v3.25.2
Risk/Return Detail Data - FidelityMid-CapStockFund-AMCIZPRO - USD ($)
 12 Months Ended 36 Months Ended 60 Months Ended 72 Months Ended 96 Months Ended 120 Months Ended
Jun. 28, 2025
Jun. 28, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Jun. 28, 2025
Jun. 28, 2025
Jun. 28, 2025
Jun. 28, 2025
Jun. 28, 2025
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | Fidelity Advisor Founders Fund - Class A                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 5.75%                                
Maximum Deferred Sales Charge (as a percentage) [1] 0.00%                                
Management Fees (as a percentage of Assets) [2] 0.72%                                
Distribution and Service (12b-1) Fees 0.25%                                
Other Expenses (as a percentage of Assets): 0.10%                                
Expenses (as a percentage of Assets) 1.07%                                
Expense Example, with Redemption, 1 Year $ 678                                
Expense Example, with Redemption, 3 Years 896                                
Expense Example, with Redemption, 5 Years 1,131                                
Expense Example, with Redemption, 10 Years 1,806                                
Expense Example, No Redemption, 1 Year 678                                
Expense Example, No Redemption, 3 Years 896                                
Expense Example, No Redemption, 5 Years 1,131                                
Expense Example, No Redemption, 10 Years $ 1,806                                
Annual Return, Inception Date Feb. 14, 2019                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   24.19%                       16.13% 16.43% [3]    
Annual Return [Percent]     31.77% 33.53% (26.81%) 18.63% 46.72%                    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | Fidelity Advisor Founders Fund - Class M                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 3.50%                                
Maximum Deferred Sales Charge (as a percentage) [1] 0.00%                                
Management Fees (as a percentage of Assets) [2] 0.71%                                
Distribution and Service (12b-1) Fees 0.50%                                
Other Expenses (as a percentage of Assets): 0.10%                                
Expenses (as a percentage of Assets) 1.31%                                
Expense Example, with Redemption, 1 Year $ 479                                
Expense Example, with Redemption, 3 Years 751                                
Expense Example, with Redemption, 5 Years 1,043                                
Expense Example, with Redemption, 10 Years 1,874                                
Expense Example, No Redemption, 1 Year 479                                
Expense Example, No Redemption, 3 Years 751                                
Expense Example, No Redemption, 5 Years 1,043                                
Expense Example, No Redemption, 10 Years $ 1,874                                
Annual Return, Inception Date Feb. 14, 2019                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   26.80%                       16.42% 16.62% [4]    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | Fidelity Advisor Founders Fund - Class C                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 0.00%                                
Maximum Deferred Sales Charge (as a percentage) [5] 1.00%                                
Management Fees (as a percentage of Assets) [2] 0.72%                                
Distribution and Service (12b-1) Fees 1.00%                                
Other Expenses (as a percentage of Assets): 0.10%                                
Expenses (as a percentage of Assets) 1.82%                                
Expenses Deferred Charges [Text Block] On Class C shares redeemed less than one year after purchase.                                
Expense Example, with Redemption, 1 Year $ 285                                
Expense Example, with Redemption, 3 Years 573                                
Expense Example, with Redemption, 5 Years 985                                
Expense Example, with Redemption, 10 Years 1,940                                
Expense Example, No Redemption, 1 Year 185                                
Expense Example, No Redemption, 3 Years 573                                
Expense Example, No Redemption, 5 Years 985                                
Expense Example, No Redemption, 10 Years $ 1,940                                
Annual Return, Inception Date Feb. 14, 2019                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   29.73%                       16.64% 16.72% [6]    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | Fidelity Advisor Founders Fund - Class I                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 0.00%                                
Maximum Deferred Sales Charge (as a percentage) 0.00%                                
Management Fees (as a percentage of Assets) [2] 0.65%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.10%                                
Expenses (as a percentage of Assets) 0.75%                                
Expense Example, with Redemption, 1 Year $ 77                                
Expense Example, with Redemption, 3 Years 240                                
Expense Example, with Redemption, 5 Years 417                                
Expense Example, with Redemption, 10 Years 930                                
Expense Example, No Redemption, 1 Year 77                                
Expense Example, No Redemption, 3 Years 240                                
Expense Example, No Redemption, 5 Years 417                                
Expense Example, No Redemption, 10 Years $ 930                                
Annual Return, Inception Date Feb. 14, 2019                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   32.11%                       17.87% 17.94% [7]    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | Fidelity Advisor Founders Fund - Class Z                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 0.00%                                
Maximum Deferred Sales Charge (as a percentage) 0.00%                                
Management Fees (as a percentage of Assets) [2] 0.56%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.10%                                
Expenses (as a percentage of Assets) 0.66%                                
Expense Example, with Redemption, 1 Year $ 67                                
Expense Example, with Redemption, 3 Years 211                                
Expense Example, with Redemption, 5 Years 368                                
Expense Example, with Redemption, 10 Years 822                                
Expense Example, No Redemption, 1 Year 67                                
Expense Example, No Redemption, 3 Years 211                                
Expense Example, No Redemption, 5 Years 368                                
Expense Example, No Redemption, 10 Years $ 822                                
Annual Return, Inception Date Feb. 14, 2019                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   32.20%                       17.99% 18.07% [8]    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund /Class: Fidelity® Founders Fund /Fidelity Advisor® Founders Fund A, M, C, I, Z                                  
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Founders Fund seeks 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. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 33 of the prospectus and in the sales charge waiver appendix to the prospectus.                                
Shareholder Fees Caption [Optional Text] Shareholder fees                                
Operating Expenses Caption [Optional Text] Annual Operating Expenses                                
Portfolio Turnover [Heading] Portfolio Turnover                                
Portfolio Turnover [Text Block] The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 41 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 41.00%                                
Expenses Deferred Charges [Text Block] Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% and 0.25%, respectively.                                
Expense Breakpoint Discounts [Text] You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 33 of the prospectus                                
Expense Breakpoint, Minimum Investment Required [Amount] $ 50,000                                
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 and if you hold your shares:                                
Strategy [Heading] Principal Investment Strategies                                
Strategy Narrative [Text Block] Normally investing primarily in equity securities of founder-involved companies. Founder-involved companies are those for which, at the time of the fund's initial purchase, a founder is a member of the senior management team or the company's board of directors. When evaluating companies, the Adviser also takes into consideration a founder's personal or family share ownership in the company. Using quantitative analysis to evaluate growth potential, valuation, liquidity, and investment risk, along with fundamental analysis of factors such as each issuer's financial condition, its industry position, and market and economic conditions to select investments. Investing in either "growth" stocks or "value" stocks or both. Investing in securities of domestic and foreign issuers. Effective December 11, 2025, normally investing at least 80% of assets in securities of founder-involved companies. The Adviser considers a number of factors in determining whether a company is a founder-involved company, including whether a founder or founder family member is a member of the senior management team or the company's board of directors at the time of investment or within the past five years and a founder's personal or family share ownership in the company. Whether a company is a founder-involved company can be determined under any of these factors. 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. Normally investing primarily in equity securities.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit institutional.fidelity.com for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.                                
Performance Availability Website Address [Text] institutional.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                                
Bar Chart Narrative [Text Block] The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.                                
Bar Chart Does Not Reflect Sales Loads [Text] The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.                                
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 (7.43%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 34.74%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Jun. 30, 2022                                
Lowest Quarterly Return (19.01%)                                
Performance Table Heading Average Annual Returns                                
Performance Table Does Reflect Sales Loads Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges.                                
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 One Class of after Tax Shown [Text] After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary.                                
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 Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges. 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. After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary. 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.                                
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | After Taxes on Distributions | Fidelity Advisor Founders Fund - Class A                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   23.29%                       15.47% 15.87% [3]    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | After Taxes on Distributions and Sales | Fidelity Advisor Founders Fund - Class A                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   14.98%                       12.91% 13.33% [3]    
FidelityFoundersFund-AMCIZPRO | Fidelity Founders Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                       13.86% 14.92%    
FidelityLargeCapStockK6Fund-PRO | Fidelity Large Cap Stock K6 Fund | Fidelity Large Cap Stock K6 Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) 0.45%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.00%                                
Expenses (as a percentage of Assets) 0.45%                                
Expense Example, with Redemption, 1 Year $ 46                                
Expense Example, with Redemption, 3 Years 144                                
Expense Example, with Redemption, 5 Years 252                                
Expense Example, with Redemption, 10 Years $ 567                                
Annual Return, Inception Date May 25, 2017                                
Average Annual Return, Label [Optional Text]   Fidelity® Large Cap Stock K6 Fund                              
Average Annual Return, Percent   26.33%                       15.16%   14.10% [9]  
Annual Return [Percent]     26.33% 23.93% (5.67%) 25.66% 9.12% 31.46% (8.51%)                
FidelityLargeCapStockK6Fund-PRO | Fidelity Large Cap Stock K6 Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Large Cap Stock K6 Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Large Cap Stock K6 Fund seeks long-term growth of capital.                                
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 , 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, 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%                                
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] Normally investing at least 80% of assets in common stocks of companies with large market capitalizations. The Adviser generally defines large market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 1000 ® Index or the S&P 500 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance is not an indication of future performance. Visit www.401k.com and log in for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.                                
Performance Availability Website Address [Text] www.401k.com                                
Performance Past Does Not Indicate Future [Text] Past performance 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 (2.33%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Dec. 31, 2020                                
Highest Quarterly Return 19.34%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (24.88%)                                
Performance Table Heading Average Annual Returns                                
FidelityLargeCapStockK6Fund-PRO | Fidelity Large Cap Stock K6 Fund | SP001                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P 500® Index                              
Average Annual Return, Percent   25.02%                       14.53%   14.35%  
FidelitySeriesSmallCapDiscoveryFund-PRO | Fidelity Series Small Cap Discovery Fund | Fidelity Series Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) 0.00%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.00%                                
Expenses (as a percentage of Assets) 0.00%                                
Expense Example, with Redemption, 1 Year $ 0                                
Expense Example, with Redemption, 3 Years 0                                
Expense Example, with Redemption, 5 Years 0                                
Expense Example, with Redemption, 10 Years $ 0                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   3.18%                       9.51%     8.30%
Annual Return [Percent]     3.18% 21.77% (16.12%) 36.31% 9.64% 30.01% (12.68%) 9.59% 18.76% (4.64%)          
FidelitySeriesSmallCapDiscoveryFund-PRO | Fidelity Series Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Series Small Cap Discovery Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Series Small Cap Discovery Fund seeks long-term growth of capital.                                
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.                                
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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 80 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 80.00%                                
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] Normally investing primarily in common stocks. Normally investing at least 80% of assets in securities of companies with small market capitalizations . The Adviser generally defines small market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 2000 ® Index or the S&P SmallCap 600 ® Index. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index 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. The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level, if applicable. Visit www.fidelity.com for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index 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 (5.79%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 31.85%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (35.65%)                                
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.                                
FidelitySeriesSmallCapDiscoveryFund-PRO | Fidelity Series Small Cap Discovery Fund | After Taxes on Distributions | Fidelity Series Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   0.18%                       6.60%     6.14%
FidelitySeriesSmallCapDiscoveryFund-PRO | Fidelity Series Small Cap Discovery Fund | After Taxes on Distributions and Sales | Fidelity Series Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   3.05%                       6.96%     6.20%
FidelitySeriesSmallCapDiscoveryFund-PRO | Fidelity Series Small Cap Discovery Fund | RS002                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 2000® Index                              
Average Annual Return, Percent   11.54%                       7.40%     7.82%
FidelitySeriesSmallCapDiscoveryFund-PRO | Fidelity Series Small Cap Discovery Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                       13.86%     12.55%
FidelitySmallCapStockK6Fund-PRO | Fidelity Small Cap Stock K6 Fund | Fidelity Small Cap Stock K6 Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) 0.60%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.00%                                
Expenses (as a percentage of Assets) 0.60%                                
Expense Example, with Redemption, 1 Year $ 61                                
Expense Example, with Redemption, 3 Years 192                                
Expense Example, with Redemption, 5 Years 335                                
Expense Example, with Redemption, 10 Years $ 750                                
Annual Return, Inception Date May 25, 2017                                
Average Annual Return, Label [Optional Text]   Fidelity® Small Cap Stock K6 Fund                              
Average Annual Return, Percent   9.48%                       7.44%   8.18% [10]  
Annual Return [Percent]     9.48% 19.93% (21.40%) 20.95% 14.68% 29.83% (12.01%)                
FidelitySmallCapStockK6Fund-PRO | Fidelity Small Cap Stock K6 Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Small Cap Stock K6 Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Small Cap Stock K6 Fund seeks long-term growth of capital.                                
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 , 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 133 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 133.00%                                
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] Normally investing at least 80% of assets in common stocks of companies with small market capitalizations. The Adviser generally defines small market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 2000 ® Index or the S&P SmallCap 600 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance is not an indication of future performance. Visit www.401k.com and log in for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.                                
Performance Availability Website Address [Text] www.401k.com                                
Performance Past Does Not Indicate Future [Text] Past performance 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 (5.37%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 29.87%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (33.22%)                                
Performance Table Heading Average Annual Returns                                
FidelitySmallCapStockK6Fund-PRO | Fidelity Small Cap Stock K6 Fund | RS002                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 2000® Index                              
Average Annual Return, Percent   11.54%                       7.40%   7.93%  
FidelitySmallCapStockK6Fund-PRO | Fidelity Small Cap Stock K6 Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                       13.86%   13.73%  
FidelityFoundersFund-RetailPRO | Fidelity Founders Fund | Fidelity Founders Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) [11] 0.67%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.10%                                
Expenses (as a percentage of Assets) 0.77%                                
Expense Example, with Redemption, 1 Year $ 79                                
Expense Example, with Redemption, 3 Years 246                                
Expense Example, with Redemption, 5 Years 428                                
Expense Example, with Redemption, 10 Years $ 954                                
Annual Return, Inception Date Feb. 14, 2019                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   32.09%                       17.84% 17.91% [12]    
Annual Return [Percent]     32.09% 33.95% (26.65%) 18.96% 47.20%                    
FidelityFoundersFund-RetailPRO | Fidelity Founders Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund /Class: Fidelity® Founders Fund /Fidelity® Founders Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Founders Fund seeks 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 41 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 41.00%                                
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] Normally investing primarily in equity securities of founder-involved companies. Founder-involved companies are those for which, at the time of the fund's initial purchase, a founder is a member of the senior management team or the company's board of directors. When evaluating companies, the Adviser also takes into consideration a founder's personal or family share ownership in the company. Using quantitative analysis to evaluate growth potential, valuation, liquidity, and investment risk, along with fundamental analysis of factors such as each issuer's financial condition, its industry position, and market and economic conditions to select investments. Investing in either "growth" stocks or "value" stocks or both. Investing in securities of domestic and foreign issuers. Effective December 11, 2025, normally investing at least 80% of assets in securities of founder-involved companies. The Adviser considers a number of factors in determining whether a company is a founder-involved company, including whether a founder or founder family member is a member of the senior management team or the company's board of directors at the time of investment or within the past five years and a founder's personal or family share ownership in the company. Whether a company is a founder-involved company can be determined under any of these factors. 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. Normally investing primarily in equity securities.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears 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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index 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 (7.36%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 34.74%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Jun. 30, 2022                                
Lowest Quarterly Return (18.98%)                                
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.                                
FidelityFoundersFund-RetailPRO | Fidelity Founders Fund | After Taxes on Distributions | Fidelity Founders Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   31.14%                       17.14% 17.31% [12]    
FidelityFoundersFund-RetailPRO | Fidelity Founders Fund | After Taxes on Distributions and Sales | Fidelity Founders Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   19.69%                       14.34% 14.60% [12]    
FidelityFoundersFund-RetailPRO | Fidelity Founders Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                       13.86% 14.92%    
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Large Cap Stock Fund | Fidelity Large Cap Stock Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) [13] 0.74%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 0.75%                                
Expense Example, with Redemption, 1 Year $ 77                                
Expense Example, with Redemption, 3 Years 240                                
Expense Example, with Redemption, 5 Years 417                                
Expense Example, with Redemption, 10 Years $ 930                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   26.28%                       14.52%     12.13%
Annual Return [Percent]     26.28% 23.52% (7.95%) 25.83% 9.00% 31.55% (9.15%) 18.15% 16.70% (3.17%)          
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Large Cap Stock Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Large Cap Stock Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Large Cap Stock Fund seeks long-term growth of capital.                                
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 , 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 17 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 17.00%                                
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] Normally investing at least 80% of assets in common stocks of companies with large market capitalizations. The Adviser generally defines large market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 1000 ® Index or the S&P 500 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears 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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index 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 (2.29%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Dec. 31, 2020                                
Highest Quarterly Return 19.07%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (24.95%)                                
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.                                
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Large Cap Stock Fund | After Taxes on Distributions | Fidelity Large Cap Stock Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   24.98%                       13.46%     10.84%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Large Cap Stock Fund | After Taxes on Distributions and Sales | Fidelity Large Cap Stock Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   16.40%                       11.42%     9.61%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Large Cap Stock Fund | SP001                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P 500® Index                              
Average Annual Return, Percent   25.02%                       14.53%     13.10%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Mid-Cap Stock Fund | Fidelity Mid-Cap Stock Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) [14] 0.66%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 0.67%                                
Expense Example, with Redemption, 1 Year $ 68                                
Expense Example, with Redemption, 3 Years 214                                
Expense Example, with Redemption, 5 Years 373                                
Expense Example, with Redemption, 10 Years $ 835                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   14.59%                       11.31%     10.23%
Annual Return [Percent]     14.59% 11.04% (6.29%) 28.66% 11.37% 25.35% (6.47%) 18.68% 14.94% (3.08%)          
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Mid-Cap Stock Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund /Class: Fidelity® Mid-Cap Stock Fund /Fidelity® Mid-Cap Stock Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Mid-Cap Stock Fund seeks long-term growth of capital.                                
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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 51 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 51.00%                                
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] Normally investing at least 80% of assets in common stocks of companies with medium market capitalizations. The Adviser generally defines medium market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell Midcap ® Index or the S&P MidCap 400 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Potentially investing in companies with smaller or larger market capitalizations. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index 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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index 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 (5.80%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 21.35%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (28.54%)                                
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.                                
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Mid-Cap Stock Fund | After Taxes on Distributions | Fidelity Mid-Cap Stock Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   12.18%                       9.41%     8.00%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Mid-Cap Stock Fund | After Taxes on Distributions and Sales | Fidelity Mid-Cap Stock Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   10.17%                       8.69%     7.71%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Mid-Cap Stock Fund | SP001                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P 500® Index                              
Average Annual Return, Percent   25.02%                       14.53%     13.10%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Mid-Cap Stock Fund | SP004                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P MidCap 400® Index                              
Average Annual Return, Percent   13.93%                       10.34%     9.68%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Small Cap Stock Fund | Fidelity Small Cap Stock Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) [15] 0.85%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.02%                                
Expenses (as a percentage of Assets) [16] 0.87%                                
Expense Example, with Redemption, 1 Year $ 89                                
Expense Example, with Redemption, 3 Years 278                                
Expense Example, with Redemption, 5 Years 482                                
Expense Example, with Redemption, 10 Years $ 1,073                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   9.28%                       6.75%     7.65%
Annual Return [Percent]     9.28% 19.70% (22.54%) 20.23% 13.80% 29.46% (11.56%) 13.84% 12.94% 2.40%          
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Small Cap Stock Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Small Cap Stock Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Small Cap Stock Fund seeks long-term growth of capital.                                
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 , 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 124 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 124.00%                                
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text] Differs from the ratios of expenses to average net assets in the Financial Highlights section of the prospectus because of acquired fund fees and expenses. For the period, acquired fund fees and expenses are less than 0.01% and are included in other expenses.                                
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] Normally investing at least 80% of assets in common stocks of companies with small market capitalizations. The Adviser generally defines small market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 2000 ® Index or the S&P SmallCap 600 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index 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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index 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 (5.52%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 29.80%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (33.33%)                                
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.                                
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Small Cap Stock Fund | After Taxes on Distributions | Fidelity Small Cap Stock Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   8.67%                       5.00%     5.64%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Small Cap Stock Fund | After Taxes on Distributions and Sales | Fidelity Small Cap Stock Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   5.69%                       4.94%     5.64%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Small Cap Stock Fund | RS002                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 2000® Index                              
Average Annual Return, Percent   11.54%                       7.40%     7.82%
FidelitySmallCapStockFundMid-CapStockFundLargeCapStockFund-RetailComboPRO | Fidelity Small Cap Stock Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                       13.86%     12.55%
FidelityMid-CapStockK6Fund-PRO | Fidelity Mid-Cap Stock K6 Fund | Fidelity Mid-Cap Stock K6 Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) 0.45%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.00%                                
Expenses (as a percentage of Assets) 0.45%                                
Expense Example, with Redemption, 1 Year $ 46                                
Expense Example, with Redemption, 3 Years 144                                
Expense Example, with Redemption, 5 Years 252                                
Expense Example, with Redemption, 10 Years $ 567                                
Annual Return, Inception Date Jun. 13, 2019                                
Average Annual Return, Label [Optional Text]   Fidelity® Mid-Cap Stock K6 Fund                              
Average Annual Return, Percent   14.71%                       11.24% 11.77% [17]    
Annual Return [Percent]     14.71% 11.56% (5.92%) 27.14% 11.27%                    
FidelityMid-CapStockK6Fund-PRO | Fidelity Mid-Cap Stock K6 Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Mid-Cap Stock K6 Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Mid-Cap Stock K6 Fund seeks long-term growth of capital.                                
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 , 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 69 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 69.00%                                
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] Normally investing at least 80% of assets in common stocks of companies with medium market capitalizations. The Adviser generally defines medium market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell Midcap ® Index or the S&P MidCap 400 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Potentially investing in companies with smaller or larger market capitalizations. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance is not an indication of future performance. Visit www.401k.com and log in for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.                                
Performance Availability Website Address [Text] www.401k.com                                
Performance Past Does Not Indicate Future [Text] Past performance 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 (5.90%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 21.55%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (28.78%)                                
Performance Table Heading Average Annual Returns                                
FidelityMid-CapStockK6Fund-PRO | Fidelity Mid-Cap Stock K6 Fund | SP001                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P 500® Index                              
Average Annual Return, Percent   25.02%                       14.53% 15.48%    
FidelityMid-CapStockK6Fund-PRO | Fidelity Mid-Cap Stock K6 Fund | SP004                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P MidCap 400® Index                              
Average Annual Return, Percent   13.93%                       10.34% 10.95%    
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | Fidelity Advisor Mid-Cap Stock Fund - Class A                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 5.75%                                
Maximum Deferred Sales Charge (as a percentage) [18] 0.00%                                
Management Fees (as a percentage of Assets) [19],[20] 0.66%                                
Distribution and Service (12b-1) Fees 0.25%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 0.92%                                
Expense Example, with Redemption, 1 Year $ 663                                
Expense Example, with Redemption, 3 Years 851                                
Expense Example, with Redemption, 5 Years 1,055                                
Expense Example, with Redemption, 10 Years 1,641                                
Expense Example, No Redemption, 1 Year 663                                
Expense Example, No Redemption, 3 Years 851                                
Expense Example, No Redemption, 5 Years 1,055                                
Expense Example, No Redemption, 10 Years $ 1,641                                
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | Fidelity Advisor Mid-Cap Stock Fund - Class M                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 3.50%                                
Maximum Deferred Sales Charge (as a percentage) [18] 0.00%                                
Management Fees (as a percentage of Assets) [19],[20] 0.67%                                
Distribution and Service (12b-1) Fees 0.50%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 1.18%                                
Expense Example, with Redemption, 1 Year $ 466                                
Expense Example, with Redemption, 3 Years 712                                
Expense Example, with Redemption, 5 Years 976                                
Expense Example, with Redemption, 10 Years 1,732                                
Expense Example, No Redemption, 1 Year 466                                
Expense Example, No Redemption, 3 Years 712                                
Expense Example, No Redemption, 5 Years 976                                
Expense Example, No Redemption, 10 Years $ 1,732                                
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | Fidelity Advisor Mid-Cap Stock Fund - Class C                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 0.00%                                
Maximum Deferred Sales Charge (as a percentage) [21] 1.00%                                
Management Fees (as a percentage of Assets) [19],[20] 0.68%                                
Distribution and Service (12b-1) Fees 1.00%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 1.69%                                
Expenses Deferred Charges [Text Block] On Class C shares redeemed less than one year after purchase.                                
Expense Example, with Redemption, 1 Year $ 272                                
Expense Example, with Redemption, 3 Years 533                                
Expense Example, with Redemption, 5 Years 918                                
Expense Example, with Redemption, 10 Years 1,793                                
Expense Example, No Redemption, 1 Year 172                                
Expense Example, No Redemption, 3 Years 533                                
Expense Example, No Redemption, 5 Years 918                                
Expense Example, No Redemption, 10 Years $ 1,793                                
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | Fidelity Advisor Mid-Cap Stock Fund - Class I                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 0.00%                                
Maximum Deferred Sales Charge (as a percentage) 0.00%                                
Management Fees (as a percentage of Assets) [19],[20] 0.66%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 0.67%                                
Expense Example, with Redemption, 1 Year $ 68                                
Expense Example, with Redemption, 3 Years 214                                
Expense Example, with Redemption, 5 Years 373                                
Expense Example, with Redemption, 10 Years 835                                
Expense Example, No Redemption, 1 Year 68                                
Expense Example, No Redemption, 3 Years 214                                
Expense Example, No Redemption, 5 Years 373                                
Expense Example, No Redemption, 10 Years $ 835                                
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | Fidelity Advisor Mid-Cap Stock Fund - Class Z                                  
Prospectus Line Items                                  
Maximum Cumulative Sales Charge (as a percentage of Offering Price) 0.00%                                
Maximum Deferred Sales Charge (as a percentage) 0.00%                                
Management Fees (as a percentage of Assets) [19],[20] 0.55%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 0.56%                                
Expense Example, with Redemption, 1 Year $ 57                                
Expense Example, with Redemption, 3 Years 179                                
Expense Example, with Redemption, 5 Years 313                                
Expense Example, with Redemption, 10 Years 701                                
Expense Example, No Redemption, 1 Year 57                                
Expense Example, No Redemption, 3 Years 179                                
Expense Example, No Redemption, 5 Years 313                                
Expense Example, No Redemption, 10 Years $ 701                                
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund /Class: Fidelity® Mid-Cap Stock Fund /Fidelity Advisor® Mid-Cap Stock Fund A, M, C, I, Z                                  
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Mid-Cap Stock Fund seeks long-term growth of capital.                                
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. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 33 of the prospectus and in the sales charge waiver appendix to the prospectus.                                
Shareholder Fees Caption [Optional Text] Shareholder fees                                
Operating Expenses Caption [Optional Text] Annual Operating Expenses                                
Portfolio Turnover [Heading] Portfolio Turnover                                
Portfolio Turnover [Text Block] The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 51 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 51.00%                                
Expenses Deferred Charges [Text Block] Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% and 0.25%, respectively.                                
Expense Breakpoint Discounts [Text] You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 33 of the prospectus                                
Expense Breakpoint, Minimum Investment Required [Amount] $ 50,000                                
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 and if you hold your shares:                                
Strategy [Heading] Principal Investment Strategies                                
Strategy Narrative [Text Block] Normally investing at least 80% of assets in common stocks of companies with medium market capitalizations . The Adviser generally defines medium market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell Midcap ® Index or the S&P MidCap 400 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Potentially investing in companies with smaller or larger market capitalizations. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of Fidelity® Mid-Cap Stock Fund, a class of shares of the fund, from year to year and compares the performance of this class to the performance of a securities market index and an additional index over various periods of time. The additional index 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 for Fidelity® Mid-Cap Stock Fund, a class of shares of the fund . Performance history will be available at institutional.fidelity.com for Class A, Class M, Class C, Class I, and Class Z after Class A, Class M, Class C, Class I, and Class Z have been in operation for one calendar year.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of Fidelity® Mid-Cap Stock Fund, a class of shares of the fund, from year to year and compares the performance of this class to the performance of a securities market index and an additional index over various periods of time.                                
Performance One Year or Less [Text] Performance history will be available at institutional.fidelity.com for Class A, Class M, Class C, Class I, and Class Z after Class A, Class M, Class C, Class I, and Class Z have been in operation for one calendar year.                                
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 (5.80%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 21.35%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (28.54%)                                
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.                                
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | SP001                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P 500® Index                              
Average Annual Return, Percent   25.02%                       14.53%     13.10%
FidelityMid-CapStockFund-AMCIZPRO | Fidelity Mid-Cap Stock Fund | SP004                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P MidCap 400® Index                              
Average Annual Return, Percent   13.93%                       10.34%     9.68%
FidelitySeriesSmallCapCoreFund-PRO | Fidelity Series Small Cap Core Fund | Fidelity Series Small Cap Core Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) 0.00%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.00%                                
Expenses (as a percentage of Assets) 0.00%                                
Expense Example, with Redemption, 1 Year $ 0                                
Expense Example, with Redemption, 3 Years 0                                
Expense Example, with Redemption, 5 Years 0                                
Expense Example, with Redemption, 10 Years $ 0                                
Annual Return, Inception Date Nov. 04, 2022                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   10.16%                     11.45% [22]        
Annual Return [Percent]     10.16% 16.80%                          
FidelitySeriesSmallCapCoreFund-PRO | Fidelity Series Small Cap Core Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Series Small Cap Core Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Series Small Cap Core Fund seeks 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.                                
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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 42 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 42.00%                                
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] Normally investing primarily in equity securities. Normally investing at least 80% of assets in securities of companies with small market capitalizations . The Adviser generally defines small market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 2000 ® Index or the S&P SmallCap 600 ® Index. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index 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. The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level, if applicable. Visit www.fidelity.com for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index 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 (11.30%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Dec. 31, 2023                                
Highest Quarterly Return 15.66%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Sep. 30, 2023                                
Lowest Quarterly Return (3.80%)                                
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.                                
FidelitySeriesSmallCapCoreFund-PRO | Fidelity Series Small Cap Core Fund | After Taxes on Distributions | Fidelity Series Small Cap Core Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   9.62%                     10.89% [22]        
FidelitySeriesSmallCapCoreFund-PRO | Fidelity Series Small Cap Core Fund | After Taxes on Distributions and Sales | Fidelity Series Small Cap Core Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   6.15%                     8.68% [22]        
FidelitySeriesSmallCapCoreFund-PRO | Fidelity Series Small Cap Core Fund | RS002                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 2000® Index                              
Average Annual Return, Percent   11.54%                     12.13%        
FidelitySeriesSmallCapCoreFund-PRO | Fidelity Series Small Cap Core Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                     23.87%        
FidelityMid-CapStockFund-KPRO | Fidelity Mid-Cap Stock Fund | Fidelity Mid-Cap Stock Fund - Class K                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) [23] 0.58%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.02%                                
Expenses (as a percentage of Assets) 0.60%                                
Expense Example, with Redemption, 1 Year $ 61                                
Expense Example, with Redemption, 3 Years 192                                
Expense Example, with Redemption, 5 Years 335                                
Expense Example, with Redemption, 10 Years $ 750                                
Average Annual Return, Label [Optional Text]   Class K                              
Average Annual Return, Percent   14.69%                       11.41%     10.34%
Annual Return [Percent]     14.69% 11.14% (6.19%) 28.74% 11.51% 25.47% (6.36%) 18.80% 15.10% (2.97%)          
FidelityMid-CapStockFund-KPRO | Fidelity Mid-Cap Stock Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund /Class: Fidelity® Mid-Cap Stock Fund /K                                  
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Mid-Cap Stock Fund seeks long-term growth of capital.                                
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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 51 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 51.00%                                
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] Normally investing at least 80% of assets in common stocks of companies with medium market capitalizations. The Adviser generally defines medium market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell Midcap ® Index or the S&P MidCap 400 ® Index. Common stocks (including depositary receipts evidencing ownership of common stock) are a type of equity security that represents an ownership interest in an issuer. 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. Potentially investing in companies with smaller or larger market capitalizations. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance is not an indication of future performance. Visit www.401k.com and log in for more recent performance information.                                
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.                                
Performance Availability Website Address [Text] www.401k.com                                
Performance Past Does Not Indicate Future [Text] Past performance 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 (5.79%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 21.39%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (28.53%)                                
Performance Table Heading Average Annual Returns                                
FidelityMid-CapStockFund-KPRO | Fidelity Mid-Cap Stock Fund | SP001                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P 500® Index                              
Average Annual Return, Percent   25.02%                       14.53%     13.10%
FidelityMid-CapStockFund-KPRO | Fidelity Mid-Cap Stock Fund | SP004                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   S&P MidCap 400® Index                              
Average Annual Return, Percent   13.93%                       10.34%     9.68%
FidelitySmallCapDiscoveryFund-PRO | Fidelity Small Cap Discovery Fund | Fidelity Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Management Fees (as a percentage of Assets) [24] 0.90%                                
Distribution and Service (12b-1) Fees 0.00%                                
Other Expenses (as a percentage of Assets): 0.01%                                
Expenses (as a percentage of Assets) 0.91%                                
Expense Example, with Redemption, 1 Year $ 93                                
Expense Example, with Redemption, 3 Years 290                                
Expense Example, with Redemption, 5 Years 504                                
Expense Example, with Redemption, 10 Years $ 1,120                                
Average Annual Return, Label [Optional Text]   Return Before Taxes                              
Average Annual Return, Percent   2.85%                       8.61%     7.29%
Annual Return [Percent]     2.85% 21.32% (16.46%) 35.67% 6.89% 27.27% (13.75%) 7.91% 20.29% (6.17%)          
FidelitySmallCapDiscoveryFund-PRO | Fidelity Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Risk/Return [Heading] Fund Summary Fund: Fidelity® Small Cap Discovery Fund                                
Objective [Heading] Investment Objective                                
Objective, Primary [Text Block] Fidelity® Small Cap Discovery Fund seeks long-term growth of capital.                                
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 , 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 pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 67 % of the average value of its portfolio.                                
Portfolio Turnover, Rate 67.00%                                
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] Normally investing primarily in common stocks. Normally investing at least 80% of assets in securities of companies with small market capitalizations . The Adviser generally defines small market capitalization companies as those whose market capitalization is similar to the market capitalization of companies in the Russell 2000 ® Index or the S&P SmallCap 600 ® Index. 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. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.                                
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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index 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 changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index 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 (5.80%)                                
Highest Quarterly Return, Label [Optional Text]    Highest Quarter Return                                
Highest Quarterly Return, Date Jun. 30, 2020                                
Highest Quarterly Return 30.45%                                
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                                
Lowest Quarterly Return, Date Mar. 31, 2020                                
Lowest Quarterly Return (36.56%)                                
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.                                
FidelitySmallCapDiscoveryFund-PRO | Fidelity Small Cap Discovery Fund | After Taxes on Distributions | Fidelity Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                              
Average Annual Return, Percent   (0.43%)                       6.67%     4.99%
FidelitySmallCapDiscoveryFund-PRO | Fidelity Small Cap Discovery Fund | After Taxes on Distributions and Sales | Fidelity Small Cap Discovery Fund                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                              
Average Annual Return, Percent   3.36%                       6.56%     5.34%
FidelitySmallCapDiscoveryFund-PRO | Fidelity Small Cap Discovery Fund | RS002                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 2000® Index                              
Average Annual Return, Percent   11.54%                       7.40%     7.82%
FidelitySmallCapDiscoveryFund-PRO | Fidelity Small Cap Discovery Fund | RS003                                  
Prospectus Line Items                                  
Average Annual Return, Label [Optional Text]   Russell 3000® Index                              
Average Annual Return, Percent   23.81%                       13.86%     12.55%
Document Type 485BPOS                                
Registrant Name Fidelity Concord Street Trust                                
[1]
A Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% and 0.25%, respectively.
[2]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.10% based on the performance of the fund or a designated class of the fund relative to that of the Russell 3000® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[3]
A From February 14, 2019 .
[4]
B From February 14, 2019 .
[5]
B On Class C shares redeemed less than one year after purchase.
[6]
C From February 14, 2019 .
[7]
D From February 14, 2019 .
[8]
E From February 14, 2019 .
[9]
A From May 25, 2017 .
[10]
A From May 25, 2017 .
[11]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.10% based on the performance of the fund or a designated class of the fund relative to that of the Russell 3000® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[12]
A From February 14, 2019 .
[13]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.20% based on the performance of the fund or a designated class of the fund relative to that of the S&P 500® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[14]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.20% based on the performance of the fund or a designated class of the fund relative to that of the S&P MidCap 400® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[15]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.20% based on the performance of the fund or a designated class of the fund relative to that of the Russell 2000® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[16]
B Differs from the ratios of expenses to average net assets in the Financial Highlights section of the prospectus because of acquired fund fees and expenses. For the period, acquired fund fees and expenses are less than 0.01% and are included in other expenses.
[17]
A From June 13, 2019 .
[18]
A Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% and 0.25%, respectively.
[19]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.20% based on the performance of the fund or a designated class of the fund relative to that of the S&P MidCap 400® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[20]
B The performance fee was calculated for the period October 8, 2024 (commencement of class operations) through April 30, 2025 .
[21]
B On Class C shares redeemed less than one year after purchase.
[22]
A From November 4, 2022 .
[23]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.20% based on the performance of the fund or a designated class of the fund relative to that of the S&P MidCap 400® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.
[24]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.20% based on the performance of the fund or a designated class of the fund relative to that of the Russell 2000® Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.