Shareholder Report |
12 Months Ended | 39 Months Ended | 40 Months Ended | 53 Months Ended | 96 Months Ended | 98 Months Ended | 106 Months Ended | ||||||||||||||||
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| 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 | Aug. 31, 2026 | ||||||||||||||||||||||
| Fidelity Sustainable Low Duration Bond Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Trading Symbol | FAPGX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
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| Expenses Paid, Amount | $ 25 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.25% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 47% of fund assets, down from 48% a year ago. Exposure to U.S. Treasurys ticked up from about 30% to roughly 31% of assets during the fiscal year, while exposure to ABS decreased from 19% to approximately 18% of assets as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Fidelity® Sustainable Low Duration Bond Fund $10,000 $10,001 $10,404 $11,006 $11,535 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Sustainable Low Duration Bond Fund 3.70% 4.17% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | |||||||||||||||
| Holdings Count | shares | 390 | 390 | 390 | 390 | 390 | 390 | 390 | 390 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 110,034 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 57.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 31.3 AAA 16.5 AA 2.6 A 29.1 BBB 15.5 BB 0.0 Not Rated 3.1 Short-Term Investments and Net Other Assets (Liabilities) 1.9 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 31.3 AAA - 16.5 AA - 2.6 A - 29.1 BBB - 15.5 BB - 0.0 Not Rated - 3.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 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. Corporate Bonds 46.9 U.S. Treasury Obligations 31.3 Asset-Backed Securities 18.3 CMOs and Other Mortgage Related Securities 1.3 Other Investments 0.3 Short-Term Investments and Net Other Assets (Liabilities) 1.9 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 46.9 U.S. Treasury Obligations - 31.3 Asset-Backed Securities - 18.3 CMOs and Other Mortgage Related Securities - 1.3 Other Investments - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 United States 79.4 Canada 5.6 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.6 Japan 1.6 Switzerland 0.9 Netherlands 0.8 France 0.8 Germany 0.7 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.4 Canada - 5.6 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.6 Japan - 1.6 Switzerland - 0.9 Netherlands - 0.8 France - 0.8 Germany - 0.7 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 15.9 US Treasury Bill 15.4 Wells Fargo & Co 1.7 Bank of America Corp 1.6 JPMorgan Chase & Co 1.5 Royal Bank of Canada 1.3 Bank of Nova Scotia/The 1.1 Goldman Sachs Group Inc/The 1.0 Canadian Imperial Bank of Commerce 0.9 PNC Financial Services Group Inc/The 0.9 41.3 | ||||||||||||||||||||||
| Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Low Duration Bond Fund Class Z | ||||||||||||||||||||||
| Trading Symbol | FAPEX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 20 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.20% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 47% of fund assets, down from 48% a year ago. Exposure to U.S. Treasurys ticked up from about 30% to roughly 31% of assets during the fiscal year, while exposure to ABS decreased from 19% to approximately 18% of assets as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Class Z $10,000 $10,003 $10,411 $11,019 $11,555 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class Z 3.75% 4.22% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | |||||||||||||||
| Holdings Count | shares | 390 | 390 | 390 | 390 | 390 | 390 | 390 | 390 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 110,034 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 57.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 31.3 AAA 16.5 AA 2.6 A 29.1 BBB 15.5 BB 0.0 Not Rated 3.1 Short-Term Investments and Net Other Assets (Liabilities) 1.9 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 31.3 AAA - 16.5 AA - 2.6 A - 29.1 BBB - 15.5 BB - 0.0 Not Rated - 3.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 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. Corporate Bonds 46.9 U.S. Treasury Obligations 31.3 Asset-Backed Securities 18.3 CMOs and Other Mortgage Related Securities 1.3 Other Investments 0.3 Short-Term Investments and Net Other Assets (Liabilities) 1.9 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 46.9 U.S. Treasury Obligations - 31.3 Asset-Backed Securities - 18.3 CMOs and Other Mortgage Related Securities - 1.3 Other Investments - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 United States 79.4 Canada 5.6 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.6 Japan 1.6 Switzerland 0.9 Netherlands 0.8 France 0.8 Germany 0.7 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.4 Canada - 5.6 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.6 Japan - 1.6 Switzerland - 0.9 Netherlands - 0.8 France - 0.8 Germany - 0.7 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 15.9 US Treasury Bill 15.4 Wells Fargo & Co 1.7 Bank of America Corp 1.6 JPMorgan Chase & Co 1.5 Royal Bank of Canada 1.3 Bank of Nova Scotia/The 1.1 Goldman Sachs Group Inc/The 1.0 Canadian Imperial Bank of Commerce 0.9 PNC Financial Services Group Inc/The 0.9 41.3 | ||||||||||||||||||||||
| Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Low Duration Bond Fund Class M | ||||||||||||||||||||||
| Trading Symbol | FAPBX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
|
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| Expenses Paid, Amount | $ 42 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.42% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 47% of fund assets, down from 48% a year ago. Exposure to U.S. Treasurys ticked up from about 30% to roughly 31% of assets during the fiscal year, while exposure to ABS decreased from 19% to approximately 18% of assets as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000 and the current sales charge was paid. Class M $9,850 $9,845 $10,224 $10,796 $11,296 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class M (incl. 1.50% sales charge) 1.98% 3.63% Class M (without 1.50% sales charge) 3.53% 3.99% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | |||||||||||||||
| Holdings Count | shares | 390 | 390 | 390 | 390 | 390 | 390 | 390 | 390 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 110,034 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 57.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 31.3 AAA 16.5 AA 2.6 A 29.1 BBB 15.5 BB 0.0 Not Rated 3.1 Short-Term Investments and Net Other Assets (Liabilities) 1.9 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 31.3 AAA - 16.5 AA - 2.6 A - 29.1 BBB - 15.5 BB - 0.0 Not Rated - 3.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 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. Corporate Bonds 46.9 U.S. Treasury Obligations 31.3 Asset-Backed Securities 18.3 CMOs and Other Mortgage Related Securities 1.3 Other Investments 0.3 Short-Term Investments and Net Other Assets (Liabilities) 1.9 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 46.9 U.S. Treasury Obligations - 31.3 Asset-Backed Securities - 18.3 CMOs and Other Mortgage Related Securities - 1.3 Other Investments - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 United States 79.4 Canada 5.6 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.6 Japan 1.6 Switzerland 0.9 Netherlands 0.8 France 0.8 Germany 0.7 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.4 Canada - 5.6 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.6 Japan - 1.6 Switzerland - 0.9 Netherlands - 0.8 France - 0.8 Germany - 0.7 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 15.9 US Treasury Bill 15.4 Wells Fargo & Co 1.7 Bank of America Corp 1.6 JPMorgan Chase & Co 1.5 Royal Bank of Canada 1.3 Bank of Nova Scotia/The 1.1 Goldman Sachs Group Inc/The 1.0 Canadian Imperial Bank of Commerce 0.9 PNC Financial Services Group Inc/The 0.9 41.3 | ||||||||||||||||||||||
| Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Low Duration Bond Fund Class I | ||||||||||||||||||||||
| Trading Symbol | FAPDX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 25 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.25% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 47% of fund assets, down from 48% a year ago. Exposure to U.S. Treasurys ticked up from about 30% to roughly 31% of assets during the fiscal year, while exposure to ABS decreased from 19% to approximately 18% of assets as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Class I $10,000 $10,001 $10,404 $11,006 $11,536 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class I 3.70% 4.17% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | |||||||||||||||
| Holdings Count | shares | 390 | 390 | 390 | 390 | 390 | 390 | 390 | 390 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 110,034 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 57.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 31.3 AAA 16.5 AA 2.6 A 29.1 BBB 15.5 BB 0.0 Not Rated 3.1 Short-Term Investments and Net Other Assets (Liabilities) 1.9 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 31.3 AAA - 16.5 AA - 2.6 A - 29.1 BBB - 15.5 BB - 0.0 Not Rated - 3.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 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. Corporate Bonds 46.9 U.S. Treasury Obligations 31.3 Asset-Backed Securities 18.3 CMOs and Other Mortgage Related Securities 1.3 Other Investments 0.3 Short-Term Investments and Net Other Assets (Liabilities) 1.9 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 46.9 U.S. Treasury Obligations - 31.3 Asset-Backed Securities - 18.3 CMOs and Other Mortgage Related Securities - 1.3 Other Investments - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 United States 79.4 Canada 5.6 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.6 Japan 1.6 Switzerland 0.9 Netherlands 0.8 France 0.8 Germany 0.7 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.4 Canada - 5.6 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.6 Japan - 1.6 Switzerland - 0.9 Netherlands - 0.8 France - 0.8 Germany - 0.7 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 15.9 US Treasury Bill 15.4 Wells Fargo & Co 1.7 Bank of America Corp 1.6 JPMorgan Chase & Co 1.5 Royal Bank of Canada 1.3 Bank of Nova Scotia/The 1.1 Goldman Sachs Group Inc/The 1.0 Canadian Imperial Bank of Commerce 0.9 PNC Financial Services Group Inc/The 0.9 41.3 | ||||||||||||||||||||||
| Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Low Duration Bond Fund Class C | ||||||||||||||||||||||
| Trading Symbol | FANDX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
|
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| Expenses Paid, Amount | $ 130 | ||||||||||||||||||||||
| Expense Ratio, Percent | 1.28% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 47% of fund assets, down from 48% a year ago. Exposure to U.S. Treasurys ticked up from about 30% to roughly 31% of assets during the fiscal year, while exposure to ABS decreased from 19% to approximately 18% of assets as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Class C $10,000 $9,957 $10,253 $10,735 $11,137 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class C (incl. contingent deferred sales charge) 1.75% 3.12% Class C 2.74% 3.12% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | |||||||||||||||
| Holdings Count | shares | 390 | 390 | 390 | 390 | 390 | 390 | 390 | 390 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 110,034 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 57.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 31.3 AAA 16.5 AA 2.6 A 29.1 BBB 15.5 BB 0.0 Not Rated 3.1 Short-Term Investments and Net Other Assets (Liabilities) 1.9 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 31.3 AAA - 16.5 AA - 2.6 A - 29.1 BBB - 15.5 BB - 0.0 Not Rated - 3.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 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. Corporate Bonds 46.9 U.S. Treasury Obligations 31.3 Asset-Backed Securities 18.3 CMOs and Other Mortgage Related Securities 1.3 Other Investments 0.3 Short-Term Investments and Net Other Assets (Liabilities) 1.9 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 46.9 U.S. Treasury Obligations - 31.3 Asset-Backed Securities - 18.3 CMOs and Other Mortgage Related Securities - 1.3 Other Investments - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 United States 79.4 Canada 5.6 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.6 Japan 1.6 Switzerland 0.9 Netherlands 0.8 France 0.8 Germany 0.7 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.4 Canada - 5.6 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.6 Japan - 1.6 Switzerland - 0.9 Netherlands - 0.8 France - 0.8 Germany - 0.7 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 15.9 US Treasury Bill 15.4 Wells Fargo & Co 1.7 Bank of America Corp 1.6 JPMorgan Chase & Co 1.5 Royal Bank of Canada 1.3 Bank of Nova Scotia/The 1.1 Goldman Sachs Group Inc/The 1.0 Canadian Imperial Bank of Commerce 0.9 PNC Financial Services Group Inc/The 0.9 41.3 | ||||||||||||||||||||||
| Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Low Duration Bond Fund Class A | ||||||||||||||||||||||
| Trading Symbol | FAMZX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 46 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.45% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 47% of fund assets, down from 48% a year ago. Exposure to U.S. Treasurys ticked up from about 30% to roughly 31% of assets during the fiscal year, while exposure to ABS decreased from 19% to approximately 18% of assets as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000 and the current sales charge was paid. Class A $9,850 $9,845 $10,221 $10,791 $11,288 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class A (incl. 1.50% sales charge) 1.94% 3.61% Class A (without 1.50% sales charge) 3.50% 3.97% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | $ 76,612,817 | |||||||||||||||
| Holdings Count | shares | 390 | 390 | 390 | 390 | 390 | 390 | 390 | 390 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 110,034 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 57.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 31.3 AAA 16.5 AA 2.6 A 29.1 BBB 15.5 BB 0.0 Not Rated 3.1 Short-Term Investments and Net Other Assets (Liabilities) 1.9 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 31.3 AAA - 16.5 AA - 2.6 A - 29.1 BBB - 15.5 BB - 0.0 Not Rated - 3.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 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. Corporate Bonds 46.9 U.S. Treasury Obligations 31.3 Asset-Backed Securities 18.3 CMOs and Other Mortgage Related Securities 1.3 Other Investments 0.3 Short-Term Investments and Net Other Assets (Liabilities) 1.9 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 46.9 U.S. Treasury Obligations - 31.3 Asset-Backed Securities - 18.3 CMOs and Other Mortgage Related Securities - 1.3 Other Investments - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 1.9 United States 79.4 Canada 5.6 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.6 Japan 1.6 Switzerland 0.9 Netherlands 0.8 France 0.8 Germany 0.7 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.4 Canada - 5.6 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.6 Japan - 1.6 Switzerland - 0.9 Netherlands - 0.8 France - 0.8 Germany - 0.7 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 15.9 US Treasury Bill 15.4 Wells Fargo & Co 1.7 Bank of America Corp 1.6 JPMorgan Chase & Co 1.5 Royal Bank of Canada 1.3 Bank of Nova Scotia/The 1.1 Goldman Sachs Group Inc/The 1.0 Canadian Imperial Bank of Commerce 0.9 PNC Financial Services Group Inc/The 0.9 41.3 | ||||||||||||||||||||||
| Fidelity Sustainable Core Plus Bond Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Trading Symbol | FIAEX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Core Plus Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 45 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.45% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, allocations to "plus sectors," led by high-yield bonds, notably contributed to the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Modest non-benchmark exposure to leveraged loans also provided a boost.
•Among investment-grade bonds, overweight holdings and investment choices among asset-backed securities, especially collateralized loan obligations, added value.
•In contrast, underweight holdings in investment-grade corporate bonds, particularly below-benchmark exposure to industrials, detracted from the fund's relative performance.
•An underweight in mortgage-backed securities modestly hurt as well.
•Notable changes over the past 12 months included management's decision to gradually lower the fund's overall risk profile by slightly reducing exposure to investment-grade corporate bonds and increasing the allocation to mortgage-backed securities in the second half of the period.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Fidelity® Sustainable Core Plus Bond Fund $10,000 $9,592 $9,547 $10,275 $10,645 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,702 $9,590 $10,286 $10,612 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Sustainable Core Plus Bond Fund 1.70% 1.83% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 1.79% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | |||||||||||||||
| Holdings Count | shares | 777 | 777 | 777 | 777 | 777 | 777 | 777 | 777 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 198,203 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 171.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 56.9 AAA 5.2 AA 1.1 A 12.2 BBB 13.8 BB 3.5 B 1.8 CCC,CC,C 0.7 Not Rated 3.8 Equities 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 56.9 AAA - 5.2 AA - 1.1 A - 12.2 BBB - 13.8 BB - 3.5 B - 1.8 CCC,CC,C - 0.7 Not Rated - 3.8 Equities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 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. U.S. Treasury Obligations 39.8 Corporate Bonds 31.7 U.S. Government Agency - Mortgage Securities 17.1 Asset-Backed Securities 6.7 CMOs and Other Mortgage Related Securities 1.9 Bank Loan Obligations 0.9 Foreign Government and Government Agency Obligations 0.8 Preferred Securities 0.1 Preferred Stocks 0.0 Common Stocks 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 39.8 Corporate Bonds - 31.7 U.S. Government Agency - Mortgage Securities - 17.1 Asset-Backed Securities - 6.7 CMOs and Other Mortgage Related Securities - 1.9 Bank Loan Obligations - 0.9 Foreign Government and Government Agency Obligations - 0.8 Preferred Securities - 0.1 Preferred Stocks - 0.0 Common Stocks - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 United States 83.5 Grand Cayman (UK Overseas Ter) 4.5 United Kingdom 2.3 Japan 1.6 Bailiwick Of Jersey 1.4 Italy 1.0 Germany 0.9 Netherlands 0.7 France 0.6 Others 3.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Grand Cayman (UK Overseas Ter) - 4.5 United Kingdom - 2.3 Japan - 1.6 Bailiwick Of Jersey - 1.4 Italy - 1.0 Germany - 0.9 Netherlands - 0.7 France - 0.6 Others - 3.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 28.0 US Treasury Bonds 11.8 Fannie Mae Mortgage pass-thru certificates 5.6 Uniform Mortgage Backed Securities 4.2 Ginnie Mae II Pool 3.2 Freddie Mac Gold Pool 2.9 Morgan Stanley 1.0 JPMorgan Chase & Co 1.0 Bank of America Corp 0.9 NTT Finance Corp 0.6 59.2 | ||||||||||||||||||||||
| Material Fund Change [Text Block] |
How has the Fund changed?
This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
|
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| Material Fund Change Strategies [Text Block] |
The fund modified its principal investment strategies during the reporting period.
|
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| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 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 | <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 | <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 | <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 Sustainable Core Plus Bond Fund - Class Z | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Core Plus Bond Fund Class Z | ||||||||||||||||||||||
| Trading Symbol | FIAMX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Core Plus Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
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| Expenses Paid, Amount | $ 36 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.36% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, allocations to "plus sectors," led by high-yield bonds, notably contributed to the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Modest non-benchmark exposure to leveraged loans also provided a boost.
•Among investment-grade bonds, overweight holdings and investment choices among asset-backed securities, especially collateralized loan obligations, added value.
•In contrast, underweight holdings in investment-grade corporate bonds, particularly below-benchmark exposure to industrials, detracted from the fund's relative performance.
•An underweight in mortgage-backed securities modestly hurt as well.
•Notable changes over the past 12 months included management's decision to gradually lower the fund's overall risk profile by slightly reducing exposure to investment-grade corporate bonds and increasing the allocation to mortgage-backed securities in the second half of the period.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Class Z $10,000 $9,595 $9,559 $10,308 $10,677 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,702 $9,590 $10,286 $10,612 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class Z 1.79% 1.92% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 1.79% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | |||||||||||||||
| Holdings Count | shares | 777 | 777 | 777 | 777 | 777 | 777 | 777 | 777 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 198,203 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 171.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 56.9 AAA 5.2 AA 1.1 A 12.2 BBB 13.8 BB 3.5 B 1.8 CCC,CC,C 0.7 Not Rated 3.8 Equities 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 56.9 AAA - 5.2 AA - 1.1 A - 12.2 BBB - 13.8 BB - 3.5 B - 1.8 CCC,CC,C - 0.7 Not Rated - 3.8 Equities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 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. U.S. Treasury Obligations 39.8 Corporate Bonds 31.7 U.S. Government Agency - Mortgage Securities 17.1 Asset-Backed Securities 6.7 CMOs and Other Mortgage Related Securities 1.9 Bank Loan Obligations 0.9 Foreign Government and Government Agency Obligations 0.8 Preferred Securities 0.1 Preferred Stocks 0.0 Common Stocks 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 39.8 Corporate Bonds - 31.7 U.S. Government Agency - Mortgage Securities - 17.1 Asset-Backed Securities - 6.7 CMOs and Other Mortgage Related Securities - 1.9 Bank Loan Obligations - 0.9 Foreign Government and Government Agency Obligations - 0.8 Preferred Securities - 0.1 Preferred Stocks - 0.0 Common Stocks - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 United States 83.5 Grand Cayman (UK Overseas Ter) 4.5 United Kingdom 2.3 Japan 1.6 Bailiwick Of Jersey 1.4 Italy 1.0 Germany 0.9 Netherlands 0.7 France 0.6 Others 3.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Grand Cayman (UK Overseas Ter) - 4.5 United Kingdom - 2.3 Japan - 1.6 Bailiwick Of Jersey - 1.4 Italy - 1.0 Germany - 0.9 Netherlands - 0.7 France - 0.6 Others - 3.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 28.0 US Treasury Bonds 11.8 Fannie Mae Mortgage pass-thru certificates 5.6 Uniform Mortgage Backed Securities 4.2 Ginnie Mae II Pool 3.2 Freddie Mac Gold Pool 2.9 Morgan Stanley 1.0 JPMorgan Chase & Co 1.0 Bank of America Corp 0.9 NTT Finance Corp 0.6 59.2 | ||||||||||||||||||||||
| Material Fund Change [Text Block] |
How has the Fund changed?
This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
|
||||||||||||||||||||||
| Material Fund Change Strategies [Text Block] |
The fund modified its principal investment strategies during the reporting period.
|
||||||||||||||||||||||
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 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 | <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 | <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 | <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 Sustainable Core Plus Bond Fund - Class M | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Core Plus Bond Fund Class M | ||||||||||||||||||||||
| Trading Symbol | FIAKX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Core Plus Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 74 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.73% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, allocations to "plus sectors," led by high-yield bonds, notably contributed to the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Modest non-benchmark exposure to leveraged loans also provided a boost.
•Among investment-grade bonds, overweight holdings and investment choices among asset-backed securities, especially collateralized loan obligations, added value.
•In contrast, underweight holdings in investment-grade corporate bonds, particularly below-benchmark exposure to industrials, detracted from the fund's relative performance.
•An underweight in mortgage-backed securities modestly hurt as well.
•Notable changes over the past 12 months included management's decision to gradually lower the fund's overall risk profile by slightly reducing exposure to investment-grade corporate bonds and increasing the allocation to mortgage-backed securities in the second half of the period.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000 and the current sales charge was paid. Class M $9,600 $9,202 $9,139 $9,814 $10,138 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,702 $9,590 $10,286 $10,612 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class M (incl. 4.00% sales charge) -2.64% 0.64% Class M (without 4.00% sales charge) 1.41% 1.58% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 1.79% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | |||||||||||||||
| Holdings Count | shares | 777 | 777 | 777 | 777 | 777 | 777 | 777 | 777 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 198,203 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 171.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 56.9 AAA 5.2 AA 1.1 A 12.2 BBB 13.8 BB 3.5 B 1.8 CCC,CC,C 0.7 Not Rated 3.8 Equities 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 56.9 AAA - 5.2 AA - 1.1 A - 12.2 BBB - 13.8 BB - 3.5 B - 1.8 CCC,CC,C - 0.7 Not Rated - 3.8 Equities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 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. U.S. Treasury Obligations 39.8 Corporate Bonds 31.7 U.S. Government Agency - Mortgage Securities 17.1 Asset-Backed Securities 6.7 CMOs and Other Mortgage Related Securities 1.9 Bank Loan Obligations 0.9 Foreign Government and Government Agency Obligations 0.8 Preferred Securities 0.1 Preferred Stocks 0.0 Common Stocks 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 39.8 Corporate Bonds - 31.7 U.S. Government Agency - Mortgage Securities - 17.1 Asset-Backed Securities - 6.7 CMOs and Other Mortgage Related Securities - 1.9 Bank Loan Obligations - 0.9 Foreign Government and Government Agency Obligations - 0.8 Preferred Securities - 0.1 Preferred Stocks - 0.0 Common Stocks - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 United States 83.5 Grand Cayman (UK Overseas Ter) 4.5 United Kingdom 2.3 Japan 1.6 Bailiwick Of Jersey 1.4 Italy 1.0 Germany 0.9 Netherlands 0.7 France 0.6 Others 3.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Grand Cayman (UK Overseas Ter) - 4.5 United Kingdom - 2.3 Japan - 1.6 Bailiwick Of Jersey - 1.4 Italy - 1.0 Germany - 0.9 Netherlands - 0.7 France - 0.6 Others - 3.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 28.0 US Treasury Bonds 11.8 Fannie Mae Mortgage pass-thru certificates 5.6 Uniform Mortgage Backed Securities 4.2 Ginnie Mae II Pool 3.2 Freddie Mac Gold Pool 2.9 Morgan Stanley 1.0 JPMorgan Chase & Co 1.0 Bank of America Corp 0.9 NTT Finance Corp 0.6 59.2 | ||||||||||||||||||||||
| Material Fund Change [Text Block] |
How has the Fund changed?
This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
|
||||||||||||||||||||||
| Material Fund Change Strategies [Text Block] |
The fund modified its principal investment strategies during the reporting period.
|
||||||||||||||||||||||
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 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 | <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 | <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 | <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 Sustainable Core Plus Bond Fund - Class I | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Core Plus Bond Fund Class I | ||||||||||||||||||||||
| Trading Symbol | FIALX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Core Plus Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 45 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.45% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, allocations to "plus sectors," led by high-yield bonds, notably contributed to the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Modest non-benchmark exposure to leveraged loans also provided a boost.
•Among investment-grade bonds, overweight holdings and investment choices among asset-backed securities, especially collateralized loan obligations, added value.
•In contrast, underweight holdings in investment-grade corporate bonds, particularly below-benchmark exposure to industrials, detracted from the fund's relative performance.
•An underweight in mortgage-backed securities modestly hurt as well.
•Notable changes over the past 12 months included management's decision to gradually lower the fund's overall risk profile by slightly reducing exposure to investment-grade corporate bonds and increasing the allocation to mortgage-backed securities in the second half of the period.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Class I $10,000 $9,594 $9,553 $10,284 $10,655 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,702 $9,590 $10,286 $10,612 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class I 1.70% 1.85% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 1.79% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | |||||||||||||||
| Holdings Count | shares | 777 | 777 | 777 | 777 | 777 | 777 | 777 | 777 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 198,203 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 171.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 56.9 AAA 5.2 AA 1.1 A 12.2 BBB 13.8 BB 3.5 B 1.8 CCC,CC,C 0.7 Not Rated 3.8 Equities 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 56.9 AAA - 5.2 AA - 1.1 A - 12.2 BBB - 13.8 BB - 3.5 B - 1.8 CCC,CC,C - 0.7 Not Rated - 3.8 Equities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 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. U.S. Treasury Obligations 39.8 Corporate Bonds 31.7 U.S. Government Agency - Mortgage Securities 17.1 Asset-Backed Securities 6.7 CMOs and Other Mortgage Related Securities 1.9 Bank Loan Obligations 0.9 Foreign Government and Government Agency Obligations 0.8 Preferred Securities 0.1 Preferred Stocks 0.0 Common Stocks 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 39.8 Corporate Bonds - 31.7 U.S. Government Agency - Mortgage Securities - 17.1 Asset-Backed Securities - 6.7 CMOs and Other Mortgage Related Securities - 1.9 Bank Loan Obligations - 0.9 Foreign Government and Government Agency Obligations - 0.8 Preferred Securities - 0.1 Preferred Stocks - 0.0 Common Stocks - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 United States 83.5 Grand Cayman (UK Overseas Ter) 4.5 United Kingdom 2.3 Japan 1.6 Bailiwick Of Jersey 1.4 Italy 1.0 Germany 0.9 Netherlands 0.7 France 0.6 Others 3.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Grand Cayman (UK Overseas Ter) - 4.5 United Kingdom - 2.3 Japan - 1.6 Bailiwick Of Jersey - 1.4 Italy - 1.0 Germany - 0.9 Netherlands - 0.7 France - 0.6 Others - 3.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 28.0 US Treasury Bonds 11.8 Fannie Mae Mortgage pass-thru certificates 5.6 Uniform Mortgage Backed Securities 4.2 Ginnie Mae II Pool 3.2 Freddie Mac Gold Pool 2.9 Morgan Stanley 1.0 JPMorgan Chase & Co 1.0 Bank of America Corp 0.9 NTT Finance Corp 0.6 59.2 | ||||||||||||||||||||||
| Material Fund Change [Text Block] |
How has the Fund changed?
This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
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| Material Fund Change Strategies [Text Block] |
The fund modified its principal investment strategies during the reporting period.
|
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| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 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 | <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 | <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 | <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 Sustainable Core Plus Bond Fund - Class C | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Core Plus Bond Fund Class C | ||||||||||||||||||||||
| Trading Symbol | FIAJX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Core Plus Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
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| Expenses Paid, Amount | $ 151 | ||||||||||||||||||||||
| Expense Ratio, Percent | 1.51% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, allocations to "plus sectors," led by high-yield bonds, notably contributed to the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Modest non-benchmark exposure to leveraged loans also provided a boost.
•Among investment-grade bonds, overweight holdings and investment choices among asset-backed securities, especially collateralized loan obligations, added value.
•In contrast, underweight holdings in investment-grade corporate bonds, particularly below-benchmark exposure to industrials, detracted from the fund's relative performance.
•An underweight in mortgage-backed securities modestly hurt as well.
•Notable changes over the past 12 months included management's decision to gradually lower the fund's overall risk profile by slightly reducing exposure to investment-grade corporate bonds and increasing the allocation to mortgage-backed securities in the second half of the period.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Class C $10,000 $9,559 $9,423 $10,046 $10,289 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,702 $9,590 $10,286 $10,612 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class C (incl. contingent deferred sales charge) -0.24% 0.82% Class C 0.74% 0.82% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 1.79% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | |||||||||||||||
| Holdings Count | shares | 777 | 777 | 777 | 777 | 777 | 777 | 777 | 777 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 198,203 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 171.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 56.9 AAA 5.2 AA 1.1 A 12.2 BBB 13.8 BB 3.5 B 1.8 CCC,CC,C 0.7 Not Rated 3.8 Equities 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 56.9 AAA - 5.2 AA - 1.1 A - 12.2 BBB - 13.8 BB - 3.5 B - 1.8 CCC,CC,C - 0.7 Not Rated - 3.8 Equities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 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. U.S. Treasury Obligations 39.8 Corporate Bonds 31.7 U.S. Government Agency - Mortgage Securities 17.1 Asset-Backed Securities 6.7 CMOs and Other Mortgage Related Securities 1.9 Bank Loan Obligations 0.9 Foreign Government and Government Agency Obligations 0.8 Preferred Securities 0.1 Preferred Stocks 0.0 Common Stocks 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 39.8 Corporate Bonds - 31.7 U.S. Government Agency - Mortgage Securities - 17.1 Asset-Backed Securities - 6.7 CMOs and Other Mortgage Related Securities - 1.9 Bank Loan Obligations - 0.9 Foreign Government and Government Agency Obligations - 0.8 Preferred Securities - 0.1 Preferred Stocks - 0.0 Common Stocks - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 United States 83.5 Grand Cayman (UK Overseas Ter) 4.5 United Kingdom 2.3 Japan 1.6 Bailiwick Of Jersey 1.4 Italy 1.0 Germany 0.9 Netherlands 0.7 France 0.6 Others 3.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Grand Cayman (UK Overseas Ter) - 4.5 United Kingdom - 2.3 Japan - 1.6 Bailiwick Of Jersey - 1.4 Italy - 1.0 Germany - 0.9 Netherlands - 0.7 France - 0.6 Others - 3.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 28.0 US Treasury Bonds 11.8 Fannie Mae Mortgage pass-thru certificates 5.6 Uniform Mortgage Backed Securities 4.2 Ginnie Mae II Pool 3.2 Freddie Mac Gold Pool 2.9 Morgan Stanley 1.0 JPMorgan Chase & Co 1.0 Bank of America Corp 0.9 NTT Finance Corp 0.6 59.2 | ||||||||||||||||||||||
| Material Fund Change [Text Block] |
How has the Fund changed?
This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
|
||||||||||||||||||||||
| Material Fund Change Strategies [Text Block] |
The fund modified its principal investment strategies during the reporting period.
|
||||||||||||||||||||||
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 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 | <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 | <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 | <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 Sustainable Core Plus Bond Fund - Class A | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainable Core Plus Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Sustainable Core Plus Bond Fund Class A | ||||||||||||||||||||||
| Trading Symbol | FIAIX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainable Core Plus Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 69 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.68% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, allocations to "plus sectors," led by high-yield bonds, notably contributed to the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Modest non-benchmark exposure to leveraged loans also provided a boost.
•Among investment-grade bonds, overweight holdings and investment choices among asset-backed securities, especially collateralized loan obligations, added value.
•In contrast, underweight holdings in investment-grade corporate bonds, particularly below-benchmark exposure to industrials, detracted from the fund's relative performance.
•An underweight in mortgage-backed securities modestly hurt as well.
•Notable changes over the past 12 months included management's decision to gradually lower the fund's overall risk profile by slightly reducing exposure to investment-grade corporate bonds and increasing the allocation to mortgage-backed securities in the second half of the period.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000 and the current sales charge was paid. Class A $9,600 $9,202 $9,137 $9,812 $10,142 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,702 $9,590 $10,286 $10,612 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class A (incl. 4.00% sales charge) -2.59% 0.66% Class A (without 4.00% sales charge) 1.47% 1.60% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 1.79% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | $ 63,062,395 | |||||||||||||||
| Holdings Count | shares | 777 | 777 | 777 | 777 | 777 | 777 | 777 | 777 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 198,203 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 171.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 56.9 AAA 5.2 AA 1.1 A 12.2 BBB 13.8 BB 3.5 B 1.8 CCC,CC,C 0.7 Not Rated 3.8 Equities 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 56.9 AAA - 5.2 AA - 1.1 A - 12.2 BBB - 13.8 BB - 3.5 B - 1.8 CCC,CC,C - 0.7 Not Rated - 3.8 Equities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 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. U.S. Treasury Obligations 39.8 Corporate Bonds 31.7 U.S. Government Agency - Mortgage Securities 17.1 Asset-Backed Securities 6.7 CMOs and Other Mortgage Related Securities 1.9 Bank Loan Obligations 0.9 Foreign Government and Government Agency Obligations 0.8 Preferred Securities 0.1 Preferred Stocks 0.0 Common Stocks 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 39.8 Corporate Bonds - 31.7 U.S. Government Agency - Mortgage Securities - 17.1 Asset-Backed Securities - 6.7 CMOs and Other Mortgage Related Securities - 1.9 Bank Loan Obligations - 0.9 Foreign Government and Government Agency Obligations - 0.8 Preferred Securities - 0.1 Preferred Stocks - 0.0 Common Stocks - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - 1.0 United States 83.5 Grand Cayman (UK Overseas Ter) 4.5 United Kingdom 2.3 Japan 1.6 Bailiwick Of Jersey 1.4 Italy 1.0 Germany 0.9 Netherlands 0.7 France 0.6 Others 3.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Grand Cayman (UK Overseas Ter) - 4.5 United Kingdom - 2.3 Japan - 1.6 Bailiwick Of Jersey - 1.4 Italy - 1.0 Germany - 0.9 Netherlands - 0.7 France - 0.6 Others - 3.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 28.0 US Treasury Bonds 11.8 Fannie Mae Mortgage pass-thru certificates 5.6 Uniform Mortgage Backed Securities 4.2 Ginnie Mae II Pool 3.2 Freddie Mac Gold Pool 2.9 Morgan Stanley 1.0 JPMorgan Chase & Co 1.0 Bank of America Corp 0.9 NTT Finance Corp 0.6 59.2 | ||||||||||||||||||||||
| Material Fund Change [Text Block] |
How has the Fund changed?
This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
|
||||||||||||||||||||||
| Material Fund Change Strategies [Text Block] |
The fund modified its principal investment strategies during the reporting period.
|
||||||||||||||||||||||
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since September 1, 2025. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2026 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 | <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 | <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 | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span> | ||||||||||||||||||||||
| Fidelity Sustainability Bond Index Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Sustainability Bond Index Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Sustainability Bond Index Fund | ||||||||||||||||||||||
| Trading Symbol | FNDSX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Sustainability Bond Index Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 10 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.10% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•We construct the portfolio using optimization. This approach minimizes the differences between risk exposures of the fund relative to the index. We attempt to hold all positions held by the index in the same relative proportions.
•Exposures include duration, key-rate durations, sector, and other factors.
|
||||||||||||||||||||||
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 June 19, 2018 through August 31, 2026. Initial investment of $10,000. Fidelity® Sustainability Bond Index Fund $10,000 $10,076 $11,088 $11,813 $11,746 $10,407 $10,280 $11,006 $11,348 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $10,090 $11,103 $11,834 $11,805 $10,466 $10,344 $11,096 $11,447 Bloomberg U.S. Aggregate Bond Index $10,000 $10,091 $11,117 $11,837 $11,827 $10,465 $10,340 $11,094 $11,442 2018 2019 2020 2021 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Fidelity® Sustainability Bond Index Fund 1.72% -0.35% 1.76% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% -0.24% 1.89% Bloomberg U.S. Aggregate Bond Index 1.89% -0.29% 1.89% A From June 19, 2018 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 | Jun. 19, 2018 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 676,648,455 | $ 676,648,455 | $ 676,648,455 | $ 676,648,455 | $ 676,648,455 | $ 676,648,455 | $ 676,648,455 | $ 676,648,455 | |||||||||||||||
| Holdings Count | shares | 3,633 | 3,633 | 3,633 | 3,633 | 3,633 | 3,633 | 3,633 | 3,633 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 643,242 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 74.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 68.5 AAA 3.2 AA 3.5 A 13.3 BBB 11.0 BB 0.4 Not Rated 0.5 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 68.5 AAA - 3.2 AA - 3.5 A - 13.3 BBB - 11.0 BB - 0.4 Not Rated - 0.5 Short-Term Investments and Net Other Assets (Liabilities) - (0.4)% 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. U.S. Treasury Obligations 45.3 Corporate Bonds 27.6 U.S. Government Agency - Mortgage Securities 23.1 Foreign Government and Government Agency Obligations 2.2 CMOs and Other Mortgage Related Securities 1.3 Asset-Backed Securities 0.6 Other Investments 0.2 U.S. Government Agency Obligations 0.1 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 45.3 Corporate Bonds - 27.6 U.S. Government Agency - Mortgage Securities - 23.1 Foreign Government and Government Agency Obligations - 2.2 CMOs and Other Mortgage Related Securities - 1.3 Asset-Backed Securities - 0.6 Other Investments - 0.2 U.S. Government Agency Obligations - 0.1 Short-Term Investments and Net Other Assets (Liabilities) - (0.4)% United States 92.2 United Kingdom 1.2 Canada 1.2 Multi-national 0.9 Japan 0.7 Mexico 0.5 Germany 0.4 Israel 0.3 Netherlands 0.3 Others 2.3 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 92.2 United Kingdom - 1.2 Canada - 1.2 Multi-national - 0.9 Japan - 0.7 Mexico - 0.5 Germany - 0.4 Israel - 0.3 Netherlands - 0.3 Others - 2.3 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 35.3 US Treasury Bonds 10.0 Fannie Mae Mortgage pass-thru certificates 8.9 Freddie Mac Gold Pool 7.4 Ginnie Mae II Pool 4.2 Ginnie Mae I Pool 1.4 Morgan Stanley 0.8 JPMorgan Chase & Co 0.8 Freddie Mac Multifamily Structured pass-thru certificates 0.8 Uniform Mortgage Backed Securities 0.7 70.3 | ||||||||||||||||||||||
| Fidelity Short-Term Bond Index Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Short-Term Bond Index Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Short-Term Bond Index Fund | ||||||||||||||||||||||
| Trading Symbol | FNSOX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Short-Term Bond Index Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
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| Expenses Paid, Amount | $ 3 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.03% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•We construct the portfolio using optimization. This approach minimizes the differences between risk exposures of the fund relative to the index. We attempt to hold all positions held by the index in the same relative proportions.
•Exposures include duration, key-rate durations, sector, and other factors.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 October 18, 2017 through August 31, 2026. Initial investment of $10,000. Fidelity® Short-Term Bond Index Fund $10,000 $9,969 $10,565 $11,052 $11,073 $10,427 $10,551 $11,255 $11,789 $12,045 Bloomberg U.S. 1-5 Year Government/Credit Bond Index $10,000 $9,990 $10,586 $11,086 $11,122 $10,472 $10,596 $11,303 $11,844 $12,098 Bloomberg U.S. Aggregate Bond Index $10,000 $9,938 $10,949 $11,658 $11,648 $10,307 $10,184 $10,927 $11,269 $11,482 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Fidelity® Short-Term Bond Index Fund 2.17% 1.70% 2.12% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 2.15% 1.70% 2.17% Bloomberg U.S. Aggregate Bond Index 1.89% -0.29% 1.57% A From October 18, 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 | Oct. 18, 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 4,344,570,616 | $ 4,344,570,616 | $ 4,344,570,616 | $ 4,344,570,616 | $ 4,344,570,616 | $ 4,344,570,616 | $ 4,344,570,616 | $ 4,344,570,616 | |||||||||||||||
| Holdings Count | shares | 1,590 | 1,590 | 1,590 | 1,590 | 1,590 | 1,590 | 1,590 | 1,590 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 1,108,418 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 39.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 73.1 AAA 0.8 AA 3.4 A 12.3 BBB 10.8 BB 0.4 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 73.1 AAA - 0.8 AA - 3.4 A - 12.3 BBB - 10.8 BB - 0.4 Short-Term Investments and Net Other Assets (Liabilities) - (0.8)% 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. U.S. Treasury Obligations 72.8 Corporate Bonds 26.5 Foreign Government and Government Agency Obligations 0.7 Other Investments 0.5 U.S. Government Agency Obligations 0.3 Municipal Securities 0.0 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 72.8 Corporate Bonds - 26.5 Foreign Government and Government Agency Obligations - 0.7 Other Investments - 0.5 U.S. Government Agency Obligations - 0.3 Municipal Securities - 0.0 Short-Term Investments and Net Other Assets (Liabilities) - (0.8)% United States 93.8 Canada 1.2 United Kingdom 1.2 Japan 0.9 Germany 0.5 Multi-national 0.4 Spain 0.3 Australia 0.3 Korea (South) 0.2 Others 1.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 93.8 Canada - 1.2 United Kingdom - 1.2 Japan - 0.9 Germany - 0.5 Multi-national - 0.4 Spain - 0.3 Australia - 0.3 Korea (South) - 0.2 Others - 1.2 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 72.8 JPMorgan Chase & Co 0.9 Morgan Stanley 0.8 Goldman Sachs Group Inc/The 0.7 Bank of America Corp 0.6 Wells Fargo & Co 0.5 Citigroup Inc 0.4 Amazon.com Inc 0.4 HSBC Holdings PLC 0.3 Barclays PLC 0.3 77.7 | ||||||||||||||||||||||
| Fidelity Series Sustainable Investment Grade Bond Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Series Sustainable Investment Grade Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Series Sustainable Investment Grade Bond Fund | ||||||||||||||||||||||
| Trading Symbol | FIGDX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Series Sustainable Investment Grade Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Additional Information Phone Number | 1-800-544-8544 | ||||||||||||||||||||||
| 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)
AAmount represents less than $.50
BAmount represents less than 0.005%
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 0 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.00% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, an underweight in agency mortgage-backed securities detracted from the fund's performance versus the benchmark Bloomberg U.S. Aggregate Index for the fiscal year.
•Among corporate-backed bonds, below-benchmark exposure to the debt of industrial firms hurt as well.
•The fund's yield-curve positioning was another drag on relative performance.
•In contrast, overweight holdings and investment choices among asset-backed securities, particularly collateralized loan obligations, contributed to the fund's performance versus the benchmark
•Notable changes over the past 12 months included management's decisions to modestly increase exposure to investment-grade corporate bonds and slightly reduce the allocation to U.S. Treasurys.
Application of FMR's environmental, social, and governance ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions and countries and may affect the Fund's performance.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 11, 2023 through August 31, 2026. Initial investment of $10,000. Fidelity® Series Sustainable Investment Grade Bond Fund $10,000 $9,778 $10,503 $10,844 Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index $10,000 $9,772 $10,481 $10,814 Bloomberg U.S. Aggregate Bond Index $10,000 $9,768 $10,480 $10,809 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® Series Sustainable Investment Grade Bond Fund 1.81% 3.04% Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index 1.87% 2.97% Bloomberg U.S. Aggregate Bond Index 1.89% 2.96% A From May 11, 2023 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 11, 2023 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 15,067,981 | $ 15,067,981 | $ 15,067,981 | $ 15,067,981 | $ 15,067,981 | $ 15,067,981 | $ 15,067,981 | $ 15,067,981 | |||||||||||||||
| Holdings Count | shares | 260 | 260 | 260 | 260 | 260 | 260 | 260 | 260 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 0 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 337.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 65.7 AAA 4.5 AA 0.4 A 11.6 BBB 10.3 BB 0.8 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 2.4 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 65.7 AAA - 4.5 AA - 0.4 A - 11.6 BBB - 10.3 BB - 0.8 Not Rated - 4.3 Short-Term Investments and Net Other Assets (Liabilities) - 2.4 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. U.S. Treasury Obligations 49.4 Corporate Bonds 22.3 U.S. Government Agency - Mortgage Securities 16.3 Asset-Backed Securities 6.3 CMOs and Other Mortgage Related Securities 3.0 Foreign Government and Government Agency Obligations 0.3 Short-Term Investments and Net Other Assets (Liabilities) 2.4 ASSET ALLOCATION (% of Fund's net assets) U.S. Treasury Obligations - 49.4 Corporate Bonds - 22.3 U.S. Government Agency - Mortgage Securities - 16.3 Asset-Backed Securities - 6.3 CMOs and Other Mortgage Related Securities - 3.0 Foreign Government and Government Agency Obligations - 0.3 Short-Term Investments and Net Other Assets (Liabilities) - 2.4 United States 92.9 Grand Cayman (UK Overseas Ter) 4.7 Bailiwick Of Jersey 1.0 Canada 0.4 Mexico 0.3 Netherlands 0.2 Germany 0.2 United Kingdom 0.2 Australia 0.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 92.9 Grand Cayman (UK Overseas Ter) - 4.7 Bailiwick Of Jersey - 1.0 Canada - 0.4 Mexico - 0.3 Netherlands - 0.2 Germany - 0.2 United Kingdom - 0.2 Australia - 0.1 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 36.6 US Treasury Bonds 12.8 Uniform Mortgage Backed Securities 5.5 Fannie Mae Mortgage pass-thru certificates 3.8 Ginnie Mae II Pool 3.1 Freddie Mac Gold Pool 2.4 Magnetite XXVI Ltd / Magnetite XXVI LLC 1.7 Flatiron CLO 29 Ltd 1.7 JPMorgan Chase & Co 1.4 Morgan Stanley 1.3 70.3 | ||||||||||||||||||||||
| Fidelity Series Corporate Bond Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Series Corporate Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Series Corporate Bond Fund | ||||||||||||||||||||||
| Trading Symbol | FHMFX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Series Corporate Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Additional Information Phone Number | 1-800-544-8544 | ||||||||||||||||||||||
| 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)
AAmount represents less than $.50
BAmount represents less than 0.005%
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 0 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.00% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, security selection contributed to the fund's performance versus the benchmark Bloomberg U.S. Credit Bond Index for the fiscal year, whereas sector positioning slightly detracted.
•Bond picks among companies in the financials and industrials sectors contributed this year. Within financials, broadly diversified exposure to banks and insurance companies, along with holdings of real estate investment trusts, helped the most.
•Within industrials, companies in consumer-related industries added the most value. In consumer non-cyclicals, pharmaceutical company Bayer was a notable standout.
•Outside of corporate credit, an allocation to U.S. Treasurys and cash - held for liquidity and risk-management purposes - meaningfully dampened the fund's relative result. Underweighting sovereign bonds was another modest detractor. These negatives were somewhat offset by steering clear of other government-related categories, as these bonds lagged credit amid extensive government borrowing, persistent inflation and rising yields.
•During the period, the fund's managers continued to emphasize issuers rated BBB, as they believe there is opportunity for alpha potential over time resulting from improving credit quality.
•Noteworthy positioning changes included increasing the allocation to technology issuers, mainly by adding AI-linked companies, such as Nvidia, Alphabet, Meta Platforms and Oracle. Additionally, the fund increased its exposure to finance companies, primarily aircraft lessors.
•As of August 31, the fund maintained overweight allocations in financial institutions and utilities, and underweight exposure to industrials.
•As the fund's managers continued to put capital to work in the corporate market, the portfolio's combined allocation to Treasurys and cash was significantly reduced during the period, from roughly 15% at the beginning to about 6% at the end.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 August 17, 2018 through August 31, 2026. Initial investment of $10,000. Fidelity® Series Corporate Bond Fund $10,000 $9,963 $11,296 $12,221 $12,610 $10,698 $10,807 $11,903 $12,421 Bloomberg U.S. Credit Bond Index $10,000 $10,005 $11,305 $12,107 $12,381 $10,594 $10,684 $11,644 $12,100 Bloomberg U.S. Aggregate Bond Index $10,000 $10,014 $11,033 $11,747 $11,737 $10,386 $10,262 $11,010 $11,356 2018 2019 2020 2021 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Fidelity® Series Corporate Bond Fund 2.20% 0.13% 3.01% Bloomberg U.S. Credit Bond Index 1.98% -0.07% 2.65% Bloomberg U.S. Aggregate Bond Index 1.89% -0.29% 1.83% A From August 17, 2018 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 | Aug. 17, 2018 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 829,996,433 | $ 829,996,433 | $ 829,996,433 | $ 829,996,433 | $ 829,996,433 | $ 829,996,433 | $ 829,996,433 | $ 829,996,433 | |||||||||||||||
| Holdings Count | shares | 631 | 631 | 631 | 631 | 631 | 631 | 631 | 631 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 0 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 43.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 4.9 AAA 0.2 AA 3.5 A 28.9 BBB 52.8 BB 5.1 B 0.8 Not Rated 0.6 Short-Term Investments and Net Other Assets (Liabilities) 3.2 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 4.9 AAA - 0.2 AA - 3.5 A - 28.9 BBB - 52.8 BB - 5.1 B - 0.8 Not Rated - 0.6 Short-Term Investments and Net Other Assets (Liabilities) - 3.2 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. Corporate Bonds 88.7 U.S. Treasury Obligations 4.9 Asset-Backed Securities 1.7 CMOs and Other Mortgage Related Securities 0.7 Foreign Government and Government Agency Obligations 0.6 Preferred Securities 0.2 Short-Term Investments and Net Other Assets (Liabilities) 3.2 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 88.7 U.S. Treasury Obligations - 4.9 Asset-Backed Securities - 1.7 CMOs and Other Mortgage Related Securities - 0.7 Foreign Government and Government Agency Obligations - 0.6 Preferred Securities - 0.2 Short-Term Investments and Net Other Assets (Liabilities) - 3.2 United States 84.6 United Kingdom 4.0 Canada 2.6 Ireland 1.7 Japan 1.3 Germany 1.3 Australia 0.7 Belgium 0.7 Netherlands 0.6 Others 2.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 84.6 United Kingdom - 4.0 Canada - 2.6 Ireland - 1.7 Japan - 1.3 Germany - 1.3 Australia - 0.7 Belgium - 0.7 Netherlands - 0.6 Others - 2.5 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Bonds 4.9 JPMorgan Chase & Co 2.8 Bank of America Corp 2.3 Morgan Stanley 2.3 Wells Fargo & Co 2.0 Oracle Corp 1.9 Broadcom Inc 1.8 Meta Platforms Inc 1.2 CVS Health Corp 1.1 Charter Communications Operating LLC / Charter Communications Operating Capital 1.1 21.4 | ||||||||||||||||||||||
| Fidelity SAI Sustainable Low Duration Bond Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® SAI Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity® SAI Sustainable Low Duration Bond Fund | ||||||||||||||||||||||
| Trading Symbol | FAPFX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® SAI Sustainable Low Duration Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 20 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.20% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, and industrial firms, particularly in the consumer cyclical and consumer non-cyclical segments, added notable value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also meaningfully helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•At period end, corporates made up about 49% of fund assets, up from 45% a year ago. Exposure to U.S. Treasurys increased from about 31% to roughly 34% of assets, while exposure to ABS decreased from roughly 18% of assets to about 16% as of August 31.
Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 April 13, 2022 through August 31, 2026. Initial investment of $10,000. Fidelity® SAI Sustainable Low Duration Bond Fund $10,000 $10,009 $10,431 $11,045 $11,574 Bloomberg US Treasury Bill: 6-9 Months Index $10,000 $9,990 $10,301 $10,854 $11,320 Bloomberg U.S. Aggregate Bond Index $10,000 $9,696 $9,581 $10,280 $10,602 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® SAI Sustainable Low Duration Bond Fund 3.79% 4.27% Bloomberg US Treasury Bill: 6-9 Months Index 3.53% 3.68% Bloomberg U.S. Aggregate Bond Index 1.89% 1.78% A From April 13, 2022 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 | Apr. 13, 2022 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 128,865,342 | $ 128,865,342 | $ 128,865,342 | $ 128,865,342 | $ 128,865,342 | $ 128,865,342 | $ 128,865,342 | $ 128,865,342 | |||||||||||||||
| Holdings Count | shares | 431 | 431 | 431 | 431 | 431 | 431 | 431 | 431 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 139,570 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 48.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 34.3 AAA 14.4 AA 2.4 A 28.7 BBB 17.0 BB 0.0 Not Rated 2.1 Short-Term Investments and Net Other Assets (Liabilities) 1.1 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 34.3 AAA - 14.4 AA - 2.4 A - 28.7 BBB - 17.0 BB - 0.0 Not Rated - 2.1 Short-Term Investments and Net Other Assets (Liabilities) - 1.1 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. Corporate Bonds 47.7 U.S. Treasury Obligations 34.3 Asset-Backed Securities 15.8 CMOs and Other Mortgage Related Securities 0.7 Other Investments 0.4 Short-Term Investments and Net Other Assets (Liabilities) 1.1 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 47.7 U.S. Treasury Obligations - 34.3 Asset-Backed Securities - 15.8 CMOs and Other Mortgage Related Securities - 0.7 Other Investments - 0.4 Short-Term Investments and Net Other Assets (Liabilities) - 1.1 United States 79.6 Canada 5.5 United Kingdom 4.3 Grand Cayman (UK Overseas Ter) 3.4 Japan 1.5 France 1.1 Germany 0.9 Switzerland 0.9 Netherlands 0.7 Others 2.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 79.6 Canada - 5.5 United Kingdom - 4.3 Grand Cayman (UK Overseas Ter) - 3.4 Japan - 1.5 France - 1.1 Germany - 0.9 Switzerland - 0.9 Netherlands - 0.7 Others - 2.1 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Bill 21.4 US Treasury Notes 12.9 Wells Fargo & Co 1.7 Bank of America Corp 1.7 JPMorgan Chase & Co 1.7 Goldman Sachs Group Inc/The 1.4 Morgan Stanley 1.3 Royal Bank of Canada 1.0 Citigroup Inc 1.0 Barclays PLC 1.0 45.1 | ||||||||||||||||||||||
| Fidelity SAI Investment Grade Securitized Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® SAI Investment Grade Securitized Fund | ||||||||||||||||||||||
| Class Name | Fidelity® SAI Investment Grade Securitized Fund | ||||||||||||||||||||||
| Trading Symbol | FSMOX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® SAI Investment Grade Securitized Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
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| Expenses Paid, Amount | $ 31 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.31% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, fast-growing government debt and heavy U.S. Treasury issuance.
•Against this backdrop, an overweight in select agency mortgage-backed securities that benefited from spread tightening contributed to the fund's performance versus the benchmark, the Bloomberg U.S. Securitized Index, for the fiscal year, including specified mortgage pools with coupons greater than 5.0%.
•Non-benchmark holdings in residential mortgage-backed securities and asset-backed securities boosted relative performance.
•Timely purchases and sales of interest-rate swaps were beneficial, as was a pay-fixed position in two-year interest-rate swaps.
•In contrast, an overweight in conventional securities with a 2% coupon detracted from performance versus the benchmark the past 12 months, as did the fund's longer duration (interest rate) positioning.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 17, 2023 through August 31, 2026. Initial investment of $10,000. Fidelity® SAI Investment Grade Securitized Fund $10,000 $9,858 $10,632 $11,009 Bloomberg U.S. Securitized Index $10,000 $9,861 $10,606 $10,979 Bloomberg U.S. Aggregate Bond Index $10,000 $9,877 $10,598 $10,930 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Fidelity® SAI Investment Grade Securitized Fund 3.28% 3.98% Bloomberg U.S. Securitized Index 2.98% 3.80% Bloomberg U.S. Aggregate Bond Index 1.89% 3.32% A From May 17, 2023 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 17, 2023 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 866,770,204 | $ 866,770,204 | $ 866,770,204 | $ 866,770,204 | $ 866,770,204 | $ 866,770,204 | $ 866,770,204 | $ 866,770,204 | |||||||||||||||
| Holdings Count | shares | 1,520 | 1,520 | 1,520 | 1,520 | 1,520 | 1,520 | 1,520 | 1,520 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 2,852,272 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 650.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 86.2 AAA 8.9 AA 0.5 A 0.0 BBB 0.1 BB 0.1 B 0.0 CCC,CC,C 0.0 Not Rated 26.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 86.2 AAA - 8.9 AA - 0.5 A - 0.0 BBB - 0.1 BB - 0.1 B - 0.0 CCC,CC,C - 0.0 Not Rated - 26.0 Short-Term Investments and Net Other Assets (Liabilities) - (21.8)% 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. U.S. Government Agency - Mortgage Securities 81.4 CMOs and Other Mortgage Related Securities 31.8 U.S. Treasury Obligations 4.8 Asset-Backed Securities 3.6 Options 0.2 ASSET ALLOCATION (% of Fund's net assets) U.S. Government Agency - Mortgage Securities - 81.4 CMOs and Other Mortgage Related Securities - 31.8 U.S. Treasury Obligations - 4.8 Asset-Backed Securities - 3.6 Options - 0.2 Short-Term Investments and Net Other Assets (Liabilities) - (21.8)% United States 100.0 Canada 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 100.0 Canada - 0.0 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) Fannie Mae Mortgage pass-thru certificates 31.1 Freddie Mac Gold Pool 18.6 Ginnie Mae II Pool 18.3 Freddie Mac Multifamily Structured pass-thru certificates 13.3 Uniform Mortgage Backed Securities 9.2 Fannie Mae Guaranteed REMIC 4.3 US Treasury Notes 4.0 Ginnie Mae I Pool 3.8 Freddie Mac Non Gold Pool 1.9 US Treasury Bonds 0.8 105.3 | ||||||||||||||||||||||
| Fidelity Conservative Income Bond Fund | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Conservative Income Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity® Conservative Income Bond Fund | ||||||||||||||||||||||
| Trading Symbol | FCNVX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Conservative Income Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 26 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.25% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, but also industrial firms, particularly in the consumer cyclical segment, added value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•A roughly 9% average allocation to cash - which the fund maintained for liquidity and solid interest return - also hurt.
•At period end, corporates made up about 51% of fund assets, down from roughly 53% a year ago. At the same time, we increased exposure to U.S. Treasurys from 18% to 25% of assets, while the portfolio's position in ABS ticked down from approximately 16% of assets to about 15% as of August 31.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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 past 10 years? CUMULATIVE PERFORMANCE August 31, 2016 through August 31, 2026. Initial investment of $10,000. Fidelity® Conservative Income Bond Fund $10,000 $10,127 $10,317 $10,584 $10,783 $10,804 $10,808 $11,331 $11,989 $12,567 $13,057 Bloomberg U.S. 3-6 Month Treasury Bill Index $10,000 $10,067 $10,216 $10,473 $10,630 $10,640 $10,669 $11,126 $11,743 $12,284 $12,759 Bloomberg U.S. Aggregate Bond Index $10,000 $10,049 $9,944 $10,955 $11,665 $11,655 $10,313 $10,189 $10,933 $11,276 $11,489 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year 10 Year Fidelity® Conservative Income Bond Fund 3.89% 3.86% 2.70% Bloomberg U.S. 3-6 Month Treasury Bill Index 3.87% 3.70% 2.47% Bloomberg U.S. Aggregate Bond Index 1.89% -0.29% 1.40% 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. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit www.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | |||||||||||||||
| Holdings Count | shares | 304 | 304 | 304 | 304 | 304 | 304 | 304 | 304 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 14,003,134 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 76.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 24.8 AAA 13.8 AA 5.5 A 29.7 BBB 7.5 Not Rated 0.7 Short-Term Investments and Net Other Assets (Liabilities) 18.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.8 AAA - 13.8 AA - 5.5 A - 29.7 BBB - 7.5 Not Rated - 0.7 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 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. Corporate Bonds 42.3 U.S. Treasury Obligations 24.8 Asset-Backed Securities 14.5 Other Investments 0.4 Short-Term Investments and Net Other Assets (Liabilities) 18.0 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 42.3 U.S. Treasury Obligations - 24.8 Asset-Backed Securities - 14.5 Other Investments - 0.4 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 United States 83.5 Canada 5.0 United Kingdom 3.7 Germany 2.0 Netherlands 1.6 Switzerland 0.8 Denmark 0.6 Ireland 0.6 Australia 0.6 Others 1.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Canada - 5.0 United Kingdom - 3.7 Germany - 2.0 Netherlands - 1.6 Switzerland - 0.8 Denmark - 0.6 Ireland - 0.6 Australia - 0.6 Others - 1.6 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 12.8 US Treasury Bill 12.0 Wells Fargo & Co 1.9 JPMorgan Chase & Co 1.8 Bank of America Corp 1.7 Goldman Sachs Group Inc/The 1.3 Mitsubishi UFJ Trust & Banking Corp/NY 1.3 Bank of Montreal 1.2 Royal Bank of Canada 1.0 GMF Floorplan Owner Revolving Trust 1.0 36.0 | ||||||||||||||||||||||
| Fidelity Advisor Conservative Income Bond Fund - Class Z | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Conservative Income Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Conservative Income Bond Fund Class Z | ||||||||||||||||||||||
| Trading Symbol | FCNYX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Conservative Income Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
|
||||||||||||||||||||||
| Expenses Paid, Amount | $ 20 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.20% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, but also industrial firms, particularly in the consumer cyclical segment, added value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•A roughly 9% average allocation to cash - which the fund maintained for liquidity and solid interest return - also hurt.
•At period end, corporates made up about 51% of fund assets, down from roughly 53% a year ago. At the same time, we increased exposure to U.S. Treasurys from 18% to 25% of assets, while the portfolio's position in ABS ticked down from approximately 16% of assets to about 15% as of August 31.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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, 2023 through August 31, 2026. Initial investment of $10,000. Class Z $10,000 $10,156 $10,762 $11,275 Bloomberg U.S. 3-6 Month Treasury Bill Index $10,000 $10,143 $10,706 $11,198 Bloomberg U.S. Aggregate Bond Index $10,000 $10,014 $10,744 $11,081 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class Z 3.94% 4.97% Bloomberg U.S. 3-6 Month Treasury Bill Index 3.87% 4.73% Bloomberg U.S. Aggregate Bond Index 1.89% 3.78% A From May 25, 2023 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, 2023 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | |||||||||||||||
| Holdings Count | shares | 304 | 304 | 304 | 304 | 304 | 304 | 304 | 304 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 14,003,134 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 76.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
||||||||||||||||||||||
| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 24.8 AAA 13.8 AA 5.5 A 29.7 BBB 7.5 Not Rated 0.7 Short-Term Investments and Net Other Assets (Liabilities) 18.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.8 AAA - 13.8 AA - 5.5 A - 29.7 BBB - 7.5 Not Rated - 0.7 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 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. Corporate Bonds 42.3 U.S. Treasury Obligations 24.8 Asset-Backed Securities 14.5 Other Investments 0.4 Short-Term Investments and Net Other Assets (Liabilities) 18.0 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 42.3 U.S. Treasury Obligations - 24.8 Asset-Backed Securities - 14.5 Other Investments - 0.4 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 United States 83.5 Canada 5.0 United Kingdom 3.7 Germany 2.0 Netherlands 1.6 Switzerland 0.8 Denmark 0.6 Ireland 0.6 Australia 0.6 Others 1.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Canada - 5.0 United Kingdom - 3.7 Germany - 2.0 Netherlands - 1.6 Switzerland - 0.8 Denmark - 0.6 Ireland - 0.6 Australia - 0.6 Others - 1.6 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 12.8 US Treasury Bill 12.0 Wells Fargo & Co 1.9 JPMorgan Chase & Co 1.8 Bank of America Corp 1.7 Goldman Sachs Group Inc/The 1.3 Mitsubishi UFJ Trust & Banking Corp/NY 1.3 Bank of Montreal 1.2 Royal Bank of Canada 1.0 GMF Floorplan Owner Revolving Trust 1.0 36.0 | ||||||||||||||||||||||
| Fidelity Advisor Conservative Income Bond Fund - Class I | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Conservative Income Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Conservative Income Bond Fund Class I | ||||||||||||||||||||||
| Trading Symbol | FCNWX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Conservative Income Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
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| Expenses Paid, Amount | $ 25 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.25% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, but also industrial firms, particularly in the consumer cyclical segment, added value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•A roughly 9% average allocation to cash - which the fund maintained for liquidity and solid interest return - also hurt.
•At period end, corporates made up about 51% of fund assets, down from roughly 53% a year ago. At the same time, we increased exposure to U.S. Treasurys from 18% to 25% of assets, while the portfolio's position in ABS ticked down from approximately 16% of assets to about 15% as of August 31.
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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, 2023 through August 31, 2026. Initial investment of $10,000. Class I $10,000 $10,155 $10,756 $11,263 Bloomberg U.S. 3-6 Month Treasury Bill Index $10,000 $10,143 $10,706 $11,198 Bloomberg U.S. Aggregate Bond Index $10,000 $10,014 $10,744 $11,081 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class I 3.89% 4.92% Bloomberg U.S. 3-6 Month Treasury Bill Index 3.87% 4.73% Bloomberg U.S. Aggregate Bond Index 1.89% 3.78% A From May 25, 2023 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, 2023 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | |||||||||||||||
| Holdings Count | shares | 304 | 304 | 304 | 304 | 304 | 304 | 304 | 304 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 14,003,134 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 76.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 24.8 AAA 13.8 AA 5.5 A 29.7 BBB 7.5 Not Rated 0.7 Short-Term Investments and Net Other Assets (Liabilities) 18.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.8 AAA - 13.8 AA - 5.5 A - 29.7 BBB - 7.5 Not Rated - 0.7 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 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. Corporate Bonds 42.3 U.S. Treasury Obligations 24.8 Asset-Backed Securities 14.5 Other Investments 0.4 Short-Term Investments and Net Other Assets (Liabilities) 18.0 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 42.3 U.S. Treasury Obligations - 24.8 Asset-Backed Securities - 14.5 Other Investments - 0.4 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 United States 83.5 Canada 5.0 United Kingdom 3.7 Germany 2.0 Netherlands 1.6 Switzerland 0.8 Denmark 0.6 Ireland 0.6 Australia 0.6 Others 1.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Canada - 5.0 United Kingdom - 3.7 Germany - 2.0 Netherlands - 1.6 Switzerland - 0.8 Denmark - 0.6 Ireland - 0.6 Australia - 0.6 Others - 1.6 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 12.8 US Treasury Bill 12.0 Wells Fargo & Co 1.9 JPMorgan Chase & Co 1.8 Bank of America Corp 1.7 Goldman Sachs Group Inc/The 1.3 Mitsubishi UFJ Trust & Banking Corp/NY 1.3 Bank of Montreal 1.2 Royal Bank of Canada 1.0 GMF Floorplan Owner Revolving Trust 1.0 36.0 | ||||||||||||||||||||||
| Fidelity Advisor Conservative Income Bond Fund - Class A | |||||||||||||||||||||||
| Shareholder Report [Line Items] | |||||||||||||||||||||||
| Fund Name | Fidelity® Conservative Income Bond Fund | ||||||||||||||||||||||
| Class Name | Fidelity Advisor® Conservative Income Bond Fund Class A | ||||||||||||||||||||||
| Trading Symbol | FCNQX | ||||||||||||||||||||||
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains information about Fidelity® Conservative Income Bond Fund for the period September 1, 2025 to August 31, 2026. | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| 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)
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| Expenses Paid, Amount | $ 46 | ||||||||||||||||||||||
| Expense Ratio, Percent | 0.45% | ||||||||||||||||||||||
| Factors Affecting Performance [Text Block] | What affected the Fund's performance this period?
•U.S. taxable investment-grade bonds achieved a gain for the 12 months ending August 31, 2026, buoyed by three policy interest-rate cuts by the Federal Reserve in late 2025, but pulled down since then by rising bond yields amid higher consumer inflation, a resilient economy and heavy U.S. Treasury issuance.
•Against this backdrop, the fund's strategy of holding short-term debt in high-quality corporations contributed to performance versus the all-U.S.-Treasury benchmark for the fiscal year. Within corporates, debt holdings among financial institutions, especially banks, but also industrial firms, particularly in the consumer cyclical segment, added value.
•Non-benchmark exposure to asset-backed securities, primarily car loan debt, also helped.
•In contrast, the fund's yield-curve positioning detracted from relative performance.
•A roughly 9% average allocation to cash - which the fund maintained for liquidity and solid interest return - also hurt.
•At period end, corporates made up about 51% of fund assets, down from roughly 53% a year ago. At the same time, we increased exposure to U.S. Treasurys from 18% to 25% of assets, while the portfolio's position in ABS ticked down from approximately 16% of assets to about 15% as of August 31.
|
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| Performance Past Does Not Indicate Future [Text] | <span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:italic;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, 2023 through August 31, 2026. Initial investment of $10,000 and the current sales charge was paid. Class A $9,850 $9,998 $10,569 $11,045 Bloomberg U.S. 3-6 Month Treasury Bill Index $10,000 $10,143 $10,706 $11,198 Bloomberg U.S. Aggregate Bond Index $10,000 $10,014 $10,744 $11,081 2023 2024 2025 2026 | ||||||||||||||||||||||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS: 1 Year Life of Fund A Class A (incl. 1.50% sales charge) 2.13% 4.23% Class A (without 1.50% sales charge) 3.69% 4.71% Bloomberg U.S. 3-6 Month Treasury Bill Index 3.87% 4.73% Bloomberg U.S. Aggregate Bond Index 1.89% 3.78% A From May 25, 2023 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, 2023 | ||||||||||||||||||||||
| 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. | ||||||||||||||||||||||
| Updated Performance Information Location [Text Block] | Visit institutional.fidelity.com for more recent performance information. | ||||||||||||||||||||||
| Net Assets | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | $ 6,422,960,004 | |||||||||||||||
| Holdings Count | shares | 304 | 304 | 304 | 304 | 304 | 304 | 304 | 304 | |||||||||||||||
| Advisory Fees Paid, Amount | $ 14,003,134 | ||||||||||||||||||||||
| Investment Company Portfolio Turnover | 76.00% | ||||||||||||||||||||||
| Additional Fund Statistics [Text Block] | Key Fund Statistics
(as of August 31, 2026)
|
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| Holdings [Text Block] | U.S. Government and U.S. Government Agency Obligations 24.8 AAA 13.8 AA 5.5 A 29.7 BBB 7.5 Not Rated 0.7 Short-Term Investments and Net Other Assets (Liabilities) 18.0 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.8 AAA - 13.8 AA - 5.5 A - 29.7 BBB - 7.5 Not Rated - 0.7 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 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. Corporate Bonds 42.3 U.S. Treasury Obligations 24.8 Asset-Backed Securities 14.5 Other Investments 0.4 Short-Term Investments and Net Other Assets (Liabilities) 18.0 ASSET ALLOCATION (% of Fund's net assets) Corporate Bonds - 42.3 U.S. Treasury Obligations - 24.8 Asset-Backed Securities - 14.5 Other Investments - 0.4 Short-Term Investments and Net Other Assets (Liabilities) - 18.0 United States 83.5 Canada 5.0 United Kingdom 3.7 Germany 2.0 Netherlands 1.6 Switzerland 0.8 Denmark 0.6 Ireland 0.6 Australia 0.6 Others 1.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 83.5 Canada - 5.0 United Kingdom - 3.7 Germany - 2.0 Netherlands - 1.6 Switzerland - 0.8 Denmark - 0.6 Ireland - 0.6 Australia - 0.6 Others - 1.6 | ||||||||||||||||||||||
| Largest Holdings [Text Block] | TOP HOLDINGS(% of Fund's net assets) US Treasury Notes 12.8 US Treasury Bill 12.0 Wells Fargo & Co 1.9 JPMorgan Chase & Co 1.8 Bank of America Corp 1.7 Goldman Sachs Group Inc/The 1.3 Mitsubishi UFJ Trust & Banking Corp/NY 1.3 Bank of Montreal 1.2 Royal Bank of Canada 1.0 GMF Floorplan Owner Revolving Trust 1.0 36.0 | ||||||||||||||||||||||