Summary - FidelitySAISustainableInternationalEquityEmergingMarketsEquityFunds-ComboPRO - FidelitySAISustainableInternationalEquityEmergingMarketsEquityFunds-ComboPRO - Fidelity SAI Sustainable International Equity Fund	Dec. 30, 2024
Risk Lose Money [Text]
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Risk Text Block	You could lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]
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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 .
GeographicExposureToJapanMember
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Risk Text Block	Geographic Exposure to Japan. Because the fund invests a meaningful portion of its assets in Japan, the fund's performance is expected to be closely tied to social, political, and economic conditions within Japan and to be more volatile than the performance of more geographically diversified funds.
IssuerSpecificChangesMember
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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
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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.
ManagementRiskMember
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Risk Text Block	Management Risk. The Adviser's application of the fund's strategy criteria may not achieve its intended results. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies .
ForeignExposureMember
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Risk Text Block	Foreign Exposure. 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.
SustainabilityRiskMember
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Risk Text Block	Sustainability Risk. Application of Fidelity Management & Research Company LLC's (FMR) (the Adviser) ESG ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance depending on whether certain investments are in or out of favor. The criteria related to the fund's ESG ratings process and/or adherence to its sustainable investing exclusion criteria may result in the fund forgoing opportunities to buy certain securities when it might otherwise be advantageous to do so, or selling securities for ESG reasons when it might be otherwise disadvantageous for it to do so. As a result, the fund's performance may at times be better or worse than the performance of funds that do not use ESG or sustainability criteria. There are significant differences in interpretations of what it means for an issuer to have positive ESG factors. While the Adviser believes its definitions are reasonable, the portfolio decisions it makes may differ with other investors' or advisers' views. When evaluating an issuer, the Adviser is dependent on information or data obtained through voluntary or third-party reporting that may be incomplete, inaccurate, or unavailable, which could cause the Adviser to incorrectly assess an issuer's business practices.
GeographicExposureToEuropeMember
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Risk Text Block	Geographic Exposure to Europe. Because the fund invests a meaningful portion of its assets in Europe, the fund's performance is expected to be closely tied to social, political, and economic conditions within Europe and to be more volatile than the performance of more geographically diversified funds.