| Form N-CSR Cover | 12 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Fidelity Salem Street Trust |
| Entity Central Index Key | 0000035315 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 12 Months Ended |
| Jun. 30, 2024 USD ($) shares | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Fidelity Salem Street Trust |
| Entity Central Index Key | 0000035315 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Fidelity Small Cap Value Index Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Small Cap Value Index Fund |
| Class Name | Fidelity® Small Cap Value Index Fund |
| Trading Symbol | FISVX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Small Cap Value Index Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Small Cap Value Index Fund $ 0.05 % |
| Expenses Paid, Amount | $ 6 |
| Expense Ratio, Percent | 0.05% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • • • • • |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B25"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE July 11, 2019 through June 30, 2024. Initial investment of $10,000. Fidelity® Small Cap Value Index Fund $10,000 $8,311 $14,387 $12,042 $12,781 $14,165 Russell 2000® Value Index $10,000 $8,323 $14,423 $12,075 $12,800 $14,195 Russell 3000® Index $10,000 $10,459 $15,078 $12,987 $15,449 $19,021 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Small Cap Value Index Fund 10.83% 7.25% Russell 2000® Value Index 10.90% 7.29% Russell 3000® Index 23.13% 13.80% A From July 11, 2019 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | Jul. 11, 2019 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 1,152,113,306 |
| Holdings Count | shares | 1,453 |
| Advisory Fees Paid, Amount | $ 487,130 |
| Investment Company Portfolio Turnover | 37% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 1,453 Total Advisory Fee $ Portfolio Turnover 37 % |
| Holdings [Text Block] | MARKET SECTORS (% of Fund's net assets) Financials 26.9 Industrials 12.3 Real Estate 10.7 Consumer Discretionary 10.0 Energy 9.2 Health Care 9.1 Information Technology 6.1 Materials 5.2 Utilities 5.0 Communication Services 2.8 Consumer Staples 2.2 Common Stocks 99.5 Short-Term Investments and Net Other Assets (Liabilities) 0.5 ASSET ALLOCATION (% of Fund's net assets) United States 96.1 Canada 0.8 Puerto Rico 0.5 Norway 0.5 Monaco 0.4 Bailiwick Of Jersey 0.3 Bermuda 0.3 Cameroon 0.3 Brazil 0.2 Others 0.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) |
| Largest Holdings [Text Block] | TOP HOLDINGS (% of Fund's net assets) Commercial Metals Co 0.6 Murphy Oil Corp 0.6 Essent Group Ltd 0.6 SouthState Corp 0.6 Meritage Homes Corp 0.6 Taylor Morrison Home Corp 0.5 Terreno Realty Corp 0.5 Jackson Financial Inc 0.5 Cytokinetics Inc 0.5 Old National Bancorp/IN 0.5 5.5 |
| Fidelity Small Cap Growth Index Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Small Cap Growth Index Fund |
| Class Name | Fidelity® Small Cap Growth Index Fund |
| Trading Symbol | FECGX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Small Cap Growth Index Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Small Cap Growth Index Fund $ 0.05 % |
| Expenses Paid, Amount | $ 6 |
| Expense Ratio, Percent | 0.05% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • • • • • |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B52"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE July 11, 2019 through June 30, 2024. Initial investment of $10,000. Fidelity® Small Cap Growth Index Fund $10,000 $10,359 $15,675 $10,451 $12,413 $13,562 Russell 2000® Growth Index $10,000 $10,369 $15,695 $10,448 $12,384 $13,516 Russell 3000® Index $10,000 $10,459 $15,078 $12,987 $15,449 $19,021 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Small Cap Growth Index Fund 9.26% 6.32% Russell 2000® Growth Index 9.14% 6.24% Russell 3000® Index 23.13% 13.80% A From July 11, 2019 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | Jul. 11, 2019 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 654,727,211 |
| Holdings Count | shares | 1,131 |
| Advisory Fees Paid, Amount | $ 279,883 |
| Investment Company Portfolio Turnover | 48% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 1,131 Total Advisory Fee $ Portfolio Turnover 48 % |
| Holdings [Text Block] | MARKET SECTORS (% of Fund's net assets) Health Care 25.3 Industrials 22.0 Information Technology 20.6 Consumer Discretionary 10.0 Financials 7.9 Energy 4.2 Materials 3.9 Consumer Staples 3.2 Communication Services 2.1 Real Estate 1.4 Utilities 0.5 Common Stocks 101.1 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (1.1)% United States 97.1 Thailand 0.8 Singapore 0.3 Brazil 0.2 Ghana 0.2 India 0.2 Puerto Rico 0.2 Canada 0.2 Norway 0.2 Others 0.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) |
| Largest Holdings [Text Block] | TOP HOLDINGS (% of Fund's net assets) Insmed Inc 0.9 FTAI Aviation Ltd 0.9 Abercrombie & Fitch Co Class A 0.8 Fabrinet 0.8 Vaxcyte Inc 0.8 Sprouts Farmers Market Inc 0.7 Applied Industrial Technologies Inc 0.7 HealthEquity Inc 0.7 SPS Commerce Inc 0.7 Ensign Group Inc/The 0.6 7.6 |
| Fidelity Mid Cap Growth Index Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Mid Cap Growth Index Fund |
| Class Name | Fidelity® Mid Cap Growth Index Fund |
| Trading Symbol | FMDGX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Mid Cap Growth Index Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Mid Cap Growth Index Fund $ 0.05 % |
| Expenses Paid, Amount | $ 6 |
| Expense Ratio, Percent | 0.05% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • • • • • |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B79"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE July 11, 2019 through June 30, 2024. Initial investment of $10,000. Fidelity® Mid Cap Growth Index Fund $10,000 $10,886 $15,643 $11,018 $13,566 $15,601 Russell Midcap® Growth Index $10,000 $10,946 $15,738 $11,083 $13,647 $15,702 Russell 3000® Index $10,000 $10,459 $15,078 $12,987 $15,449 $19,021 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Mid Cap Growth Index Fund 15.01% 9.35% Russell Midcap® Growth Index 15.05% 9.49% Russell 3000® Index 23.13% 13.80% A From July 11, 2019 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | Jul. 11, 2019 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 1,106,274,971 |
| Holdings Count | shares | 292 |
| Advisory Fees Paid, Amount | $ 419,189 |
| Investment Company Portfolio Turnover | 54% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 292 Total Advisory Fee $ Portfolio Turnover 54 % |
| Holdings [Text Block] | MARKET SECTORS (% of Fund's net assets) Information Technology 24.7 Industrials 17.0 Consumer Discretionary 15.1 Health Care 14.4 Financials 12.4 Communication Services 4.4 Energy 4.0 Consumer Staples 2.8 Utilities 1.4 Materials 1.4 Real Estate 1.2 Common Stocks 98.8 Short-Term Investments and Net Other Assets (Liabilities) 1.2 ASSET ALLOCATION (% of Fund's net assets) United States 97.5 Brazil 1.6 Korea (South) 0.9 Puerto Rico 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) |
| Largest Holdings [Text Block] | TOP HOLDINGS (% of Fund's net assets) Palantir Technologies Inc Class A 1.9 Dexcom Inc 1.8 Trade Desk Inc (The) Class A 1.6 NU Holdings Ltd/Cayman Islands Class A 1.6 Super Micro Computer Inc 1.6 IDEXX Laboratories Inc 1.5 Ameriprise Financial Inc 1.5 Datadog Inc Class A 1.5 Verisk Analytics Inc 1.5 Monolithic Power Sys Inc 1.4 15.9 |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Municipal Income 2025 Fund |
| Class Name | Fidelity Advisor® Municipal Income 2025 Fund Class I |
| Trading Symbol | FAMYX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Municipal Income 2025 Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-877-208-0098 |
| 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class I $ 0.40 % |
| Expenses Paid, Amount | $ 41 |
| Expense Ratio, Percent | 0.40% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • U.S. tax-exempt municipal bonds achieved a solid gain for the 12 months ending June 30, 2024. The full-year advance was largely the result of bond market rallies in the final months of 2023 and the final month of the period, but the 12 months were marked by high levels of volatility, as investors anxiously awaited the arrival of interest-rate reductions by the U.S. Federal Reserve. • The past 12 months, we focused on long-term objectives and sought to generate attractive tax-exempt income and a competitive risk-adjusted return. • Versus the 2025 index, the fund's carry advantage, meaning its larger-than-index exposure to higher-coupon municipal bonds, was the biggest contributor by far this period. • An overweight to lower-rated investment-grade municipal bonds also added value. These securities, helped by strong demand from investors seeking higher levels of income, bested higher-quality bonds this period. • Specifically, larger-than-index exposure to lower-rated health care and higher education bonds was helpful. Exposure to lower-rated tax-backed bonds that received credit rating upgrades was beneficial as well. • In contrast, differences in the way fund holdings and index components were priced detracted from relative performance. Fund holdings are priced by a third-party pricing service and validated daily by Fidelity Management and Research's fair-value processes. Securities within the index, however, are priced by the index provider. |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B107"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE May 25, 2017 through June 30, 2024. Initial investment of $10,000. Class I $10,000 $9,964 $9,960 $10,709 $10,984 $11,413 $10,848 $10,920 Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index $10,000 $10,001 $10,008 $10,749 $11,225 $11,480 $10,989 $11,072 Bloomberg Municipal Bond Index $10,000 $10,005 $10,162 $10,843 $11,325 $11,797 $10,786 $11,130 2017 2018 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Class I 3.20% 1.03% 1.70% Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index 2.94% 1.18% 1.86% Bloomberg Municipal Bond Index 3.21% 1.16% 1.97% A From May 25, 2017 Visit institutional.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | May 25, 2017 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 23,727,435 |
| Holdings Count | shares | 123 |
| Advisory Fees Paid, Amount | $ 73,069 |
| Investment Company Portfolio Turnover | 6% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 123 Total Advisory Fee $ Portfolio Turnover 6 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) Health Care 27.1 Transportation 23.5 Education 21.0 General Obligations 9.9 Housing 5.4 Others(Individually Less Than 5%) 13.1 100.0 AAA 6.7 AA 21.2 A 47.7 BBB 14.4 BB 2.4 B 0.4 Not Rated 3.8 Short-Term Investments and Net Other Assets (Liabilities) 3.4 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. TOP STATES (% of Fund's net assets) Connecticut 11.0 Pennsylvania 10.3 Illinois 8.0 Florida 6.7 Massachusetts 5.8 |
| Material Fund Change [Text Block] | How has the Fund changed? This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund closed to new investors on June 28, 2024, in anticipation of its liquidation shortly after its target end date of June 30, 2025. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . |
| Updated Prospectus Phone Number | 1-877-208-0098</span>" id="sjs-B120"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span> |
| Updated Prospectus Email Address | fidfunddocuments@fidelity.com</span>" id="sjs-B121"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span> |
| Updated Prospectus Web Address | fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B122"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span> |
| Fidelity Municipal Bond Index Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Municipal Bond Index Fund |
| Class Name | Fidelity® Municipal Bond Index Fund |
| Trading Symbol | FMBIX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Municipal Bond Index Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Municipal Bond Index Fund $ 0.07 % |
| Expenses Paid, Amount | $ 7 |
| Expense Ratio, Percent | 0.07% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • U.S. tax-exempt municipal bonds achieved a solid gain for the 12 months ending June 30, 2024. The full-year advance was largely the result of bond market rallies in the final months of 2023 and the final month of the period, but the 12 months were marked by high levels of volatility, as investors anxiously awaited the arrival of interest-rate reductions by the U.S. Federal Reserve. • Our goal is to produce monthly returns, before expenses, that closely match the benchmark's return. • We use statistical sampling techniques based on duration, maturity, interest-rate sensitivity, security structure and credit quality to attempt to replicate the returns of the Bloomberg Municipal Bond Index using a smaller number of securities. • This period, trading costs associated with the purchase and sale of municipal securities detracted from performance versus the benchmark, as market volatility triggered uneven shareholder flows. • Differences in the way fund holdings and index components were priced also detracted from the fund's relative performance. Fund holdings are priced by a third-party pricing service and validated daily by Fidelity Management & Research's (FMR) fair-value processes. Securities within the index, however, are priced by the index provider. |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B138"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE July 11, 2019 through June 30, 2024. Initial investment of $10,000. Fidelity® Municipal Bond Index Fund $10,000 $10,146 $10,518 $9,544 $9,796 $10,091 Bloomberg Municipal Bond Index $10,000 $10,410 $10,843 $9,914 $10,230 $10,558 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Municipal Bond Index Fund 3.01% 0.18% Bloomberg Municipal Bond Index 3.21% 1.10% A From July 11, 2019 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | Jul. 11, 2019 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 164,812,968 |
| Holdings Count | shares | 1,847 |
| Advisory Fees Paid, Amount | $ 108,081 |
| Investment Company Portfolio Turnover | 15% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 1,847 Total Advisory Fee $ Portfolio Turnover 15 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) General Obligations 35.7 Transportation 15.6 Special Tax 11.1 Water & Sewer 10.4 Health Care 8.7 Education 6.7 Others(Individually Less Than 5%) 11.8 100.0 AAA 19.2 AA 52.4 A 22.9 BBB 3.3 BB 0.0 B 0.0 Not Rated 1.2 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. TOP STATES (% of Fund's net assets) California 22.9 New York 15.0 Texas 7.8 Florida 4.7 Illinois 4.6 |
| Fidelity Mid Cap Value Index Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Mid Cap Value Index Fund |
| Class Name | Fidelity® Mid Cap Value Index Fund |
| Trading Symbol | FIMVX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Mid Cap Value Index Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Mid Cap Value Index Fund $ 0.06 % |
| Expenses Paid, Amount | $ 6 |
| Expense Ratio, Percent | 0.06% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • • • • • |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B165"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE July 11, 2019 through June 30, 2024. Initial investment of $10,000. Fidelity® Mid Cap Value Index Fund $10,000 $8,735 $13,349 $12,003 $13,271 $14,858 Russell Midcap® Value Index $10,000 $8,756 $13,402 $12,062 $13,329 $14,925 Russell 3000® Index $10,000 $10,459 $15,078 $12,987 $15,449 $19,021 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Mid Cap Value Index Fund 11.96% 8.28% Russell Midcap® Value Index 11.98% 8.38% Russell 3000® Index 23.13% 13.80% A From July 11, 2019 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | Jul. 11, 2019 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 854,245,859 |
| Holdings Count | shares | 717 |
| Advisory Fees Paid, Amount | $ 426,336 |
| Investment Company Portfolio Turnover | 38% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 717 Total Advisory Fee $ Portfolio Turnover 38 % |
| Holdings [Text Block] | MARKET SECTORS (% of Fund's net assets) Industrials 17.3 Financials 16.7 Real Estate 9.9 Consumer Discretionary 9.6 Information Technology 9.3 Health Care 9.3 Materials 7.6 Utilities 6.7 Consumer Staples 6.3 Energy 6.0 Communication Services 3.2 Common Stocks 101.9 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (1.9)% United States 99.3 Canada 0.2 Bermuda 0.1 United Kingdom 0.1 Brazil 0.1 Belgium 0.1 Puerto Rico 0.1 Japan 0.0 Finland 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) |
| Largest Holdings [Text Block] | TOP HOLDINGS (% of Fund's net assets) Arthur J Gallagher & Co 0.7 Williams Cos Inc/The 0.7 Digital Realty Trust Inc 0.7 Microchip Technology Inc 0.7 ONEOK Inc 0.7 Humana Inc 0.7 AFLAC Inc 0.6 Realty Income Corp 0.6 Bank of New York Mellon Corp/The 0.6 L3Harris Technologies Inc 0.6 6.6 |
| Material Fund Change [Text Block] | How has the Fund changed? This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Operating expenses |
| Material Fund Change Expenses [Text Block] | The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Operating expenses |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . |
| Updated Prospectus Phone Number | 1-800-544-8544</span>" id="sjs-B180"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-800-544-8544</span> |
| Updated Prospectus Email Address | fidfunddocuments@fidelity.com</span>" id="sjs-B181"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span> |
| Updated Prospectus Web Address | fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B182"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span> |
| Fidelity SAI Municipal Bond Index Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® SAI Municipal Bond Index Fund |
| Class Name | Fidelity® SAI Municipal Bond Index Fund |
| Trading Symbol | FSABX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® SAI Municipal Bond Index Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com. |
| Additional Information Phone Number | 1-800-544-3455 |
| 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® SAI Municipal Bond Index Fund $ 0.07 % |
| Expenses Paid, Amount | $ 7 |
| Expense Ratio, Percent | 0.07% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • U.S. tax-exempt municipal bonds achieved a solid gain for the 12 months ending June 30, 2024. The full-year advance was largely the result of bond market rallies in the final months of 2023 and the final month of the period, but the 12 months were marked by high levels of volatility, as investors anxiously awaited the arrival of interest-rate reductions by the U.S. Federal Reserve. • Our goal is to produce monthly returns, before expenses, that closely match the benchmark's return. • We use statistical sampling techniques based on duration, maturity, interest-rate sensitivity, security structure and credit quality to attempt to replicate the returns of the Bloomberg Municipal Bond Index using a smaller number of securities. • This period, trading costs associated with the purchase and sale of municipal securities detracted from performance versus the benchmark, as market volatility triggered uneven shareholder flows. • Differences in the way fund holdings and index components were priced also detracted from the fund's relative performance. Fund holdings are priced by a third-party pricing service and validated daily by Fidelity Management & Research's (FMR) fair-value processes. Securities within the index, however, are priced by the index provider. |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B198"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE July 11, 2019 through June 30, 2024. Initial investment of $10,000. Fidelity® SAI Municipal Bond Index Fund $10,000 $10,296 $10,656 $9,618 $9,876 $10,163 Bloomberg Municipal Bond Index $10,000 $10,410 $10,843 $9,914 $10,230 $10,558 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® SAI Municipal Bond Index Fund 2.90% 0.33% Bloomberg Municipal Bond Index 3.21% 1.10% A From July 11, 2019 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | Jul. 11, 2019 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 80,747,568 |
| Holdings Count | shares | 1,351 |
| Advisory Fees Paid, Amount | $ 41,212 |
| Investment Company Portfolio Turnover | 17% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 1,351 Total Advisory Fee $ Portfolio Turnover 17 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) General Obligations 34.0 Transportation 16.0 Special Tax 13.8 Water & Sewer 9.3 Health Care 9.0 Electric Utilities 6.1 Education 6.0 Others(Individually Less Than 5%) 5.8 100.0 AAA 16.7 AA 55.7 A 22.0 BBB 4.3 B 0.0 Not Rated 1.0 Short-Term Investments and Net Other Assets (Liabilities) 0.3 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. TOP STATES (% of Fund's net assets) California 19.3 New York 16.9 Texas 8.1 Illinois 4.7 Washington 4.3 |
| Fidelity Municipal Income 2025 Fund | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Municipal Income 2025 Fund |
| Class Name | Fidelity® Municipal Income 2025 Fund |
| Trading Symbol | FIMSX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Municipal Income 2025 Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Municipal Income 2025 Fund $ 0.40 % |
| Expenses Paid, Amount | $ 41 |
| Expense Ratio, Percent | 0.40% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • U.S. tax-exempt municipal bonds achieved a solid gain for the 12 months ending June 30, 2024. The full-year advance was largely the result of bond market rallies in the final months of 2023 and the final month of the period, but the 12 months were marked by high levels of volatility, as investors anxiously awaited the arrival of interest-rate reductions by the U.S. Federal Reserve. • The past 12 months, we focused on long-term objectives and sought to generate attractive tax-exempt income and a competitive risk-adjusted return. • Versus the 2025 index, the fund's carry advantage, meaning its larger-than-index exposure to higher-coupon municipal bonds, was the biggest contributor by far this period. • An overweight to lower-rated investment-grade municipal bonds also added value. These securities, helped by strong demand from investors seeking higher levels of income, bested higher-quality bonds this period. • Specifically, larger-than-index exposure to lower-rated health care and higher education bonds was helpful. Exposure to lower-rated tax-backed bonds that received credit rating upgrades was beneficial as well. • In contrast, differences in the way fund holdings and index components were priced detracted from relative performance. Fund holdings are priced by a third-party pricing service and validated daily by Fidelity Management and Research's fair-value processes. Securities within the index, however, are priced by the index provider. |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B225"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE May 25, 2017 through June 30, 2024. Initial investment of $10,000. Fidelity® Municipal Income 2025 Fund $10,000 $9,964 $9,960 $10,709 $10,973 $11,413 $10,849 $10,920 Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index $10,000 $10,001 $10,008 $10,749 $11,225 $11,480 $10,989 $11,072 Bloomberg Municipal Bond Index $10,000 $10,005 $10,162 $10,843 $11,325 $11,797 $10,786 $11,130 2017 2018 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Fidelity® Municipal Income 2025 Fund 3.20% 1.03% 1.70% Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index 2.94% 1.18% 1.86% Bloomberg Municipal Bond Index 3.21% 1.16% 1.97% A From May 25, 2017 Visit www.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | May 25, 2017 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 23,727,435 |
| Holdings Count | shares | 123 |
| Advisory Fees Paid, Amount | $ 73,069 |
| Investment Company Portfolio Turnover | 6% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 123 Total Advisory Fee $ Portfolio Turnover 6 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) Health Care 27.1 Transportation 23.5 Education 21.0 General Obligations 9.9 Housing 5.4 Others(Individually Less Than 5%) 13.1 100.0 AAA 6.7 AA 21.2 A 47.7 BBB 14.4 BB 2.4 B 0.4 Not Rated 3.8 Short-Term Investments and Net Other Assets (Liabilities) 3.4 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. TOP STATES (% of Fund's net assets) Connecticut 11.0 Pennsylvania 10.3 Illinois 8.0 Florida 6.7 Massachusetts 5.8 |
| Material Fund Change [Text Block] | How has the Fund changed? This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . The fund closed to new investors on June 28, 2024, in anticipation of its liquidation shortly after its target end date of June 30, 2025. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . |
| Updated Prospectus Phone Number | 1-800-544-8544</span>" id="sjs-B238"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-800-544-8544</span> |
| Updated Prospectus Email Address | fidfunddocuments@fidelity.com</span>" id="sjs-B239"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span> |
| Updated Prospectus Web Address | fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B240"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span> |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | |
| Shareholder Report [Line Items] | |
| Fund Name | Fidelity® Municipal Income 2025 Fund |
| Class Name | Fidelity Advisor® Municipal Income 2025 Fund Class A |
| Trading Symbol | FAMHX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Municipal Income 2025 Fund for the period July 1, 2023 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | 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 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-877-208-0098 |
| 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 year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $ 0.65 % |
| Expenses Paid, Amount | $ 66 |
| Expense Ratio, Percent | 0.65% |
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period? • U.S. tax-exempt municipal bonds achieved a solid gain for the 12 months ending June 30, 2024. The full-year advance was largely the result of bond market rallies in the final months of 2023 and the final month of the period, but the 12 months were marked by high levels of volatility, as investors anxiously awaited the arrival of interest-rate reductions by the U.S. Federal Reserve. • The past 12 months, we focused on long-term objectives and sought to generate attractive tax-exempt income and a competitive risk-adjusted return. • Versus the 2025 index, the fund's carry advantage, meaning its larger-than-index exposure to higher-coupon municipal bonds, was the biggest contributor by far this period. • An overweight to lower-rated investment-grade municipal bonds also added value. These securities, helped by strong demand from investors seeking higher levels of income, bested higher-quality bonds this period. • Specifically, larger-than-index exposure to lower-rated health care and higher education bonds was helpful. Exposure to lower-rated tax-backed bonds that received credit rating upgrades was beneficial as well. • In contrast, differences in the way fund holdings and index components were priced detracted from relative performance. Fund holdings are priced by a third-party pricing service and validated daily by Fidelity Management and Research's fair-value processes. Securities within the index, however, are priced by the index provider. |
| Performance Past Does Not Indicate Future [Text] | The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B257"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.</span> |
| Line Graph [Table Text Block] | How did the Fund perform over the life of Fund? CUMULATIVE PERFORMANCE May 25, 2017 through June 30, 2024. Initial investment of $10,000 and the current sales charge was paid. Class A $9,725 $9,688 $9,660 $10,360 $10,589 $10,986 $10,417 $10,459 Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index $10,000 $10,001 $10,008 $10,749 $11,225 $11,480 $10,989 $11,072 Bloomberg Municipal Bond Index $10,000 $10,005 $10,162 $10,843 $11,325 $11,797 $10,786 $11,130 2017 2018 2019 2020 2021 2022 2023 2024 |
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Class A (incl. 2.75% sales charge) 0.11% 0.21% 1.05% Class A (without 2.75% sales charge) 2.94% 0.77% 1.44% Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index 2.94% 1.18% 1.86% Bloomberg Municipal Bond Index 3.21% 1.16% 1.97% A From May 25, 2017 Visit institutional.fidelity.com for more recent performance information. The Fund's past performance is not a good predictor of the Fund's future performance. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Performance Inception Date | May 25, 2017 |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. |
| Net Assets | $ 23,727,435 |
| Holdings Count | shares | 123 |
| Advisory Fees Paid, Amount | $ 73,069 |
| Investment Company Portfolio Turnover | 6% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 123 Total Advisory Fee $ Portfolio Turnover 6 % |
| Holdings [Text Block] | REVENUE SOURCES (% of Fund's net assets) Health Care 27.1 Transportation 23.5 Education 21.0 General Obligations 9.9 Housing 5.4 Others(Individually Less Than 5%) 13.1 100.0 AAA 6.7 AA 21.2 A 47.7 BBB 14.4 BB 2.4 B 0.4 Not Rated 3.8 Short-Term Investments and Net Other Assets (Liabilities) 3.4 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. TOP STATES (% of Fund's net assets) Connecticut 11.0 Pennsylvania 10.3 Illinois 8.0 Florida 6.7 Massachusetts 5.8 |
| Material Fund Change [Text Block] | How has the Fund changed? This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund closed to new investors on June 28, 2024, in anticipation of its liquidation shortly after its target end date of June 30, 2025. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since July 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by August 29, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . |
| Updated Prospectus Phone Number | 1-877-208-0098</span>" id="sjs-B270"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span> |
| Updated Prospectus Email Address | fidfunddocuments@fidelity.com</span>" id="sjs-B271"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span> |
| Updated Prospectus Web Address | fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B272"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span> |
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | 60 Months Ended | 72 Months Ended | 96 Months Ended | |||||||
| Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2017 | |
| C000212599_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 23.13% | ||||||||||
| C000212599_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 13.80% | ||||||||||
| C000212598_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 23.13% | ||||||||||
| C000212598_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 13.80% | ||||||||||
| C000212596_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 23.13% | ||||||||||
| C000212596_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 13.80% | ||||||||||
| C000183198_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.21% | ||||||||||
| C000183198_1_BBIndexMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.16% | ||||||||||
| C000183198_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.97% | ||||||||||
| C000212594_0_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.21% | ||||||||||
| C000212594_0_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.10% | ||||||||||
| C000212597_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 23.13% | ||||||||||
| C000212597_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 13.80% | ||||||||||
| C000212595_0_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.21% | ||||||||||
| C000212595_0_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.10% | ||||||||||
| C000183196_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.21% | ||||||||||
| C000183196_1_BBIndexMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.16% | ||||||||||
| C000183196_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.97% | ||||||||||
| C000183197_1_BBIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.21% | ||||||||||
| C000183197_1_BBIndexMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.16% | ||||||||||
| C000183197_1_BBIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.97% | ||||||||||
| C000212599_LG_ClassMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® Small Cap Value Index Fund</span>" id="sjs-D68"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Small Cap Value Index Fund</span> | ||||||||||
| C000212599_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,000 | ||||||||||
| C000212599_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 8,311 | ||||||||||
| C000212599_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 14,387 | ||||||||||
| C000212599_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 12,042 | ||||||||||
| C000212599_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 12,781 | ||||||||||
| C000212599_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 14,165 | $ 14,165 | $ 14,165 | $ 14,165 | |||||||
| C000212599_LG_1_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 2000® Value Index</span>" id="sjs-D89"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell 2000® Value Index</span> | ||||||||||
| C000212599_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212599_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 8,323 | ||||||||||
| C000212599_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 14,423 | ||||||||||
| C000212599_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,075 | ||||||||||
| C000212599_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,800 | ||||||||||
| C000212599_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 14,195 | 14,195 | $ 14,195 | 14,195 | |||||||
| C000212599_LG_2_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 3000® Index</span>" id="sjs-D110"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell 3000® Index</span> | ||||||||||
| C000212599_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212599_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,459 | ||||||||||
| C000212599_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,078 | ||||||||||
| C000212599_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,987 | ||||||||||
| C000212599_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,449 | ||||||||||
| C000212599_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 19,021 | 19,021 | $ 19,021 | 19,021 | |||||||
| C000212599_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 10.83% | ||||||||||
| C000212599_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 7.25% | ||||||||||
| C000212599_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 10.90% | ||||||||||
| C000212599_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 7.29% | ||||||||||
| C000212598_LG_ClassMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® Small Cap Growth Index Fund</span>" id="sjs-D143"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Small Cap Growth Index Fund</span> | ||||||||||
| C000212598_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212598_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,359 | ||||||||||
| C000212598_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,675 | ||||||||||
| C000212598_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,451 | ||||||||||
| C000212598_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,413 | ||||||||||
| C000212598_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 13,562 | 13,562 | $ 13,562 | 13,562 | |||||||
| C000212598_LG_1_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 2000® Growth Index</span>" id="sjs-D164"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell 2000® Growth Index</span> | ||||||||||
| C000212598_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212598_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,369 | ||||||||||
| C000212598_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,695 | ||||||||||
| C000212598_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,448 | ||||||||||
| C000212598_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,384 | ||||||||||
| C000212598_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,516 | 13,516 | $ 13,516 | 13,516 | |||||||
| C000212598_LG_2_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 3000® Index</span>" id="sjs-D185"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell 3000® Index</span> | ||||||||||
| C000212598_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212598_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,459 | ||||||||||
| C000212598_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,078 | ||||||||||
| C000212598_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,987 | ||||||||||
| C000212598_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,449 | ||||||||||
| C000212598_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 19,021 | 19,021 | $ 19,021 | 19,021 | |||||||
| C000212598_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 9.26% | ||||||||||
| C000212598_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 6.32% | ||||||||||
| C000212598_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 9.14% | ||||||||||
| C000212598_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 6.24% | ||||||||||
| C000212596_LG_ClassMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® Mid Cap Growth Index Fund</span>" id="sjs-D218"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Mid Cap Growth Index Fund</span> | ||||||||||
| C000212596_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212596_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,886 | ||||||||||
| C000212596_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,643 | ||||||||||
| C000212596_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,018 | ||||||||||
| C000212596_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,566 | ||||||||||
| C000212596_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 15,601 | 15,601 | $ 15,601 | 15,601 | |||||||
| C000212596_LG_1_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell Midcap® Growth Index</span>" id="sjs-D239"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell Midcap® Growth Index</span> | ||||||||||
| C000212596_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212596_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,946 | ||||||||||
| C000212596_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,738 | ||||||||||
| C000212596_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,083 | ||||||||||
| C000212596_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,647 | ||||||||||
| C000212596_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,702 | 15,702 | $ 15,702 | 15,702 | |||||||
| C000212596_LG_2_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 3000® Index</span>" id="sjs-D260"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell 3000® Index</span> | ||||||||||
| C000212596_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212596_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,459 | ||||||||||
| C000212596_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,078 | ||||||||||
| C000212596_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,987 | ||||||||||
| C000212596_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,449 | ||||||||||
| C000212596_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 19,021 | 19,021 | $ 19,021 | $ 19,021 | |||||||
| C000212596_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 15.01% | ||||||||||
| C000212596_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 9.35% | ||||||||||
| C000212596_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 15.05% | ||||||||||
| C000212596_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 9.49% | ||||||||||
| C000183198_LG_ClassMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Class I</span>" id="sjs-E293"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I</span> | ||||||||||
| C000183198_ClassMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,000 | ||||||||||
| C000183198_ClassMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 9,964 | ||||||||||
| C000183198_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,960 | ||||||||||
| C000183198_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,709 | ||||||||||
| C000183198_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,984 | ||||||||||
| C000183198_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,413 | ||||||||||
| C000183198_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,848 | ||||||||||
| C000183198_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,920 | 10,920 | 10,920 | $ 10,920 | |||||||
| C000183198_LG_1_AdditionalIndexMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index</span>" id="sjs-E320"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index</span> | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,001 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,008 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,749 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,225 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,480 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,989 | ||||||||||
| C000183198_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,072 | 11,072 | 11,072 | $ 11,072 | |||||||
| C000183198_LG_2_AdditionalIndexMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index</span>" id="sjs-E347"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span> | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,005 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,162 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,843 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,325 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,797 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,786 | ||||||||||
| C000183198_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 11,130 | $ 11,130 | $ 11,130 | $ 11,130 | |||||||
| C000183198_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.20% | ||||||||||
| C000183198_NoLoadClassMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.03% | ||||||||||
| C000183198_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.70% | ||||||||||
| C000183198_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 2.94% | ||||||||||
| C000183198_0_AdditionalIndexMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.18% | ||||||||||
| C000183198_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.86% | ||||||||||
| C000212594_LG_ClassMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® Municipal Bond Index Fund</span>" id="sjs-D392"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Municipal Bond Index Fund</span> | ||||||||||
| C000212594_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212594_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,146 | ||||||||||
| C000212594_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,518 | ||||||||||
| C000212594_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,544 | ||||||||||
| C000212594_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,796 | ||||||||||
| C000212594_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,091 | $ 10,091 | $ 10,091 | 10,091 | |||||||
| C000212594_LG_1_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index</span>" id="sjs-D413"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span> | ||||||||||
| C000212594_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212594_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,410 | ||||||||||
| C000212594_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,843 | ||||||||||
| C000212594_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,914 | ||||||||||
| C000212594_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,230 | ||||||||||
| C000212594_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,558 | 10,558 | $ 10,558 | 10,558 | |||||||
| C000212594_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.01% | ||||||||||
| C000212594_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 0.18% | ||||||||||
| C000212597_LG_ClassMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® Mid Cap Value Index Fund</span>" id="sjs-D440"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Mid Cap Value Index Fund</span> | ||||||||||
| C000212597_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212597_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 8,735 | ||||||||||
| C000212597_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,349 | ||||||||||
| C000212597_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,003 | ||||||||||
| C000212597_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,271 | ||||||||||
| C000212597_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 14,858 | 14,858 | $ 14,858 | 14,858 | |||||||
| C000212597_LG_1_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell Midcap® Value Index</span>" id="sjs-D461"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell Midcap® Value Index</span> | ||||||||||
| C000212597_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212597_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 8,756 | ||||||||||
| C000212597_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,402 | ||||||||||
| C000212597_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,062 | ||||||||||
| C000212597_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 13,329 | ||||||||||
| C000212597_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 14,925 | 14,925 | $ 14,925 | 14,925 | |||||||
| C000212597_LG_2_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 3000® Index</span>" id="sjs-D482"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Russell 3000® Index</span> | ||||||||||
| C000212597_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212597_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,459 | ||||||||||
| C000212597_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,078 | ||||||||||
| C000212597_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 12,987 | ||||||||||
| C000212597_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 15,449 | ||||||||||
| C000212597_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 19,021 | 19,021 | $ 19,021 | 19,021 | |||||||
| C000212597_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 11.96% | ||||||||||
| C000212597_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 8.28% | ||||||||||
| C000212597_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 11.98% | ||||||||||
| C000212597_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 8.38% | ||||||||||
| C000212595_LG_ClassMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® SAI Municipal Bond Index Fund</span>" id="sjs-D515"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® SAI Municipal Bond Index Fund</span> | ||||||||||
| C000212595_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212595_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,296 | ||||||||||
| C000212595_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,656 | ||||||||||
| C000212595_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,618 | ||||||||||
| C000212595_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,876 | ||||||||||
| C000212595_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,163 | 10,163 | $ 10,163 | 10,163 | |||||||
| C000212595_LG_1_AdditionalIndexMember_6YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index</span>" id="sjs-D536"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span> | ||||||||||
| C000212595_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000212595_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,410 | ||||||||||
| C000212595_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,843 | ||||||||||
| C000212595_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,914 | ||||||||||
| C000212595_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,230 | ||||||||||
| C000212595_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,558 | 10,558 | $ 10,558 | $ 10,558 | |||||||
| C000212595_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 2.90% | ||||||||||
| C000212595_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 0.33% | ||||||||||
| C000183196_LG_ClassMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Fidelity® Municipal Income 2025 Fund</span>" id="sjs-E563"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Municipal Income 2025 Fund</span> | ||||||||||
| C000183196_ClassMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000183196_ClassMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,964 | ||||||||||
| C000183196_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,960 | ||||||||||
| C000183196_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,709 | ||||||||||
| C000183196_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,973 | ||||||||||
| C000183196_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,413 | ||||||||||
| C000183196_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,849 | ||||||||||
| C000183196_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,920 | 10,920 | 10,920 | $ 10,920 | |||||||
| C000183196_LG_1_AdditionalIndexMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index</span>" id="sjs-E590"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index</span> | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,001 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,008 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,749 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,225 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,480 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,989 | ||||||||||
| C000183196_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,072 | 11,072 | 11,072 | $ 11,072 | |||||||
| C000183196_LG_2_AdditionalIndexMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index</span>" id="sjs-E617"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span> | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,005 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,162 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,843 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,325 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,797 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,786 | ||||||||||
| C000183196_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 11,130 | $ 11,130 | 11,130 | $ 11,130 | |||||||
| C000183196_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 3.20% | ||||||||||
| C000183196_NoLoadClassMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.03% | ||||||||||
| C000183196_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.70% | ||||||||||
| C000183196_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 2.94% | ||||||||||
| C000183196_0_AdditionalIndexMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.18% | ||||||||||
| C000183196_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.86% | ||||||||||
| C000183197_LG_ClassMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Class A</span>" id="sjs-E662"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A</span> | ||||||||||
| C000183197_ClassMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,725 | ||||||||||
| C000183197_ClassMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,688 | ||||||||||
| C000183197_ClassMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 9,660 | ||||||||||
| C000183197_ClassMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,360 | ||||||||||
| C000183197_ClassMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,589 | ||||||||||
| C000183197_ClassMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,986 | ||||||||||
| C000183197_ClassMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,417 | ||||||||||
| C000183197_ClassMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,459 | $ 10,459 | 10,459 | $ 10,459 | |||||||
| C000183197_LG_1_AdditionalIndexMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index</span>" id="sjs-E689"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond 2025 Ex Tobacco/Prepaid Gas Index</span> | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,000 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,001 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,008 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,749 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,225 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,480 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 10,989 | ||||||||||
| C000183197_1_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | 11,072 | 11,072 | 11,072 | $ 11,072 | |||||||
| C000183197_LG_2_AdditionalIndexMember_8YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index</span>" id="sjs-E716"><span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span> | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2017Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,000 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2018Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,005 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2019Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,162 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2020Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,843 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2021Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 11,325 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2022Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 11,797 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2023Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 10,786 | ||||||||||
| C000183197_2_AdditionalIndexMember_AsOf_2024Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Account Value | $ 11,130 | $ 11,130 | $ 11,130 | $ 11,130 | |||||||
| C000183197_ClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 0.11% | ||||||||||
| C000183197_ClassMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 0.21% | ||||||||||
| C000183197_ClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.05% | ||||||||||
| C000183197_NoLoadClassMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 2.94% | ||||||||||
| C000183197_NoLoadClassMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 0.77% | ||||||||||
| C000183197_NoLoadClassMember_2023-07-01_2024-06-30Member | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.44% | ||||||||||
| C000183197_0_AdditionalIndexMember_1YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 2.94% | ||||||||||
| C000183197_0_AdditionalIndexMember_5YRMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.18% | ||||||||||
| C000183197_0_AdditionalIndexMember_LOCMember | |||||||||||
| Account Value [Line Items] | |||||||||||
| Average Annual Return, Percent | 1.86% |
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| Fidelity Small Cap Value Index Fund | TH0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Value Index Fund | TH1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Value Index Fund | TH2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Value Index Fund | TH3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Value Index Fund | TH4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Value Index Fund | TH5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | TH6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | TH7Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | TH8Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | TH9Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | MSFinancialsSectorMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 26.90% |
| Fidelity Small Cap Value Index Fund | Information Technology Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.10% |
| Fidelity Small Cap Value Index Fund | Healthcare Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.10% |
| Fidelity Small Cap Value Index Fund | Real Estate Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.70% |
| Fidelity Small Cap Value Index Fund | Industrial Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.30% |
| Fidelity Small Cap Value Index Fund | Materials Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.20% |
| Fidelity Small Cap Value Index Fund | Consumer Discretionary Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10% |
| Fidelity Small Cap Value Index Fund | Consumer Staples Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| Fidelity Small Cap Value Index Fund | Communications Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| Fidelity Small Cap Value Index Fund | Energy Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.20% |
| Fidelity Small Cap Value Index Fund | Utilities Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5% |
| Fidelity Small Cap Value Index Fund | United States | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 96.10% |
| Fidelity Small Cap Value Index Fund | Canada | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.80% |
| Fidelity Small Cap Value Index Fund | Puerto Rico | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | Norway | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Value Index Fund | Monaco | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.40% |
| Fidelity Small Cap Value Index Fund | BailiwickOfJerseyMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| Fidelity Small Cap Value Index Fund | Bermuda | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| Fidelity Small Cap Value Index Fund | Cameroon | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| Fidelity Small Cap Value Index Fund | Brazil | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Value Index Fund | OtherMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Value Index Fund | AACommonStocksMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 99.50% |
| Fidelity Small Cap Value Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Growth Index Fund | TH0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.90% |
| Fidelity Small Cap Growth Index Fund | TH1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.90% |
| Fidelity Small Cap Growth Index Fund | TH2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.80% |
| Fidelity Small Cap Growth Index Fund | TH3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.80% |
| Fidelity Small Cap Growth Index Fund | TH4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.80% |
| Fidelity Small Cap Growth Index Fund | TH5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Small Cap Growth Index Fund | TH6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Small Cap Growth Index Fund | TH7Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Small Cap Growth Index Fund | TH8Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Small Cap Growth Index Fund | TH9Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Growth Index Fund | MSFinancialsSectorMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.90% |
| Fidelity Small Cap Growth Index Fund | Information Technology Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 20.60% |
| Fidelity Small Cap Growth Index Fund | Healthcare Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 25.30% |
| Fidelity Small Cap Growth Index Fund | Real Estate Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| Fidelity Small Cap Growth Index Fund | Industrial Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 22% |
| Fidelity Small Cap Growth Index Fund | Materials Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.90% |
| Fidelity Small Cap Growth Index Fund | Consumer Discretionary Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10% |
| Fidelity Small Cap Growth Index Fund | Consumer Staples Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| Fidelity Small Cap Growth Index Fund | Communications Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| Fidelity Small Cap Growth Index Fund | Energy Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.20% |
| Fidelity Small Cap Growth Index Fund | Utilities Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.50% |
| Fidelity Small Cap Growth Index Fund | United States | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 97.10% |
| Fidelity Small Cap Growth Index Fund | Canada | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Growth Index Fund | Puerto Rico | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Growth Index Fund | Norway | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Growth Index Fund | Brazil | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Growth Index Fund | OtherMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Small Cap Growth Index Fund | Thailand | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.80% |
| Fidelity Small Cap Growth Index Fund | Singapore | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| Fidelity Small Cap Growth Index Fund | Ghana | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Growth Index Fund | India | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Small Cap Growth Index Fund | AACommonStocksMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 101.10% |
| Fidelity Mid Cap Growth Index Fund | TH0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.90% |
| Fidelity Mid Cap Growth Index Fund | TH1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.80% |
| Fidelity Mid Cap Growth Index Fund | TH2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| Fidelity Mid Cap Growth Index Fund | TH3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| Fidelity Mid Cap Growth Index Fund | TH4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| Fidelity Mid Cap Growth Index Fund | TH5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Fidelity Mid Cap Growth Index Fund | TH6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Fidelity Mid Cap Growth Index Fund | TH7Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Fidelity Mid Cap Growth Index Fund | TH8Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| Fidelity Mid Cap Growth Index Fund | TH9Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| Fidelity Mid Cap Growth Index Fund | MSFinancialsSectorMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.40% |
| Fidelity Mid Cap Growth Index Fund | Information Technology Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.70% |
| Fidelity Mid Cap Growth Index Fund | Healthcare Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14.40% |
| Fidelity Mid Cap Growth Index Fund | Real Estate Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| Fidelity Mid Cap Growth Index Fund | Industrial Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17% |
| Fidelity Mid Cap Growth Index Fund | Materials Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| Fidelity Mid Cap Growth Index Fund | Consumer Discretionary Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.10% |
| Fidelity Mid Cap Growth Index Fund | Consumer Staples Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| Fidelity Mid Cap Growth Index Fund | Communications Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.40% |
| Fidelity Mid Cap Growth Index Fund | Energy Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4% |
| Fidelity Mid Cap Growth Index Fund | Utilities Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| Fidelity Mid Cap Growth Index Fund | United States | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 97.50% |
| Fidelity Mid Cap Growth Index Fund | Puerto Rico | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| Fidelity Mid Cap Growth Index Fund | Brazil | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| Fidelity Mid Cap Growth Index Fund | Korea, Republic of | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.90% |
| Fidelity Mid Cap Growth Index Fund | AACommonStocksMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 98.80% |
| Fidelity Mid Cap Growth Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | TS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | TS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.30% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | TS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | TS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | TS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.80% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 27.10% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.50% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.90% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | RS5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.10% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 47.70% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | QDBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | QDBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| Fidelity Advisor Municipal Income 2025 Fund - Class I | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| Fidelity Municipal Bond Index Fund | TS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 22.90% |
| Fidelity Municipal Bond Index Fund | TS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15% |
| Fidelity Municipal Bond Index Fund | TS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.80% |
| Fidelity Municipal Bond Index Fund | TS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| Fidelity Municipal Bond Index Fund | TS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.60% |
| Fidelity Municipal Bond Index Fund | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 35.70% |
| Fidelity Municipal Bond Index Fund | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.60% |
| Fidelity Municipal Bond Index Fund | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.10% |
| Fidelity Municipal Bond Index Fund | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.40% |
| Fidelity Municipal Bond Index Fund | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.70% |
| Fidelity Municipal Bond Index Fund | RS5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| Fidelity Municipal Bond Index Fund | RS6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.80% |
| Fidelity Municipal Bond Index Fund | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 22.90% |
| Fidelity Municipal Bond Index Fund | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.30% |
| Fidelity Municipal Bond Index Fund | QDBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| Fidelity Municipal Bond Index Fund | QDBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| Fidelity Municipal Bond Index Fund | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| Fidelity Municipal Bond Index Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| Fidelity Mid Cap Value Index Fund | TH0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Mid Cap Value Index Fund | TH1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Mid Cap Value Index Fund | TH2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Mid Cap Value Index Fund | TH3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Mid Cap Value Index Fund | TH4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Mid Cap Value Index Fund | TH5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| Fidelity Mid Cap Value Index Fund | TH6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Mid Cap Value Index Fund | TH7Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Mid Cap Value Index Fund | TH8Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Mid Cap Value Index Fund | TH9Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| Fidelity Mid Cap Value Index Fund | MSFinancialsSectorMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.70% |
| Fidelity Mid Cap Value Index Fund | Information Technology Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.30% |
| Fidelity Mid Cap Value Index Fund | Healthcare Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.30% |
| Fidelity Mid Cap Value Index Fund | Real Estate Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.90% |
| Fidelity Mid Cap Value Index Fund | Industrial Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.30% |
| Fidelity Mid Cap Value Index Fund | Materials Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.60% |
| Fidelity Mid Cap Value Index Fund | Consumer Discretionary Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.60% |
| Fidelity Mid Cap Value Index Fund | Consumer Staples Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| Fidelity Mid Cap Value Index Fund | Communications Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.20% |
| Fidelity Mid Cap Value Index Fund | Energy Sector | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| Fidelity Mid Cap Value Index Fund | Utilities Sector Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| Fidelity Mid Cap Value Index Fund | United States | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 99.30% |
| Fidelity Mid Cap Value Index Fund | Canada | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.20% |
| Fidelity Mid Cap Value Index Fund | Puerto Rico | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| Fidelity Mid Cap Value Index Fund | Bermuda | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| Fidelity Mid Cap Value Index Fund | Brazil | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| Fidelity Mid Cap Value Index Fund | United Kingdom | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| Fidelity Mid Cap Value Index Fund | Belgium | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| Fidelity Mid Cap Value Index Fund | Japan | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| Fidelity Mid Cap Value Index Fund | Finland | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| Fidelity Mid Cap Value Index Fund | AACommonStocksMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 101.90% |
| Fidelity SAI Municipal Bond Index Fund | TS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 19.30% |
| Fidelity SAI Municipal Bond Index Fund | TS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.90% |
| Fidelity SAI Municipal Bond Index Fund | TS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.10% |
| Fidelity SAI Municipal Bond Index Fund | TS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| Fidelity SAI Municipal Bond Index Fund | TS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.30% |
| Fidelity SAI Municipal Bond Index Fund | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 34% |
| Fidelity SAI Municipal Bond Index Fund | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16% |
| Fidelity SAI Municipal Bond Index Fund | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.80% |
| Fidelity SAI Municipal Bond Index Fund | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.30% |
| Fidelity SAI Municipal Bond Index Fund | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9% |
| Fidelity SAI Municipal Bond Index Fund | RS5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.10% |
| Fidelity SAI Municipal Bond Index Fund | RS6Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| Fidelity SAI Municipal Bond Index Fund | RS7Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.80% |
| Fidelity SAI Municipal Bond Index Fund | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 22% |
| Fidelity SAI Municipal Bond Index Fund | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.30% |
| Fidelity SAI Municipal Bond Index Fund | QDBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0% |
| Fidelity SAI Municipal Bond Index Fund | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1% |
| Fidelity SAI Municipal Bond Index Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.30% |
| Fidelity Municipal Income 2025 Fund | TS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11% |
| Fidelity Municipal Income 2025 Fund | TS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.30% |
| Fidelity Municipal Income 2025 Fund | TS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| Fidelity Municipal Income 2025 Fund | TS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| Fidelity Municipal Income 2025 Fund | TS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.80% |
| Fidelity Municipal Income 2025 Fund | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 27.10% |
| Fidelity Municipal Income 2025 Fund | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.50% |
| Fidelity Municipal Income 2025 Fund | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21% |
| Fidelity Municipal Income 2025 Fund | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.90% |
| Fidelity Municipal Income 2025 Fund | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| Fidelity Municipal Income 2025 Fund | RS5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.10% |
| Fidelity Municipal Income 2025 Fund | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 47.70% |
| Fidelity Municipal Income 2025 Fund | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14.40% |
| Fidelity Municipal Income 2025 Fund | QDBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| Fidelity Municipal Income 2025 Fund | QDBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.40% |
| Fidelity Municipal Income 2025 Fund | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| Fidelity Municipal Income 2025 Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | TS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | TS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.30% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | TS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | TS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | TS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.80% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | RS0Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 27.10% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | RS1Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.50% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | RS2Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | RS3Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.90% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | RS4Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | RS5Member | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.10% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | QDAMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 47.70% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | QDBBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 14.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | QDBBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | QDBMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.40% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | QDNotRatedMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| Fidelity Advisor Municipal Income 2025 Fund - Class A | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| Label | Element | Value |
| C000183196 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 21.20% |
| C000183196 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 6.70% |
| C000183198 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 21.20% |
| C000183198 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 6.70% |
| C000212594 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 52.40% |
| C000212594 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 19.20% |
| C000212595 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 55.70% |
| C000212595 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 16.70% |
| C000183197 [Member] | QDAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 21.20% |
| C000183197 [Member] | QDAAAMember [Member] | ||
| Percent of Net Asset Value | oef_PctOfNav | 6.70% |
