Fidelity Limited Term Bond Fund (FJRLX) N-CSR 23 Oct 24 Certified annual shareholder report (management investment company) Financial data

Form N-CSR Cover

Form N-CSR Cover	12 Months Ended
	Aug. 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	Aug. 31, 2024

Shareholder Report

Shareholder Report	12 Months Ended
	Aug. 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	Aug. 31, 2024
Fidelity Advisor Mortgage Securities Fund - Class A
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Mortgage Securities Fund
Class Name	Fidelity Advisor® Mortgage Securities Fund Class A
Trading Symbol	FMGAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Mortgage Securities Fund for the period September 1, 2023 to August 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 $ 0.81 %
Expenses Paid, Amount	$ 84
Expense Ratio, Percent	0.81%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B26">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class A   $9,600 $9,832   $10,175   $10,231   $10,116   $10,797   $11,281   $11,251   $10,079   $9,789   $10,496   Bloomberg U.S. MBS Index   $10,000 $10,266   $10,670   $10,756   $10,698   $11,454   $11,974   $11,953   $10,790   $10,564   $11,352   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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)   2.94% -1.37% 0.49% Class A (without 4.00% sales charge) 7.23% -0.56% 0.90% Bloomberg U.S. MBS Index 7.46% -0.18% 1.28% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 608,638,893
Holdings Count | shares	1,455
Advisory Fees Paid, Amount	$ 1,455,960
Investment Company Portfolio Turnover	767%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,455 Total Advisory Fee $ Portfolio Turnover 767 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 107.0 AAA 8.8 AA 0.5 A 0.1 BBB 0.0 CCC,CC,C 0.0 Not Rated 7.5 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (23.9)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Government Agency - Mortgage Securities 101.3 CMOs and Other Mortgage Related Securities 13.2 U.S. Treasury Obligations 5.7 Asset-Backed Securities 3.3 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (23.9)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 31.5     Ginnie Mae II Pool 25.7     Uniform Mortgage Backed Securities 20.8     Freddie Mac Gold Pool 19.1     US Treasury Notes 3.3     Ginnie Mae I Pool 3.1     US Treasury Bonds 2.4     Freddie Mac Multiclass Mortgage participation certificates 2.3     Fannie Mae Guaranteed REMICS 2.2     Freddie Mac Non Gold Pool 1.1       111.5
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's contractual management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractual management fee was reduced during the reporting period.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B40">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B41">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B42">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Limited Term Securitized Completion Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Limited Term Securitized Completion Fund
Class Name	Fidelity® Limited Term Securitized Completion Fund
Trading Symbol	FLTGX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Limited Term Securitized Completion Fund for the period May 30, 2024 to August 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.
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® Limited Term Securitized Completion Fund A $ B 0.00 % C A Expenses for the full reporting period would be higher. B Amount represents less than $.50 C Amount represents less than 0.005%
Expenses Paid, Amount	$ 0
Expense Ratio, Percent	0%
Expenses Short Period Footnote [Text Block]	Expenses for the full reporting period would be higher.
Average Annual Return [Table Text Block]
Net Assets	$ 10,384,570
Holdings Count | shares	89
Advisory Fees Paid, Amount	$ 0
Investment Company Portfolio Turnover	182%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 89 Total Advisory Fee $ Portfolio Turnover A 182 % A Amount not annualized
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 19.5 AAA 69.5 AA 1.1 Not Rated 14.7 QUALITY DIVERSIFICATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (5.0)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Asset-Backed Securities 48.6 CMOs and Other Mortgage Related Securities 36.7 U.S. Government Agency - Mortgage Securities 18.7 U.S. Treasury Obligations 0.8 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (5.0)% United States 98.3 Canada 1.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 10.5     Freddie Mac Multiclass Mortgage participation certificates 9.0     Uniform Mortgage Backed Securities 5.1     DLLAD 4.0     Kubota Credit Owner Trust 3.9     Ford Credit Floorplan Master Owner Trust A 3.9     Verizon Master Trust 3.9     Freddie Mac Gold Pool 3.1     Gs Mtg Secs Tr 2018-Gs10 3.1     Bank of America Credit Card Master Trust 3.0       49.5
Fidelity Mortgage Securities Fund
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Mortgage Securities Fund
Class Name	Fidelity® Mortgage Securities Fund
Trading Symbol	FMSFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Mortgage Securities Fund for the period September 1, 2023 to August 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® Mortgage Securities Fund $ 0.45 %
Expenses Paid, Amount	$ 47
Expense Ratio, Percent	0.45%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B82">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000. Fidelity® Mortgage Securities Fund   $10,000 $10,268   $10,672   $10,768   $10,675   $11,442   $11,995   $12,008   $10,797   $10,515   $11,324   Bloomberg U.S. MBS Index   $10,000 $10,266   $10,670   $10,756   $10,698   $11,454   $11,974   $11,953   $10,790   $10,564   $11,352   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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 Fidelity® Mortgage Securities Fund 7.70% -0.21% 1.25% Bloomberg U.S. MBS Index 7.46% -0.18% 1.28% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   Visit www.fidelity.com for more recent performance information.   The Fund's past performance is not a good predictor of the Fund's future performance.  The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 608,638,893
Holdings Count | shares	1,455
Advisory Fees Paid, Amount	$ 1,455,960
Investment Company Portfolio Turnover	767%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,455 Total Advisory Fee $ Portfolio Turnover 767 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 107.0 AAA 8.8 AA 0.5 A 0.1 BBB 0.0 CCC,CC,C 0.0 Not Rated 7.5 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (23.9)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Government Agency - Mortgage Securities 101.3 CMOs and Other Mortgage Related Securities 13.2 U.S. Treasury Obligations 5.7 Asset-Backed Securities 3.3 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (23.9)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 31.5     Ginnie Mae II Pool 25.7     Uniform Mortgage Backed Securities 20.8     Freddie Mac Gold Pool 19.1     US Treasury Notes 3.3     Ginnie Mae I Pool 3.1     US Treasury Bonds 2.4     Freddie Mac Multiclass Mortgage participation certificates 2.3     Fannie Mae Guaranteed REMICS 2.2     Freddie Mac Non Gold Pool 1.1       111.5
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's contractual management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractual management fee was reduced during the reporting period.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-800-544-8544</span>" id="sjs-B96">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-800-544-8544&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B97">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B98">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Limited Term Bond Fund - Class M
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Limited Term Bond Fund
Class Name	Fidelity Advisor® Limited Term Bond Fund Class M
Trading Symbol	FTBRX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Limited Term Bond Fund for the period September 1, 2023 to August 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 $ 0.60 %
Expenses Paid, Amount	$ 62
Expense Ratio, Percent	0.60%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B115">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class M   $9,725 $9,766   $10,043   $10,152   $10,100   $10,687   $11,165   $11,209   $10,453   $10,678   $11,466   Fidelity Limited Term Composite Index℠   $10,000 $10,112   $10,423   $10,582   $10,568   $11,244   $11,810   $11,920   $11,202   $11,405   $12,263   Bloomberg U.S. 1-5 Year Government/Credit Bond Index   $10,000 $10,127   $10,368   $10,464   $10,419   $11,040   $11,562   $11,599   $10,922   $11,051   $11,788   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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. 2.75% sales charge)   4.43% 0.85% 1.38% Class M (without 2.75% sales charge) 7.39% 1.42% 1.66% Fidelity Limited Term Composite Index℠ 7.52% 1.75% 2.06% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 6.67% 1.32% 1.66% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 2,043,654,532
Holdings Count | shares	778
Advisory Fees Paid, Amount	$ 4,283,907
Investment Company Portfolio Turnover	65%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 778 Total Advisory Fee $ Portfolio Turnover 65 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 8.4 AAA 9.9 AA 1.1 A 25.7 BBB 38.9 BB 5.6 B 4.1 CCC,CC,C 0.4 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 1.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Corporate Bonds 70.3 Asset-Backed Securities 9.0 CMOs and Other Mortgage Related Securities 8.5 U.S. Treasury Obligations 8.2 Bank Loan Obligations 1.4 Other Investments 0.5 U.S. Government Agency - Mortgage Securities 0.2 Foreign Government and Government Agency Obligations 0.2 Preferred Securities 0.1 Short-Term Investments and Net Other Assets (Liabilities) 1.6 ASSET ALLOCATION (% of Fund's net assets)   United States 72.9 United Kingdom 4.9 Germany 3.7 Grand Cayman (UK Overseas Ter) 3.6 Canada 2.5 Japan 2.2 France 2.0 Netherlands 2.0 Ireland 1.7 Others 4.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 8.2     Bank of America Corp 2.8     JPMorgan Chase & Co 2.2     Wells Fargo & Co 1.7     General Motors Financial Co Inc 1.4     Morgan Stanley 1.3     Barclays PLC 1.3     Citigroup Inc 1.3     BAT International Finance PLC 1.2     Ford Motor Credit Co LLC 1.2       22.6
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses
Material Fund Change Strategies [Text Block]	The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B130">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B131">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B132">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Mortgage Securities Fund - Class M
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Mortgage Securities Fund
Class Name	Fidelity Advisor® Mortgage Securities Fund Class M
Trading Symbol	FMSAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Mortgage Securities Fund for the period September 1, 2023 to August 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 $ 0.81 %
Expenses Paid, Amount	$ 83
Expense Ratio, Percent	0.81%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B149">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class M   $9,600 $9,824   $10,166   $10,222   $10,107   $10,795   $11,268   $11,247   $10,069   $9,781   $10,488   Bloomberg U.S. MBS Index   $10,000 $10,266   $10,670   $10,756   $10,698   $11,454   $11,974   $11,953   $10,790   $10,564   $11,352   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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)   2.93% -1.38% 0.48% Class M (without 4.00% sales charge) 7.22% -0.58% 0.89% Bloomberg U.S. MBS Index 7.46% -0.18% 1.28% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 608,638,893
Holdings Count | shares	1,455
Advisory Fees Paid, Amount	$ 1,455,960
Investment Company Portfolio Turnover	767%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,455 Total Advisory Fee $ Portfolio Turnover 767 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 107.0 AAA 8.8 AA 0.5 A 0.1 BBB 0.0 CCC,CC,C 0.0 Not Rated 7.5 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (23.9)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Government Agency - Mortgage Securities 101.3 CMOs and Other Mortgage Related Securities 13.2 U.S. Treasury Obligations 5.7 Asset-Backed Securities 3.3 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (23.9)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 31.5     Ginnie Mae II Pool 25.7     Uniform Mortgage Backed Securities 20.8     Freddie Mac Gold Pool 19.1     US Treasury Notes 3.3     Ginnie Mae I Pool 3.1     US Treasury Bonds 2.4     Freddie Mac Multiclass Mortgage participation certificates 2.3     Fannie Mae Guaranteed REMICS 2.2     Freddie Mac Non Gold Pool 1.1       111.5
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's contractual management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractual management fee was reduced during the reporting period.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B163">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B164">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B165">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Limited Term Bond Fund - Class A
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Limited Term Bond Fund
Class Name	Fidelity Advisor® Limited Term Bond Fund Class A
Trading Symbol	FDIAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Limited Term Bond Fund for the period September 1, 2023 to August 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 $ 0.60 %
Expenses Paid, Amount	$ 63
Expense Ratio, Percent	0.60%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B182">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class A   $9,725 $9,775   $10,043   $10,162   $10,111   $10,691   $11,179   $11,223   $10,466   $10,682   $11,481   Fidelity Limited Term Composite Index℠   $10,000 $10,112   $10,423   $10,582   $10,568   $11,244   $11,810   $11,920   $11,202   $11,405   $12,263   Bloomberg U.S. 1-5 Year Government/Credit Bond Index   $10,000 $10,127   $10,368   $10,464   $10,419   $11,040   $11,562   $11,599   $10,922   $11,051   $11,788   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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. 2.75% sales charge)   4.53% 0.87% 1.39% Class A (without 2.75% sales charge) 7.48% 1.44% 1.67% Fidelity Limited Term Composite Index℠ 7.52% 1.75% 2.06% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 6.67% 1.32% 1.66% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 2,043,654,532
Holdings Count | shares	778
Advisory Fees Paid, Amount	$ 4,283,907
Investment Company Portfolio Turnover	65%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 778 Total Advisory Fee $ Portfolio Turnover 65 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 8.4 AAA 9.9 AA 1.1 A 25.7 BBB 38.9 BB 5.6 B 4.1 CCC,CC,C 0.4 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 1.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Corporate Bonds 70.3 Asset-Backed Securities 9.0 CMOs and Other Mortgage Related Securities 8.5 U.S. Treasury Obligations 8.2 Bank Loan Obligations 1.4 Other Investments 0.5 U.S. Government Agency - Mortgage Securities 0.2 Foreign Government and Government Agency Obligations 0.2 Preferred Securities 0.1 Short-Term Investments and Net Other Assets (Liabilities) 1.6 ASSET ALLOCATION (% of Fund's net assets)   United States 72.9 United Kingdom 4.9 Germany 3.7 Grand Cayman (UK Overseas Ter) 3.6 Canada 2.5 Japan 2.2 France 2.0 Netherlands 2.0 Ireland 1.7 Others 4.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 8.2     Bank of America Corp 2.8     JPMorgan Chase & Co 2.2     Wells Fargo & Co 1.7     General Motors Financial Co Inc 1.4     Morgan Stanley 1.3     Barclays PLC 1.3     Citigroup Inc 1.3     BAT International Finance PLC 1.2     Ford Motor Credit Co LLC 1.2       22.6
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses
Material Fund Change Strategies [Text Block]	The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B197">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B198">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B199">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Series Investment Grade Securitized Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Series Investment Grade Securitized Fund
Class Name	Fidelity® Series Investment Grade Securitized Fund
Trading Symbol	FHPFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Series Investment Grade Securitized Fund for the period September 1, 2023 to August 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.
Additional Information Phone Number	1-800-544-8544
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last year? (based on hypothetical $10,000 investment) FUND COST (PREVIOUS YEAR) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Series Investment Grade Securitized Fund $ A 0.00 % B A Amount represents less than $.50 B Amount represents less than 0.005%
Expenses Paid, Amount	$ 0
Expense Ratio, Percent	0%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B214">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the life of Fund?      CUMULATIVE PERFORMANCE August 17, 2018 through August 31, 2024. Initial investment of $10,000. Fidelity® Series Investment Grade Securitized Fund   $10,000 $10,008   $10,791   $11,361   $11,397   $10,270   $10,093   Bloomberg U.S. Securitized Index   $10,000 $10,016   $10,745   $11,241   $11,237   $10,145   $9,947   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,014   $11,033   $11,747   $11,737   $10,386   $10,262     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® Series Investment Grade Securitized Fund 8.25% 0.25% 1.48% Bloomberg U.S. Securitized Index 7.55% -0.09% 1.12% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.61% A   From August 17, 2018   Visit www.fidelity.com for more recent performance information.   The Fund's past performance is not a good predictor of the Fund's future performance.  The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Performance Inception Date	Aug. 17, 2018
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 586,398,251
Holdings Count | shares	1,059
Advisory Fees Paid, Amount	$ 0
Investment Company Portfolio Turnover	721%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,059 Total Advisory Fee $ Portfolio Turnover 721 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 98.4 AAA 14.2 AA 0.4 A 0.1 Not Rated 14.2 QUALITY DIVERSIFICATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (27.3)%   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.     U.S. Government Agency - Mortgage Securities 94.6 CMOs and Other Mortgage Related Securities 22.6 Asset-Backed Securities 5.9 U.S. Treasury Obligations 3.8 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (27.3)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 33.5     Ginnie Mae II Pool 25.1     Freddie Mac Gold Pool 20.5     Uniform Mortgage Backed Securities 12.0     Freddie Mac Multiclass Mortgage participation certificates 7.7     US Treasury Bonds 2.5     Ginnie Mae I Pool 2.5     Fannie Mae Guaranteed REMICS 2.1     US Treasury Notes 1.3     Freddie Mac Non Gold Pool 1.0       108.2
Fidelity Advisor Mortgage Securities Fund - Class Z
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Mortgage Securities Fund
Class Name	Fidelity Advisor® Mortgage Securities Fund Class Z
Trading Symbol	FIKUX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Mortgage Securities Fund for the period September 1, 2023 to August 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 $ 0.36 %
Expenses Paid, Amount	$ 37
Expense Ratio, Percent	0.36%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B242">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the life of Fund?      CUMULATIVE PERFORMANCE October 2, 2018 through August 31, 2024. Initial investment of $10,000. Class Z   $10,000 $10,782   $11,305   $11,333   $10,196   $9,948   $10,713   Bloomberg U.S. MBS Index   $10,000 $10,771   $11,260   $11,240   $10,146   $9,934   $10,675   Bloomberg U.S. Aggregate Bond Index   $10,000 $11,086   $11,804   $11,794   $10,436   $10,311   $11,064     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 7.70% -0.13% 1.17% Bloomberg U.S. MBS Index 7.46% -0.18% 1.11% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.72% 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	$ 608,638,893
Holdings Count | shares	1,455
Advisory Fees Paid, Amount	$ 1,455,960
Investment Company Portfolio Turnover	767%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,455 Total Advisory Fee $ Portfolio Turnover 767 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 107.0 AAA 8.8 AA 0.5 A 0.1 BBB 0.0 CCC,CC,C 0.0 Not Rated 7.5 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (23.9)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Government Agency - Mortgage Securities 101.3 CMOs and Other Mortgage Related Securities 13.2 U.S. Treasury Obligations 5.7 Asset-Backed Securities 3.3 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (23.9)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 31.5     Ginnie Mae II Pool 25.7     Uniform Mortgage Backed Securities 20.8     Freddie Mac Gold Pool 19.1     US Treasury Notes 3.3     Ginnie Mae I Pool 3.1     US Treasury Bonds 2.4     Freddie Mac Multiclass Mortgage participation certificates 2.3     Fannie Mae Guaranteed REMICS 2.2     Freddie Mac Non Gold Pool 1.1       111.5
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's contractual management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractual management fee was reduced during the reporting period.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B257">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B258">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B259">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Limited Term Bond Fund
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Limited Term Bond Fund
Class Name	Fidelity® Limited Term Bond Fund
Trading Symbol	FJRLX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Limited Term Bond Fund for the period September 1, 2023 to August 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® Limited Term Bond Fund $ 0.30 %
Expenses Paid, Amount	$ 31
Expense Ratio, Percent	0.30%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B276">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000. Fidelity® Limited Term Bond Fund   $10,000 $10,083   $10,391   $10,537   $10,526   $11,162   $11,706   $11,788   $11,028   $11,290   $12,170   Fidelity Limited Term Composite Index℠   $10,000 $10,112   $10,423   $10,582   $10,568   $11,244   $11,810   $11,920   $11,202   $11,405   $12,263   Bloomberg U.S. 1-5 Year Government/Credit Bond Index   $10,000 $10,127   $10,368   $10,464   $10,419   $11,040   $11,562   $11,599   $10,922   $11,051   $11,788   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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 Fidelity® Limited Term Bond Fund 7.80% 1.74% 1.98% Fidelity Limited Term Composite Index℠ 7.52% 1.75% 2.06% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 6.67% 1.32% 1.66% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   Visit www.fidelity.com for more recent performance information.   The Fund's past performance is not a good predictor of the Fund's future performance.  The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 2,043,654,532
Holdings Count | shares	778
Advisory Fees Paid, Amount	$ 4,283,907
Investment Company Portfolio Turnover	65%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 778 Total Advisory Fee $ Portfolio Turnover 65 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 8.4 AAA 9.9 AA 1.1 A 25.7 BBB 38.9 BB 5.6 B 4.1 CCC,CC,C 0.4 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 1.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Corporate Bonds 70.3 Asset-Backed Securities 9.0 CMOs and Other Mortgage Related Securities 8.5 U.S. Treasury Obligations 8.2 Bank Loan Obligations 1.4 Other Investments 0.5 U.S. Government Agency - Mortgage Securities 0.2 Foreign Government and Government Agency Obligations 0.2 Preferred Securities 0.1 Short-Term Investments and Net Other Assets (Liabilities) 1.6 ASSET ALLOCATION (% of Fund's net assets)   United States 72.9 United Kingdom 4.9 Germany 3.7 Grand Cayman (UK Overseas Ter) 3.6 Canada 2.5 Japan 2.2 France 2.0 Netherlands 2.0 Ireland 1.7 Others 4.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 8.2     Bank of America Corp 2.8     JPMorgan Chase & Co 2.2     Wells Fargo & Co 1.7     General Motors Financial Co Inc 1.4     Morgan Stanley 1.3     Barclays PLC 1.3     Citigroup Inc 1.3     BAT International Finance PLC 1.2     Ford Motor Credit Co LLC 1.2       22.6
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses
Material Fund Change Strategies [Text Block]	The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-800-544-8544 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-800-544-8544</span>" id="sjs-B291">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-800-544-8544&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B292">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B293">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Mortgage Securities Fund - Class C
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Mortgage Securities Fund
Class Name	Fidelity Advisor® Mortgage Securities Fund Class C
Trading Symbol	FOMCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Mortgage Securities Fund for the period September 1, 2023 to August 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 $ 1.60 %
Expenses Paid, Amount	$ 165
Expense Ratio, Percent	1.60%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B310">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000. Class C   $10,000 $10,159   $10,436   $10,416   $10,222   $10,839   $11,228   $11,121   $9,875   $9,591   $10,284   Bloomberg U.S. MBS Index   $10,000 $10,266   $10,670   $10,756   $10,698   $11,454   $11,974   $11,953   $10,790   $10,564   $11,352   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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) 5.42% -1.34% 0.28% Class C 6.42% -1.34% 0.28% Bloomberg U.S. MBS Index 7.46% -0.18% 1.28% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 608,638,893
Holdings Count | shares	1,455
Advisory Fees Paid, Amount	$ 1,455,960
Investment Company Portfolio Turnover	767%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,455 Total Advisory Fee $ Portfolio Turnover 767 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 107.0 AAA 8.8 AA 0.5 A 0.1 BBB 0.0 CCC,CC,C 0.0 Not Rated 7.5 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (23.9)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Government Agency - Mortgage Securities 101.3 CMOs and Other Mortgage Related Securities 13.2 U.S. Treasury Obligations 5.7 Asset-Backed Securities 3.3 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (23.9)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 31.5     Ginnie Mae II Pool 25.7     Uniform Mortgage Backed Securities 20.8     Freddie Mac Gold Pool 19.1     US Treasury Notes 3.3     Ginnie Mae I Pool 3.1     US Treasury Bonds 2.4     Freddie Mac Multiclass Mortgage participation certificates 2.3     Fannie Mae Guaranteed REMICS 2.2     Freddie Mac Non Gold Pool 1.1       111.5
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fund's contractual management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractual management fee was reduced during the reporting period.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B324">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B325">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B326">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Mortgage Securities Fund - Class I
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Mortgage Securities Fund
Class Name	Fidelity Advisor® Mortgage Securities Fund Class I
Trading Symbol	FMSCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Mortgage Securities Fund for the period September 1, 2023 to August 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 $ 0.58 %
Expenses Paid, Amount	$ 60
Expense Ratio, Percent	0.58%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B343">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000. Class I   $10,000 $10,264   $10,662   $10,744   $10,654   $11,418   $11,957   $11,976   $10,757   $10,467   $11,265   Bloomberg U.S. MBS Index   $10,000 $10,266   $10,670   $10,756   $10,698   $11,454   $11,974   $11,953   $10,790   $10,564   $11,352   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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 7.62% -0.27% 1.20% Bloomberg U.S. MBS Index 7.46% -0.18% 1.28% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 608,638,893
Holdings Count | shares	1,455
Advisory Fees Paid, Amount	$ 1,455,960
Investment Company Portfolio Turnover	767%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 1,455 Total Advisory Fee $ Portfolio Turnover 767 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 107.0 AAA 8.8 AA 0.5 A 0.1 BBB 0.0 CCC,CC,C 0.0 Not Rated 7.5 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (23.9)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Government Agency - Mortgage Securities 101.3 CMOs and Other Mortgage Related Securities 13.2 U.S. Treasury Obligations 5.7 Asset-Backed Securities 3.3 Purchased Swaptions 0.4 ASSET ALLOCATION (% of Fund's net assets) Short-Term Investments and Net Other Assets (Liabilities) - (23.9)% United States 99.9 Canada 0.1 United Kingdom 0.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     Fannie Mae Mortgage pass-thru certificates 31.5     Ginnie Mae II Pool 25.7     Uniform Mortgage Backed Securities 20.8     Freddie Mac Gold Pool 19.1     US Treasury Notes 3.3     Ginnie Mae I Pool 3.1     US Treasury Bonds 2.4     Freddie Mac Multiclass Mortgage participation certificates 2.3     Fannie Mae Guaranteed REMICS 2.2     Freddie Mac Non Gold Pool 1.1       111.5
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fund's contractual management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fund's contractual management fee was reduced during the reporting period.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B357">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B358">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B359">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Limited Term Bond Fund - Class Z
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Limited Term Bond Fund
Class Name	Fidelity Advisor® Limited Term Bond Fund Class Z
Trading Symbol	FIKRX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Limited Term Bond Fund for the period September 1, 2023 to August 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 $ 0.25 %
Expenses Paid, Amount	$ 26
Expense Ratio, Percent	0.25%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B376">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the life of Fund?      CUMULATIVE PERFORMANCE October 2, 2018 through August 31, 2024. Initial investment of $10,000. Class Z   $10,000 $10,618   $11,145   $11,234   $10,519   $10,776   $11,622   Fidelity Limited Term Composite Index℠   $10,000 $10,650   $11,185   $11,290   $10,610   $10,802   $11,615   Bloomberg U.S. 1-5 Year Government/Credit Bond Index   $10,000 $10,616   $11,117   $11,153   $10,502   $10,626   $11,335   Bloomberg U.S. Aggregate Bond Index   $10,000 $11,086   $11,804   $11,794   $10,436   $10,311   $11,064     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 7.85% 1.82% 2.57% Fidelity Limited Term Composite Index℠ 7.52% 1.75% 2.56% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 6.67% 1.32% 2.14% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.72% 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	$ 2,043,654,532
Holdings Count | shares	778
Advisory Fees Paid, Amount	$ 4,283,907
Investment Company Portfolio Turnover	65%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 778 Total Advisory Fee $ Portfolio Turnover 65 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 8.4 AAA 9.9 AA 1.1 A 25.7 BBB 38.9 BB 5.6 B 4.1 CCC,CC,C 0.4 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 1.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Corporate Bonds 70.3 Asset-Backed Securities 9.0 CMOs and Other Mortgage Related Securities 8.5 U.S. Treasury Obligations 8.2 Bank Loan Obligations 1.4 Other Investments 0.5 U.S. Government Agency - Mortgage Securities 0.2 Foreign Government and Government Agency Obligations 0.2 Preferred Securities 0.1 Short-Term Investments and Net Other Assets (Liabilities) 1.6 ASSET ALLOCATION (% of Fund's net assets)   United States 72.9 United Kingdom 4.9 Germany 3.7 Grand Cayman (UK Overseas Ter) 3.6 Canada 2.5 Japan 2.2 France 2.0 Netherlands 2.0 Ireland 1.7 Others 4.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 8.2     Bank of America Corp 2.8     JPMorgan Chase & Co 2.2     Wells Fargo & Co 1.7     General Motors Financial Co Inc 1.4     Morgan Stanley 1.3     Barclays PLC 1.3     Citigroup Inc 1.3     BAT International Finance PLC 1.2     Ford Motor Credit Co LLC 1.2       22.6
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The class' contractual expense cap was removed during the reporting period. The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The class' contractual expense cap was removed during the reporting period. The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The class' contractual expense cap was removed during the reporting period. The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The class' contractual expense cap was removed during the reporting period.
Material Fund Change Strategies [Text Block]	The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B392">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B393">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B394">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Limited Term Bond Fund - Class I
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Limited Term Bond Fund
Class Name	Fidelity Advisor® Limited Term Bond Fund Class I
Trading Symbol	EFIPX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Limited Term Bond Fund for the period September 1, 2023 to August 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 $ 0.30 %
Expenses Paid, Amount	$ 31
Expense Ratio, Percent	0.30%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B411">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000. Class I   $10,000 $10,078   $10,390   $10,531   $10,506   $11,136   $11,673   $11,749   $10,986   $11,244   $12,120   Fidelity Limited Term Composite Index℠   $10,000 $10,112   $10,423   $10,582   $10,568   $11,244   $11,810   $11,920   $11,202   $11,405   $12,263   Bloomberg U.S. 1-5 Year Government/Credit Bond Index   $10,000 $10,127   $10,368   $10,464   $10,419   $11,040   $11,562   $11,599   $10,922   $11,051   $11,788   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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 7.80% 1.71% 1.94% Fidelity Limited Term Composite Index℠ 7.52% 1.75% 2.06% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 6.67% 1.32% 1.66% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 2,043,654,532
Holdings Count | shares	778
Advisory Fees Paid, Amount	$ 4,283,907
Investment Company Portfolio Turnover	65%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 778 Total Advisory Fee $ Portfolio Turnover 65 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 8.4 AAA 9.9 AA 1.1 A 25.7 BBB 38.9 BB 5.6 B 4.1 CCC,CC,C 0.4 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 1.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Corporate Bonds 70.3 Asset-Backed Securities 9.0 CMOs and Other Mortgage Related Securities 8.5 U.S. Treasury Obligations 8.2 Bank Loan Obligations 1.4 Other Investments 0.5 U.S. Government Agency - Mortgage Securities 0.2 Foreign Government and Government Agency Obligations 0.2 Preferred Securities 0.1 Short-Term Investments and Net Other Assets (Liabilities) 1.6 ASSET ALLOCATION (% of Fund's net assets)   United States 72.9 United Kingdom 4.9 Germany 3.7 Grand Cayman (UK Overseas Ter) 3.6 Canada 2.5 Japan 2.2 France 2.0 Netherlands 2.0 Ireland 1.7 Others 4.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 8.2     Bank of America Corp 2.8     JPMorgan Chase & Co 2.2     Wells Fargo & Co 1.7     General Motors Financial Co Inc 1.4     Morgan Stanley 1.3     Barclays PLC 1.3     Citigroup Inc 1.3     BAT International Finance PLC 1.2     Ford Motor Credit Co LLC 1.2       22.6
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses • Expense reductions
Material Fund Change Strategies [Text Block]	The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B426">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B427">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B428">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/span>
Fidelity Advisor Limited Term Bond Fund - Class C
Shareholder Report [Line Items]
Fund Name	Fidelity Advisor® Limited Term Bond Fund
Class Name	Fidelity Advisor® Limited Term Bond Fund Class C
Trading Symbol	FNBCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity Advisor® Limited Term Bond Fund for the period September 1, 2023 to August 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 $ 1.37 %
Expenses Paid, Amount	$ 142
Expense Ratio, Percent	1.37%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • •
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B445">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">The Fund's past performance is not a good predictor of the Fund's future performance.&lt;/span>
Line Graph [Table Text Block]	How did the Fund perform over the past 10 years?      CUMULATIVE PERFORMANCE August 31, 2014 through August 31, 2024. Initial investment of $10,000. Class C   $10,000 $9,965   $10,169   $10,201   $10,071   $10,575   $10,962   $10,920   $10,103   $10,311   $11,082   Fidelity Limited Term Composite Index℠   $10,000 $10,112   $10,423   $10,582   $10,568   $11,244   $11,810   $11,920   $11,202   $11,405   $12,263   Bloomberg U.S. 1-5 Year Government/Credit Bond Index   $10,000 $10,127   $10,368   $10,464   $10,419   $11,040   $11,562   $11,599   $10,922   $11,051   $11,788   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,156   $10,761   $10,814   $10,701   $11,789   $12,553   $12,542   $11,098   $10,965   $11,765     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) 5.67% 0.63% 1.03% Class C 6.67% 0.63% 1.03% Fidelity Limited Term Composite Index℠ 7.52% 1.75% 2.06% Bloomberg U.S. 1-5 Year Government/Credit Bond Index 6.67% 1.32% 1.66% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.64%   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	$ 2,043,654,532
Holdings Count | shares	778
Advisory Fees Paid, Amount	$ 4,283,907
Investment Company Portfolio Turnover	65%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 778 Total Advisory Fee $ Portfolio Turnover 65 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 8.4 AAA 9.9 AA 1.1 A 25.7 BBB 38.9 BB 5.6 B 4.1 CCC,CC,C 0.4 Not Rated 4.3 Short-Term Investments and Net Other Assets (Liabilities) 1.6 QUALITY DIVERSIFICATION (% of Fund's net assets)     We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     Corporate Bonds 70.3 Asset-Backed Securities 9.0 CMOs and Other Mortgage Related Securities 8.5 U.S. Treasury Obligations 8.2 Bank Loan Obligations 1.4 Other Investments 0.5 U.S. Government Agency - Mortgage Securities 0.2 Foreign Government and Government Agency Obligations 0.2 Preferred Securities 0.1 Short-Term Investments and Net Other Assets (Liabilities) 1.6 ASSET ALLOCATION (% of Fund's net assets)   United States 72.9 United Kingdom 4.9 Germany 3.7 Grand Cayman (UK Overseas Ter) 3.6 Canada 2.5 Japan 2.2 France 2.0 Netherlands 2.0 Ireland 1.7 Others 4.5 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 8.2     Bank of America Corp 2.8     JPMorgan Chase & Co 2.2     Wells Fargo & Co 1.7     General Motors Financial Co Inc 1.4     Morgan Stanley 1.3     Barclays PLC 1.3     Citigroup Inc 1.3     BAT International Finance PLC 1.2     Ford Motor Credit Co LLC 1.2       22.6
Material Fund Change [Text Block]	How has the Fund changed? This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com . The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Material Fund Change Expenses [Text Block]	The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses The fees associated with this class changed during the reporting year. The variations in class fees are primarily the result of the following changes: • Management fee • Operating expenses
Material Fund Change Strategies [Text Block]	The fund's principal investment strategies were modified during the reporting period, as described in the prospectus.
Summary of Change Legend [Text Block]	This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by October 30, 2024 at fundresearch.fidelity.com/prospectus/sec or upon request at 1-877-208-0098 or by sending an e-mail to fidfunddocuments fidelity.com .
Updated Prospectus Phone Number	1-877-208-0098</span>" id="sjs-B460">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">1-877-208-0098&lt;/span>
Updated Prospectus Email Address	fidfunddocuments@fidelity.com</span>" id="sjs-B461">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;">fidfunddocuments@fidelity.com&lt;/span>
Updated Prospectus Web Address	fundresearch.fidelity.com/prospectus/sec</span>" id="sjs-B462">&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;">fundresearch.fidelity.com/prospectus/sec&lt;/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

Aug. 31, 2024

Aug. 31, 2024

Aug. 31, 2024

Aug. 31, 2024

Aug. 31, 2024

Aug. 31, 2023

Aug. 31, 2022

Aug. 31, 2021

Aug. 31, 2020

Aug. 31, 2019

Aug. 31, 2018

Aug. 31, 2017

Aug. 31, 2016

Aug. 31, 2015

Aug. 31, 2014

C000014042_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014042_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014042_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014129_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014129_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014129_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014035_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F23">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014035_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000014035_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 10,156

C000014035_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 10,761

C000014035_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 10,814

C000014035_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 10,701

C000014035_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 11,789

C000014035_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 12,553

C000014035_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 12,542

C000014035_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 11,098

C000014035_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 10,965

C000014035_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

C000014035_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014035_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014035_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014045_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014045_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014045_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014032_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F77">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014032_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014032_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014032_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014032_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014032_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014032_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014032_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014032_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014032_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014032_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014032_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014032_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014032_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014032_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000203455_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000203455_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000203455_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.61%

C000204997_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000204997_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000204997_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.72%

C000132104_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F140">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000132104_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000132104_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000132104_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000132104_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000132104_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000132104_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000132104_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000132104_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000132104_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000132104_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000132104_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

C000132104_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000132104_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000132104_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014044_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014044_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014044_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014046_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014046_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014046_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000204996_0_LG_BBIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-D203">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000204996_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204996_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,086

C000204996_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,804

C000204996_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,794

C000204996_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,436

C000204996_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,311

C000204996_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,064

$ 11,064

$ 11,064

$ 11,064

$ 11,064

C000204996_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000204996_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000204996_2_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.72%

C000014036_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F236">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014036_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014036_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014036_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014036_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014036_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014036_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014036_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014036_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014036_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014036_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014036_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014036_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014036_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014036_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014034_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F281">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014034_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014034_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014034_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014034_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014034_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014034_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014034_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014034_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014034_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014034_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014034_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014034_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000014034_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000014034_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000014042_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class A</span>" id="sjs-F326">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A&lt;/span>

C000014042_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000014042_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,832

C000014042_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,175

C000014042_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,231

C000014042_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,116

C000014042_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,797

C000014042_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,281

C000014042_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,251

C000014042_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,079

C000014042_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,789

C000014042_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,496

$ 10,496

10,496

$ 10,496

$ 10,496

C000014042_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. MBS Index</span>" id="sjs-F362">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. MBS Index&lt;/span>

C000014042_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014042_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,266

C000014042_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,670

C000014042_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,756

C000014042_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,698

C000014042_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,454

C000014042_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,974

C000014042_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,953

C000014042_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,790

C000014042_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,564

C000014042_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,352

11,352

11,352

11,352

$ 11,352

C000014042_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F398">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014042_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014042_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014042_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014042_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014042_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014042_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014042_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014042_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014042_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014042_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014042_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014042_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.94%

C000014042_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.37%)

C000014042_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.49%

C000014042_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.23%

C000014042_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000014042_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.90%

C000014042_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.46%

C000014042_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.18%)

C000014042_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.28%

C000014129_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Mortgage Securities Fund</span>" id="sjs-F461">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Mortgage Securities Fund&lt;/span>

C000014129_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014129_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,268

C000014129_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,672

C000014129_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,768

C000014129_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,675

C000014129_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,442

C000014129_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,995

C000014129_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,008

C000014129_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,797

C000014129_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,515

C000014129_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,324

$ 11,324

11,324

$ 11,324

$ 11,324

C000014129_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. MBS Index</span>" id="sjs-F497">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. MBS Index&lt;/span>

C000014129_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014129_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,266

C000014129_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,670

C000014129_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,756

C000014129_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,698

C000014129_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,454

C000014129_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,974

C000014129_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,953

C000014129_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,790

C000014129_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,564

C000014129_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,352

11,352

11,352

11,352

$ 11,352

C000014129_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F533">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014129_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014129_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014129_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014129_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014129_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014129_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014129_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014129_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014129_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014129_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014129_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014129_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.70%

C000014129_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.21%)

C000014129_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.25%

C000014129_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.46%

C000014129_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.18%)

C000014129_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.28%

C000014035_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class M</span>" id="sjs-F587">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M&lt;/span>

C000014035_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,725

C000014035_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,766

C000014035_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,043

C000014035_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,152

C000014035_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,100

C000014035_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,687

C000014035_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,165

C000014035_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,209

C000014035_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,453

C000014035_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,678

C000014035_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,466

$ 11,466

11,466

$ 11,466

$ 11,466

C000014035_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Limited Term Composite Index℠</span>" id="sjs-F623">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Limited Term Composite Index℠&lt;/span>

C000014035_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014035_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,112

C000014035_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,423

C000014035_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,582

C000014035_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,568

C000014035_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,244

C000014035_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,810

C000014035_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,920

C000014035_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,202

C000014035_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,405

C000014035_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,263

12,263

12,263

12,263

$ 12,263

C000014035_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. 1-5 Year Government/Credit Bond Index</span>" id="sjs-F659">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-5 Year Government/Credit Bond Index&lt;/span>

C000014035_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014035_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,127

C000014035_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,368

C000014035_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,464

C000014035_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,419

C000014035_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,040

C000014035_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,562

C000014035_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,599

C000014035_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,922

C000014035_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,051

C000014035_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,788

$ 11,788

11,788

$ 11,788

$ 11,788

C000014035_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

4.43%

C000014035_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.85%

C000014035_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.38%

C000014035_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.39%

C000014035_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.42%

C000014035_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

C000014035_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.52%

C000014035_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000014035_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.06%

C000014035_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000014035_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000014035_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

C000014045_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class M</span>" id="sjs-F731">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M&lt;/span>

C000014045_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000014045_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,824

C000014045_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,166

C000014045_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,222

C000014045_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,107

C000014045_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,795

C000014045_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,268

C000014045_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,247

C000014045_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,069

C000014045_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,781

C000014045_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,488

$ 10,488

10,488

$ 10,488

$ 10,488

C000014045_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. MBS Index</span>" id="sjs-F767">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. MBS Index&lt;/span>

C000014045_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014045_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,266

C000014045_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,670

C000014045_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,756

C000014045_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,698

C000014045_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,454

C000014045_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,974

C000014045_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,953

C000014045_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,790

C000014045_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,564

C000014045_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,352

11,352

11,352

11,352

$ 11,352

C000014045_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F803">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014045_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014045_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014045_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014045_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014045_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014045_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014045_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014045_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014045_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014045_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014045_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014045_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.93%

C000014045_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.38%)

C000014045_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.48%

C000014045_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.22%

C000014045_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.58%)

C000014045_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.89%

C000014045_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.46%

C000014045_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.18%)

C000014045_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.28%

C000014032_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class A</span>" id="sjs-F866">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A&lt;/span>

C000014032_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,725

C000014032_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,775

C000014032_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,043

C000014032_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,162

C000014032_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,111

C000014032_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,691

C000014032_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,179

C000014032_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,223

C000014032_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,466

C000014032_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,682

C000014032_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,481

$ 11,481

11,481

$ 11,481

$ 11,481

C000014032_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Limited Term Composite Index℠</span>" id="sjs-F902">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Limited Term Composite Index℠&lt;/span>

C000014032_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014032_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,112

C000014032_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,423

C000014032_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,582

C000014032_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,568

C000014032_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,244

C000014032_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,810

C000014032_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,920

C000014032_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,202

C000014032_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,405

C000014032_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,263

12,263

12,263

12,263

$ 12,263

C000014032_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. 1-5 Year Government/Credit Bond Index</span>" id="sjs-F938">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-5 Year Government/Credit Bond Index&lt;/span>

C000014032_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014032_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,127

C000014032_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,368

C000014032_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,464

C000014032_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,419

C000014032_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,040

C000014032_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,562

C000014032_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,599

C000014032_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,922

C000014032_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,051

C000014032_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,788

$ 11,788

$ 11,788

$ 11,788

$ 11,788

C000014032_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

4.53%

C000014032_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.87%

C000014032_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.39%

C000014032_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.48%

C000014032_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.44%

C000014032_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.67%

C000014032_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.52%

C000014032_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000014032_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.06%

C000014032_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000014032_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000014032_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

C000203455_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Series Investment Grade Securitized Fund</span>" id="sjs-D1010">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Series Investment Grade Securitized Fund&lt;/span>

C000203455_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000203455_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,008

C000203455_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

10,791

C000203455_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,361

C000203455_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,397

C000203455_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,270

C000203455_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,093

$ 10,093

$ 10,093

$ 10,093

10,093

C000203455_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Securitized Index</span>" id="sjs-D1034">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Securitized Index&lt;/span>

C000203455_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000203455_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,016

C000203455_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

10,745

C000203455_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,241

C000203455_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,237

C000203455_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,145

C000203455_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

9,947

9,947

$ 9,947

9,947

9,947

C000203455_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-D1058">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000203455_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000203455_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,014

C000203455_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,033

C000203455_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,747

C000203455_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,737

C000203455_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,386

C000203455_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,262

$ 10,262

$ 10,262

10,262

10,262

C000203455_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.25%

C000203455_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.25%

C000203455_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

1.48%

C000203455_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.55%

C000203455_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.09%)

C000203455_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.12%

C000204997_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class Z</span>" id="sjs-D1100">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z&lt;/span>

C000204997_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204997_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,782

C000204997_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,305

C000204997_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,333

C000204997_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,196

C000204997_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,948

C000204997_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,713

$ 10,713

$ 10,713

10,713

10,713

C000204997_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. MBS Index</span>" id="sjs-D1124">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. MBS Index&lt;/span>

C000204997_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204997_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,771

C000204997_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,260

C000204997_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,240

C000204997_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,146

C000204997_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,934

C000204997_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

10,675

10,675

$ 10,675

10,675

10,675

C000204997_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-D1148">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000204997_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204997_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,086

C000204997_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,804

C000204997_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,794

C000204997_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,436

C000204997_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,311

C000204997_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,064

$ 11,064

$ 11,064

11,064

$ 11,064

C000204997_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.70%

C000204997_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.13%)

C000204997_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

1.17%

C000204997_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.46%

C000204997_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.18%)

C000204997_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.11%

C000132104_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Limited Term Bond Fund</span>" id="sjs-F1190">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Limited Term Bond Fund&lt;/span>

C000132104_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000132104_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,083

C000132104_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,391

C000132104_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,537

C000132104_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,526

C000132104_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,162

C000132104_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,706

C000132104_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,788

C000132104_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,028

C000132104_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,290

C000132104_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 12,170

$ 12,170

12,170

12,170

$ 12,170

C000132104_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Limited Term Composite Index℠</span>" id="sjs-F1226">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Limited Term Composite Index℠&lt;/span>

C000132104_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000132104_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,112

C000132104_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,423

C000132104_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,582

C000132104_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,568

C000132104_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,244

C000132104_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,810

C000132104_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,920

C000132104_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,202

C000132104_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,405

C000132104_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,263

12,263

12,263

12,263

$ 12,263

C000132104_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. 1-5 Year Government/Credit Bond Index</span>" id="sjs-F1262">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-5 Year Government/Credit Bond Index&lt;/span>

C000132104_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000132104_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,127

C000132104_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,368

C000132104_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,464

C000132104_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,419

C000132104_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,040

C000132104_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,562

C000132104_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,599

C000132104_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,922

C000132104_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,051

C000132104_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,788

$ 11,788

11,788

$ 11,788

$ 11,788

C000132104_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.80%

C000132104_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.74%

C000132104_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.98%

C000132104_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.52%

C000132104_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000132104_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.06%

C000132104_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000132104_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000132104_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

C000014044_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class C</span>" id="sjs-F1325">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C&lt;/span>

C000014044_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014044_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,159

C000014044_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,436

C000014044_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,416

C000014044_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,222

C000014044_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,839

C000014044_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,228

C000014044_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,121

C000014044_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

9,875

C000014044_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,591

C000014044_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,284

$ 10,284

10,284

$ 10,284

$ 10,284

C000014044_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. MBS Index</span>" id="sjs-F1361">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. MBS Index&lt;/span>

C000014044_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014044_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,266

C000014044_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,670

C000014044_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,756

C000014044_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,698

C000014044_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,454

C000014044_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,974

C000014044_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,953

C000014044_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,790

C000014044_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,564

C000014044_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,352

11,352

11,352

11,352

$ 11,352

C000014044_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F1397">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014044_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014044_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014044_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014044_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014044_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014044_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014044_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014044_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014044_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014044_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014044_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000014044_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.42%

C000014044_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.34%)

C000014044_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.28%

C000014044_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.42%

C000014044_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.34%)

C000014044_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.28%

C000014044_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.46%

C000014044_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.18%)

C000014044_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.28%

C000014046_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class I</span>" id="sjs-F1460">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I&lt;/span>

C000014046_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014046_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,264

C000014046_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,662

C000014046_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,744

C000014046_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,654

C000014046_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,418

C000014046_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,957

C000014046_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,976

C000014046_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,757

C000014046_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,467

C000014046_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,265

$ 11,265

11,265

$ 11,265

$ 11,265

C000014046_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. MBS Index</span>" id="sjs-F1496">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. MBS Index&lt;/span>

C000014046_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014046_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,266

C000014046_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,670

C000014046_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,756

C000014046_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,698

C000014046_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,454

C000014046_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,974

C000014046_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,953

C000014046_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,790

C000014046_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,564

C000014046_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,352

11,352

11,352

11,352

$ 11,352

C000014046_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F1532">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Aggregate Bond Index&lt;/span>

C000014046_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014046_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000014046_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000014046_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000014046_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000014046_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000014046_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000014046_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000014046_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000014046_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000014046_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

C000014046_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.62%

C000014046_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.27%)

C000014046_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.20%

C000014046_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.46%

C000014046_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.18%)

C000014046_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.28%

C000204996_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class Z</span>" id="sjs-D1586">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z&lt;/span>

C000204996_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204996_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,618

C000204996_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,145

C000204996_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,234

C000204996_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,519

C000204996_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,776

C000204996_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,622

$ 11,622

$ 11,622

$ 11,622

11,622

C000204996_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Limited Term Composite Index℠</span>" id="sjs-D1610">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Limited Term Composite Index℠&lt;/span>

C000204996_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204996_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,650

C000204996_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,185

C000204996_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,290

C000204996_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,610

C000204996_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,802

C000204996_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,615

11,615

$ 11,615

11,615

11,615

C000204996_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. 1-5 Year Government/Credit Bond Index</span>" id="sjs-D1634">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-5 Year Government/Credit Bond Index&lt;/span>

C000204996_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000204996_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,616

C000204996_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,117

C000204996_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,153

C000204996_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,502

C000204996_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,626

C000204996_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,335

$ 11,335

$ 11,335

11,335

$ 11,335

C000204996_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.85%

C000204996_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.82%

C000204996_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

2.57%

C000204996_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.52%

C000204996_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000204996_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

2.56%

C000204996_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000204996_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000204996_1_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

2.14%

C000014036_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class I</span>" id="sjs-F1685">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I&lt;/span>

C000014036_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014036_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,078

C000014036_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,390

C000014036_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,531

C000014036_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,506

C000014036_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,136

C000014036_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,673

C000014036_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,749

C000014036_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,986

C000014036_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,244

C000014036_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 12,120

$ 12,120

12,120

12,120

$ 12,120

C000014036_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Limited Term Composite Index℠</span>" id="sjs-F1721">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Limited Term Composite Index℠&lt;/span>

C000014036_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014036_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,112

C000014036_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,423

C000014036_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,582

C000014036_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,568

C000014036_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,244

C000014036_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,810

C000014036_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,920

C000014036_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,202

C000014036_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,405

C000014036_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,263

12,263

12,263

12,263

$ 12,263

C000014036_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. 1-5 Year Government/Credit Bond Index</span>" id="sjs-F1757">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-5 Year Government/Credit Bond Index&lt;/span>

C000014036_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014036_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,127

C000014036_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,368

C000014036_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,464

C000014036_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,419

C000014036_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,040

C000014036_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,562

C000014036_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,599

C000014036_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,922

C000014036_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,051

C000014036_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,788

$ 11,788

11,788

$ 11,788

$ 11,788

C000014036_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.80%

C000014036_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.71%

C000014036_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.94%

C000014036_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.52%

C000014036_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000014036_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.06%

C000014036_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000014036_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000014036_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

C000014034_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class C</span>" id="sjs-F1820">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C&lt;/span>

C000014034_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014034_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,965

C000014034_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,169

C000014034_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,201

C000014034_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,071

C000014034_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,575

C000014034_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

10,962

C000014034_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,920

C000014034_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,103

C000014034_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,311

C000014034_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,082

$ 11,082

11,082

$ 11,082

$ 11,082

C000014034_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity Limited Term Composite Index℠</span>" id="sjs-F1856">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity Limited Term Composite Index℠&lt;/span>

C000014034_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000014034_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,112

C000014034_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,423

C000014034_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,582

C000014034_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,568

C000014034_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,244

C000014034_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,810

C000014034_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,920

C000014034_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,202

C000014034_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,405

C000014034_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,263

12,263

12,263

12,263

$ 12,263

C000014034_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. 1-5 Year Government/Credit Bond Index</span>" id="sjs-F1892">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. 1-5 Year Government/Credit Bond Index&lt;/span>

C000014034_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000014034_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 10,127

C000014034_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 10,368

C000014034_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 10,464

C000014034_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 10,419

C000014034_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 11,040

C000014034_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 11,562

C000014034_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 11,599

C000014034_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 10,922

C000014034_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 11,051

C000014034_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,788

$ 11,788

$ 11,788

$ 11,788

$ 11,788

C000014034_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.67%

C000014034_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.63%

C000014034_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.03%

C000014034_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000014034_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.63%

C000014034_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.03%

C000014034_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.52%

C000014034_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000014034_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.06%

C000014034_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.67%

C000014034_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000014034_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.66%

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Aug. 31, 2024
Fidelity Advisor Mortgage Securities Fund - Class A | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	31.50%
Fidelity Advisor Mortgage Securities Fund - Class A | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Mortgage Securities Fund - Class A | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.80%
Fidelity Advisor Mortgage Securities Fund - Class A | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	19.10%
Fidelity Advisor Mortgage Securities Fund - Class A | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class A | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Mortgage Securities Fund - Class A | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Mortgage Securities Fund - Class A | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.30%
Fidelity Advisor Mortgage Securities Fund - Class A | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Mortgage Securities Fund - Class A | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Mortgage Securities Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	107%
Fidelity Advisor Mortgage Securities Fund - Class A | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Mortgage Securities Fund - Class A | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Mortgage Securities Fund - Class A | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class A | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class A | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class A | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Mortgage Securities Fund - Class A | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Advisor Mortgage Securities Fund - Class A | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class A | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class A | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	101.30%
Fidelity Advisor Mortgage Securities Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Advisor Mortgage Securities Fund - Class A | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Advisor Mortgage Securities Fund - Class A | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class A | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Limited Term Securitized Completion Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	10.50%
Fidelity Limited Term Securitized Completion Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Limited Term Securitized Completion Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.10%
Fidelity Limited Term Securitized Completion Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Limited Term Securitized Completion Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Limited Term Securitized Completion Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Limited Term Securitized Completion Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Limited Term Securitized Completion Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Limited Term Securitized Completion Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Limited Term Securitized Completion Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	3%
Fidelity Limited Term Securitized Completion Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	19.50%
Fidelity Limited Term Securitized Completion Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	69.50%
Fidelity Limited Term Securitized Completion Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Limited Term Securitized Completion Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	14.70%
Fidelity Limited Term Securitized Completion Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	98.30%
Fidelity Limited Term Securitized Completion Fund | Canada
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Limited Term Securitized Completion Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	18.70%
Fidelity Limited Term Securitized Completion Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	36.70%
Fidelity Limited Term Securitized Completion Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Limited Term Securitized Completion Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Mortgage Securities Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	31.50%
Fidelity Mortgage Securities Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Mortgage Securities Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.80%
Fidelity Mortgage Securities Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	19.10%
Fidelity Mortgage Securities Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Mortgage Securities Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Mortgage Securities Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Mortgage Securities Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.30%
Fidelity Mortgage Securities Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Mortgage Securities Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Mortgage Securities Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	107%
Fidelity Mortgage Securities Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Mortgage Securities Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Mortgage Securities Fund | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Mortgage Securities Fund | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Mortgage Securities Fund | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Mortgage Securities Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Mortgage Securities Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Mortgage Securities Fund | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Mortgage Securities Fund | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Mortgage Securities Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	101.30%
Fidelity Mortgage Securities Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Mortgage Securities Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Mortgage Securities Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Mortgage Securities Fund | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class M | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class M | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Advisor Limited Term Bond Fund - Class M | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class M | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class M | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class M | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class M | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class M | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class M | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class M | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class M | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.40%
Fidelity Advisor Limited Term Bond Fund - Class M | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Advisor Limited Term Bond Fund - Class M | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Limited Term Bond Fund - Class M | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Limited Term Bond Fund - Class M | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Fidelity Advisor Limited Term Bond Fund - Class M | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class M | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Advisor Limited Term Bond Fund - Class M | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Limited Term Bond Fund - Class M | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Advisor Limited Term Bond Fund - Class M | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class M | United States
Holdings [Line Items]
Percent of Net Asset Value	72.90%
Fidelity Advisor Limited Term Bond Fund - Class M | Canada
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Advisor Limited Term Bond Fund - Class M | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Limited Term Bond Fund - Class M | Germany
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Limited Term Bond Fund - Class M | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Limited Term Bond Fund - Class M | Japan
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class M | France
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class M | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class M | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class M | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Advisor Limited Term Bond Fund - Class M | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Limited Term Bond Fund - Class M | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class M | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Advisor Limited Term Bond Fund - Class M | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	70.30%
Fidelity Advisor Limited Term Bond Fund - Class M | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class M | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Limited Term Bond Fund - Class M | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class M | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Limited Term Bond Fund - Class M | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Mortgage Securities Fund - Class M | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	31.50%
Fidelity Advisor Mortgage Securities Fund - Class M | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Mortgage Securities Fund - Class M | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.80%
Fidelity Advisor Mortgage Securities Fund - Class M | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	19.10%
Fidelity Advisor Mortgage Securities Fund - Class M | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class M | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Mortgage Securities Fund - Class M | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Mortgage Securities Fund - Class M | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.30%
Fidelity Advisor Mortgage Securities Fund - Class M | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Mortgage Securities Fund - Class M | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Mortgage Securities Fund - Class M | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	107%
Fidelity Advisor Mortgage Securities Fund - Class M | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Mortgage Securities Fund - Class M | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Mortgage Securities Fund - Class M | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class M | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class M | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class M | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Mortgage Securities Fund - Class M | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Advisor Mortgage Securities Fund - Class M | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class M | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class M | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	101.30%
Fidelity Advisor Mortgage Securities Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Advisor Mortgage Securities Fund - Class M | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Advisor Mortgage Securities Fund - Class M | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class M | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class A | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class A | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Advisor Limited Term Bond Fund - Class A | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class A | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class A | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class A | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class A | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class A | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class A | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class A | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.40%
Fidelity Advisor Limited Term Bond Fund - Class A | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Advisor Limited Term Bond Fund - Class A | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Limited Term Bond Fund - Class A | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Limited Term Bond Fund - Class A | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Fidelity Advisor Limited Term Bond Fund - Class A | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class A | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Advisor Limited Term Bond Fund - Class A | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Limited Term Bond Fund - Class A | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Advisor Limited Term Bond Fund - Class A | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class A | United States
Holdings [Line Items]
Percent of Net Asset Value	72.90%
Fidelity Advisor Limited Term Bond Fund - Class A | Canada
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Advisor Limited Term Bond Fund - Class A | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Limited Term Bond Fund - Class A | Germany
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Limited Term Bond Fund - Class A | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Limited Term Bond Fund - Class A | Japan
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class A | France
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class A | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class A | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class A | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Advisor Limited Term Bond Fund - Class A | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Limited Term Bond Fund - Class A | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class A | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Advisor Limited Term Bond Fund - Class A | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	70.30%
Fidelity Advisor Limited Term Bond Fund - Class A | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class A | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Limited Term Bond Fund - Class A | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class A | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Limited Term Bond Fund - Class A | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Series Investment Grade Securitized Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	33.50%
Fidelity Series Investment Grade Securitized Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.10%
Fidelity Series Investment Grade Securitized Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.50%
Fidelity Series Investment Grade Securitized Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	12%
Fidelity Series Investment Grade Securitized Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Series Investment Grade Securitized Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Series Investment Grade Securitized Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Series Investment Grade Securitized Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Series Investment Grade Securitized Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Series Investment Grade Securitized Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Series Investment Grade Securitized Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	98.40%
Fidelity Series Investment Grade Securitized Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	14.20%
Fidelity Series Investment Grade Securitized Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Series Investment Grade Securitized Fund | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Series Investment Grade Securitized Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	14.20%
Fidelity Series Investment Grade Securitized Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Series Investment Grade Securitized Fund | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Series Investment Grade Securitized Fund | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Series Investment Grade Securitized Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	94.60%
Fidelity Series Investment Grade Securitized Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.60%
Fidelity Series Investment Grade Securitized Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	3.80%
Fidelity Series Investment Grade Securitized Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	5.90%
Fidelity Series Investment Grade Securitized Fund | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	31.50%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.80%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	19.10%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.30%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Mortgage Securities Fund - Class Z | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	107%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class Z | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Mortgage Securities Fund - Class Z | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Advisor Mortgage Securities Fund - Class Z | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class Z | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class Z | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	101.30%
Fidelity Advisor Mortgage Securities Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Advisor Mortgage Securities Fund - Class Z | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Advisor Mortgage Securities Fund - Class Z | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class Z | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Limited Term Bond Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Limited Term Bond Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Limited Term Bond Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Limited Term Bond Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Limited Term Bond Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Limited Term Bond Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Limited Term Bond Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Limited Term Bond Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Limited Term Bond Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Limited Term Bond Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Limited Term Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.40%
Fidelity Limited Term Bond Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Limited Term Bond Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Limited Term Bond Fund | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Limited Term Bond Fund | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Fidelity Limited Term Bond Fund | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Limited Term Bond Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Limited Term Bond Fund | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Limited Term Bond Fund | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Limited Term Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Limited Term Bond Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	72.90%
Fidelity Limited Term Bond Fund | Canada
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Limited Term Bond Fund | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Limited Term Bond Fund | Germany
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Limited Term Bond Fund | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Limited Term Bond Fund | Japan
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Limited Term Bond Fund | France
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Limited Term Bond Fund | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Limited Term Bond Fund | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Limited Term Bond Fund | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Limited Term Bond Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Limited Term Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Limited Term Bond Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Limited Term Bond Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Limited Term Bond Fund | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	70.30%
Fidelity Limited Term Bond Fund | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Limited Term Bond Fund | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Limited Term Bond Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Limited Term Bond Fund | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Limited Term Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Mortgage Securities Fund - Class C | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	31.50%
Fidelity Advisor Mortgage Securities Fund - Class C | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Mortgage Securities Fund - Class C | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.80%
Fidelity Advisor Mortgage Securities Fund - Class C | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	19.10%
Fidelity Advisor Mortgage Securities Fund - Class C | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class C | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Mortgage Securities Fund - Class C | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Mortgage Securities Fund - Class C | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.30%
Fidelity Advisor Mortgage Securities Fund - Class C | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Mortgage Securities Fund - Class C | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Mortgage Securities Fund - Class C | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	107%
Fidelity Advisor Mortgage Securities Fund - Class C | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Mortgage Securities Fund - Class C | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Mortgage Securities Fund - Class C | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class C | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class C | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class C | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Mortgage Securities Fund - Class C | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Advisor Mortgage Securities Fund - Class C | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class C | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class C | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	101.30%
Fidelity Advisor Mortgage Securities Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Advisor Mortgage Securities Fund - Class C | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Advisor Mortgage Securities Fund - Class C | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class C | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Mortgage Securities Fund - Class I | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	31.50%
Fidelity Advisor Mortgage Securities Fund - Class I | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Mortgage Securities Fund - Class I | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	20.80%
Fidelity Advisor Mortgage Securities Fund - Class I | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	19.10%
Fidelity Advisor Mortgage Securities Fund - Class I | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class I | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Mortgage Securities Fund - Class I | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Mortgage Securities Fund - Class I | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.30%
Fidelity Advisor Mortgage Securities Fund - Class I | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Mortgage Securities Fund - Class I | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Mortgage Securities Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	107%
Fidelity Advisor Mortgage Securities Fund - Class I | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Mortgage Securities Fund - Class I | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Mortgage Securities Fund - Class I | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class I | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class I | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class I | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Advisor Mortgage Securities Fund - Class I | United States
Holdings [Line Items]
Percent of Net Asset Value	99.90%
Fidelity Advisor Mortgage Securities Fund - Class I | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Mortgage Securities Fund - Class I | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Mortgage Securities Fund - Class I | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	101.30%
Fidelity Advisor Mortgage Securities Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Advisor Mortgage Securities Fund - Class I | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Advisor Mortgage Securities Fund - Class I | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.30%
Fidelity Advisor Mortgage Securities Fund - Class I | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.40%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Advisor Limited Term Bond Fund - Class Z | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class Z | United States
Holdings [Line Items]
Percent of Net Asset Value	72.90%
Fidelity Advisor Limited Term Bond Fund - Class Z | Canada
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Advisor Limited Term Bond Fund - Class Z | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Limited Term Bond Fund - Class Z | Germany
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Limited Term Bond Fund - Class Z | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Limited Term Bond Fund - Class Z | Japan
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | France
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class Z | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class Z | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class Z | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Advisor Limited Term Bond Fund - Class Z | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	70.30%
Fidelity Advisor Limited Term Bond Fund - Class Z | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Limited Term Bond Fund - Class Z | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class I | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class I | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Advisor Limited Term Bond Fund - Class I | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class I | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class I | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class I | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class I | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class I | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class I | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class I | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.40%
Fidelity Advisor Limited Term Bond Fund - Class I | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Advisor Limited Term Bond Fund - Class I | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Limited Term Bond Fund - Class I | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Limited Term Bond Fund - Class I | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Fidelity Advisor Limited Term Bond Fund - Class I | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class I | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Advisor Limited Term Bond Fund - Class I | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Limited Term Bond Fund - Class I | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Advisor Limited Term Bond Fund - Class I | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class I | United States
Holdings [Line Items]
Percent of Net Asset Value	72.90%
Fidelity Advisor Limited Term Bond Fund - Class I | Canada
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Advisor Limited Term Bond Fund - Class I | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Limited Term Bond Fund - Class I | Germany
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Limited Term Bond Fund - Class I | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Limited Term Bond Fund - Class I | Japan
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class I | France
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class I | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class I | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class I | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Advisor Limited Term Bond Fund - Class I | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Limited Term Bond Fund - Class I | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class I | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Advisor Limited Term Bond Fund - Class I | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	70.30%
Fidelity Advisor Limited Term Bond Fund - Class I | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class I | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Limited Term Bond Fund - Class I | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class I | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Limited Term Bond Fund - Class I | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class C | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class C | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Advisor Limited Term Bond Fund - Class C | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class C | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class C | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class C | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class C | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class C | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Limited Term Bond Fund - Class C | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class C | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Limited Term Bond Fund - Class C | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.40%
Fidelity Advisor Limited Term Bond Fund - Class C | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Advisor Limited Term Bond Fund - Class C | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Limited Term Bond Fund - Class C | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	25.70%
Fidelity Advisor Limited Term Bond Fund - Class C | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	38.90%
Fidelity Advisor Limited Term Bond Fund - Class C | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Limited Term Bond Fund - Class C | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Advisor Limited Term Bond Fund - Class C | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Limited Term Bond Fund - Class C | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Advisor Limited Term Bond Fund - Class C | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Limited Term Bond Fund - Class C | United States
Holdings [Line Items]
Percent of Net Asset Value	72.90%
Fidelity Advisor Limited Term Bond Fund - Class C | Canada
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Advisor Limited Term Bond Fund - Class C | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Limited Term Bond Fund - Class C | Germany
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity Advisor Limited Term Bond Fund - Class C | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Limited Term Bond Fund - Class C | Japan
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Limited Term Bond Fund - Class C | France
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class C | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Advisor Limited Term Bond Fund - Class C | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Limited Term Bond Fund - Class C | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Advisor Limited Term Bond Fund - Class C | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	8.50%
Fidelity Advisor Limited Term Bond Fund - Class C | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	8.20%
Fidelity Advisor Limited Term Bond Fund - Class C | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Advisor Limited Term Bond Fund - Class C | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	70.30%
Fidelity Advisor Limited Term Bond Fund - Class C | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Limited Term Bond Fund - Class C | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Advisor Limited Term Bond Fund - Class C | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Advisor Limited Term Bond Fund - Class C | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Limited Term Bond Fund - Class C | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.60%