Fidelity Limited Term Bond Fund (FJRLX) N-CSR21 Feb 25Certified annual shareholder report (management investment company)Financial data

Company Profile

Form N-CSR Cover

Form N-CSR Cover	12 Months Ended
Form N-CSR Cover	Dec. 31, 2024
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	Fidelity Advisor Series II
Entity Central Index Key	0000795422
Entity Investment Company Type	N-1A
Document Period End Date	Dec. 31, 2024

Shareholder Report

Shareholder Report	12 Months Ended
Shareholder Report	Dec. 31, 2024 USD ($) shares
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	Fidelity Advisor Series II
Entity Central Index Key	0000795422
Entity Investment Company Type	N-1A
Document Period End Date	Dec. 31, 2024
Fidelity Strategic Income Fund
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Strategic Income Fund
Class Name	Fidelity® Strategic Income Fund
Trading Symbol	FADMX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Strategic Income Fund for the period January 1, 2024 to December 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	1-800-544-8544
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Strategic Income Fund $ 0.65 %
Expenses Paid, Amount	$ 67
Expense Ratio, Percent	0.65%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • SM , security selection among high-yield bonds meaningfully contributed to the fund's result, especially picks in the energy, technology & electronics and financial services categories. • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B26"><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, 2018 through December 31, 2024. Initial investment of $10,000. Fidelity® Strategic Income Fund $10,000 $9,722 $10,796 $11,609 $12,069 $10,725 $11,747 Fidelity Strategic Income Composite Index℠ $10,000 $9,852 $10,889 $11,612 $11,757 $10,383 $11,369 Bloomberg U.S. Universal Bond Index $10,000 $10,131 $11,072 $11,911 $11,780 $10,249 $10,882 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Fidelity® Strategic Income Fund 6.05% 2.90% 3.32% Fidelity Strategic Income Composite Index℠ 5.23% 1.90% 2.70% Bloomberg U.S. Universal Bond Index 2.04% 0.06% 1.57% A From April 13, 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	Apr. 13, 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.
Net Assets	$ 14,350,001,407
Holdings Count \| shares	970
Advisory Fees Paid, Amount	$ 87,853,110
Investment Company Portfolio Turnover	76%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of December 31, 2024) KEY FACTS Fund Size $ Number of Holdings 970 Total Advisory Fee $ Portfolio Turnover 76 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 24.6 AAA 2.9 AA 2.1 A 1.9 BBB 7.5 BB 13.4 B 17.2 CCC,CC,C 5.6 D 0.0 Not Rated 8.6 Equities 6.9 Short-Term Investments and Net Other Assets (Liabilities) 9.3 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.6 AAA - 2.9 AA - 2.1 A - 1.9 BBB - 7.5 BB - 13.4 B - 17.2 CCC,CC,C - 5.6 D - 0.0 Not Rated - 8.6 Equities - 6.9 Short-Term Investments and Net Other Assets (Liabilities) - 9.3 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. High-Yield Debt 40.8 U.S. Government & Investment Grade-Debt 30.2 Emerging-Markets Debt 15.5 Foreign Developed-Markets Debt 8.5 Floating-Rate debt 5.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets) High-Yield Debt - 40.8 U.S. Government & Investment Grade-Debt - 30.2 Emerging-Markets Debt - 15.5 Foreign Developed-Markets Debt - 8.5 Floating-Rate debt - 5.0 Short-Term Investments and Net Other Assets (Liabilities) - 0.0 United States 74.4 Germany 6.0 Mexico 1.6 Brazil 1.2 United Kingdom 1.1 Canada 1.0 France 0.9 Saudi Arabia 0.9 United Arab Emirates 0.8 Others 12.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 74.4 Germany - 6.0 Mexico - 1.6 Brazil - 1.2 United Kingdom - 1.1 Canada - 1.0 France - 0.9 Saudi Arabia - 0.9 United Arab Emirates - 0.8 Others - 12.1
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 18.6 US Treasury Bonds 5.6 German Federal Republic 5.6 Freddie Mac Multifamily Structured pass-thru certificates 3.7 TransDigm Inc 1.1 EchoStar Corp 0.8 Argentine Republic 0.7 Turkish Republic 0.7 NVIDIA Corp 0.6 Ally Financial Inc 0.6 38.0
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Material Fund Change Expenses [Text Block]	The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-800-544-8544</span>" id="sjs-B41"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-800-544-8544</span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B42"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B43"><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 Strategic Income Fund - Class A
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Strategic Income Fund
Class Name	Fidelity Advisor® Strategic Income Fund Class A
Trading Symbol	FSTAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Strategic Income Fund for the period January 1, 2024 to December 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	1-877-208-0098
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $ 0.94 %
Expenses Paid, Amount	$ 97
Expense Ratio, Percent	0.94%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • SM , security selection among high-yield bonds meaningfully contributed to the fund's result, especially picks in the energy, technology & electronics and financial services categories. • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B60"><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 December 31, 2014 through December 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class A $9,600 $9,423 $10,216 $11,020 $10,695 $11,843 $12,695 $13,150 $11,665 $12,737 $13,471 Fidelity Strategic Income Composite Index℠ $10,000 $9,764 $10,671 $11,388 $11,224 $12,406 $13,229 $13,394 $11,829 $12,952 $13,629 Bloomberg U.S. Universal Bond Index $10,000 $10,043 $10,436 $10,863 $10,835 $11,842 $12,739 $12,598 $10,961 $11,638 $11,875 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year 10 Year Class A (incl. 4.00% sales charge) 1.53% 1.78% 3.02% Class A (without 4.00% sales charge) 5.76% 2.61% 3.45% Fidelity Strategic Income Composite Index℠ 5.23% 1.90% 3.14% Bloomberg U.S. Universal Bond Index 2.04% 0.06% 1.73% 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.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 14,350,001,407
Holdings Count \| shares	970
Advisory Fees Paid, Amount	$ 87,853,110
Investment Company Portfolio Turnover	76%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of December 31, 2024) KEY FACTS Fund Size $ Number of Holdings 970 Total Advisory Fee $ Portfolio Turnover 76 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 24.6 AAA 2.9 AA 2.1 A 1.9 BBB 7.5 BB 13.4 B 17.2 CCC,CC,C 5.6 D 0.0 Not Rated 8.6 Equities 6.9 Short-Term Investments and Net Other Assets (Liabilities) 9.3 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.6 AAA - 2.9 AA - 2.1 A - 1.9 BBB - 7.5 BB - 13.4 B - 17.2 CCC,CC,C - 5.6 D - 0.0 Not Rated - 8.6 Equities - 6.9 Short-Term Investments and Net Other Assets (Liabilities) - 9.3 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. High-Yield Debt 40.8 U.S. Government & Investment Grade-Debt 30.2 Emerging-Markets Debt 15.5 Foreign Developed-Markets Debt 8.5 Floating-Rate debt 5.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets) High-Yield Debt - 40.8 U.S. Government & Investment Grade-Debt - 30.2 Emerging-Markets Debt - 15.5 Foreign Developed-Markets Debt - 8.5 Floating-Rate debt - 5.0 Short-Term Investments and Net Other Assets (Liabilities) - 0.0 United States 74.4 Germany 6.0 Mexico 1.6 Brazil 1.2 United Kingdom 1.1 Canada 1.0 France 0.9 Saudi Arabia 0.9 United Arab Emirates 0.8 Others 12.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 74.4 Germany - 6.0 Mexico - 1.6 Brazil - 1.2 United Kingdom - 1.1 Canada - 1.0 France - 0.9 Saudi Arabia - 0.9 United Arab Emirates - 0.8 Others - 12.1
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 18.6 US Treasury Bonds 5.6 German Federal Republic 5.6 Freddie Mac Multifamily Structured pass-thru certificates 3.7 TransDigm Inc 1.1 EchoStar Corp 0.8 Argentine Republic 0.7 Turkish Republic 0.7 NVIDIA Corp 0.6 Ally Financial Inc 0.6 38.0
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Material Fund Change Expenses [Text Block]	The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B74"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B75"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B76"><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 Strategic Income Fund - Class I
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Strategic Income Fund
Class Name	Fidelity Advisor® Strategic Income Fund Class I
Trading Symbol	FSRIX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Strategic Income Fund for the period January 1, 2024 to December 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	1-877-208-0098
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class I $ 0.70 %
Expenses Paid, Amount	$ 72
Expense Ratio, Percent	0.70%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • SM , security selection among high-yield bonds meaningfully contributed to the fund's result, especially picks in the energy, technology & electronics and financial services categories. • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B93"><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 December 31, 2014 through December 31, 2024. Initial investment of $10,000. Class I $10,000 $9,827 $10,692 $11,554 $11,241 $12,477 $13,411 $13,935 $12,377 $13,552 $14,365 Fidelity Strategic Income Composite Index℠ $10,000 $9,764 $10,671 $11,388 $11,224 $12,406 $13,229 $13,394 $11,829 $12,952 $13,629 Bloomberg U.S. Universal Bond Index $10,000 $10,043 $10,436 $10,863 $10,835 $11,842 $12,739 $12,598 $10,961 $11,638 $11,875 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year 10 Year Class I 6.00% 2.86% 3.69% Fidelity Strategic Income Composite Index℠ 5.23% 1.90% 3.14% Bloomberg U.S. Universal Bond Index 2.04% 0.06% 1.73% 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.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 14,350,001,407
Holdings Count \| shares	970
Advisory Fees Paid, Amount	$ 87,853,110
Investment Company Portfolio Turnover	76%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of December 31, 2024) KEY FACTS Fund Size $ Number of Holdings 970 Total Advisory Fee $ Portfolio Turnover 76 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 24.6 AAA 2.9 AA 2.1 A 1.9 BBB 7.5 BB 13.4 B 17.2 CCC,CC,C 5.6 D 0.0 Not Rated 8.6 Equities 6.9 Short-Term Investments and Net Other Assets (Liabilities) 9.3 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.6 AAA - 2.9 AA - 2.1 A - 1.9 BBB - 7.5 BB - 13.4 B - 17.2 CCC,CC,C - 5.6 D - 0.0 Not Rated - 8.6 Equities - 6.9 Short-Term Investments and Net Other Assets (Liabilities) - 9.3 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. High-Yield Debt 40.8 U.S. Government & Investment Grade-Debt 30.2 Emerging-Markets Debt 15.5 Foreign Developed-Markets Debt 8.5 Floating-Rate debt 5.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets) High-Yield Debt - 40.8 U.S. Government & Investment Grade-Debt - 30.2 Emerging-Markets Debt - 15.5 Foreign Developed-Markets Debt - 8.5 Floating-Rate debt - 5.0 Short-Term Investments and Net Other Assets (Liabilities) - 0.0 United States 74.4 Germany 6.0 Mexico 1.6 Brazil 1.2 United Kingdom 1.1 Canada 1.0 France 0.9 Saudi Arabia 0.9 United Arab Emirates 0.8 Others 12.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 74.4 Germany - 6.0 Mexico - 1.6 Brazil - 1.2 United Kingdom - 1.1 Canada - 1.0 France - 0.9 Saudi Arabia - 0.9 United Arab Emirates - 0.8 Others - 12.1
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 18.6 US Treasury Bonds 5.6 German Federal Republic 5.6 Freddie Mac Multifamily Structured pass-thru certificates 3.7 TransDigm Inc 1.1 EchoStar Corp 0.8 Argentine Republic 0.7 Turkish Republic 0.7 NVIDIA Corp 0.6 Ally Financial Inc 0.6 38.0
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Material Fund Change Expenses [Text Block]	The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B107"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B108"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B109"><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 Strategic Income Fund - Class Z
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Strategic Income Fund
Class Name	Fidelity Advisor® Strategic Income Fund Class Z
Trading Symbol	FIWDX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Strategic Income Fund for the period January 1, 2024 to December 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	1-877-208-0098
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class Z $ 0.60 %
Expenses Paid, Amount	$ 62
Expense Ratio, Percent	0.60%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • SM , security selection among high-yield bonds meaningfully contributed to the fund's result, especially picks in the energy, technology & electronics and financial services categories. • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B126"><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 2, 2018 through December 31, 2024. Initial investment of $10,000. Class Z $10,000 $9,738 $10,828 $11,650 $12,107 $10,775 $11,809 Fidelity Strategic Income Composite Index℠ $10,000 $9,856 $10,893 $11,616 $11,762 $10,387 $11,373 Bloomberg U.S. Universal Bond Index $10,000 $10,114 $11,054 $11,891 $11,760 $10,232 $10,864 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year Life of Fund A Class Z 6.11% 2.96% 3.67% Fidelity Strategic Income Composite Index℠ 5.23% 1.90% 2.92% Bloomberg U.S. Universal Bond Index 2.04% 0.06% 1.66% A From October 2, 2018 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	Oct. 02, 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.
Net Assets	$ 14,350,001,407
Holdings Count \| shares	970
Advisory Fees Paid, Amount	$ 87,853,110
Investment Company Portfolio Turnover	76%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of December 31, 2024) KEY FACTS Fund Size $ Number of Holdings 970 Total Advisory Fee $ Portfolio Turnover 76 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 24.6 AAA 2.9 AA 2.1 A 1.9 BBB 7.5 BB 13.4 B 17.2 CCC,CC,C 5.6 D 0.0 Not Rated 8.6 Equities 6.9 Short-Term Investments and Net Other Assets (Liabilities) 9.3 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.6 AAA - 2.9 AA - 2.1 A - 1.9 BBB - 7.5 BB - 13.4 B - 17.2 CCC,CC,C - 5.6 D - 0.0 Not Rated - 8.6 Equities - 6.9 Short-Term Investments and Net Other Assets (Liabilities) - 9.3 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. High-Yield Debt 40.8 U.S. Government & Investment Grade-Debt 30.2 Emerging-Markets Debt 15.5 Foreign Developed-Markets Debt 8.5 Floating-Rate debt 5.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets) High-Yield Debt - 40.8 U.S. Government & Investment Grade-Debt - 30.2 Emerging-Markets Debt - 15.5 Foreign Developed-Markets Debt - 8.5 Floating-Rate debt - 5.0 Short-Term Investments and Net Other Assets (Liabilities) - 0.0 United States 74.4 Germany 6.0 Mexico 1.6 Brazil 1.2 United Kingdom 1.1 Canada 1.0 France 0.9 Saudi Arabia 0.9 United Arab Emirates 0.8 Others 12.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 74.4 Germany - 6.0 Mexico - 1.6 Brazil - 1.2 United Kingdom - 1.1 Canada - 1.0 France - 0.9 Saudi Arabia - 0.9 United Arab Emirates - 0.8 Others - 12.1
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 18.6 US Treasury Bonds 5.6 German Federal Republic 5.6 Freddie Mac Multifamily Structured pass-thru certificates 3.7 TransDigm Inc 1.1 EchoStar Corp 0.8 Argentine Republic 0.7 Turkish Republic 0.7 NVIDIA Corp 0.6 Ally Financial Inc 0.6 38.0
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Material Fund Change Expenses [Text Block]	The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B141"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B142"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B143"><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 Strategic Income Fund - Class C
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Strategic Income Fund
Class Name	Fidelity Advisor® Strategic Income Fund Class C
Trading Symbol	FSRCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Strategic Income Fund for the period January 1, 2024 to December 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	1-877-208-0098
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $ 1.69 %
Expenses Paid, Amount	$ 173
Expense Ratio, Percent	1.69%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • SM , security selection among high-yield bonds meaningfully contributed to the fund's result, especially picks in the energy, technology & electronics and financial services categories. • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B160"><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 December 31, 2014 through December 31, 2024. Initial investment of $10,000. Class C $10,000 $9,741 $10,485 $11,219 $10,815 $11,890 $12,652 $13,008 $11,447 $12,499 $13,220 Fidelity Strategic Income Composite Index℠ $10,000 $9,764 $10,671 $11,388 $11,224 $12,406 $13,229 $13,394 $11,829 $12,952 $13,629 Bloomberg U.S. Universal Bond Index $10,000 $10,043 $10,436 $10,863 $10,835 $11,842 $12,739 $12,598 $10,961 $11,638 $11,875 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year 10 Year Class C (incl. contingent deferred sales charge) 3.89% 1.82% 2.83% Class C 4.89% 1.82% 2.83% Fidelity Strategic Income Composite Index℠ 5.23% 1.90% 3.14% Bloomberg U.S. Universal Bond Index 2.04% 0.06% 1.73% 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.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 14,350,001,407
Holdings Count \| shares	970
Advisory Fees Paid, Amount	$ 87,853,110
Investment Company Portfolio Turnover	76%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of December 31, 2024) KEY FACTS Fund Size $ Number of Holdings 970 Total Advisory Fee $ Portfolio Turnover 76 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 24.6 AAA 2.9 AA 2.1 A 1.9 BBB 7.5 BB 13.4 B 17.2 CCC,CC,C 5.6 D 0.0 Not Rated 8.6 Equities 6.9 Short-Term Investments and Net Other Assets (Liabilities) 9.3 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.6 AAA - 2.9 AA - 2.1 A - 1.9 BBB - 7.5 BB - 13.4 B - 17.2 CCC,CC,C - 5.6 D - 0.0 Not Rated - 8.6 Equities - 6.9 Short-Term Investments and Net Other Assets (Liabilities) - 9.3 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. High-Yield Debt 40.8 U.S. Government & Investment Grade-Debt 30.2 Emerging-Markets Debt 15.5 Foreign Developed-Markets Debt 8.5 Floating-Rate debt 5.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets) High-Yield Debt - 40.8 U.S. Government & Investment Grade-Debt - 30.2 Emerging-Markets Debt - 15.5 Foreign Developed-Markets Debt - 8.5 Floating-Rate debt - 5.0 Short-Term Investments and Net Other Assets (Liabilities) - 0.0 United States 74.4 Germany 6.0 Mexico 1.6 Brazil 1.2 United Kingdom 1.1 Canada 1.0 France 0.9 Saudi Arabia 0.9 United Arab Emirates 0.8 Others 12.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 74.4 Germany - 6.0 Mexico - 1.6 Brazil - 1.2 United Kingdom - 1.1 Canada - 1.0 France - 0.9 Saudi Arabia - 0.9 United Arab Emirates - 0.8 Others - 12.1
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 18.6 US Treasury Bonds 5.6 German Federal Republic 5.6 Freddie Mac Multifamily Structured pass-thru certificates 3.7 TransDigm Inc 1.1 EchoStar Corp 0.8 Argentine Republic 0.7 Turkish Republic 0.7 NVIDIA Corp 0.6 Ally Financial Inc 0.6 38.0
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Material Fund Change Expenses [Text Block]	The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B174"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B175"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B176"><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 Strategic Income Fund - Class M
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Strategic Income Fund
Class Name	Fidelity Advisor® Strategic Income Fund Class M
Trading Symbol	FSIAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Strategic Income Fund for the period January 1, 2024 to December 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-877-208-0098 or by sending an e-mail to fidfunddocuments@fidelity.com.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	1-877-208-0098
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class M $ 0.94 %
Expenses Paid, Amount	$ 97
Expense Ratio, Percent	0.94%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • SM , security selection among high-yield bonds meaningfully contributed to the fund's result, especially picks in the energy, technology & electronics and financial services categories. • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B193"><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 December 31, 2014 through December 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class M $9,600 $9,415 $10,217 $11,012 $10,687 $11,836 $12,699 $13,155 $11,659 $12,732 $13,467 Fidelity Strategic Income Composite Index℠ $10,000 $9,764 $10,671 $11,388 $11,224 $12,406 $13,229 $13,394 $11,829 $12,952 $13,629 Bloomberg U.S. Universal Bond Index $10,000 $10,043 $10,436 $10,863 $10,835 $11,842 $12,739 $12,598 $10,961 $11,638 $11,875 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS: 1 Year 5 Year 10 Year Class M (incl. 4.00% sales charge) 1.54% 1.78% 3.02% Class M (without 4.00% sales charge) 5.77% 2.61% 3.44% Fidelity Strategic Income Composite Index℠ 5.23% 1.90% 3.14% Bloomberg U.S. Universal Bond Index 2.04% 0.06% 1.73% 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.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 14,350,001,407
Holdings Count \| shares	970
Advisory Fees Paid, Amount	$ 87,853,110
Investment Company Portfolio Turnover	76%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of December 31, 2024) KEY FACTS Fund Size $ Number of Holdings 970 Total Advisory Fee $ Portfolio Turnover 76 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 24.6 AAA 2.9 AA 2.1 A 1.9 BBB 7.5 BB 13.4 B 17.2 CCC,CC,C 5.6 D 0.0 Not Rated 8.6 Equities 6.9 Short-Term Investments and Net Other Assets (Liabilities) 9.3 QUALITY DIVERSIFICATION (% of Fund's net assets) U.S. Government and U.S. Government Agency Obligations - 24.6 AAA - 2.9 AA - 2.1 A - 1.9 BBB - 7.5 BB - 13.4 B - 17.2 CCC,CC,C - 5.6 D - 0.0 Not Rated - 8.6 Equities - 6.9 Short-Term Investments and Net Other Assets (Liabilities) - 9.3 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. High-Yield Debt 40.8 U.S. Government & Investment Grade-Debt 30.2 Emerging-Markets Debt 15.5 Foreign Developed-Markets Debt 8.5 Floating-Rate debt 5.0 Short-Term Investments and Net Other Assets (Liabilities) 0.0 ASSET ALLOCATION (% of Fund's net assets) High-Yield Debt - 40.8 U.S. Government & Investment Grade-Debt - 30.2 Emerging-Markets Debt - 15.5 Foreign Developed-Markets Debt - 8.5 Floating-Rate debt - 5.0 Short-Term Investments and Net Other Assets (Liabilities) - 0.0 United States 74.4 Germany 6.0 Mexico 1.6 Brazil 1.2 United Kingdom 1.1 Canada 1.0 France 0.9 Saudi Arabia 0.9 United Arab Emirates 0.8 Others 12.1 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets) United States - 74.4 Germany - 6.0 Mexico - 1.6 Brazil - 1.2 United Kingdom - 1.1 Canada - 1.0 France - 0.9 Saudi Arabia - 0.9 United Arab Emirates - 0.8 Others - 12.1
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 18.6 US Treasury Bonds 5.6 German Federal Republic 5.6 Freddie Mac Multifamily Structured pass-thru certificates 3.7 TransDigm Inc 1.1 EchoStar Corp 0.8 Argentine Republic 0.7 Turkish Republic 0.7 NVIDIA Corp 0.6 Ally Financial Inc 0.6 38.0
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Material Fund Change Expenses [Text Block]	The fund's transfer agent and pricing & bookkeeping fees were changed to a fixed rate effective December 1, 2023. Effective March 1, 2024, the fund's management contract was amended to incorporate administrative services previously covered under separate services agreements (transfer agent and pricing & bookkeeping). The amended contract incorporates a management fee rate that may vary by class. The Adviser or an affiliate pays certain expenses of managing and operating the fund out of each class's management fee.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by March 1, 2025 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B207"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098</span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B208"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com</span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B209"><span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec</span>

Shareholder Report, Line Graph

Shareholder Report, Line Graph (Details) - USD ($)

12 Months Ended

60 Months Ended

84 Months Ended

120 Months Ended

132 Months Ended

Dec. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

C000200078_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.04%

C000200078_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.06%

C000200078_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.57%

C000014110_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.04%

C000014110_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.06%

C000014110_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.73%

C000014114_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.04%

C000014114_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.06%

C000014114_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.73%

C000204998_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.04%

C000204998_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.06%

C000204998_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

C000014112_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.04%

C000014112_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.06%

C000014112_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.73%

C000014113_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.04%

C000014113_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.06%

C000014113_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.73%

C000200078_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Strategic Income Fund" id="sjs-D59">Fidelity® Strategic Income Fund

C000200078_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 10,000

C000200078_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 9,722

C000200078_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 10,796

C000200078_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 11,609

C000200078_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 12,069

C000200078_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 10,725

C000200078_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,747

C000200078_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Strategic Income Composite Index℠" id="sjs-D83">Fidelity Strategic Income Composite Index℠

C000200078_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000200078_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

9,852

C000200078_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

10,889

C000200078_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,612

C000200078_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,757

C000200078_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,383

C000200078_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,369

$ 11,369

11,369

C000200078_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index" id="sjs-D107">Bloomberg U.S. Universal Bond Index

C000200078_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000200078_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,131

C000200078_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,072

C000200078_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,911

C000200078_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,780

C000200078_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,249

C000200078_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,882

10,882

$ 10,882

C000200078_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.05%

C000200078_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.90%

C000200078_NoLoadClassMember_2024-01-01_2024-12-31Member

Account Value [Line Items]

Average Annual Return, Percent

3.32%

C000200078_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000200078_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000200078_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

2.70%

C000014110_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class A" id="sjs-F149">Class A

C000014110_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 9,600

C000014110_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 9,423

C000014110_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 10,216

C000014110_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 11,020

C000014110_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,695

C000014110_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,843

C000014110_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,695

C000014110_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,150

C000014110_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,665

C000014110_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,737

C000014110_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 13,471

13,471

$ 13,471

C000014110_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Strategic Income Composite Index℠" id="sjs-F185">Fidelity Strategic Income Composite Index℠

C000014110_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014110_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,764

C000014110_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,671

C000014110_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,388

C000014110_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

11,224

C000014110_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,406

C000014110_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

13,229

C000014110_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,394

C000014110_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,829

C000014110_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,952

C000014110_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

13,629

$ 13,629

C000014110_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index" id="sjs-F221">Bloomberg U.S. Universal Bond Index

C000014110_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014110_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,043

C000014110_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,436

C000014110_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,863

C000014110_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,835

C000014110_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,842

C000014110_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,739

C000014110_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,598

C000014110_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,961

C000014110_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,638

C000014110_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,875

11,875

$ 11,875

C000014110_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.53%

C000014110_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.78%

C000014110_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.02%

C000014110_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.76%

C000014110_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.61%

C000014110_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.45%

C000014110_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000014110_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000014110_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.14%

C000014114_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class I" id="sjs-F284">Class I

C000014114_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014114_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,827

C000014114_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,692

C000014114_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,554

C000014114_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

11,241

C000014114_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,477

C000014114_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

13,411

C000014114_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,935

C000014114_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

12,377

C000014114_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

13,552

C000014114_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 14,365

14,365

$ 14,365

C000014114_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Strategic Income Composite Index℠" id="sjs-F320">Fidelity Strategic Income Composite Index℠

C000014114_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014114_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,764

C000014114_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,671

C000014114_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,388

C000014114_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

11,224

C000014114_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,406

C000014114_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

13,229

C000014114_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,394

C000014114_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,829

C000014114_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,952

C000014114_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

13,629

$ 13,629

C000014114_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index" id="sjs-F356">Bloomberg U.S. Universal Bond Index

C000014114_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014114_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,043

C000014114_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,436

C000014114_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,863

C000014114_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,835

C000014114_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,842

C000014114_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,739

C000014114_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,598

C000014114_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,961

C000014114_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,638

C000014114_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,875

C000014114_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

C000014114_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.86%

C000014114_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.69%

C000014114_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000014114_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000014114_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.14%

C000204998_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class Z" id="sjs-D410">Class Z

C000204998_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204998_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

9,738

C000204998_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

10,828

C000204998_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,650

C000204998_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

12,107

C000204998_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,775

C000204998_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,809

11,809

C000204998_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Strategic Income Composite Index℠" id="sjs-D434">Fidelity Strategic Income Composite Index℠

C000204998_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204998_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

9,856

C000204998_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

10,893

C000204998_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,616

C000204998_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,762

C000204998_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,387

C000204998_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,373

$ 11,373

11,373

C000204998_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index" id="sjs-D458">Bloomberg U.S. Universal Bond Index

C000204998_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204998_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,114

C000204998_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,054

C000204998_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,891

C000204998_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,760

C000204998_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,232

C000204998_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,864

10,864

$ 10,864

C000204998_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.11%

C000204998_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.96%

C000204998_NoLoadClassMember_2024-01-01_2024-12-31Member

Account Value [Line Items]

Average Annual Return, Percent

3.67%

C000204998_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000204998_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000204998_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

2.92%

C000014112_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class C" id="sjs-F500">Class C

C000014112_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014112_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,741

C000014112_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,485

C000014112_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,219

C000014112_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,815

C000014112_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,890

C000014112_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,652

C000014112_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,008

C000014112_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,447

C000014112_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,499

C000014112_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 13,220

13,220

$ 13,220

C000014112_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Strategic Income Composite Index℠" id="sjs-F536">Fidelity Strategic Income Composite Index℠

C000014112_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014112_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,764

C000014112_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,671

C000014112_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,388

C000014112_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

11,224

C000014112_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,406

C000014112_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

13,229

C000014112_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,394

C000014112_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,829

C000014112_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,952

C000014112_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

13,629

$ 13,629

C000014112_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index" id="sjs-F572">Bloomberg U.S. Universal Bond Index

C000014112_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014112_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,043

C000014112_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,436

C000014112_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,863

C000014112_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,835

C000014112_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,842

C000014112_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,739

C000014112_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,598

C000014112_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,961

C000014112_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,638

C000014112_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,875

11,875

$ 11,875

C000014112_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.89%

C000014112_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.82%

C000014112_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.83%

C000014112_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

4.89%

C000014112_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.82%

C000014112_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.83%

C000014112_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000014112_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000014112_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.14%

C000014113_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class M" id="sjs-F635">Class M

C000014113_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000014113_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,415

C000014113_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,217

C000014113_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,012

C000014113_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,687

C000014113_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,836

C000014113_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,699

C000014113_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,155

C000014113_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,659

C000014113_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,732

C000014113_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 13,467

13,467

$ 13,467

C000014113_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Strategic Income Composite Index℠" id="sjs-F671">Fidelity Strategic Income Composite Index℠

C000014113_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014113_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,764

C000014113_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,671

C000014113_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,388

C000014113_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

11,224

C000014113_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,406

C000014113_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

13,229

C000014113_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,394

C000014113_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,829

C000014113_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

12,952

C000014113_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

13,629

$ 13,629

C000014113_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index" id="sjs-F707">Bloomberg U.S. Universal Bond Index

C000014113_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000014113_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 10,043

C000014113_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 10,436

C000014113_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 10,863

C000014113_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 10,835

C000014113_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 11,842

C000014113_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 12,739

C000014113_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 12,598

C000014113_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 10,961

C000014113_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 11,638

C000014113_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,875

C000014113_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.54%

C000014113_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.78%

C000014113_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.02%

C000014113_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.77%

C000014113_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.61%

C000014113_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.44%

C000014113_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000014113_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000014113_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.14%

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Dec. 31, 2024
Fidelity Strategic Income Fund \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Strategic Income Fund \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Strategic Income Fund \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Strategic Income Fund \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Strategic Income Fund \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Strategic Income Fund \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Strategic Income Fund \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Strategic Income Fund \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Strategic Income Fund \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Strategic Income Fund \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Strategic Income Fund \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	24.60%
Fidelity Strategic Income Fund \| QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Strategic Income Fund \| QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Strategic Income Fund \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Strategic Income Fund \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Strategic Income Fund \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Strategic Income Fund \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	17.20%
Fidelity Strategic Income Fund \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Strategic Income Fund \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Strategic Income Fund \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	8.60%
Fidelity Strategic Income Fund \| QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Strategic Income Fund \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Strategic Income Fund \| United States
Holdings [Line Items]
Percent of Net Asset Value	74.40%
Fidelity Strategic Income Fund \| Germany
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity Strategic Income Fund \| Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Strategic Income Fund \| Brazil
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Strategic Income Fund \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Strategic Income Fund \| Canada
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Strategic Income Fund \| France
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Strategic Income Fund \| Saudi Arabia
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Strategic Income Fund \| United Arab Emirates
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Strategic Income Fund \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	12.10%
Fidelity Strategic Income Fund \| AAHighYieldDebtMember
Holdings [Line Items]
Percent of Net Asset Value	40.80%
Fidelity Strategic Income Fund \| AAUSGovernmentInvestmentGradeDebtMember
Holdings [Line Items]
Percent of Net Asset Value	30.20%
Fidelity Strategic Income Fund \| AAEmergingMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity Strategic Income Fund \| AAForeignDevelopedMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Strategic Income Fund \| AAFloatingRatedebtMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Strategic Income Fund \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class A \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Strategic Income Fund - Class A \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class A \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class A \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Strategic Income Fund - Class A \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class A \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class A \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class A \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class A \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class A \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class A \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	24.60%
Fidelity Advisor Strategic Income Fund - Class A \| QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Strategic Income Fund - Class A \| QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Strategic Income Fund - Class A \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Strategic Income Fund - Class A \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Strategic Income Fund - Class A \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Advisor Strategic Income Fund - Class A \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	17.20%
Fidelity Advisor Strategic Income Fund - Class A \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class A \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class A \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	8.60%
Fidelity Advisor Strategic Income Fund - Class A \| QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Advisor Strategic Income Fund - Class A \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Strategic Income Fund - Class A \| United States
Holdings [Line Items]
Percent of Net Asset Value	74.40%
Fidelity Advisor Strategic Income Fund - Class A \| Germany
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity Advisor Strategic Income Fund - Class A \| Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Strategic Income Fund - Class A \| Brazil
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Strategic Income Fund - Class A \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class A \| Canada
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Strategic Income Fund - Class A \| France
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class A \| Saudi Arabia
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class A \| United Arab Emirates
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class A \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	12.10%
Fidelity Advisor Strategic Income Fund - Class A \| AAHighYieldDebtMember
Holdings [Line Items]
Percent of Net Asset Value	40.80%
Fidelity Advisor Strategic Income Fund - Class A \| AAUSGovernmentInvestmentGradeDebtMember
Holdings [Line Items]
Percent of Net Asset Value	30.20%
Fidelity Advisor Strategic Income Fund - Class A \| AAEmergingMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity Advisor Strategic Income Fund - Class A \| AAForeignDevelopedMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Strategic Income Fund - Class A \| AAFloatingRatedebtMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Strategic Income Fund - Class A \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class I \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Strategic Income Fund - Class I \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class I \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class I \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Strategic Income Fund - Class I \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class I \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class I \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class I \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class I \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class I \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class I \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	24.60%
Fidelity Advisor Strategic Income Fund - Class I \| QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Strategic Income Fund - Class I \| QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Strategic Income Fund - Class I \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Strategic Income Fund - Class I \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Strategic Income Fund - Class I \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Advisor Strategic Income Fund - Class I \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	17.20%
Fidelity Advisor Strategic Income Fund - Class I \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class I \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class I \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	8.60%
Fidelity Advisor Strategic Income Fund - Class I \| QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Advisor Strategic Income Fund - Class I \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Strategic Income Fund - Class I \| United States
Holdings [Line Items]
Percent of Net Asset Value	74.40%
Fidelity Advisor Strategic Income Fund - Class I \| Germany
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity Advisor Strategic Income Fund - Class I \| Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Strategic Income Fund - Class I \| Brazil
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Strategic Income Fund - Class I \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class I \| Canada
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Strategic Income Fund - Class I \| France
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class I \| Saudi Arabia
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class I \| United Arab Emirates
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class I \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	12.10%
Fidelity Advisor Strategic Income Fund - Class I \| AAHighYieldDebtMember
Holdings [Line Items]
Percent of Net Asset Value	40.80%
Fidelity Advisor Strategic Income Fund - Class I \| AAUSGovernmentInvestmentGradeDebtMember
Holdings [Line Items]
Percent of Net Asset Value	30.20%
Fidelity Advisor Strategic Income Fund - Class I \| AAEmergingMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity Advisor Strategic Income Fund - Class I \| AAForeignDevelopedMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Strategic Income Fund - Class I \| AAFloatingRatedebtMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Strategic Income Fund - Class I \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class Z \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Strategic Income Fund - Class Z \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class Z \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class Z \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Strategic Income Fund - Class Z \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class Z \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class Z \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class Z \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class Z \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class Z \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class Z \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	24.60%
Fidelity Advisor Strategic Income Fund - Class Z \| QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Strategic Income Fund - Class Z \| QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Strategic Income Fund - Class Z \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Strategic Income Fund - Class Z \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Strategic Income Fund - Class Z \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Advisor Strategic Income Fund - Class Z \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	17.20%
Fidelity Advisor Strategic Income Fund - Class Z \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class Z \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class Z \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	8.60%
Fidelity Advisor Strategic Income Fund - Class Z \| QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Advisor Strategic Income Fund - Class Z \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Strategic Income Fund - Class Z \| United States
Holdings [Line Items]
Percent of Net Asset Value	74.40%
Fidelity Advisor Strategic Income Fund - Class Z \| Germany
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity Advisor Strategic Income Fund - Class Z \| Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Strategic Income Fund - Class Z \| Brazil
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Strategic Income Fund - Class Z \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class Z \| Canada
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Strategic Income Fund - Class Z \| France
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class Z \| Saudi Arabia
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class Z \| United Arab Emirates
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class Z \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	12.10%
Fidelity Advisor Strategic Income Fund - Class Z \| AAHighYieldDebtMember
Holdings [Line Items]
Percent of Net Asset Value	40.80%
Fidelity Advisor Strategic Income Fund - Class Z \| AAUSGovernmentInvestmentGradeDebtMember
Holdings [Line Items]
Percent of Net Asset Value	30.20%
Fidelity Advisor Strategic Income Fund - Class Z \| AAEmergingMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity Advisor Strategic Income Fund - Class Z \| AAForeignDevelopedMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Strategic Income Fund - Class Z \| AAFloatingRatedebtMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Strategic Income Fund - Class Z \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class C \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Strategic Income Fund - Class C \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class C \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class C \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Strategic Income Fund - Class C \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class C \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class C \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class C \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class C \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class C \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class C \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	24.60%
Fidelity Advisor Strategic Income Fund - Class C \| QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Strategic Income Fund - Class C \| QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Strategic Income Fund - Class C \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Strategic Income Fund - Class C \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Strategic Income Fund - Class C \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Advisor Strategic Income Fund - Class C \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	17.20%
Fidelity Advisor Strategic Income Fund - Class C \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class C \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class C \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	8.60%
Fidelity Advisor Strategic Income Fund - Class C \| QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Advisor Strategic Income Fund - Class C \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Strategic Income Fund - Class C \| United States
Holdings [Line Items]
Percent of Net Asset Value	74.40%
Fidelity Advisor Strategic Income Fund - Class C \| Germany
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity Advisor Strategic Income Fund - Class C \| Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Strategic Income Fund - Class C \| Brazil
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Strategic Income Fund - Class C \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class C \| Canada
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Strategic Income Fund - Class C \| France
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class C \| Saudi Arabia
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class C \| United Arab Emirates
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class C \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	12.10%
Fidelity Advisor Strategic Income Fund - Class C \| AAHighYieldDebtMember
Holdings [Line Items]
Percent of Net Asset Value	40.80%
Fidelity Advisor Strategic Income Fund - Class C \| AAUSGovernmentInvestmentGradeDebtMember
Holdings [Line Items]
Percent of Net Asset Value	30.20%
Fidelity Advisor Strategic Income Fund - Class C \| AAEmergingMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity Advisor Strategic Income Fund - Class C \| AAForeignDevelopedMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Strategic Income Fund - Class C \| AAFloatingRatedebtMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Strategic Income Fund - Class C \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class M \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Strategic Income Fund - Class M \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class M \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class M \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Strategic Income Fund - Class M \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class M \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class M \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class M \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Strategic Income Fund - Class M \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class M \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Strategic Income Fund - Class M \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	24.60%
Fidelity Advisor Strategic Income Fund - Class M \| QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Strategic Income Fund - Class M \| QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Strategic Income Fund - Class M \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Strategic Income Fund - Class M \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Strategic Income Fund - Class M \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Advisor Strategic Income Fund - Class M \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	17.20%
Fidelity Advisor Strategic Income Fund - Class M \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Strategic Income Fund - Class M \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Strategic Income Fund - Class M \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	8.60%
Fidelity Advisor Strategic Income Fund - Class M \| QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Advisor Strategic Income Fund - Class M \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Strategic Income Fund - Class M \| United States
Holdings [Line Items]
Percent of Net Asset Value	74.40%
Fidelity Advisor Strategic Income Fund - Class M \| Germany
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity Advisor Strategic Income Fund - Class M \| Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Strategic Income Fund - Class M \| Brazil
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Strategic Income Fund - Class M \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Strategic Income Fund - Class M \| Canada
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Strategic Income Fund - Class M \| France
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class M \| Saudi Arabia
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Strategic Income Fund - Class M \| United Arab Emirates
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Strategic Income Fund - Class M \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	12.10%
Fidelity Advisor Strategic Income Fund - Class M \| AAHighYieldDebtMember
Holdings [Line Items]
Percent of Net Asset Value	40.80%
Fidelity Advisor Strategic Income Fund - Class M \| AAUSGovernmentInvestmentGradeDebtMember
Holdings [Line Items]
Percent of Net Asset Value	30.20%
Fidelity Advisor Strategic Income Fund - Class M \| AAEmergingMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity Advisor Strategic Income Fund - Class M \| AAForeignDevelopedMarketsDebtMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Strategic Income Fund - Class M \| AAFloatingRatedebtMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Strategic Income Fund - Class M \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0%