Risk/Return Detail Data - FidelityTrendFund-RetailPRO - USD ($)			12 Months Ended											60 Months Ended	120 Months Ended
		Feb. 28, 2026	Feb. 28, 2026	Dec. 31, 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	Feb. 28, 2026	Feb. 28, 2026
FidelityTrendFund-RetailPRO | Fidelity Trend Fund | Fidelity Trend Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)	[1]	0.73%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.01%
Expenses (as a percentage of Assets)		0.74%
Expense Example, with Redemption, 1 Year		$ 76
Expense Example, with Redemption, 3 Years		237
Expense Example, with Redemption, 5 Years		411
Expense Example, with Redemption, 10 Years		$ 918
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			18.73%											14.40%	17.79%
Annual Return [Percent]				18.73%	40.16%	44.39%	(33.64%)	22.86%	47.00%	35.88%	(2.96%)	29.42%	4.57%
FidelityTrendFund-RetailPRO | Fidelity Trend Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® Trend Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Trend Fund seeks 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 60 % of the average value of its portfolio.
Portfolio Turnover, Rate		60.00%
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. Investing in companies that Fidelity Management & Research Company LLC (FMR) believes have above-average growth potential (stocks of these companies are often called "growth" stocks). Investing in domestic and foreign issuers. 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
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Jun. 30, 2020
Highest Quarterly Return		28.87%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Jun. 30, 2022
Lowest Quarterly Return		(24.69%)
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.
FidelityTrendFund-RetailPRO | Fidelity Trend Fund | After Taxes on Distributions | Fidelity Trend Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			16.33%											12.26%	15.59%
FidelityTrendFund-RetailPRO | Fidelity Trend Fund | After Taxes on Distributions and Sales | Fidelity Trend Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			12.46%											11.09%	14.31%
FidelityTrendFund-RetailPRO | Fidelity Trend Fund | RS004
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Russell 1000® Growth Index
Average Annual Return, Percent			18.56%											15.32%	18.13%
FidelityTrendFund-RetailPRO | Fidelity Trend Fund | RS001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Russell 1000® Index
Average Annual Return, Percent			17.37%											13.59%	14.59%
Document Type		485BPOS
Registrant Name		Fidelity Trend Fund

[1] 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 1000® Growth Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.