v3.26.1
Risk/Return Detail Data - FidelityTelecomandUtilitiesFund-RetailPRO - USD ($)
 12 Months Ended 60 Months Ended 120 Months Ended
Apr. 01, 2026
Apr. 01, 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
Apr. 01, 2026
Apr. 01, 2026
FidelityTelecomandUtilitiesFund-RetailPRO | Fidelity Telecom and Utilities Fund | Fidelity Telecom and Utilities Fund                            
Prospectus Line Items                            
Management Fees (as a percentage of Assets) [1] 0.67%                          
Distribution and Service (12b-1) Fees 0.00%                          
Other Expenses (as a percentage of Assets): 0.01%                          
Expenses (as a percentage of Assets) 0.68%                          
Expense Example, with Redemption, 1 Year $ 69                          
Expense Example, with Redemption, 3 Years 218                          
Expense Example, with Redemption, 5 Years 379                          
Expense Example, with Redemption, 10 Years $ 847                          
Average Annual Return, Label [Optional Text]   Return Before Taxes                        
Average Annual Return, Percent   11.15%                     11.01% 11.02%
Annual Return [Percent]     11.15% 30.29% 3.38% 5.01% 7.20% 2.10% 22.02% 3.32% 11.98% 17.03%    
FidelityTelecomandUtilitiesFund-RetailPRO | Fidelity Telecom and Utilities Fund                            
Prospectus Line Items                            
Risk/Return [Heading] Fund Summary Fund: Fidelity® Telecom and Utilities Fund                          
Objective [Heading] Investment Objective                          
Objective, Primary [Text Block] Fidelity® Telecom and Utilities Fund seeks high total return through a combination of current income and 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, 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 94 % of the average value of its portfolio.                          
Portfolio Turnover, Rate 94.00%                          
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 securities of telecommunications services companies and utility companies. Telecommunications services companies and utility companies may include companies that are principally engaged in providing electricity, gas, water, cable television, radio, telecommunications services, or sanitary services to the public. For purposes of the fund's policy to normally invest at least 80% of its assets in securities of companies principally engaged in the business activity or activities identified for the fund, Fidelity may consider a company to be principally engaged in the designated business activity or activities based on: (i) the level of a company's assets, income, sales, or profits that are committed to, derived from, or related to the designated business activity or activities, or (ii) whether a third party has given the company an industry or sector classification consistent with the designated business activity or activities. Whether a company is principally engaged in the designated business activity or activities 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 common 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.                          
Strategy Portfolio Concentration [Text] Normally investing at least 80% of assets in securities of telecommunications services companies and utility companies.                          
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 Sep. 30, 2024                          
Highest Quarterly Return 17.00%                          
Lowest Quarterly Return, Label [Optional Text]    Lowest Quarter Return                          
Lowest Quarterly Return, Date Mar. 31, 2020                          
Lowest Quarterly Return (17.07%)                          
Performance Table Heading Average Annual Returns                          
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.                          
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).                          
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.                          
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.                          
FidelityTelecomandUtilitiesFund-RetailPRO | Fidelity Telecom and Utilities Fund | After Taxes on Distributions | Fidelity Telecom and Utilities Fund                            
Prospectus Line Items                            
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions                        
Average Annual Return, Percent   9.04%                     9.36% 9.43%
FidelityTelecomandUtilitiesFund-RetailPRO | Fidelity Telecom and Utilities Fund | After Taxes on Distributions and Sales | Fidelity Telecom and Utilities Fund                            
Prospectus Line Items                            
Average Annual Return, Label [Optional Text]   Return After Taxes on Distributions and Sale of Fund Shares                        
Average Annual Return, Percent   8.02%                     8.45% 8.67%
FidelityTelecomandUtilitiesFund-RetailPRO | Fidelity Telecom and Utilities Fund | RS018                            
Prospectus Line Items                            
Average Annual Return, Label [Optional Text]   Russell 3000® Telecom and Utilities Select Index                        
Average Annual Return, Percent   13.98%                     7.69% 8.64%
FidelityTelecomandUtilitiesFund-RetailPRO | Fidelity Telecom and Utilities Fund | SP001                            
Prospectus Line Items                            
Average Annual Return, Label [Optional Text]   S&P 500® Index                        
Average Annual Return, Percent   17.88%                     14.42% 14.82%
Document Type 485BPOS                          
Registrant Name Fidelity Select Portfolios                          
[1]
A The management fee comprises a basic fee, which may vary by class, that is adjusted up or down by a maximum of 0.15% based on the performance of the fund or a designated class of the fund relative to that of the Russell 3000® Telecom and Utilities Select Index. Please see "Fund Services - Fund Management - Advisory Fee(s)" for additional information.