v3.25.3
Risk/Return Detail Data - FidelitySustainableTargetDateFunds-ComboRetailPro - USD ($)
12 Months Ended 24 Months Ended
Oct. 30, 2025
Oct. 30, 2025
Dec. 31, 2024
Oct. 30, 2025
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date Retirement Fund | Fidelity Sustainable Target Date Retirement Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [1] 0.41%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [1] 0.41%      
Expense Example, with Redemption, 1 Year $ 42      
Expense Example, with Redemption, 3 Years 132      
Expense Example, with Redemption, 5 Years 230      
Expense Example, with Redemption, 10 Years $ 518      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   4.03%   4.76% [2]
Annual Return [Percent]     4.03%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date Retirement Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date Retirement Fund/Fidelity® Sustainable Target Date Retirement Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date Retirement Fund seeks high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 23% of the average value of its portfolio.      
Portfolio Turnover, Rate 23.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a stable neutral asset allocation strategy. A revised neutral asset allocation strategy (approximately 18% in U.S. equity funds, 12% in international equity funds, 33% in U.S. investment grade bond funds, 5% in international bond funds, 2% in long-term treasury bond funds, 24% in short-term inflation protected bond funds, and 7% in short-term funds; allocations do not add to 100% due to rounding) is expected to take effect by the end of the first quarter of 2027. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 2.12%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 4.56%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.41%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date Retirement Fund | After Taxes on Distributions | Fidelity Sustainable Target Date Retirement Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   2.63%   3.30% [2]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date Retirement Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date Retirement Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   2.43%   3.04% [2]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date Retirement Fund | IXUFW        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date Income Composite Index℠    
Average Annual Return, Percent   4.95%   5.48%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date Retirement Fund | LB001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Bloomberg U.S. Aggregate Bond Index    
Average Annual Return, Percent   1.25%   1.79%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2010 Fund | Fidelity Sustainable Target Date 2010 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [3] 0.41%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [3] 0.41%      
Expense Example, with Redemption, 1 Year $ 42      
Expense Example, with Redemption, 3 Years 132      
Expense Example, with Redemption, 5 Years 230      
Expense Example, with Redemption, 10 Years $ 518      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   4.77%   5.76% [4]
Annual Return [Percent]     4.77%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2010 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2010 Fund/Fidelity® Sustainable Target Date 2010 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2010 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 15% of the average value of its portfolio.      
Portfolio Turnover, Rate 15.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2010. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who retired in or within a few years of 2010 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 1.93%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 4.80%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.61%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2010 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2010 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   3.36%   4.33% [4]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2010 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2010 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   2.88%   3.84% [4]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2010 Fund | LB001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Bloomberg U.S. Aggregate Bond Index    
Average Annual Return, Percent   1.25%   1.79%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2010 Fund | IXUFX        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2010 Composite Index℠    
Average Annual Return, Percent   5.77%   6.46%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2015 Fund | Fidelity Sustainable Target Date 2015 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [5] 0.42%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [5] 0.42%      
Expense Example, with Redemption, 1 Year $ 43      
Expense Example, with Redemption, 3 Years 135      
Expense Example, with Redemption, 5 Years 235      
Expense Example, with Redemption, 10 Years $ 530      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   5.75%   6.88% [6]
Annual Return [Percent]     5.75%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2015 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2015 Fund/Fidelity® Sustainable Target Date 2015 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2015 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 19% of the average value of its portfolio.      
Portfolio Turnover, Rate 19.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2015. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who retired in or within a few years of 2015 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 1.61%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 5.19%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.85%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2015 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2015 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   4.51%   5.61% [6]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2015 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2015 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   3.56%   4.80% [6]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2015 Fund | LB001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Bloomberg U.S. Aggregate Bond Index    
Average Annual Return, Percent   1.25%   1.79%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2015 Fund | IXUFY        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2015 Composite Index℠    
Average Annual Return, Percent   6.71%   7.54%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2020 Fund | Fidelity Sustainable Target Date 2020 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [7] 0.43%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [7] 0.43%      
Expense Example, with Redemption, 1 Year $ 44      
Expense Example, with Redemption, 3 Years 138      
Expense Example, with Redemption, 5 Years 241      
Expense Example, with Redemption, 10 Years $ 542      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   6.65%   7.96% [8]
Annual Return [Percent]     6.65%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2020 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2020 Fund/Fidelity® Sustainable Target Date 2020 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2020 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 22% of the average value of its portfolio.      
Portfolio Turnover, Rate 22.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2020. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who retired in or within a few years of 2020 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 1.39%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 5.54%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (3.07%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2020 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2020 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   5.61%   6.87% [8]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2020 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2020 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   4.08%   5.71% [8]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2020 Fund | LB001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Bloomberg U.S. Aggregate Bond Index    
Average Annual Return, Percent   1.25%   1.79%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2020 Fund | IXUFZ        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2020 Composite Index℠    
Average Annual Return, Percent   7.65%   8.61%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2025 Fund | Fidelity Sustainable Target Date 2025 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [9] 0.44%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [9] 0.44%      
Expense Example, with Redemption, 1 Year $ 45      
Expense Example, with Redemption, 3 Years 141      
Expense Example, with Redemption, 5 Years 246      
Expense Example, with Redemption, 10 Years $ 555      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   7.32%   8.92% [10]
Annual Return [Percent]     7.32%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2025 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2025 Fund/Fidelity® Sustainable Target Date 2025 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2025 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 28% of the average value of its portfolio.      
Portfolio Turnover, Rate 28.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2025. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2025 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 1.18%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 5.71%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (3.24%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2025 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2025 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   6.49%   8.00% [10]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2025 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2025 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   4.52%   6.54% [10]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2025 Fund | IXUG2        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2025 Composite Index℠    
Average Annual Return, Percent   8.48%   9.58%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2025 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2030 Fund | Fidelity Sustainable Target Date 2030 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [11] 0.46%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [11] 0.46%      
Expense Example, with Redemption, 1 Year $ 47      
Expense Example, with Redemption, 3 Years 148      
Expense Example, with Redemption, 5 Years 258      
Expense Example, with Redemption, 10 Years $ 579      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   8.36%   10.09% [12]
Annual Return [Percent]     8.36%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2030 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2030 Fund/Fidelity® Sustainable Target Date 2030 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2030 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 31% of the average value of its portfolio.      
Portfolio Turnover, Rate 31.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2030. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2030 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 0.80%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 5.70%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (3.04%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2030 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2030 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   7.63%   9.30% [12]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2030 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2030 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   5.14%   7.51% [12]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2030 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2030 Fund | IXUG3        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2030 Composite Index℠    
Average Annual Return, Percent   9.51%   10.73%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2035 Fund | Fidelity Sustainable Target Date 2035 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [13] 0.47%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [13] 0.47%      
Expense Example, with Redemption, 1 Year $ 48      
Expense Example, with Redemption, 3 Years 151      
Expense Example, with Redemption, 5 Years 263      
Expense Example, with Redemption, 10 Years $ 591      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   10.03%   12.13% [14]
Annual Return [Percent]     10.03%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2035 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2035 Fund/Fidelity® Sustainable Target Date 2035 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2035 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 39% of the average value of its portfolio.      
Portfolio Turnover, Rate 39.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2035. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2035 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return 0.34%      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Sep. 30, 2024      
Highest Quarterly Return 5.89%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.86%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2035 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2035 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   9.36%   11.41% [14]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2035 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2035 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   6.16%   9.13% [14]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2035 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2035 Fund | IXUG5        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2035 Composite Index℠    
Average Annual Return, Percent   11.20%   12.68%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2040 Fund | Fidelity Sustainable Target Date 2040 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [15] 0.48%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [15] 0.48%      
Expense Example, with Redemption, 1 Year $ 49      
Expense Example, with Redemption, 3 Years 154      
Expense Example, with Redemption, 5 Years 269      
Expense Example, with Redemption, 10 Years $ 604      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   12.12%   14.36% [16]
Annual Return [Percent]     12.12%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2040 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2040 Fund/Fidelity® Sustainable Target Date 2040 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2040 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 26% of the average value of its portfolio.      
Portfolio Turnover, Rate 26.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2040. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2040 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return (0.25%)      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Mar. 31, 2024      
Highest Quarterly Return 6.64%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.68%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2040 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2040 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   11.63%   13.84% [16]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2040 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2040 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   7.44%   10.97% [16]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2040 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2040 Fund | IXUG8        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2040 Composite Index℠    
Average Annual Return, Percent   13.30%   14.86%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2045 Fund | Fidelity Sustainable Target Date 2045 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [17] 0.49%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [17] 0.49%      
Expense Example, with Redemption, 1 Year $ 50      
Expense Example, with Redemption, 3 Years 157      
Expense Example, with Redemption, 5 Years 274      
Expense Example, with Redemption, 10 Years $ 616      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   12.95%   15.15% [18]
Annual Return [Percent]     12.95%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2045 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2045 Fund/Fidelity® Sustainable Target Date 2045 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2045 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 25% of the average value of its portfolio.      
Portfolio Turnover, Rate 25.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2045. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2045 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return (0.57%)      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Mar. 31, 2024      
Highest Quarterly Return 7.07%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.54%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2045 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2045 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   12.53%   14.67% [18]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2045 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2045 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   7.95%   11.61% [18]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2045 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2045 Fund | IXUG9        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2045 Composite Index℠    
Average Annual Return, Percent   14.11%   15.60%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2050 Fund | Fidelity Sustainable Target Date 2050 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [19] 0.49%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [19] 0.49%      
Expense Example, with Redemption, 1 Year $ 50      
Expense Example, with Redemption, 3 Years 157      
Expense Example, with Redemption, 5 Years 274      
Expense Example, with Redemption, 10 Years $ 616      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   12.96%   15.15% [20]
Annual Return [Percent]     12.96%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2050 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2050 Fund/Fidelity® Sustainable Target Date 2050 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2050 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 21% of the average value of its portfolio.      
Portfolio Turnover, Rate 21.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2050. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2050 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return (0.57%)      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Mar. 31, 2024      
Highest Quarterly Return 7.07%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.52%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2050 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2050 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   12.58%   14.69% [20]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2050 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2050 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   7.96%   11.62% [20]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2050 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2050 Fund | IXUGA        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2050 Composite Index℠    
Average Annual Return, Percent   14.11%   15.60%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2055 Fund | Fidelity Sustainable Target Date 2055 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [21] 0.49%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [21] 0.49%      
Expense Example, with Redemption, 1 Year $ 50      
Expense Example, with Redemption, 3 Years 157      
Expense Example, with Redemption, 5 Years 274      
Expense Example, with Redemption, 10 Years $ 616      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   12.97%   15.21% [22]
Annual Return [Percent]     12.97%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2055 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2055 Fund/Fidelity® Sustainable Target Date 2055 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2055 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 28% of the average value of its portfolio.      
Portfolio Turnover, Rate 28.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2055. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2055 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return (0.65%)      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Mar. 31, 2024      
Highest Quarterly Return 7.06%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.53%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2055 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2055 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   12.60%   14.77% [22]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2055 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2055 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   7.98%   11.68% [22]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2055 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2055 Fund | IXUGF        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2055 Composite Index℠    
Average Annual Return, Percent   14.11%   15.60%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2060 Fund | Fidelity Sustainable Target Date 2060 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [23] 0.49%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [23] 0.49%      
Expense Example, with Redemption, 1 Year $ 50      
Expense Example, with Redemption, 3 Years 157      
Expense Example, with Redemption, 5 Years 274      
Expense Example, with Redemption, 10 Years $ 616      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   13.04%   15.21% [24]
Annual Return [Percent]     13.04%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2060 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2060 Fund/Fidelity® Sustainable Target Date 2060 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2060 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 24% of the average value of its portfolio.      
Portfolio Turnover, Rate 24.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2060. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2060 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return (0.65%)      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Mar. 31, 2024      
Highest Quarterly Return 7.16%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.49%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2060 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2060 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   12.63%   14.74% [24]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2060 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2060 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   8.01%   11.66% [24]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2060 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2060 Fund | IXUGG        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2060 Composite Index℠    
Average Annual Return, Percent   14.11%   15.60%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2065 Fund | Fidelity Sustainable Target Date 2065 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [25] 0.49%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [25] 0.49%      
Expense Example, with Redemption, 1 Year $ 50      
Expense Example, with Redemption, 3 Years 157      
Expense Example, with Redemption, 5 Years 274      
Expense Example, with Redemption, 10 Years $ 616      
Annual Return, Inception Date May 11, 2023      
Average Annual Return, Label [Optional Text]   Return Before Taxes    
Average Annual Return, Percent   13.00%   15.18% [26]
Annual Return [Percent]     13.00%  
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2065 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2065 Fund/Fidelity® Sustainable Target Date 2065 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2065 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 23% of the average value of its portfolio.      
Portfolio Turnover, Rate 23.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2065. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2065 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time. The hypothetical composite of market indexes has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.      
Performance Information Illustrates Variability of Returns [Text] The information illustrates the performance of the fund's shares over the past year and compares the performance of the fund's shares to the performance of a securities market index and a hypothetical composite of market indexes over various periods of time.      
Performance Availability Website Address [Text] www.fidelity.com      
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.      
Bar Chart [Heading] Year-by-Year Returns      
Year to Date Return, Label [Optional Text]    Year-to-Date Return      
Bar Chart, Year to Date Return, Date Mar. 31, 2025      
Bar Chart, Year to Date Return (0.65%)      
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return      
Highest Quarterly Return, Date Mar. 31, 2024      
Highest Quarterly Return 7.07%      
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return      
Lowest Quarterly Return, Date Dec. 31, 2024      
Lowest Quarterly Return (2.57%)      
Performance Table Heading Average Annual Returns      
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.      
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).      
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2065 Fund | After Taxes on Distributions | Fidelity Sustainable Target Date 2065 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions    
Average Annual Return, Percent   12.59%   14.71% [26]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2065 Fund | After Taxes on Distributions and Sales | Fidelity Sustainable Target Date 2065 Fund        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares    
Average Annual Return, Percent   7.97%   11.64% [26]
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2065 Fund | SP001        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   S&P 500® Index    
Average Annual Return, Percent   25.02%   25.84%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2065 Fund | IXUGH        
Prospectus Line Items        
Average Annual Return, Label [Optional Text]   Fidelity Sustainable Target Date 2065 Composite Index℠    
Average Annual Return, Percent   14.11%   15.60%
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2070 Fund | Fidelity Sustainable Target Date 2070 Fund        
Prospectus Line Items        
Management Fees (as a percentage of Assets) [27] 0.49%      
Distribution and Service (12b-1) Fees 0.00%      
Other Expenses (as a percentage of Assets): 0.00%      
Expenses (as a percentage of Assets) [27] 0.49%      
Expense Example, with Redemption, 1 Year $ 50      
Expense Example, with Redemption, 3 Years 157      
Expense Example, with Redemption, 5 Years 274      
Expense Example, with Redemption, 10 Years $ 616      
FidelitySustainableTargetDateFunds-ComboRetailPro | Fidelity Sustainable Target Date 2070 Fund        
Prospectus Line Items        
Risk/Return [Heading] Fund Summary Fund/Class: Fidelity® Sustainable Target Date 2070 Fund/Fidelity® Sustainable Target Date 2070 Fund      
Objective [Heading] Investment Objective      
Objective, Primary [Text Block] Fidelity® Sustainable Target Date 2070 Fund seeks high total return until its target retirement date. Thereafter the fund's objective will be to seek high current income and, as a      
Objective, Secondary [Text Block] secondary objective, capital appreciation.      
Expense Heading [Optional Text] Fee Table      
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.      
Shareholder Fees Caption [Optional Text] Shareholder fees      
Shareholder Fee, Other $ 0      
Operating Expenses Caption [Optional Text] Annual Operating Expenses      
Portfolio Turnover [Heading] Portfolio Turnover      
Portfolio Turnover [Text Block] The fund will not incur transaction costs, such as commissions, when it buys and sells shares of underlying Fidelity® funds (or "turns over" its portfolio), but it could incur transaction costs if it were to buy and sell other types of securities directly. If the fund were to buy and sell other types of securities directly, a higher portfolio turnover rate could indicate higher transaction costs and could result in higher taxes when fund shares are held in a taxable account. Such costs, if incurred, would not be reflected in annual operating expenses or in the example and would affect the fund's performance. For the period from June 28, 2024 to March 31, 2025, the fund's portfolio turnover rate was 20% (annualized) of the average value of its portfolio.      
Portfolio Turnover, Rate 20.00%      
Expenses Restated to Reflect Current [Text] Adjusted to reflect current fees.      
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:      
Strategy [Heading] Principal Investment Strategies      
Strategy Narrative [Text Block] Investing at least 80% of assets in underlying funds that are (i) Fidelity® funds that invest in securities of issuers that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have proven or improving sustainability practices or positive environmental, social and governance (ESG) characteristics (Fidelity® Sustainable Funds), (ii) Fidelity index funds that track an ESG Index (Fidelity® Sustainable Index Funds), and (iii) Fidelity® funds that do not have a principal ESG investment strategy but invest at least 80% of assets in U.S. and international sovereign or government-related debt securities that the Fidelity® Sustainable Target Date Fund Adviser believes have positive ESG characteristics (Fidelity® Traditional Funds) (collectively, underlying Fidelity® Funds). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which a Fidelity® Traditional Fund invests to determine whether 80% of assets are invested in sovereign or government-related debt securities whose issuers have positive ESG characteristics by considering the sustainability practices of the country or other issues based on an evaluation of such issuer's individual ESG profile using the Adviser's proprietary ESG ratings process.The Adviser's proprietary ESG ratings process evaluates the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provides a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team.Allocating assets according to a neutral asset allocation strategy shown in the glide path below that adjusts over time until it reaches an allocation similar to that of the Fidelity® Sustainable Target Date Retirement Fund, approximately 10 to 19 years after the year 2070. The Adviser may modify the fund's neutral asset allocations from time to time when in the interests of shareholders. A revised neutral asset allocation strategy for the fund is expected to take effect by the end of the first quarter of 2027, as illustrated in the following chart. During the fourth quarter of 2025, the Adviser will begin transitioning the neutral asset allocation percentages to achieve the desired allocations. The neutral asset allocation shown in the glide path depicts the allocation to U.S. equity funds, international equity funds, bond funds (including U.S. investment grade bond, international bond, long-term inflation-protected bond, short-term inflation protected bond, and long-term treasury bond funds), and short-term funds.Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.The Adviser, under normal market conditions, will make investments that are consistent with seeking high total return for several years beyond the fund's target retirement date in an effort to achieve the fund's overall investment objective.The Adviser, under normal market conditions, will use an active asset allocation strategy to increase or decrease asset class exposures relative to the neutral asset allocations reflected above by up to 10% for equity funds, bond funds and short-term funds to reflect the Adviser's market outlook, which is primarily focused on the intermediate term. The asset allocations in the glide path above are referred to as neutral because they do not reflect any decisions made by the Adviser to overweight or underweight an asset class.The Adviser may also make active asset allocations within other asset classes (such as commodities, high yield debt (also referred to as junk bonds), floating rate debt, real estate debt, and emerging markets debt) from 0% to 10% of the fund's total assets individually, but no more than 25% in aggregate within those other asset classes. Such asset classes are not reflected in the neutral asset allocations reflected in the glide path above. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.Designed for investors who anticipate retiring in or within a few years of 2070 (target retirement date) at or around age 65.Fidelity® Sustainable Funds employ sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Description of Underlying Fidelity® Funds" for additional information. When the neutral asset allocation of a fund matches Fidelity® Sustainable Target Date Retirement Fund's neutral asset allocation (approximately 10 to 19 years after the year indicated in the fund's name), the Board of Trustees may combine the fund with Fidelity® Sustainable Target Date Retirement Fund, without shareholder approval, and the fund's shareholders will become shareholders of Fidelity® Sustainable Target Date Retirement Fund.      
Bar Chart and Performance Table [Heading] Performance      
Performance Narrative [Text Block] Performance history will be available for the fund after the fund has been in operation for one calendar year.      
Performance One Year or Less [Text] Performance history will be available for the fund after the fund has been in operation for one calendar year.      
Document Type 497      
Registrant Name Fidelity Aberdeen Street Trust      
[1] AAdjusted to reflect current fees.
[2] AFrom May 11, 2023.
[3] AAdjusted to reflect current fees.
[4] AFrom May 11, 2023.
[5] AAdjusted to reflect current fees.
[6] AFrom May 11, 2023.
[7] AAdjusted to reflect current fees.
[8] AFrom May 11, 2023.
[9] AAdjusted to reflect current fees.
[10] AFrom May 11, 2023.
[11] AAdjusted to reflect current fees.
[12] AFrom May 11, 2023.
[13] AAdjusted to reflect current fees.
[14] AFrom May 11, 2023.
[15] AAdjusted to reflect current fees.
[16] AFrom May 11, 2023.
[17] AAdjusted to reflect current fees.
[18] AFrom May 11, 2023.
[19] AAdjusted to reflect current fees.
[20] AFrom May 11, 2023.
[21] AAdjusted to reflect current fees.
[22] AFrom May 11, 2023.
[23] AAdjusted to reflect current fees.
[24] AFrom May 11, 2023.
[25] AAdjusted to reflect current fees.
[26] AFrom May 11, 2023.
[27] AAdjusted to reflect current fees.