| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Fidelity Trend Fund |
| Entity Central Index Key | 0000035402 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) shares | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Fidelity Trend Fund |
| Entity Central Index Key | 0000035402 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Fidelity Trend Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Trend Fund |
| Class Name | Fidelity® Trend Fund |
| Trading Symbol | FTRNX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains information about Fidelity® Trend Fund for the period January 1, 2024 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com. |
| Additional Information Phone Number | 1-800-544-8544 |
| Additional Information Email | fidfunddocuments@fidelity.com |
| Additional Information Website | fundresearch.fidelity.com/prospectus/sec |
| Expenses [Text Block] | What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Trend Fund $ 0.58 % |
| Expenses Paid, Amount | $ 32 |
| Expense Ratio, Percent | 0.58% |
| Net Assets | $ 3,570,346,726 |
| Holdings Count | shares | 81 |
| Investment Company Portfolio Turnover | 65% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 81 Portfolio Turnover 65 % |
| Holdings [Text Block] | MARKET SECTORS (% of Fund's net assets) Information Technology 47.2 Industrials 17.5 Consumer Discretionary 15.2 Communication Services 10.5 Financials 3.3 Health Care 3.2 Real Estate 1.0 Utilities 0.4 Consumer Staples 0.3 Common Stocks 98.6 Short-Term Investments and Net Other Assets (Liabilities) 1.4 ASSET ALLOCATION (% of Fund's net assets) United States 94.4 Italy 1.0 Netherlands 0.9 France 0.8 Germany 0.7 Canada 0.5 Taiwan 0.5 Japan 0.5 China 0.3 Others 0.4 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) |
| Largest Holdings [Text Block] | TOP HOLDINGS (% of Fund's net assets) NVIDIA Corp 12.7 Microsoft Corp 10.0 Apple Inc 8.9 Amazon.com Inc 8.1 Meta Platforms Inc Class A 4.7 Alphabet Inc Class A 3.8 Eli Lilly & Co 2.6 Fair Isaac Corp 2.0 Micron Technology Inc 1.8 Broadcom Inc 1.7 56.3 |
| Shareholder Report, Holdings (Details) - Fidelity Trend Fund | Jun. 30, 2024 |
| TH0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.70% |
| TH1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10% |
| TH2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.90% |
| TH3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.10% |
| TH4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| TH5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| TH6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| TH7Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| TH8Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.80% |
| TH9Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| MSFinancialsSectorMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| Information Technology Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 47.20% |
| Healthcare Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| Real Estate Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| Industrial Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.50% |
| Consumer Discretionary Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.20% |
| Consumer Staples Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| Communications Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.50% |
| Utilities Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.40% |
| United States | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 94.40% |
| Italy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| Netherlands | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.90% |
| France | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.80% |
| Germany | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Canada | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Taiwan | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Japan | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| China | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| OtherMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.40% |
| AACommonStocksMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 98.60% |
| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
