Fidelity Managed Retirement 2015 Fund (FIRSX) 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 Income Fund
Entity Central Index Key	0000751199
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 Income Fund
Entity Central Index Key	0000751199
Entity Investment Company Type	N-1A
Document Period End Date	Aug. 31, 2024
Fidelity Advisor Government Income Fund - Class C
Shareholder Report [Line Items]
Fund Name	Fidelity® Government Income Fund
Class Name	Fidelity Advisor® Government Income Fund Class C
Trading Symbol	FVICX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Government Income 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 $ 1.54 %
Expenses Paid, Amount	$ 158
Expense Ratio, Percent	1.54%
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. Class C   $10,000 $10,088   $10,403   $10,247   $9,977   $10,798   $11,312   $11,016   $9,719   $9,440   $10,017   Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index   $10,000 $10,237   $10,723   $10,676   $10,542   $11,543   $12,274   $12,083   $10,820   $10,602   $11,280   Bloomberg U.S. Government Bond Index   $10,000 $10,227   $10,739   $10,649   $10,489   $11,570   $12,371   $12,121   $10,825   $10,608   $11,248   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) 4.23% -1.79% 0.02% Class C 5.23% -1.79% 0.02% Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index 6.40% -0.46% 1.21% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.18% 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	$ 2,324,957,949
Holdings Count | shares	2,073
Advisory Fees Paid, Amount	$ 8,233,532
Investment Company Portfolio Turnover	393%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 2,073 Total Advisory Fee $ Portfolio Turnover 393 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) Zero coupon bonds 0.0   0.01 - 0.99% 0.0   1 - 1.99% 7.0   2 - 2.99% 32.8   3 - 3.99% 22.8   4 - 4.99% 18.6   5 - 5.99% 4.9   6 - 6.99% 3.2   7 - 7.99% 0.0   8 - 8.99% 0.0     U.S. Treasury Obligations 43.0 CMOs and Other Mortgage Related Securities 23.3 U.S. Government Agency - Mortgage Securities 22.4 U.S. Government Agency Obligations 0.6 Short-Term Investments and Net Other Assets (Liabilities) 10.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 26.9     US Treasury Bonds 16.1     Fannie Mae Mortgage pass-thru certificates 14.9     Freddie Mac Multiclass Mortgage participation certificates 14.6     Freddie Mac Gold Pool 9.3     Fannie Mae Guaranteed REMICS 5.4     Ginnie Mae II Pool 3.5     Ginnie Mae I Pool 1.4     Ginnie Mae REMIC pass-thru certificates 1.1     Freddie Mac Non Gold Pool 0.8       94.0
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 contractural management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractural 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 Intermediate Government Income Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Intermediate Government Income Fund
Class Name	Fidelity® Intermediate Government Income Fund
Trading Symbol	FSTGX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Intermediate Government Income 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® Intermediate Government Income Fund $ 0.45 %
Expenses Paid, Amount	$ 46
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-B59">&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® Intermediate Government Income Fund   $10,000 $10,150   $10,416   $10,424   $10,265   $11,015   $11,574   $11,449   $10,516   $10,441   $11,061   Bloomberg U.S. Intermediate Government Bond Index   $10,000 $10,189   $10,497   $10,506   $10,375   $11,148   $11,753   $11,676   $10,796   $10,782   $11,457   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® Intermediate Government Income Fund 5.94% 0.08% 1.01% Bloomberg U.S. Intermediate Government Bond Index 6.26% 0.55% 1.37% 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	$ 467,016,210
Holdings Count | shares	243
Advisory Fees Paid, Amount	$ 1,256,127
Investment Company Portfolio Turnover	199%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 243 Total Advisory Fee $ Portfolio Turnover 199 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) 0.01 - 0.99% 4.8   1 - 1.99% 13.9   2 - 2.99% 21.0   3 - 3.99% 16.4   4 - 4.99% 33.6   5 - 5.99% -0.2   6 - 6.99% 0.6     U.S. Treasury Obligations 75.8 CMOs and Other Mortgage Related Securities 13.4 U.S. Government Agency - Mortgage Securities 0.6 U.S. Government Agency Obligations 0.3 Short-Term Investments and Net Other Assets (Liabilities) 9.9 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 74.3     Freddie Mac Multiclass Mortgage participation certificates 9.7     Fannie Mae Mortgage pass-thru certificates 2.8     Freddie Mac Gold Pool 2.2     Fannie Mae Guaranteed REMICS 2.0     US Treasury Bonds 1.5     Fremf 2015-Kplb Mortgage Trust 0.9     Freddie Mac Multifamily Structured Pass Through Certificates 0.7     Private Export Funding Corp 0.3     Ginnie Mae I Pool 0.2       94.6
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 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-B73">&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-B74">&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-B75">&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 Total Bond Fund - Class M
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond Fund
Class Name	Fidelity Advisor® Total Bond Fund Class M
Trading Symbol	FEPTX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total 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 $ 0.75 %
Expenses Paid, Amount	$ 78
Expense Ratio, Percent	0.75%
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-B92">&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 $9,645   $10,291   $10,472   $10,372   $11,340   $12,169   $12,423   $10,980   $10,986   $11,876   Bloomberg U.S. Universal Bond Index   $10,000 $10,113   $10,770   $10,915   $10,814   $11,903   $12,666   $12,778   $11,264   $11,219   $12,108   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)   3.77% 0.11% 1.73% Class M (without 4.00% sales charge) 8.10% 0.93% 2.15% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.93% 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	$ 39,553,262,535
Holdings Count | shares	6,935
Advisory Fees Paid, Amount	$ 100,486,629
Investment Company Portfolio Turnover	206%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 6,935 Total Advisory Fee $ Portfolio Turnover 206 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 54.7 AAA 8.8 AA 1.1 A 7.7 BBB 16.3 BB 4.6 B 5.6 CCC,CC,C 0.8 D 0.0 Not Rated 3.9 Equities 0.1 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 34.8 Corporate Bonds 27.7 U.S. Government Agency - Mortgage Securities 19.9 Asset-Backed Securities 7.4 CMOs and Other Mortgage Related Securities 6.8 Bank Loan Obligations 5.0 Foreign Government and Government Agency Obligations 1.2 Preferred Securities 0.4 Common Stocks 0.1 Other Investments 0.1 Purchased Swaptions 0.1 Supranational Obligations 0.1 Preferred Stocks 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)% United States 86.3 Grand Cayman (UK Overseas Ter) 4.2 United Kingdom 1.5 Mexico 1.3 Germany 1.1 Ireland 0.8 Switzerland 0.7 Canada 0.6 France 0.3 Others 3.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 25.4     US Treasury Bonds 9.4     Fannie Mae Mortgage pass-thru certificates 6.6     Ginnie Mae II Pool 5.2     Uniform Mortgage Backed Securities 3.9     Freddie Mac Gold Pool 3.6     JPMorgan Chase & Co 1.2     Petroleos Mexicanos 1.1     Freddie Mac Multiclass Mortgage participation certificates 1.0     Bank of America Corp 0.9       58.3
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-B106">&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-B107">&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-B108">&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 Total Bond Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond Fund
Class Name	Fidelity® Total Bond Fund
Trading Symbol	FTBFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total 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® Total Bond 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-B125">&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® Total Bond Fund   $10,000 $10,088   $10,788   $11,012   $10,951   $12,008   $12,923   $13,232   $11,721   $11,764   $12,766   Bloomberg U.S. Universal Bond Index   $10,000 $10,113   $10,770   $10,915   $10,814   $11,903   $12,666   $12,778   $11,264   $11,219   $12,108   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® Total Bond Fund 8.52% 1.23% 2.47% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.93% 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	$ 39,553,262,535
Holdings Count | shares	6,935
Advisory Fees Paid, Amount	$ 100,486,629
Investment Company Portfolio Turnover	206%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 6,935 Total Advisory Fee $ Portfolio Turnover 206 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 54.7 AAA 8.8 AA 1.1 A 7.7 BBB 16.3 BB 4.6 B 5.6 CCC,CC,C 0.8 D 0.0 Not Rated 3.9 Equities 0.1 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 34.8 Corporate Bonds 27.7 U.S. Government Agency - Mortgage Securities 19.9 Asset-Backed Securities 7.4 CMOs and Other Mortgage Related Securities 6.8 Bank Loan Obligations 5.0 Foreign Government and Government Agency Obligations 1.2 Preferred Securities 0.4 Common Stocks 0.1 Other Investments 0.1 Purchased Swaptions 0.1 Supranational Obligations 0.1 Preferred Stocks 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)% United States 86.3 Grand Cayman (UK Overseas Ter) 4.2 United Kingdom 1.5 Mexico 1.3 Germany 1.1 Ireland 0.8 Switzerland 0.7 Canada 0.6 France 0.3 Others 3.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 25.4     US Treasury Bonds 9.4     Fannie Mae Mortgage pass-thru certificates 6.6     Ginnie Mae II Pool 5.2     Uniform Mortgage Backed Securities 3.9     Freddie Mac Gold Pool 3.6     JPMorgan Chase & Co 1.2     Petroleos Mexicanos 1.1     Freddie Mac Multiclass Mortgage participation certificates 1.0     Bank of America Corp 0.9       58.3
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-B139">&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-B140">&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-B141">&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 Total Bond Fund - Class C
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond Fund
Class Name	Fidelity Advisor® Total Bond Fund Class C
Trading Symbol	FCEPX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total 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 $ 1.51 %
Expenses Paid, Amount	$ 157
Expense Ratio, Percent	1.51%
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-B158">&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 $9,980   $10,569   $10,674   $10,503   $11,394   $12,133   $12,292   $10,774   $10,782   $11,653   Bloomberg U.S. Universal Bond Index   $10,000 $10,113   $10,770   $10,915   $10,814   $11,903   $12,666   $12,778   $11,264   $11,219   $12,108   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) 6.27% 0.14% 1.54% Class C 7.27% 0.14% 1.54% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.93% 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	$ 39,553,262,535
Holdings Count | shares	6,935
Advisory Fees Paid, Amount	$ 100,486,629
Investment Company Portfolio Turnover	206%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 6,935 Total Advisory Fee $ Portfolio Turnover 206 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 54.7 AAA 8.8 AA 1.1 A 7.7 BBB 16.3 BB 4.6 B 5.6 CCC,CC,C 0.8 D 0.0 Not Rated 3.9 Equities 0.1 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 34.8 Corporate Bonds 27.7 U.S. Government Agency - Mortgage Securities 19.9 Asset-Backed Securities 7.4 CMOs and Other Mortgage Related Securities 6.8 Bank Loan Obligations 5.0 Foreign Government and Government Agency Obligations 1.2 Preferred Securities 0.4 Common Stocks 0.1 Other Investments 0.1 Purchased Swaptions 0.1 Supranational Obligations 0.1 Preferred Stocks 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)% United States 86.3 Grand Cayman (UK Overseas Ter) 4.2 United Kingdom 1.5 Mexico 1.3 Germany 1.1 Ireland 0.8 Switzerland 0.7 Canada 0.6 France 0.3 Others 3.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 25.4     US Treasury Bonds 9.4     Fannie Mae Mortgage pass-thru certificates 6.6     Ginnie Mae II Pool 5.2     Uniform Mortgage Backed Securities 3.9     Freddie Mac Gold Pool 3.6     JPMorgan Chase & Co 1.2     Petroleos Mexicanos 1.1     Freddie Mac Multiclass Mortgage participation certificates 1.0     Bank of America Corp 0.9       58.3
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-B172">&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-B173">&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-B174">&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 Government Income Fund - Class M
Shareholder Report [Line Items]
Fund Name	Fidelity® Government Income Fund
Class Name	Fidelity Advisor® Government Income Fund Class M
Trading Symbol	FVITX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Government Income 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 $ 0.76 %
Expenses Paid, Amount	$ 78
Expense Ratio, Percent	0.76%
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-B191">&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 $9,761   $10,144   $10,070   $9,881   $10,778   $11,383   $11,164   $9,934   $9,652   $10,245   Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index   $10,000 $10,237   $10,723   $10,676   $10,542   $11,543   $12,274   $12,083   $10,820   $10,602   $11,280   Bloomberg U.S. Government Bond Index   $10,000 $10,227   $10,739   $10,649   $10,489   $11,570   $12,371   $12,121   $10,825   $10,608   $11,248   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)   1.90% -1.82% 0.24% Class M (without 4.00% sales charge) 6.14% -1.01% 0.65% Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index 6.40% -0.46% 1.21% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.18% 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	$ 2,324,957,949
Holdings Count | shares	2,073
Advisory Fees Paid, Amount	$ 8,233,532
Investment Company Portfolio Turnover	393%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 2,073 Total Advisory Fee $ Portfolio Turnover 393 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) Zero coupon bonds 0.0   0.01 - 0.99% 0.0   1 - 1.99% 7.0   2 - 2.99% 32.8   3 - 3.99% 22.8   4 - 4.99% 18.6   5 - 5.99% 4.9   6 - 6.99% 3.2   7 - 7.99% 0.0   8 - 8.99% 0.0     U.S. Treasury Obligations 43.0 CMOs and Other Mortgage Related Securities 23.3 U.S. Government Agency - Mortgage Securities 22.4 U.S. Government Agency Obligations 0.6 Short-Term Investments and Net Other Assets (Liabilities) 10.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 26.9     US Treasury Bonds 16.1     Fannie Mae Mortgage pass-thru certificates 14.9     Freddie Mac Multiclass Mortgage participation certificates 14.6     Freddie Mac Gold Pool 9.3     Fannie Mae Guaranteed REMICS 5.4     Ginnie Mae II Pool 3.5     Ginnie Mae I Pool 1.4     Ginnie Mae REMIC pass-thru certificates 1.1     Freddie Mac Non Gold Pool 0.8       94.0
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 contractural management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractural 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-B205">&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-B206">&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-B207">&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 Environmental Bond Fund - Class C
Shareholder Report [Line Items]
Fund Name	Fidelity® Environmental Bond Fund
Class Name	Fidelity Advisor® Environmental Bond Fund Class C
Trading Symbol	FEBDX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Environmental 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.
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 $ 1.44 %
Expenses Paid, Amount	$ 149
Expense Ratio, Percent	1.44%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B223">&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 June 15, 2021 through August 31, 2024. Initial investment of $10,000. Class C   $10,000 $10,090   $8,736   $8,560   Bloomberg MSCI Global Green USD Bond Index (Hedged USD)   $10,000 $10,120   $8,921   $8,966   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,126   $8,960   $8,853     2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year Life of Fund A Class C  (incl. contingent deferred sales charge) 5.65% -2.80% Class C 6.65% -2.80% Bloomberg MSCI Global Green USD Bond Index (Hedged USD) 8.09% -0.97% Bloomberg U.S. Aggregate Bond Index 7.30% -1.59% A   From June 15, 2021   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	Jun. 15, 2021
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	$ 37,501,935
Holdings Count | shares	199
Advisory Fees Paid, Amount	$ 120,006
Investment Company Portfolio Turnover	97%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 199 Total Advisory Fee $ Portfolio Turnover 97 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 48.6 AAA 0.9 AA 3.1 A 15.6 BBB 23.5 BB 3.6 Not Rated 4.6 Short-Term Investments and Net Other Assets (Liabilities) 0.1 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 44.0 U.S. Treasury Obligations 27.0 U.S. Government Agency - Mortgage Securities 21.2 Asset-Backed Securities 3.2 CMOs and Other Mortgage Related Securities 2.4 Foreign Government and Government Agency Obligations 1.1 Preferred Securities 0.6 U.S. Government Agency Obligations 0.4 Short-Term Investments and Net Other Assets (Liabilities) 0.1 ASSET ALLOCATION (% of Fund's net assets)   United States 82.6 Germany 2.9 United Kingdom 2.2 Netherlands 1.9 Italy 1.4 Japan 1.4 France 1.3 Ireland 1.2 Luxembourg 1.1 Others 4.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 17.0     US Treasury Bonds 10.0     Fannie Mae Mortgage pass-thru certificates 9.8     Freddie Mac Gold Pool 8.9     Freddie Mac Multiclass Mortgage participation certificates 2.1     Uniform Mortgage Backed Securities 2.1     Bank of America Corp 1.7     Verizon Communications Inc 1.6     BNP Paribas SA 1.3     PNC Financial Services Group Inc/The 1.2       55.7
Fidelity Advisor Environmental Bond Fund - Class M
Shareholder Report [Line Items]
Fund Name	Fidelity® Environmental Bond Fund
Class Name	Fidelity Advisor® Environmental Bond Fund Class M
Trading Symbol	FEBEX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Environmental 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.
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 $ 0.68 %
Expenses Paid, Amount	$ 70
Expense Ratio, Percent	0.68%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B250">&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 June 15, 2021 through August 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class M   $9,600 $9,706   $8,466   $8,357   Bloomberg MSCI Global Green USD Bond Index (Hedged USD)   $10,000 $10,120   $8,921   $8,966   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,126   $8,960   $8,853     2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year Life of Fund A Class M (incl. 4.00% sales charge)   3.04% -3.33% Class M (without 4.00% sales charge) 7.33% -2.09% Bloomberg MSCI Global Green USD Bond Index (Hedged USD) 8.09% -0.97% Bloomberg U.S. Aggregate Bond Index 7.30% -1.59% A   From June 15, 2021   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	Jun. 15, 2021
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	$ 37,501,935
Holdings Count | shares	199
Advisory Fees Paid, Amount	$ 120,006
Investment Company Portfolio Turnover	97%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 199 Total Advisory Fee $ Portfolio Turnover 97 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 48.6 AAA 0.9 AA 3.1 A 15.6 BBB 23.5 BB 3.6 Not Rated 4.6 Short-Term Investments and Net Other Assets (Liabilities) 0.1 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 44.0 U.S. Treasury Obligations 27.0 U.S. Government Agency - Mortgage Securities 21.2 Asset-Backed Securities 3.2 CMOs and Other Mortgage Related Securities 2.4 Foreign Government and Government Agency Obligations 1.1 Preferred Securities 0.6 U.S. Government Agency Obligations 0.4 Short-Term Investments and Net Other Assets (Liabilities) 0.1 ASSET ALLOCATION (% of Fund's net assets)   United States 82.6 Germany 2.9 United Kingdom 2.2 Netherlands 1.9 Italy 1.4 Japan 1.4 France 1.3 Ireland 1.2 Luxembourg 1.1 Others 4.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 17.0     US Treasury Bonds 10.0     Fannie Mae Mortgage pass-thru certificates 9.8     Freddie Mac Gold Pool 8.9     Freddie Mac Multiclass Mortgage participation certificates 2.1     Uniform Mortgage Backed Securities 2.1     Bank of America Corp 1.7     Verizon Communications Inc 1.6     BNP Paribas SA 1.3     PNC Financial Services Group Inc/The 1.2       55.7
Fidelity Advisor Total Bond Fund - Class A
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond Fund
Class Name	Fidelity Advisor® Total Bond Fund Class A
Trading Symbol	FEPAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total 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 $ 0.75 %
Expenses Paid, Amount	$ 78
Expense Ratio, Percent	0.75%
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-B278">&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 $9,655   $10,304   $10,486   $10,387   $11,355   $12,185   $12,439   $10,997   $11,004   $11,894   Bloomberg U.S. Universal Bond Index   $10,000 $10,113   $10,770   $10,915   $10,814   $11,903   $12,666   $12,778   $11,264   $11,219   $12,108   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)   3.76% 0.11% 1.75% Class A (without 4.00% sales charge) 8.09% 0.93% 2.17% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.93% 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	$ 39,553,262,535
Holdings Count | shares	6,935
Advisory Fees Paid, Amount	$ 100,486,629
Investment Company Portfolio Turnover	206%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 6,935 Total Advisory Fee $ Portfolio Turnover 206 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 54.7 AAA 8.8 AA 1.1 A 7.7 BBB 16.3 BB 4.6 B 5.6 CCC,CC,C 0.8 D 0.0 Not Rated 3.9 Equities 0.1 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 34.8 Corporate Bonds 27.7 U.S. Government Agency - Mortgage Securities 19.9 Asset-Backed Securities 7.4 CMOs and Other Mortgage Related Securities 6.8 Bank Loan Obligations 5.0 Foreign Government and Government Agency Obligations 1.2 Preferred Securities 0.4 Common Stocks 0.1 Other Investments 0.1 Purchased Swaptions 0.1 Supranational Obligations 0.1 Preferred Stocks 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)% United States 86.3 Grand Cayman (UK Overseas Ter) 4.2 United Kingdom 1.5 Mexico 1.3 Germany 1.1 Ireland 0.8 Switzerland 0.7 Canada 0.6 France 0.3 Others 3.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 25.4     US Treasury Bonds 9.4     Fannie Mae Mortgage pass-thru certificates 6.6     Ginnie Mae II Pool 5.2     Uniform Mortgage Backed Securities 3.9     Freddie Mac Gold Pool 3.6     JPMorgan Chase & Co 1.2     Petroleos Mexicanos 1.1     Freddie Mac Multiclass Mortgage participation certificates 1.0     Bank of America Corp 0.9       58.3
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-B292">&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-B293">&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-B294">&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 Environmental Bond Fund - Class A
Shareholder Report [Line Items]
Fund Name	Fidelity® Environmental Bond Fund
Class Name	Fidelity Advisor® Environmental Bond Fund Class A
Trading Symbol	FEBBX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Environmental 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.
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 $ 0.69 %
Expenses Paid, Amount	$ 72
Expense Ratio, Percent	0.69%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
Performance Past Does Not Indicate Future [Text]	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 life of Fund?      CUMULATIVE PERFORMANCE June 15, 2021 through August 31, 2024. Initial investment of $10,000 and the current sales charge was paid. Class A   $9,600 $9,706   $8,465   $8,355   Bloomberg MSCI Global Green USD Bond Index (Hedged USD)   $10,000 $10,120   $8,921   $8,966   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,126   $8,960   $8,853     2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year Life of Fund A Class A (incl. 4.00% sales charge)   3.02% -3.34% Class A (without 4.00% sales charge) 7.31% -2.10% Bloomberg MSCI Global Green USD Bond Index (Hedged USD) 8.09% -0.97% Bloomberg U.S. Aggregate Bond Index 7.30% -1.59% A   From June 15, 2021   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	Jun. 15, 2021
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	$ 37,501,935
Holdings Count | shares	199
Advisory Fees Paid, Amount	$ 120,006
Investment Company Portfolio Turnover	97%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 199 Total Advisory Fee $ Portfolio Turnover 97 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 48.6 AAA 0.9 AA 3.1 A 15.6 BBB 23.5 BB 3.6 Not Rated 4.6 Short-Term Investments and Net Other Assets (Liabilities) 0.1 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 44.0 U.S. Treasury Obligations 27.0 U.S. Government Agency - Mortgage Securities 21.2 Asset-Backed Securities 3.2 CMOs and Other Mortgage Related Securities 2.4 Foreign Government and Government Agency Obligations 1.1 Preferred Securities 0.6 U.S. Government Agency Obligations 0.4 Short-Term Investments and Net Other Assets (Liabilities) 0.1 ASSET ALLOCATION (% of Fund's net assets)   United States 82.6 Germany 2.9 United Kingdom 2.2 Netherlands 1.9 Italy 1.4 Japan 1.4 France 1.3 Ireland 1.2 Luxembourg 1.1 Others 4.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 17.0     US Treasury Bonds 10.0     Fannie Mae Mortgage pass-thru certificates 9.8     Freddie Mac Gold Pool 8.9     Freddie Mac Multiclass Mortgage participation certificates 2.1     Uniform Mortgage Backed Securities 2.1     Bank of America Corp 1.7     Verizon Communications Inc 1.6     BNP Paribas SA 1.3     PNC Financial Services Group Inc/The 1.2       55.7
Fidelity Advisor Environmental Bond Fund - Class I
Shareholder Report [Line Items]
Fund Name	Fidelity® Environmental Bond Fund
Class Name	Fidelity Advisor® Environmental Bond Fund Class I
Trading Symbol	FEBFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Environmental 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 $ 0.52 %
Expenses Paid, Amount	$ 54
Expense Ratio, Percent	0.52%
Factors Affecting Performance [Text Block]	What affected the Fund's performance this period? • • • • • Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B338">&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 June 15, 2021 through August 31, 2024. Initial investment of $10,000. Class I   $10,000 $10,116   $8,844   $8,740   Bloomberg MSCI Global Green USD Bond Index (Hedged USD)   $10,000 $10,120   $8,921   $8,966   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,126   $8,960   $8,853     2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year Life of Fund A Class I 7.63% -1.88% Bloomberg MSCI Global Green USD Bond Index (Hedged USD) 8.09% -0.97% Bloomberg U.S. Aggregate Bond Index 7.30% -1.59% A   From June 15, 2021   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	Jun. 15, 2021
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	$ 37,501,935
Holdings Count | shares	199
Advisory Fees Paid, Amount	$ 120,006
Investment Company Portfolio Turnover	97%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 199 Total Advisory Fee $ Portfolio Turnover 97 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 48.6 AAA 0.9 AA 3.1 A 15.6 BBB 23.5 BB 3.6 Not Rated 4.6 Short-Term Investments and Net Other Assets (Liabilities) 0.1 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 44.0 U.S. Treasury Obligations 27.0 U.S. Government Agency - Mortgage Securities 21.2 Asset-Backed Securities 3.2 CMOs and Other Mortgage Related Securities 2.4 Foreign Government and Government Agency Obligations 1.1 Preferred Securities 0.6 U.S. Government Agency Obligations 0.4 Short-Term Investments and Net Other Assets (Liabilities) 0.1 ASSET ALLOCATION (% of Fund's net assets)   United States 82.6 Germany 2.9 United Kingdom 2.2 Netherlands 1.9 Italy 1.4 Japan 1.4 France 1.3 Ireland 1.2 Luxembourg 1.1 Others 4.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 17.0     US Treasury Bonds 10.0     Fannie Mae Mortgage pass-thru certificates 9.8     Freddie Mac Gold Pool 8.9     Freddie Mac Multiclass Mortgage participation certificates 2.1     Uniform Mortgage Backed Securities 2.1     Bank of America Corp 1.7     Verizon Communications Inc 1.6     BNP Paribas SA 1.3     PNC Financial Services Group Inc/The 1.2       55.7
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: • Operating expenses • Expense reductions The class added a contractual expense cap 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: • Operating expenses • Expense reductions The class added a contractual expense cap 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-B353">&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-B354">&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-B355">&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 Environmental Bond Fund - Class Z
Shareholder Report [Line Items]
Fund Name	Fidelity® Environmental Bond Fund
Class Name	Fidelity Advisor® Environmental Bond Fund Class Z
Trading Symbol	FEBGX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Environmental 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.
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? • • • • • Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B371">&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 June 15, 2021 through August 31, 2024. Initial investment of $10,000. Class Z   $10,000 $10,118   $8,851   $8,766   Bloomberg MSCI Global Green USD Bond Index (Hedged USD)   $10,000 $10,120   $8,921   $8,966   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,126   $8,960   $8,853     2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year Life of Fund A Class Z 7.67% -1.78% Bloomberg MSCI Global Green USD Bond Index (Hedged USD) 8.09% -0.97% Bloomberg U.S. Aggregate Bond Index 7.30% -1.59% A   From June 15, 2021   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	Jun. 15, 2021
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	$ 37,501,935
Holdings Count | shares	199
Advisory Fees Paid, Amount	$ 120,006
Investment Company Portfolio Turnover	97%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 199 Total Advisory Fee $ Portfolio Turnover 97 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 48.6 AAA 0.9 AA 3.1 A 15.6 BBB 23.5 BB 3.6 Not Rated 4.6 Short-Term Investments and Net Other Assets (Liabilities) 0.1 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 44.0 U.S. Treasury Obligations 27.0 U.S. Government Agency - Mortgage Securities 21.2 Asset-Backed Securities 3.2 CMOs and Other Mortgage Related Securities 2.4 Foreign Government and Government Agency Obligations 1.1 Preferred Securities 0.6 U.S. Government Agency Obligations 0.4 Short-Term Investments and Net Other Assets (Liabilities) 0.1 ASSET ALLOCATION (% of Fund's net assets)   United States 82.6 Germany 2.9 United Kingdom 2.2 Netherlands 1.9 Italy 1.4 Japan 1.4 France 1.3 Ireland 1.2 Luxembourg 1.1 Others 4.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 17.0     US Treasury Bonds 10.0     Fannie Mae Mortgage pass-thru certificates 9.8     Freddie Mac Gold Pool 8.9     Freddie Mac Multiclass Mortgage participation certificates 2.1     Uniform Mortgage Backed Securities 2.1     Bank of America Corp 1.7     Verizon Communications Inc 1.6     BNP Paribas SA 1.3     PNC Financial Services Group Inc/The 1.2       55.7
Fidelity Advisor Government Income Fund - Class Z
Shareholder Report [Line Items]
Fund Name	Fidelity® Government Income Fund
Class Name	Fidelity Advisor® Government Income Fund Class Z
Trading Symbol	FIKPX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Government Income 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-B399">&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 $11,027   $11,702   $11,520   $10,283   $10,041   $10,689   Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index   $10,000 $11,042   $11,740   $11,558   $10,350   $10,141   $10,790   Bloomberg U.S. Government Bond Index   $10,000 $11,132   $11,902   $11,662   $10,415   $10,206   $10,822   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 6.45% -0.62% 1.13% Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index 6.40% -0.46% 1.29% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.34% 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	$ 2,324,957,949
Holdings Count | shares	2,073
Advisory Fees Paid, Amount	$ 8,233,532
Investment Company Portfolio Turnover	393%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 2,073 Total Advisory Fee $ Portfolio Turnover 393 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) Zero coupon bonds 0.0   0.01 - 0.99% 0.0   1 - 1.99% 7.0   2 - 2.99% 32.8   3 - 3.99% 22.8   4 - 4.99% 18.6   5 - 5.99% 4.9   6 - 6.99% 3.2   7 - 7.99% 0.0   8 - 8.99% 0.0     U.S. Treasury Obligations 43.0 CMOs and Other Mortgage Related Securities 23.3 U.S. Government Agency - Mortgage Securities 22.4 U.S. Government Agency Obligations 0.6 Short-Term Investments and Net Other Assets (Liabilities) 10.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 26.9     US Treasury Bonds 16.1     Fannie Mae Mortgage pass-thru certificates 14.9     Freddie Mac Multiclass Mortgage participation certificates 14.6     Freddie Mac Gold Pool 9.3     Fannie Mae Guaranteed REMICS 5.4     Ginnie Mae II Pool 3.5     Ginnie Mae I Pool 1.4     Ginnie Mae REMIC pass-thru certificates 1.1     Freddie Mac Non Gold Pool 0.8       94.0
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 contractural management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractural 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-B414">&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-B415">&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-B416">&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 Government Income Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Government Income Fund
Class Name	Fidelity® Government Income Fund
Trading Symbol	FGOVX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Government Income 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® Government Income Fund $ 0.45 %
Expenses Paid, Amount	$ 46
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-B433">&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® Government Income Fund   $10,000 $10,199   $10,643   $10,598   $10,431   $11,404   $12,081   $11,893   $10,603   $10,344   $11,003   Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index   $10,000 $10,237   $10,723   $10,676   $10,542   $11,543   $12,274   $12,083   $10,820   $10,602   $11,280   Bloomberg U.S. Government Bond Index   $10,000 $10,227   $10,739   $10,649   $10,489   $11,570   $12,371   $12,121   $10,825   $10,608   $11,248   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® Government Income Fund 6.36% -0.71% 0.96% Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index 6.40% -0.46% 1.21% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.18% 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	$ 2,324,957,949
Holdings Count | shares	2,073
Advisory Fees Paid, Amount	$ 8,233,532
Investment Company Portfolio Turnover	393%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 2,073 Total Advisory Fee $ Portfolio Turnover 393 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) Zero coupon bonds 0.0   0.01 - 0.99% 0.0   1 - 1.99% 7.0   2 - 2.99% 32.8   3 - 3.99% 22.8   4 - 4.99% 18.6   5 - 5.99% 4.9   6 - 6.99% 3.2   7 - 7.99% 0.0   8 - 8.99% 0.0     U.S. Treasury Obligations 43.0 CMOs and Other Mortgage Related Securities 23.3 U.S. Government Agency - Mortgage Securities 22.4 U.S. Government Agency Obligations 0.6 Short-Term Investments and Net Other Assets (Liabilities) 10.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 26.9     US Treasury Bonds 16.1     Fannie Mae Mortgage pass-thru certificates 14.9     Freddie Mac Multiclass Mortgage participation certificates 14.6     Freddie Mac Gold Pool 9.3     Fannie Mae Guaranteed REMICS 5.4     Ginnie Mae II Pool 3.5     Ginnie Mae I Pool 1.4     Ginnie Mae REMIC pass-thru certificates 1.1     Freddie Mac Non Gold Pool 0.8       94.0
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 contractural management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractural 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-B447">&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-B448">&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-B449">&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 Government Income Fund - Class I
Shareholder Report [Line Items]
Fund Name	Fidelity® Government Income Fund
Class Name	Fidelity Advisor® Government Income Fund Class I
Trading Symbol	FVIIX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Government Income 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 $ 0.50 %
Expenses Paid, Amount	$ 52
Expense Ratio, Percent	0.50%
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-B466">&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 $10,194   $10,621   $10,572   $10,402   $11,377   $12,048   $11,856   $10,570   $10,296   $10,957   Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index   $10,000 $10,237   $10,723   $10,676   $10,542   $11,543   $12,274   $12,083   $10,820   $10,602   $11,280   Bloomberg U.S. Government Bond Index   $10,000 $10,227   $10,739   $10,649   $10,489   $11,570   $12,371   $12,121   $10,825   $10,608   $11,248   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 6.42% -0.75% 0.92% Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index 6.40% -0.46% 1.21% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.18% 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	$ 2,324,957,949
Holdings Count | shares	2,073
Advisory Fees Paid, Amount	$ 8,233,532
Investment Company Portfolio Turnover	393%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 2,073 Total Advisory Fee $ Portfolio Turnover 393 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) Zero coupon bonds 0.0   0.01 - 0.99% 0.0   1 - 1.99% 7.0   2 - 2.99% 32.8   3 - 3.99% 22.8   4 - 4.99% 18.6   5 - 5.99% 4.9   6 - 6.99% 3.2   7 - 7.99% 0.0   8 - 8.99% 0.0     U.S. Treasury Obligations 43.0 CMOs and Other Mortgage Related Securities 23.3 U.S. Government Agency - Mortgage Securities 22.4 U.S. Government Agency Obligations 0.6 Short-Term Investments and Net Other Assets (Liabilities) 10.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 26.9     US Treasury Bonds 16.1     Fannie Mae Mortgage pass-thru certificates 14.9     Freddie Mac Multiclass Mortgage participation certificates 14.6     Freddie Mac Gold Pool 9.3     Fannie Mae Guaranteed REMICS 5.4     Ginnie Mae II Pool 3.5     Ginnie Mae I Pool 1.4     Ginnie Mae REMIC pass-thru certificates 1.1     Freddie Mac Non Gold Pool 0.8       94.0
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 contractural management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractural 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-B480">&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-B481">&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-B482">&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 Total Bond K6 Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond K6 Fund
Class Name	Fidelity® Total Bond K6 Fund
Trading Symbol	FTKFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total Bond K6 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 1-800-835-5092 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number	1-800-835-5092
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® Total Bond K6 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-B498">&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 May 25, 2017 through August 31, 2024. Initial investment of $10,000. Fidelity® Total Bond K6 Fund   $10,000 $10,135   $10,068   $11,046   $11,905   $12,206   $10,854   $10,882   Bloomberg U.S. Universal Bond Index   $10,000 $10,157   $10,063   $11,077   $11,787   $11,891   $10,482   $10,441   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,154   $10,047   $11,070   $11,786   $11,776   $10,420   $10,296     2017 2018 2019 2020 2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year 5 Year Life of Fund A Fidelity® Total Bond K6 Fund 8.25% 1.29% 2.28% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.65% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.38% A   From May 25, 2017   Visit www.401k.com for more recent performance information.   The Fund's past performance is not a good predictor of the Fund's future performance.  The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Performance Inception Date	May 25, 2017
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Net Assets	$ 5,566,487,263
Holdings Count | shares	4,171
Advisory Fees Paid, Amount	$ 11,115,971
Investment Company Portfolio Turnover	306%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 4,171 Total Advisory Fee $ Portfolio Turnover 306 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 57.5 AAA 7.5 AA 0.5 A 7.1 BBB 15.1 BB 4.2 B 5.1 CCC,CC,C 0.9 D 0.0 Not Rated 3.9 Equities 0.6 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (2.4)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 37.4 Corporate Bonds 25.5 U.S. Government Agency - Mortgage Securities 20.1 Asset-Backed Securities 6.9 CMOs and Other Mortgage Related Securities 6.2 Bank Loan Obligations 4.1 Foreign Government and Government Agency Obligations 1.2 Fixed-Income Funds 0.4 Preferred Securities 0.3 Common Stocks 0.1 Alternative Funds 0.1 Purchased Swaptions 0.1 Other Investments 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (2.4)% United States 88.2 Grand Cayman (UK Overseas Ter) 3.1 United Kingdom 1.6 Mexico 1.0 Germany 0.9 Bailiwick Of Jersey 0.8 Ireland 0.7 Switzerland 0.6 Canada 0.5 Others 2.6 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 28.4     US Treasury Bonds 9.0     Uniform Mortgage Backed Securities 6.1     Ginnie Mae II Pool 5.7     Fannie Mae Mortgage pass-thru certificates 5.4     Freddie Mac Gold Pool 2.6     JPMorgan Chase & Co 1.1     Bank of America Corp 0.9     Petroleos Mexicanos 0.9     Charter Communications Operating LLC / Charter Communications Operating Capital 0.8       60.9
Fidelity Series Government Bond Index Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Series Government Bond Index Fund
Class Name	Fidelity® Series Government Bond Index Fund
Trading Symbol	FHNFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Series Government Bond Index 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 Government Bond Index 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-B524">&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 Government Bond Index Fund   $10,000 $10,010   $11,052   $11,781   $11,563   $10,330   $10,128   Bloomberg U.S. Government Bond Index   $10,000 $10,019   $11,052   $11,816   $11,578   $10,340   $10,133   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 Government Bond Index Fund 6.11% -0.56% 1.20% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.19% 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	$ 939,274,989
Holdings Count | shares	243
Advisory Fees Paid, Amount	$ 0
Investment Company Portfolio Turnover	23%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 243 Total Advisory Fee $ Portfolio Turnover 23 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) 0.01 - 0.99% 24.0   1 - 1.99% 22.5   2 - 2.99% 18.6   3 - 3.99% 14.4   4 - 4.99% 15.6   5 - 5.99% 2.5   6 - 6.99% 1.1   7 - 7.99% 0.1     U.S. Treasury Obligations 96.7 U.S. Government Agency Obligations 2.1 Short-Term Investments and Net Other Assets (Liabilities) 1.2 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 74.0     US Treasury Bonds 22.7     Fannie Mae 0.6     Federal Home Loan Bank 0.4     Freddie Mac Non Gold Pool 0.4     Federal Farm Credit Banks Funding Corp 0.4     Tennessee Valley Authority Generic Strip 0.3       98.8
Fidelity Advisor Government Income Fund - Class A
Shareholder Report [Line Items]
Fund Name	Fidelity® Government Income Fund
Class Name	Fidelity Advisor® Government Income Fund Class A
Trading Symbol	FVIAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Government Income 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 $ 0.79 %
Expenses Paid, Amount	$ 81
Expense Ratio, Percent	0.79%
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-B552">&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 $9,760   $10,143   $10,069   $9,878   $10,774   $11,376   $11,168   $9,927   $9,642   $10,232   Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index   $10,000 $10,237   $10,723   $10,676   $10,542   $11,543   $12,274   $12,083   $10,820   $10,602   $11,280   Bloomberg U.S. Government Bond Index   $10,000 $10,227   $10,739   $10,649   $10,489   $11,570   $12,371   $12,121   $10,825   $10,608   $11,248   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)   1.87% -1.83% 0.23% Class A (without 4.00% sales charge) 6.11% -1.03% 0.64% Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index 6.40% -0.46% 1.21% Bloomberg U.S. Government Bond Index 6.03% -0.56% 1.18% 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	$ 2,324,957,949
Holdings Count | shares	2,073
Advisory Fees Paid, Amount	$ 8,233,532
Investment Company Portfolio Turnover	393%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 2,073 Total Advisory Fee $ Portfolio Turnover 393 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) Zero coupon bonds 0.0   0.01 - 0.99% 0.0   1 - 1.99% 7.0   2 - 2.99% 32.8   3 - 3.99% 22.8   4 - 4.99% 18.6   5 - 5.99% 4.9   6 - 6.99% 3.2   7 - 7.99% 0.0   8 - 8.99% 0.0     U.S. Treasury Obligations 43.0 CMOs and Other Mortgage Related Securities 23.3 U.S. Government Agency - Mortgage Securities 22.4 U.S. Government Agency Obligations 0.6 Short-Term Investments and Net Other Assets (Liabilities) 10.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 26.9     US Treasury Bonds 16.1     Fannie Mae Mortgage pass-thru certificates 14.9     Freddie Mac Multiclass Mortgage participation certificates 14.6     Freddie Mac Gold Pool 9.3     Fannie Mae Guaranteed REMICS 5.4     Ginnie Mae II Pool 3.5     Ginnie Mae I Pool 1.4     Ginnie Mae REMIC pass-thru certificates 1.1     Freddie Mac Non Gold Pool 0.8       94.0
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 contractural management fee was reduced during the reporting period.
Material Fund Change Expenses [Text Block]	The fund's contractural 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-B566">&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-B567">&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-B568">&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 Environmental Bond Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Environmental Bond Fund
Class Name	Fidelity® Environmental Bond Fund
Trading Symbol	FFEBX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Environmental 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.
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® Environmental Bond 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? • • • • • Application of FMR's environmental, social, and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the Fund's exposure to certain issuers, sectors, regions, and countries and may affect the Fund's performance.
Performance Past Does Not Indicate Future [Text]	The Fund's past performance is not a good predictor of the Fund's future performance.</span>" id="sjs-B584">&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 June 15, 2021 through August 31, 2024. Initial investment of $10,000. Fidelity® Environmental Bond Fund   $10,000 $10,116   $8,841   $8,748   Bloomberg MSCI Global Green USD Bond Index (Hedged USD)   $10,000 $10,120   $8,921   $8,966   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,126   $8,960   $8,853     2021 2022 2023 2024
Average Annual Return [Table Text Block]	AVERAGE ANNUAL TOTAL RETURNS:     1 Year Life of Fund A Fidelity® Environmental Bond Fund 7.57% -1.87% Bloomberg MSCI Global Green USD Bond Index (Hedged USD) 8.09% -0.97% Bloomberg U.S. Aggregate Bond Index 7.30% -1.59% A   From June 15, 2021   Visit www.fidelity.com for more recent performance information.   The Fund's past performance is not a good predictor of the Fund's future performance.  The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.
Performance Inception Date	Jun. 15, 2021
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	$ 37,501,935
Holdings Count | shares	199
Advisory Fees Paid, Amount	$ 120,006
Investment Company Portfolio Turnover	97%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 199 Total Advisory Fee $ Portfolio Turnover 97 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 48.6 AAA 0.9 AA 3.1 A 15.6 BBB 23.5 BB 3.6 Not Rated 4.6 Short-Term Investments and Net Other Assets (Liabilities) 0.1 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 44.0 U.S. Treasury Obligations 27.0 U.S. Government Agency - Mortgage Securities 21.2 Asset-Backed Securities 3.2 CMOs and Other Mortgage Related Securities 2.4 Foreign Government and Government Agency Obligations 1.1 Preferred Securities 0.6 U.S. Government Agency Obligations 0.4 Short-Term Investments and Net Other Assets (Liabilities) 0.1 ASSET ALLOCATION (% of Fund's net assets)   United States 82.6 Germany 2.9 United Kingdom 2.2 Netherlands 1.9 Italy 1.4 Japan 1.4 France 1.3 Ireland 1.2 Luxembourg 1.1 Others 4.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 17.0     US Treasury Bonds 10.0     Fannie Mae Mortgage pass-thru certificates 9.8     Freddie Mac Gold Pool 8.9     Freddie Mac Multiclass Mortgage participation certificates 2.1     Uniform Mortgage Backed Securities 2.1     Bank of America Corp 1.7     Verizon Communications Inc 1.6     BNP Paribas SA 1.3     PNC Financial Services Group Inc/The 1.2       55.7
Fidelity Advisor Total Bond Fund - Class Z
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond Fund
Class Name	Fidelity Advisor® Total Bond Fund Class Z
Trading Symbol	FBKWX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total 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 $ 0.36 %
Expenses Paid, Amount	$ 38
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-B612">&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 December 22, 2014 through August 31, 2024. Initial investment of $10,000. Class Z   $10,000 $10,059   $10,777   $11,010   $10,948   $12,017   $12,945   $13,267   $11,771   $11,824   $12,830   Bloomberg U.S. Universal Bond Index   $10,000 $10,069   $10,724   $10,868   $10,767   $11,852   $12,612   $12,724   $11,215   $11,171   $12,056   Bloomberg U.S. Aggregate Bond Index   $10,000 $10,054   $10,654   $10,706   $10,594   $11,672   $12,427   $12,417   $10,987   $10,856   $11,648     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 Life of Fund A Class Z 8.51% 1.32% 2.60% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.95% Bloomberg U.S. Aggregate Bond Index 7.30% -0.04% 1.59% A   From December 22, 2014   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	Dec. 22, 2014
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	$ 39,553,262,535
Holdings Count | shares	6,935
Advisory Fees Paid, Amount	$ 100,486,629
Investment Company Portfolio Turnover	206%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 6,935 Total Advisory Fee $ Portfolio Turnover 206 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 54.7 AAA 8.8 AA 1.1 A 7.7 BBB 16.3 BB 4.6 B 5.6 CCC,CC,C 0.8 D 0.0 Not Rated 3.9 Equities 0.1 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 34.8 Corporate Bonds 27.7 U.S. Government Agency - Mortgage Securities 19.9 Asset-Backed Securities 7.4 CMOs and Other Mortgage Related Securities 6.8 Bank Loan Obligations 5.0 Foreign Government and Government Agency Obligations 1.2 Preferred Securities 0.4 Common Stocks 0.1 Other Investments 0.1 Purchased Swaptions 0.1 Supranational Obligations 0.1 Preferred Stocks 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)% United States 86.3 Grand Cayman (UK Overseas Ter) 4.2 United Kingdom 1.5 Mexico 1.3 Germany 1.1 Ireland 0.8 Switzerland 0.7 Canada 0.6 France 0.3 Others 3.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 25.4     US Treasury Bonds 9.4     Fannie Mae Mortgage pass-thru certificates 6.6     Ginnie Mae II Pool 5.2     Uniform Mortgage Backed Securities 3.9     Freddie Mac Gold Pool 3.6     JPMorgan Chase & Co 1.2     Petroleos Mexicanos 1.1     Freddie Mac Multiclass Mortgage participation certificates 1.0     Bank of America Corp 0.9       58.3
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-B627">&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-B628">&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-B629">&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 Total Bond Fund - Class I
Shareholder Report [Line Items]
Fund Name	Fidelity® Total Bond Fund
Class Name	Fidelity Advisor® Total Bond Fund Class I
Trading Symbol	FEPIX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains information about Fidelity® Total 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 $ 0.50 %
Expenses Paid, Amount	$ 52
Expense Ratio, Percent	0.50%
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-B646">&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 $10,073   $10,778   $10,996   $10,919   $11,968   $12,875   $13,176   $11,675   $11,711   $12,690   Bloomberg U.S. Universal Bond Index   $10,000 $10,113   $10,770   $10,915   $10,814   $11,903   $12,666   $12,778   $11,264   $11,219   $12,108   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 8.36% 1.18% 2.41% Bloomberg U.S. Universal Bond Index 7.92% 0.34% 1.93% 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	$ 39,553,262,535
Holdings Count | shares	6,935
Advisory Fees Paid, Amount	$ 100,486,629
Investment Company Portfolio Turnover	206%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of August 31, 2024) KEY FACTS Fund Size $ Number of Holdings 6,935 Total Advisory Fee $ Portfolio Turnover 206 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 54.7 AAA 8.8 AA 1.1 A 7.7 BBB 16.3 BB 4.6 B 5.6 CCC,CC,C 0.8 D 0.0 Not Rated 3.9 Equities 0.1 QUALITY DIVERSIFICATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)%   We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes.     U.S. Treasury Obligations 34.8 Corporate Bonds 27.7 U.S. Government Agency - Mortgage Securities 19.9 Asset-Backed Securities 7.4 CMOs and Other Mortgage Related Securities 6.8 Bank Loan Obligations 5.0 Foreign Government and Government Agency Obligations 1.2 Preferred Securities 0.4 Common Stocks 0.1 Other Investments 0.1 Purchased Swaptions 0.1 Supranational Obligations 0.1 Preferred Stocks 0.0 ASSET ALLOCATION (% of Fund's net assets)   Short-Term Investments and Net Other Assets (Liabilities) - (3.6)% United States 86.3 Grand Cayman (UK Overseas Ter) 4.2 United Kingdom 1.5 Mexico 1.3 Germany 1.1 Ireland 0.8 Switzerland 0.7 Canada 0.6 France 0.3 Others 3.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets)     US Treasury Notes 25.4     US Treasury Bonds 9.4     Fannie Mae Mortgage pass-thru certificates 6.6     Ginnie Mae II Pool 5.2     Uniform Mortgage Backed Securities 3.9     Freddie Mac Gold Pool 3.6     JPMorgan Chase & Co 1.2     Petroleos Mexicanos 1.1     Freddie Mac Multiclass Mortgage participation certificates 1.0     Bank of America Corp 0.9       58.3
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-B660">&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-B661">&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-B662">&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

48 Months Ended

60 Months Ended

84 Months Ended

96 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, 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

C000038100_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H5">&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>

C000038100_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000038100_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 10,156

C000038100_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 10,761

C000038100_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 10,814

C000038100_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 10,701

C000038100_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 11,789

C000038100_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 12,553

C000038100_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 12,542

C000038100_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 11,098

C000038100_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 10,965

C000038100_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

C000038100_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000038100_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000038100_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000019284_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019284_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019284_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000019276_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019276_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019276_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000019272_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019272_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019272_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000019275_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019275_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019275_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000038101_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H86">&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>

C000038101_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038101_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000038101_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000038101_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000038101_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000038101_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000038101_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000038101_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000038101_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000038101_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000038101_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

$ 11,765

11,765

$ 11,765

$ 11,765

C000038101_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000038101_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000038101_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000227905_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000227905_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(1.59%)

C000227901_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000227901_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(1.59%)

C000019273_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019273_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019273_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000227902_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000227902_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(1.59%)

C000227904_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000227904_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(1.59%)

C000227906_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000227906_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(1.59%)

C000205069_0_LG_BBIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-E170">&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>

C000205069_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000205069_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,086

C000205069_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,804

C000205069_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,794

C000205069_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,436

C000205069_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,311

C000205069_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,064

11,064

$ 11,064

$ 11,064

11,064

$ 11,064

$ 11,064

C000205069_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000205069_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000205069_2_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.72%

C000019283_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H203">&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>

C000019283_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019283_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000019283_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000019283_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000019283_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000019283_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000019283_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000019283_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000019283_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000019283_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000019283_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000019283_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019283_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019283_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000038102_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H248">&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>

C000038102_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038102_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000038102_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000038102_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000038102_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000038102_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000038102_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000038102_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000038102_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000038102_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000038102_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000038102_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000038102_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000038102_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000182864_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000182864_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000182864_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.38%

C000203458_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000203458_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000203458_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.61%

C000038098_0_LG_BBIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H311">&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>

C000038098_0_BBIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038098_0_BBIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000038098_0_BBIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000038098_0_BBIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000038098_0_BBIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000038098_0_BBIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000038098_0_BBIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000038098_0_BBIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000038098_0_BBIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000038098_0_BBIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000038098_0_BBIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000038098_2_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000038098_2_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000038098_2_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000227903_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000227903_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(1.59%)

C000150510_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000150510_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000150510_1_BBIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.59%

C000019277_1_BBIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.30%

C000019277_1_BBIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.04%)

C000019277_1_BBIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.64%

C000038100_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class C</span>" id="sjs-H380">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C&lt;/span>

C000038100_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038100_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,088

C000038100_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,403

C000038100_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,247

C000038100_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

9,977

C000038100_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,798

C000038100_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,312

C000038100_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,016

C000038100_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

9,719

C000038100_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,440

C000038100_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,017

10,017

$ 10,017

10,017

10,017

$ 10,017

$ 10,017

C000038100_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index</span>" id="sjs-H416">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index&lt;/span>

C000038100_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038100_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,237

C000038100_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,723

C000038100_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,676

C000038100_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,542

C000038100_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,543

C000038100_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,274

C000038100_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,083

C000038100_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,820

C000038100_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,602

C000038100_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,280

11,280

11,280

11,280

11,280

11,280

$ 11,280

C000038100_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-H452">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000038100_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038100_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,227

C000038100_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,739

C000038100_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,649

C000038100_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,489

C000038100_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,570

C000038100_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,371

C000038100_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,121

C000038100_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,825

C000038100_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,608

C000038100_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,248

11,248

$ 11,248

11,248

11,248

$ 11,248

$ 11,248

C000038100_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

4.23%

C000038100_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.79%)

C000038100_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.02%

C000038100_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.23%

C000038100_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.79%)

C000038100_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.02%

C000038100_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.40%

C000038100_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.46%)

C000038100_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.21%

C000038100_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000038100_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000038100_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.18%

C000019284_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Intermediate Government Income Fund</span>" id="sjs-H524">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Intermediate Government Income Fund&lt;/span>

C000019284_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019284_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,150

C000019284_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,416

C000019284_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,424

C000019284_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,265

C000019284_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,015

C000019284_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,574

C000019284_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,449

C000019284_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,516

C000019284_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,441

C000019284_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,061

11,061

$ 11,061

11,061

11,061

$ 11,061

$ 11,061

C000019284_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Intermediate Government Bond Index</span>" id="sjs-H560">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Intermediate Government Bond Index&lt;/span>

C000019284_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019284_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,189

C000019284_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,497

C000019284_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,506

C000019284_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,375

C000019284_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,148

C000019284_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,753

C000019284_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,676

C000019284_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,796

C000019284_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,782

C000019284_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,457

11,457

11,457

11,457

11,457

11,457

$ 11,457

C000019284_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H596">&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>

C000019284_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019284_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000019284_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000019284_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000019284_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000019284_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000019284_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000019284_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000019284_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000019284_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000019284_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000019284_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.94%

C000019284_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.08%

C000019284_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.01%

C000019284_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.26%

C000019284_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.55%

C000019284_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.37%

C000019276_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class M</span>" id="sjs-H650">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M&lt;/span>

C000019276_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000019276_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,645

C000019276_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,291

C000019276_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,472

C000019276_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,372

C000019276_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,340

C000019276_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,169

C000019276_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,423

C000019276_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,980

C000019276_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,986

C000019276_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,876

11,876

$ 11,876

11,876

11,876

$ 11,876

$ 11,876

C000019276_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-H686">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000019276_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019276_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,113

C000019276_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,770

C000019276_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,915

C000019276_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,814

C000019276_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,903

C000019276_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,666

C000019276_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,778

C000019276_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,264

C000019276_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,219

C000019276_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,108

12,108

12,108

12,108

12,108

12,108

$ 12,108

C000019276_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H722">&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>

C000019276_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019276_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000019276_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000019276_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000019276_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000019276_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000019276_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000019276_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000019276_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000019276_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000019276_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000019276_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.77%

C000019276_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.11%

C000019276_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.73%

C000019276_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.10%

C000019276_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.93%

C000019276_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.15%

C000019276_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000019276_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000019276_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.93%

C000019272_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Total Bond Fund</span>" id="sjs-H785">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Total Bond Fund&lt;/span>

C000019272_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019272_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,088

C000019272_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,788

C000019272_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,012

C000019272_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,951

C000019272_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,008

C000019272_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,923

C000019272_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,232

C000019272_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,721

C000019272_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,764

C000019272_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 12,766

12,766

$ 12,766

12,766

12,766

$ 12,766

$ 12,766

C000019272_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-H821">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000019272_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019272_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,113

C000019272_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,770

C000019272_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,915

C000019272_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,814

C000019272_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,903

C000019272_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,666

C000019272_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,778

C000019272_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,264

C000019272_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,219

C000019272_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,108

12,108

12,108

12,108

12,108

12,108

$ 12,108

C000019272_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H857">&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>

C000019272_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019272_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000019272_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000019272_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000019272_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000019272_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000019272_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000019272_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000019272_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000019272_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000019272_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000019272_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.52%

C000019272_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.23%

C000019272_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.47%

C000019272_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000019272_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000019272_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.93%

C000019275_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class C</span>" id="sjs-H911">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C&lt;/span>

C000019275_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019275_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,980

C000019275_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,569

C000019275_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,674

C000019275_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,503

C000019275_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,394

C000019275_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,133

C000019275_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,292

C000019275_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,774

C000019275_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,782

C000019275_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,653

11,653

$ 11,653

11,653

11,653

$ 11,653

$ 11,653

C000019275_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-H947">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000019275_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019275_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,113

C000019275_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,770

C000019275_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,915

C000019275_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,814

C000019275_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,903

C000019275_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,666

C000019275_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,778

C000019275_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,264

C000019275_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,219

C000019275_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,108

12,108

12,108

12,108

12,108

12,108

$ 12,108

C000019275_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H983">&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>

C000019275_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019275_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000019275_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000019275_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000019275_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000019275_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000019275_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000019275_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000019275_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000019275_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000019275_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000019275_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.27%

C000019275_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.14%

C000019275_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.54%

C000019275_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.27%

C000019275_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.14%

C000019275_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.54%

C000019275_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000019275_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000019275_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.93%

C000038101_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class M</span>" id="sjs-H1046">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M&lt;/span>

C000038101_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000038101_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,761

C000038101_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,144

C000038101_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,070

C000038101_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

9,881

C000038101_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,778

C000038101_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,383

C000038101_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,164

C000038101_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

9,934

C000038101_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,652

C000038101_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,245

10,245

$ 10,245

10,245

10,245

$ 10,245

$ 10,245

C000038101_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index</span>" id="sjs-H1082">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index&lt;/span>

C000038101_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038101_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,237

C000038101_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,723

C000038101_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,676

C000038101_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,542

C000038101_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,543

C000038101_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,274

C000038101_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,083

C000038101_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,820

C000038101_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,602

C000038101_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,280

11,280

11,280

11,280

11,280

11,280

$ 11,280

C000038101_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-H1118">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000038101_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038101_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,227

C000038101_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,739

C000038101_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,649

C000038101_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,489

C000038101_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,570

C000038101_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,371

C000038101_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,121

C000038101_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,825

C000038101_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,608

C000038101_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,248

$ 11,248

$ 11,248

11,248

11,248

$ 11,248

$ 11,248

C000038101_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.90%

C000038101_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.82%)

C000038101_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.24%

C000038101_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.14%

C000038101_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.01%)

C000038101_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.65%

C000038101_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.40%

C000038101_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.46%)

C000038101_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.21%

C000038101_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000038101_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000038101_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.18%

C000227905_LG_ClassMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class C</span>" id="sjs-C1190">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C&lt;/span>

C000227905_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227905_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,090

C000227905_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,736

C000227905_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,560

$ 8,560

$ 8,560

8,560

8,560

$ 8,560

8,560

C000227905_LG_1_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg MSCI Global Green USD Bond Index (Hedged USD)</span>" id="sjs-C1205">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg MSCI Global Green USD Bond Index (Hedged USD)&lt;/span>

C000227905_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227905_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,120

C000227905_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,921

C000227905_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

8,966

$ 8,966

8,966

8,966

8,966

8,966

8,966

C000227905_LG_2_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-C1220">&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>

C000227905_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227905_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,126

C000227905_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,960

C000227905_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,853

$ 8,853

8,853

8,853

8,853

8,853

8,853

C000227905_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

5.65%

C000227905_ClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(2.80%)

C000227905_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.65%

C000227905_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(2.80%)

C000227905_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000227905_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(0.97%)

C000227901_LG_ClassMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class M</span>" id="sjs-C1253">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M&lt;/span>

C000227901_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

9,600

C000227901_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

9,706

C000227901_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,466

C000227901_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,357

$ 8,357

8,357

8,357

8,357

8,357

8,357

C000227901_LG_1_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg MSCI Global Green USD Bond Index (Hedged USD)</span>" id="sjs-C1268">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg MSCI Global Green USD Bond Index (Hedged USD)&lt;/span>

C000227901_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227901_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,120

C000227901_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,921

C000227901_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

8,966

$ 8,966

8,966

8,966

8,966

8,966

8,966

C000227901_LG_2_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-C1283">&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>

C000227901_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227901_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,126

C000227901_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,960

C000227901_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,853

$ 8,853

8,853

8,853

8,853

8,853

$ 8,853

C000227901_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.04%

C000227901_ClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(3.33%)

C000227901_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.33%

C000227901_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(2.09%)

C000227901_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000227901_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(0.97%)

C000019273_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class A</span>" id="sjs-H1316">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A&lt;/span>

C000019273_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000019273_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,655

C000019273_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,304

C000019273_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,486

C000019273_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,387

C000019273_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,355

C000019273_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,185

C000019273_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,439

C000019273_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,997

C000019273_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,004

C000019273_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,894

11,894

11,894

11,894

11,894

11,894

$ 11,894

C000019273_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-H1352">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000019273_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019273_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,113

C000019273_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,770

C000019273_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,915

C000019273_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,814

C000019273_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,903

C000019273_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,666

C000019273_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,778

C000019273_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,264

C000019273_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,219

C000019273_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,108

12,108

12,108

12,108

12,108

12,108

$ 12,108

C000019273_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H1388">&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>

C000019273_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019273_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,156

C000019273_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,761

C000019273_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,814

C000019273_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,701

C000019273_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,789

C000019273_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,553

C000019273_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,542

C000019273_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,098

C000019273_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,965

C000019273_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

$ 11,765

11,765

11,765

$ 11,765

$ 11,765

C000019273_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.76%

C000019273_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.11%

C000019273_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.75%

C000019273_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000019273_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.93%

C000019273_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.17%

C000019273_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000019273_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000019273_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.93%

C000227902_LG_ClassMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class A</span>" id="sjs-C1451">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A&lt;/span>

C000227902_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

9,600

C000227902_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

9,706

C000227902_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,465

C000227902_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,355

$ 8,355

$ 8,355

8,355

8,355

$ 8,355

8,355

C000227902_LG_1_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg MSCI Global Green USD Bond Index (Hedged USD)</span>" id="sjs-C1466">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg MSCI Global Green USD Bond Index (Hedged USD)&lt;/span>

C000227902_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227902_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,120

C000227902_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,921

C000227902_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

8,966

$ 8,966

8,966

8,966

8,966

8,966

8,966

C000227902_LG_2_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-C1481">&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>

C000227902_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227902_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,126

C000227902_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,960

C000227902_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,853

$ 8,853

8,853

8,853

8,853

8,853

8,853

C000227902_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

3.02%

C000227902_ClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(3.34%)

C000227902_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.31%

C000227902_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(2.10%)

C000227902_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000227902_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(0.97%)

C000227904_LG_ClassMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class I</span>" id="sjs-C1514">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I&lt;/span>

C000227904_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227904_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,116

C000227904_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,844

C000227904_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,740

$ 8,740

8,740

8,740

8,740

8,740

8,740

C000227904_LG_1_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg MSCI Global Green USD Bond Index (Hedged USD)</span>" id="sjs-C1529">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg MSCI Global Green USD Bond Index (Hedged USD)&lt;/span>

C000227904_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227904_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,120

C000227904_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,921

C000227904_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

8,966

$ 8,966

8,966

8,966

8,966

8,966

8,966

C000227904_LG_2_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-C1544">&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>

C000227904_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227904_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,126

C000227904_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,960

C000227904_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,853

$ 8,853

8,853

8,853

8,853

8,853

8,853

C000227904_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.63%

C000227904_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(1.88%)

C000227904_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000227904_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(0.97%)

C000227906_LG_ClassMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class Z</span>" id="sjs-C1571">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z&lt;/span>

C000227906_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227906_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,118

C000227906_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,851

C000227906_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,766

$ 8,766

8,766

8,766

8,766

8,766

8,766

C000227906_LG_1_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg MSCI Global Green USD Bond Index (Hedged USD)</span>" id="sjs-C1586">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg MSCI Global Green USD Bond Index (Hedged USD)&lt;/span>

C000227906_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227906_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,120

C000227906_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,921

C000227906_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

8,966

$ 8,966

8,966

8,966

8,966

8,966

8,966

C000227906_LG_2_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-C1601">&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>

C000227906_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227906_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,126

C000227906_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,960

C000227906_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,853

$ 8,853

8,853

$ 8,853

8,853

8,853

8,853

C000227906_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.67%

C000227906_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(1.78%)

C000227906_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000227906_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(0.97%)

C000205069_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class Z</span>" id="sjs-E1628">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z&lt;/span>

C000205069_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000205069_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,027

C000205069_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,702

C000205069_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,520

C000205069_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,283

C000205069_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,041

C000205069_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,689

10,689

10,689

$ 10,689

10,689

10,689

10,689

C000205069_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index</span>" id="sjs-E1652">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index&lt;/span>

C000205069_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000205069_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,042

C000205069_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,740

C000205069_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,558

C000205069_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,350

C000205069_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,141

C000205069_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

10,790

10,790

10,790

$ 10,790

10,790

10,790

10,790

C000205069_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-E1676">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000205069_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000205069_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,132

C000205069_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,902

C000205069_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,662

C000205069_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,415

C000205069_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,206

C000205069_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,822

10,822

$ 10,822

$ 10,822

10,822

10,822

$ 10,822

C000205069_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.45%

C000205069_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.62%)

C000205069_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

1.13%

C000205069_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.40%

C000205069_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.46%)

C000205069_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.29%

C000205069_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000205069_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000205069_1_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.34%

C000019283_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Government Income Fund</span>" id="sjs-H1727">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Government Income Fund&lt;/span>

C000019283_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019283_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,199

C000019283_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,643

C000019283_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,598

C000019283_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,431

C000019283_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,404

C000019283_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,081

C000019283_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,893

C000019283_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,603

C000019283_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,344

C000019283_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,003

11,003

$ 11,003

11,003

11,003

11,003

$ 11,003

C000019283_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index</span>" id="sjs-H1763">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index&lt;/span>

C000019283_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019283_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,237

C000019283_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,723

C000019283_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,676

C000019283_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,542

C000019283_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,543

C000019283_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,274

C000019283_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,083

C000019283_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,820

C000019283_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,602

C000019283_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,280

11,280

11,280

11,280

11,280

11,280

$ 11,280

C000019283_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-H1799">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000019283_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019283_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,227

C000019283_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,739

C000019283_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,649

C000019283_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,489

C000019283_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,570

C000019283_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,371

C000019283_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,121

C000019283_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,825

C000019283_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,608

C000019283_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,248

11,248

$ 11,248

11,248

11,248

$ 11,248

$ 11,248

C000019283_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.36%

C000019283_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.71%)

C000019283_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.96%

C000019283_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.40%

C000019283_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.46%)

C000019283_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.21%

C000019283_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000019283_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000019283_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.18%

C000038102_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class I</span>" id="sjs-H1862">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I&lt;/span>

C000038102_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038102_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,194

C000038102_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,621

C000038102_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,572

C000038102_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,402

C000038102_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,377

C000038102_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,048

C000038102_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,856

C000038102_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,570

C000038102_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,296

C000038102_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,957

10,957

$ 10,957

10,957

10,957

$ 10,957

$ 10,957

C000038102_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index</span>" id="sjs-H1898">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index&lt;/span>

C000038102_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038102_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,237

C000038102_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,723

C000038102_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,676

C000038102_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,542

C000038102_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,543

C000038102_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,274

C000038102_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,083

C000038102_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,820

C000038102_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,602

C000038102_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,280

11,280

11,280

11,280

11,280

11,280

$ 11,280

C000038102_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-H1934">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000038102_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038102_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,227

C000038102_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,739

C000038102_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,649

C000038102_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,489

C000038102_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,570

C000038102_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,371

C000038102_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,121

C000038102_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,825

C000038102_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,608

C000038102_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,248

11,248

$ 11,248

11,248

$ 11,248

$ 11,248

$ 11,248

C000038102_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.42%

C000038102_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.75%)

C000038102_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.92%

C000038102_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.40%

C000038102_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.46%)

C000038102_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.21%

C000038102_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000038102_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000038102_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.18%

C000182864_LG_ClassMember_8YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Total Bond K6 Fund</span>" id="sjs-F1997">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Total Bond K6 Fund&lt;/span>

C000182864_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,000

C000182864_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,135

C000182864_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,068

C000182864_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,046

C000182864_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,905

C000182864_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

12,206

C000182864_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,854

C000182864_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,882

10,882

$ 10,882

10,882

$ 10,882

$ 10,882

10,882

C000182864_LG_1_AdditionalIndexMember_8YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-F2024">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000182864_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,000

C000182864_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,157

C000182864_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,063

C000182864_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,077

C000182864_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,787

C000182864_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,891

C000182864_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,482

C000182864_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

10,441

10,441

10,441

10,441

$ 10,441

10,441

10,441

C000182864_LG_2_AdditionalIndexMember_8YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-F2051">&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>

C000182864_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,000

C000182864_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,154

C000182864_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,047

C000182864_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,070

C000182864_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,786

C000182864_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,776

C000182864_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,420

C000182864_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,296

10,296

$ 10,296

$ 10,296

$ 10,296

10,296

10,296

C000182864_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.25%

C000182864_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.29%

C000182864_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

2.28%

C000182864_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000182864_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000182864_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.65%

C000203458_LG_ClassMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Series Government Bond Index Fund</span>" id="sjs-E2096">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Series Government Bond Index Fund&lt;/span>

C000203458_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000203458_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,010

C000203458_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,052

C000203458_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,781

C000203458_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,563

C000203458_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,330

C000203458_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,128

10,128

$ 10,128

$ 10,128

10,128

10,128

10,128

C000203458_LG_1_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-E2120">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000203458_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000203458_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,019

C000203458_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,052

C000203458_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,816

C000203458_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,578

C000203458_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,340

C000203458_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

10,133

10,133

10,133

$ 10,133

10,133

10,133

10,133

C000203458_LG_2_AdditionalIndexMember_7YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-E2144">&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>

C000203458_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,000

C000203458_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,014

C000203458_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,033

C000203458_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,747

C000203458_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,737

C000203458_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,386

C000203458_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,262

10,262

$ 10,262

$ 10,262

10,262

10,262

$ 10,262

C000203458_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.11%

C000203458_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000203458_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

1.20%

C000203458_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000203458_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000203458_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.19%

C000038098_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class A</span>" id="sjs-H2186">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A&lt;/span>

C000038098_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

9,600

C000038098_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

9,760

C000038098_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,143

C000038098_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,069

C000038098_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

9,878

C000038098_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

10,774

C000038098_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

11,376

C000038098_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

11,168

C000038098_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

9,927

C000038098_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

9,642

C000038098_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 10,232

10,232

$ 10,232

10,232

10,232

10,232

$ 10,232

C000038098_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index</span>" id="sjs-H2222">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 75% U.S. Government/25% U.S. Mortgage-Backed Securities Blended Index&lt;/span>

C000038098_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038098_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,237

C000038098_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,723

C000038098_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,676

C000038098_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,542

C000038098_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,543

C000038098_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,274

C000038098_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,083

C000038098_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,820

C000038098_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,602

C000038098_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

11,280

11,280

11,280

11,280

11,280

11,280

$ 11,280

C000038098_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Government Bond Index</span>" id="sjs-H2258">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Government Bond Index&lt;/span>

C000038098_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000038098_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,227

C000038098_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,739

C000038098_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,649

C000038098_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,489

C000038098_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,570

C000038098_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,371

C000038098_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,121

C000038098_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,825

C000038098_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,608

C000038098_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,248

$ 11,248

$ 11,248

11,248

11,248

$ 11,248

$ 11,248

C000038098_ClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.87%

C000038098_ClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.83%)

C000038098_ClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.23%

C000038098_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.11%

C000038098_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(1.03%)

C000038098_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.64%

C000038098_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.40%

C000038098_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.46%)

C000038098_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.21%

C000038098_1_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

6.03%

C000038098_1_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

(0.56%)

C000038098_1_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.18%

C000227903_LG_ClassMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Fidelity® Environmental Bond Fund</span>" id="sjs-C2330">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Environmental Bond Fund&lt;/span>

C000227903_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227903_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,116

C000227903_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,841

C000227903_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,748

$ 8,748

$ 8,748

8,748

8,748

$ 8,748

8,748

C000227903_LG_1_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg MSCI Global Green USD Bond Index (Hedged USD)</span>" id="sjs-C2345">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg MSCI Global Green USD Bond Index (Hedged USD)&lt;/span>

C000227903_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227903_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,120

C000227903_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,921

C000227903_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

8,966

$ 8,966

8,966

8,966

8,966

8,966

8,966

C000227903_LG_2_AdditionalIndexMember_4YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-C2360">&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>

C000227903_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

10,000

C000227903_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,126

C000227903_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

8,960

C000227903_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 8,853

$ 8,853

8,853

8,853

8,853

8,853

$ 8,853

C000227903_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.57%

C000227903_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

(1.87%)

C000227903_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.09%

C000227903_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

(0.97%)

C000150510_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class Z</span>" id="sjs-H2387">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z&lt;/span>

C000150510_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000150510_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,059

C000150510_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,777

C000150510_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

11,010

C000150510_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,948

C000150510_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

12,017

C000150510_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,945

C000150510_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,267

C000150510_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,771

C000150510_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,824

C000150510_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 12,830

12,830

12,830

12,830

12,830

12,830

$ 12,830

C000150510_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-H2423">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000150510_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000150510_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,069

C000150510_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,724

C000150510_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,868

C000150510_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,767

C000150510_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,852

C000150510_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,612

C000150510_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,724

C000150510_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,215

C000150510_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,171

C000150510_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,056

12,056

12,056

12,056

12,056

12,056

$ 12,056

C000150510_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H2459">&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>

C000150510_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000150510_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,054

C000150510_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,654

C000150510_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,706

C000150510_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,594

C000150510_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,672

C000150510_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,427

C000150510_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,417

C000150510_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

10,987

C000150510_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

10,856

C000150510_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,648

11,648

$ 11,648

11,648

11,648

11,648

$ 11,648

C000150510_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.51%

C000150510_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.32%

C000150510_NoLoadClassMember_2023-09-01_2024-08-31Member

Account Value [Line Items]

Average Annual Return, Percent

2.60%

C000150510_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000150510_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000150510_0_AdditionalIndexMember_LOCMember

Account Value [Line Items]

Average Annual Return, Percent

1.95%

C000019277_LG_ClassMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Class I</span>" id="sjs-H2513">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I&lt;/span>

C000019277_ClassMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019277_ClassMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,073

C000019277_ClassMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,778

C000019277_ClassMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,996

C000019277_ClassMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,919

C000019277_ClassMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,968

C000019277_ClassMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,875

C000019277_ClassMember_AsOf_2021Member

Account Value [Line Items]

Account Value

13,176

C000019277_ClassMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,675

C000019277_ClassMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,711

C000019277_ClassMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 12,690

12,690

$ 12,690

12,690

12,690

12,690

$ 12,690

C000019277_LG_1_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Universal Bond Index</span>" id="sjs-H2549">&lt;span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg U.S. Universal Bond Index&lt;/span>

C000019277_1_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

10,000

C000019277_1_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

10,113

C000019277_1_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

10,770

C000019277_1_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

10,915

C000019277_1_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

10,814

C000019277_1_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

11,903

C000019277_1_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

12,666

C000019277_1_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

12,778

C000019277_1_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

11,264

C000019277_1_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

11,219

C000019277_1_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

12,108

12,108

12,108

12,108

12,108

12,108

$ 12,108

C000019277_LG_2_AdditionalIndexMember_11YRMember

Account Value [Line Items]

Line Graph and Table Measure Name

Bloomberg U.S. Aggregate Bond Index</span>" id="sjs-H2585">&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>

C000019277_2_AdditionalIndexMember_AsOf_2014Member

Account Value [Line Items]

Account Value

$ 10,000

C000019277_2_AdditionalIndexMember_AsOf_2015Member

Account Value [Line Items]

Account Value

$ 10,156

C000019277_2_AdditionalIndexMember_AsOf_2016Member

Account Value [Line Items]

Account Value

$ 10,761

C000019277_2_AdditionalIndexMember_AsOf_2017Member

Account Value [Line Items]

Account Value

$ 10,814

C000019277_2_AdditionalIndexMember_AsOf_2018Member

Account Value [Line Items]

Account Value

$ 10,701

C000019277_2_AdditionalIndexMember_AsOf_2019Member

Account Value [Line Items]

Account Value

$ 11,789

C000019277_2_AdditionalIndexMember_AsOf_2020Member

Account Value [Line Items]

Account Value

$ 12,553

C000019277_2_AdditionalIndexMember_AsOf_2021Member

Account Value [Line Items]

Account Value

$ 12,542

C000019277_2_AdditionalIndexMember_AsOf_2022Member

Account Value [Line Items]

Account Value

$ 11,098

C000019277_2_AdditionalIndexMember_AsOf_2023Member

Account Value [Line Items]

Account Value

$ 10,965

C000019277_2_AdditionalIndexMember_AsOf_2024Member

Account Value [Line Items]

Account Value

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

$ 11,765

C000019277_NoLoadClassMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

8.36%

C000019277_NoLoadClassMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.18%

C000019277_NoLoadClassMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

2.41%

C000019277_0_AdditionalIndexMember_1YRMember

Account Value [Line Items]

Average Annual Return, Percent

7.92%

C000019277_0_AdditionalIndexMember_5YRMember

Account Value [Line Items]

Average Annual Return, Percent

0.34%

C000019277_0_AdditionalIndexMember_10YRMember

Account Value [Line Items]

Average Annual Return, Percent

1.93%

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Aug. 31, 2024
Fidelity Advisor Government Income Fund - Class C | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	26.90%
Fidelity Advisor Government Income Fund - Class C | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	16.10%
Fidelity Advisor Government Income Fund - Class C | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Fidelity Advisor Government Income Fund - Class C | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	14.60%
Fidelity Advisor Government Income Fund - Class C | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Government Income Fund - Class C | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Advisor Government Income Fund - Class C | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity Advisor Government Income Fund - Class C | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Government Income Fund - Class C | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Government Income Fund - Class C | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Government Income Fund - Class C | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class C | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class C | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	7%
Fidelity Advisor Government Income Fund - Class C | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	32.80%
Fidelity Advisor Government Income Fund - Class C | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Fidelity Advisor Government Income Fund - Class C | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Government Income Fund - Class C | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Government Income Fund - Class C | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Government Income Fund - Class C | CD8Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class C | CD9Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class C | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	43%
Fidelity Advisor Government Income Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	23.30%
Fidelity Advisor Government Income Fund - Class C | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.40%
Fidelity Advisor Government Income Fund - Class C | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Government Income Fund - Class C | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	10.70%
Fidelity Intermediate Government Income Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	74.30%
Fidelity Intermediate Government Income Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.70%
Fidelity Intermediate Government Income Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	2.80%
Fidelity Intermediate Government Income Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Intermediate Government Income Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity Intermediate Government Income Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Intermediate Government Income Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Intermediate Government Income Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Intermediate Government Income Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Intermediate Government Income Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity Intermediate Government Income Fund | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	4.80%
Fidelity Intermediate Government Income Fund | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	13.90%
Fidelity Intermediate Government Income Fund | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	21%
Fidelity Intermediate Government Income Fund | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	16.40%
Fidelity Intermediate Government Income Fund | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	33.60%
Fidelity Intermediate Government Income Fund | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	(0.20%)
Fidelity Intermediate Government Income Fund | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Intermediate Government Income Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	75.80%
Fidelity Intermediate Government Income Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	13.40%
Fidelity Intermediate Government Income Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Intermediate Government Income Fund | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Intermediate Government Income Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	9.90%
Fidelity Advisor Total Bond Fund - Class M | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	25.40%
Fidelity Advisor Total Bond Fund - Class M | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.40%
Fidelity Advisor Total Bond Fund - Class M | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.60%
Fidelity Advisor Total Bond Fund - Class M | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.20%
Fidelity Advisor Total Bond Fund - Class M | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class M | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Total Bond Fund - Class M | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class M | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class M | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Total Bond Fund - Class M | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Total Bond Fund - Class M | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	54.70%
Fidelity Advisor Total Bond Fund - Class M | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Total Bond Fund - Class M | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class M | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Advisor Total Bond Fund - Class M | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	16.30%
Fidelity Advisor Total Bond Fund - Class M | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Total Bond Fund - Class M | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Total Bond Fund - Class M | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class M | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class M | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class M | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class M | United States
Holdings [Line Items]
Percent of Net Asset Value	86.30%
Fidelity Advisor Total Bond Fund - Class M | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Advisor Total Bond Fund - Class M | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Advisor Total Bond Fund - Class M | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Total Bond Fund - Class M | Germany
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class M | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class M | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Total Bond Fund - Class M | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class M | France
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Advisor Total Bond Fund - Class M | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Total Bond Fund - Class M | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Fidelity Advisor Total Bond Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity Advisor Total Bond Fund - Class M | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	19.90%
Fidelity Advisor Total Bond Fund - Class M | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	27.70%
Fidelity Advisor Total Bond Fund - Class M | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	7.40%
Fidelity Advisor Total Bond Fund - Class M | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Total Bond Fund - Class M | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class M | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Total Bond Fund - Class M | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class M | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class M | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class M | AASupranationalObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class M | AAPreferredStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Total Bond Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	25.40%
Fidelity Total Bond Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.40%
Fidelity Total Bond Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.60%
Fidelity Total Bond Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.20%
Fidelity Total Bond Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Total Bond Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Total Bond Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Total Bond Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Total Bond Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Total Bond Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Total Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	54.70%
Fidelity Total Bond Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Total Bond Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Total Bond Fund | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Total Bond Fund | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	16.30%
Fidelity Total Bond Fund | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Total Bond Fund | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Total Bond Fund | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Total Bond Fund | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Total Bond Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Total Bond Fund | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	86.30%
Fidelity Total Bond Fund | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Total Bond Fund | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Total Bond Fund | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Total Bond Fund | Germany
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Total Bond Fund | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Total Bond Fund | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Total Bond Fund | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Total Bond Fund | France
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Total Bond Fund | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Total Bond Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Fidelity Total Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity Total Bond Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	19.90%
Fidelity Total Bond Fund | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	27.70%
Fidelity Total Bond Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	7.40%
Fidelity Total Bond Fund | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Total Bond Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Total Bond Fund | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Total Bond Fund | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond Fund | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond Fund | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond Fund | AASupranationalObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond Fund | AAPreferredStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class C | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	25.40%
Fidelity Advisor Total Bond Fund - Class C | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.40%
Fidelity Advisor Total Bond Fund - Class C | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.60%
Fidelity Advisor Total Bond Fund - Class C | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.20%
Fidelity Advisor Total Bond Fund - Class C | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class C | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Total Bond Fund - Class C | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class C | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class C | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Total Bond Fund - Class C | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Total Bond Fund - Class C | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	54.70%
Fidelity Advisor Total Bond Fund - Class C | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Total Bond Fund - Class C | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class C | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Advisor Total Bond Fund - Class C | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	16.30%
Fidelity Advisor Total Bond Fund - Class C | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Total Bond Fund - Class C | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Total Bond Fund - Class C | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class C | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class C | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class C | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class C | United States
Holdings [Line Items]
Percent of Net Asset Value	86.30%
Fidelity Advisor Total Bond Fund - Class C | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Advisor Total Bond Fund - Class C | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Advisor Total Bond Fund - Class C | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Total Bond Fund - Class C | Germany
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class C | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class C | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Total Bond Fund - Class C | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class C | France
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Advisor Total Bond Fund - Class C | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Total Bond Fund - Class C | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Fidelity Advisor Total Bond Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity Advisor Total Bond Fund - Class C | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	19.90%
Fidelity Advisor Total Bond Fund - Class C | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	27.70%
Fidelity Advisor Total Bond Fund - Class C | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	7.40%
Fidelity Advisor Total Bond Fund - Class C | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Total Bond Fund - Class C | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class C | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Total Bond Fund - Class C | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class C | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class C | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class C | AASupranationalObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class C | AAPreferredStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class M | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	26.90%
Fidelity Advisor Government Income Fund - Class M | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	16.10%
Fidelity Advisor Government Income Fund - Class M | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Fidelity Advisor Government Income Fund - Class M | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	14.60%
Fidelity Advisor Government Income Fund - Class M | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Government Income Fund - Class M | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Advisor Government Income Fund - Class M | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity Advisor Government Income Fund - Class M | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Government Income Fund - Class M | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Government Income Fund - Class M | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Government Income Fund - Class M | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class M | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class M | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	7%
Fidelity Advisor Government Income Fund - Class M | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	32.80%
Fidelity Advisor Government Income Fund - Class M | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Fidelity Advisor Government Income Fund - Class M | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Government Income Fund - Class M | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Government Income Fund - Class M | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Government Income Fund - Class M | CD8Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class M | CD9Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class M | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	43%
Fidelity Advisor Government Income Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	23.30%
Fidelity Advisor Government Income Fund - Class M | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.40%
Fidelity Advisor Government Income Fund - Class M | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Government Income Fund - Class M | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	10.70%
Fidelity Advisor Environmental Bond Fund - Class C | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	17%
Fidelity Advisor Environmental Bond Fund - Class C | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity Advisor Environmental Bond Fund - Class C | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	9.80%
Fidelity Advisor Environmental Bond Fund - Class C | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity Advisor Environmental Bond Fund - Class C | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class C | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class C | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Environmental Bond Fund - Class C | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Environmental Bond Fund - Class C | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class C | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class C | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Advisor Environmental Bond Fund - Class C | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Environmental Bond Fund - Class C | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Environmental Bond Fund - Class C | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Advisor Environmental Bond Fund - Class C | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	23.50%
Fidelity Advisor Environmental Bond Fund - Class C | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Environmental Bond Fund - Class C | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Environmental Bond Fund - Class C | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class C | United States
Holdings [Line Items]
Percent of Net Asset Value	82.60%
Fidelity Advisor Environmental Bond Fund - Class C | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Environmental Bond Fund - Class C | Germany
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Environmental Bond Fund - Class C | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class C | France
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class C | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Advisor Environmental Bond Fund - Class C | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Environmental Bond Fund - Class C | Italy
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class C | Japan
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class C | Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class C | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	27%
Fidelity Advisor Environmental Bond Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Environmental Bond Fund - Class C | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	21.20%
Fidelity Advisor Environmental Bond Fund - Class C | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Environmental Bond Fund - Class C | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class C | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	44%
Fidelity Advisor Environmental Bond Fund - Class C | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Environmental Bond Fund - Class C | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class C | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Environmental Bond Fund - Class M | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	17%
Fidelity Advisor Environmental Bond Fund - Class M | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity Advisor Environmental Bond Fund - Class M | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	9.80%
Fidelity Advisor Environmental Bond Fund - Class M | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity Advisor Environmental Bond Fund - Class M | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class M | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class M | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Environmental Bond Fund - Class M | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Environmental Bond Fund - Class M | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class M | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class M | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Advisor Environmental Bond Fund - Class M | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Environmental Bond Fund - Class M | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Environmental Bond Fund - Class M | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Advisor Environmental Bond Fund - Class M | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	23.50%
Fidelity Advisor Environmental Bond Fund - Class M | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Environmental Bond Fund - Class M | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Environmental Bond Fund - Class M | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class M | United States
Holdings [Line Items]
Percent of Net Asset Value	82.60%
Fidelity Advisor Environmental Bond Fund - Class M | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Environmental Bond Fund - Class M | Germany
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Environmental Bond Fund - Class M | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class M | France
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class M | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Advisor Environmental Bond Fund - Class M | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Environmental Bond Fund - Class M | Italy
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class M | Japan
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class M | Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class M | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	27%
Fidelity Advisor Environmental Bond Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Environmental Bond Fund - Class M | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	21.20%
Fidelity Advisor Environmental Bond Fund - Class M | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Environmental Bond Fund - Class M | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class M | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	44%
Fidelity Advisor Environmental Bond Fund - Class M | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Environmental Bond Fund - Class M | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class M | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class A | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	25.40%
Fidelity Advisor Total Bond Fund - Class A | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.40%
Fidelity Advisor Total Bond Fund - Class A | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.60%
Fidelity Advisor Total Bond Fund - Class A | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.20%
Fidelity Advisor Total Bond Fund - Class A | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class A | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Total Bond Fund - Class A | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class A | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class A | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Total Bond Fund - Class A | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Total Bond Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	54.70%
Fidelity Advisor Total Bond Fund - Class A | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Total Bond Fund - Class A | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class A | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Advisor Total Bond Fund - Class A | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	16.30%
Fidelity Advisor Total Bond Fund - Class A | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Total Bond Fund - Class A | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Total Bond Fund - Class A | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class A | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class A | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class A | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class A | United States
Holdings [Line Items]
Percent of Net Asset Value	86.30%
Fidelity Advisor Total Bond Fund - Class A | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Advisor Total Bond Fund - Class A | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Advisor Total Bond Fund - Class A | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Total Bond Fund - Class A | Germany
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class A | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class A | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Total Bond Fund - Class A | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class A | France
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Advisor Total Bond Fund - Class A | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Total Bond Fund - Class A | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Fidelity Advisor Total Bond Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity Advisor Total Bond Fund - Class A | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	19.90%
Fidelity Advisor Total Bond Fund - Class A | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	27.70%
Fidelity Advisor Total Bond Fund - Class A | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	7.40%
Fidelity Advisor Total Bond Fund - Class A | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Total Bond Fund - Class A | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class A | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Total Bond Fund - Class A | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class A | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class A | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class A | AASupranationalObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class A | AAPreferredStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Environmental Bond Fund - Class A | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	17%
Fidelity Advisor Environmental Bond Fund - Class A | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity Advisor Environmental Bond Fund - Class A | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	9.80%
Fidelity Advisor Environmental Bond Fund - Class A | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity Advisor Environmental Bond Fund - Class A | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class A | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class A | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Environmental Bond Fund - Class A | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Environmental Bond Fund - Class A | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class A | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Advisor Environmental Bond Fund - Class A | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Environmental Bond Fund - Class A | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Environmental Bond Fund - Class A | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Advisor Environmental Bond Fund - Class A | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	23.50%
Fidelity Advisor Environmental Bond Fund - Class A | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Environmental Bond Fund - Class A | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Environmental Bond Fund - Class A | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class A | United States
Holdings [Line Items]
Percent of Net Asset Value	82.60%
Fidelity Advisor Environmental Bond Fund - Class A | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Environmental Bond Fund - Class A | Germany
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Environmental Bond Fund - Class A | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class A | France
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class A | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Advisor Environmental Bond Fund - Class A | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Environmental Bond Fund - Class A | Italy
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class A | Japan
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class A | Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class A | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	27%
Fidelity Advisor Environmental Bond Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Environmental Bond Fund - Class A | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	21.20%
Fidelity Advisor Environmental Bond Fund - Class A | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Environmental Bond Fund - Class A | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class A | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	44%
Fidelity Advisor Environmental Bond Fund - Class A | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Environmental Bond Fund - Class A | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class A | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Environmental Bond Fund - Class I | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	17%
Fidelity Advisor Environmental Bond Fund - Class I | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity Advisor Environmental Bond Fund - Class I | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	9.80%
Fidelity Advisor Environmental Bond Fund - Class I | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity Advisor Environmental Bond Fund - Class I | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class I | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class I | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Environmental Bond Fund - Class I | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Environmental Bond Fund - Class I | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class I | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Advisor Environmental Bond Fund - Class I | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Environmental Bond Fund - Class I | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Environmental Bond Fund - Class I | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Advisor Environmental Bond Fund - Class I | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	23.50%
Fidelity Advisor Environmental Bond Fund - Class I | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Environmental Bond Fund - Class I | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Environmental Bond Fund - Class I | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class I | United States
Holdings [Line Items]
Percent of Net Asset Value	82.60%
Fidelity Advisor Environmental Bond Fund - Class I | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Environmental Bond Fund - Class I | Germany
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Environmental Bond Fund - Class I | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class I | France
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class I | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Advisor Environmental Bond Fund - Class I | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Environmental Bond Fund - Class I | Italy
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class I | Japan
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class I | Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class I | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	27%
Fidelity Advisor Environmental Bond Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Environmental Bond Fund - Class I | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	21.20%
Fidelity Advisor Environmental Bond Fund - Class I | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Environmental Bond Fund - Class I | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class I | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	44%
Fidelity Advisor Environmental Bond Fund - Class I | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Environmental Bond Fund - Class I | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class I | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Environmental Bond Fund - Class Z | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	17%
Fidelity Advisor Environmental Bond Fund - Class Z | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity Advisor Environmental Bond Fund - Class Z | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	9.80%
Fidelity Advisor Environmental Bond Fund - Class Z | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity Advisor Environmental Bond Fund - Class Z | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class Z | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Advisor Environmental Bond Fund - Class Z | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Advisor Environmental Bond Fund - Class Z | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Advisor Environmental Bond Fund - Class Z | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class Z | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Advisor Environmental Bond Fund - Class Z | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Environmental Bond Fund - Class Z | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Advisor Environmental Bond Fund - Class Z | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Advisor Environmental Bond Fund - Class Z | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	23.50%
Fidelity Advisor Environmental Bond Fund - Class Z | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Environmental Bond Fund - Class Z | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Environmental Bond Fund - Class Z | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class Z | United States
Holdings [Line Items]
Percent of Net Asset Value	82.60%
Fidelity Advisor Environmental Bond Fund - Class Z | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Advisor Environmental Bond Fund - Class Z | Germany
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Advisor Environmental Bond Fund - Class Z | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Environmental Bond Fund - Class Z | France
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Environmental Bond Fund - Class Z | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Advisor Environmental Bond Fund - Class Z | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Advisor Environmental Bond Fund - Class Z | Italy
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class Z | Japan
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Environmental Bond Fund - Class Z | Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class Z | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	27%
Fidelity Advisor Environmental Bond Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Advisor Environmental Bond Fund - Class Z | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	21.20%
Fidelity Advisor Environmental Bond Fund - Class Z | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Environmental Bond Fund - Class Z | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Environmental Bond Fund - Class Z | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	44%
Fidelity Advisor Environmental Bond Fund - Class Z | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Environmental Bond Fund - Class Z | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Environmental Bond Fund - Class Z | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Government Income Fund - Class Z | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	26.90%
Fidelity Advisor Government Income Fund - Class Z | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	16.10%
Fidelity Advisor Government Income Fund - Class Z | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Fidelity Advisor Government Income Fund - Class Z | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	14.60%
Fidelity Advisor Government Income Fund - Class Z | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Government Income Fund - Class Z | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Advisor Government Income Fund - Class Z | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity Advisor Government Income Fund - Class Z | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Government Income Fund - Class Z | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Government Income Fund - Class Z | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Government Income Fund - Class Z | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class Z | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class Z | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	7%
Fidelity Advisor Government Income Fund - Class Z | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	32.80%
Fidelity Advisor Government Income Fund - Class Z | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Fidelity Advisor Government Income Fund - Class Z | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Government Income Fund - Class Z | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Government Income Fund - Class Z | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Government Income Fund - Class Z | CD8Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class Z | CD9Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class Z | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	43%
Fidelity Advisor Government Income Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	23.30%
Fidelity Advisor Government Income Fund - Class Z | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.40%
Fidelity Advisor Government Income Fund - Class Z | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Government Income Fund - Class Z | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	10.70%
Fidelity Government Income Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	26.90%
Fidelity Government Income Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	16.10%
Fidelity Government Income Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Fidelity Government Income Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	14.60%
Fidelity Government Income Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Government Income Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Government Income Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity Government Income Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Government Income Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Government Income Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Government Income Fund | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Government Income Fund | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Government Income Fund | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	7%
Fidelity Government Income Fund | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	32.80%
Fidelity Government Income Fund | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Fidelity Government Income Fund | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Government Income Fund | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Government Income Fund | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Government Income Fund | CD8Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Government Income Fund | CD9Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Government Income Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	43%
Fidelity Government Income Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	23.30%
Fidelity Government Income Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.40%
Fidelity Government Income Fund | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Government Income Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	10.70%
Fidelity Advisor Government Income Fund - Class I | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	26.90%
Fidelity Advisor Government Income Fund - Class I | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	16.10%
Fidelity Advisor Government Income Fund - Class I | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Fidelity Advisor Government Income Fund - Class I | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	14.60%
Fidelity Advisor Government Income Fund - Class I | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Government Income Fund - Class I | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Advisor Government Income Fund - Class I | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity Advisor Government Income Fund - Class I | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Government Income Fund - Class I | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Government Income Fund - Class I | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Government Income Fund - Class I | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class I | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class I | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	7%
Fidelity Advisor Government Income Fund - Class I | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	32.80%
Fidelity Advisor Government Income Fund - Class I | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Fidelity Advisor Government Income Fund - Class I | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Government Income Fund - Class I | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Government Income Fund - Class I | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Government Income Fund - Class I | CD8Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class I | CD9Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class I | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	43%
Fidelity Advisor Government Income Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	23.30%
Fidelity Advisor Government Income Fund - Class I | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.40%
Fidelity Advisor Government Income Fund - Class I | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Government Income Fund - Class I | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	10.70%
Fidelity Total Bond K6 Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	28.40%
Fidelity Total Bond K6 Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9%
Fidelity Total Bond K6 Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.10%
Fidelity Total Bond K6 Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.70%
Fidelity Total Bond K6 Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Total Bond K6 Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.60%
Fidelity Total Bond K6 Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Total Bond K6 Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Total Bond K6 Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Total Bond K6 Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Total Bond K6 Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	57.50%
Fidelity Total Bond K6 Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	7.50%
Fidelity Total Bond K6 Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Total Bond K6 Fund | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.10%
Fidelity Total Bond K6 Fund | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	15.10%
Fidelity Total Bond K6 Fund | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Total Bond K6 Fund | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.10%
Fidelity Total Bond K6 Fund | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Total Bond K6 Fund | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Total Bond K6 Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Total Bond K6 Fund | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Total Bond K6 Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	88.20%
Fidelity Total Bond K6 Fund | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Total Bond K6 Fund | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Total Bond K6 Fund | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Total Bond K6 Fund | Germany
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Total Bond K6 Fund | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Total Bond K6 Fund | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Total Bond K6 Fund | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.50%
Fidelity Total Bond K6 Fund | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	2.60%
Fidelity Total Bond K6 Fund | BailiwickOfJerseyMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Total Bond K6 Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	37.40%
Fidelity Total Bond K6 Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.20%
Fidelity Total Bond K6 Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	20.10%
Fidelity Total Bond K6 Fund | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	25.50%
Fidelity Total Bond K6 Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.90%
Fidelity Total Bond K6 Fund | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity Total Bond K6 Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Total Bond K6 Fund | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Total Bond K6 Fund | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond K6 Fund | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Total Bond K6 Fund | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Total Bond K6 Fund | AAFixedIncomeFundsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Total Bond K6 Fund | AAAlternativeFundsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Series Government Bond Index Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	74%
Fidelity Series Government Bond Index Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	22.70%
Fidelity Series Government Bond Index Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Series Government Bond Index Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Series Government Bond Index Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Series Government Bond Index Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Series Government Bond Index Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Series Government Bond Index Fund | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	24%
Fidelity Series Government Bond Index Fund | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	22.50%
Fidelity Series Government Bond Index Fund | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Series Government Bond Index Fund | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	14.40%
Fidelity Series Government Bond Index Fund | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Series Government Bond Index Fund | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	2.50%
Fidelity Series Government Bond Index Fund | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Series Government Bond Index Fund | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Series Government Bond Index Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	96.70%
Fidelity Series Government Bond Index Fund | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Series Government Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Government Income Fund - Class A | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	26.90%
Fidelity Advisor Government Income Fund - Class A | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	16.10%
Fidelity Advisor Government Income Fund - Class A | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	14.90%
Fidelity Advisor Government Income Fund - Class A | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	14.60%
Fidelity Advisor Government Income Fund - Class A | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	9.30%
Fidelity Advisor Government Income Fund - Class A | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity Advisor Government Income Fund - Class A | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity Advisor Government Income Fund - Class A | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Advisor Government Income Fund - Class A | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Government Income Fund - Class A | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Government Income Fund - Class A | CD0Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class A | CD1Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class A | CD2Member
Holdings [Line Items]
Percent of Net Asset Value	7%
Fidelity Advisor Government Income Fund - Class A | CD3Member
Holdings [Line Items]
Percent of Net Asset Value	32.80%
Fidelity Advisor Government Income Fund - Class A | CD4Member
Holdings [Line Items]
Percent of Net Asset Value	22.80%
Fidelity Advisor Government Income Fund - Class A | CD5Member
Holdings [Line Items]
Percent of Net Asset Value	18.60%
Fidelity Advisor Government Income Fund - Class A | CD6Member
Holdings [Line Items]
Percent of Net Asset Value	4.90%
Fidelity Advisor Government Income Fund - Class A | CD7Member
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Government Income Fund - Class A | CD8Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class A | CD9Member
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Government Income Fund - Class A | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	43%
Fidelity Advisor Government Income Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	23.30%
Fidelity Advisor Government Income Fund - Class A | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	22.40%
Fidelity Advisor Government Income Fund - Class A | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Government Income Fund - Class A | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	10.70%
Fidelity Environmental Bond Fund | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	17%
Fidelity Environmental Bond Fund | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity Environmental Bond Fund | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	9.80%
Fidelity Environmental Bond Fund | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity Environmental Bond Fund | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Environmental Bond Fund | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity Environmental Bond Fund | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity Environmental Bond Fund | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Environmental Bond Fund | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Environmental Bond Fund | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Environmental Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	48.60%
Fidelity Environmental Bond Fund | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Environmental Bond Fund | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	3.10%
Fidelity Environmental Bond Fund | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	15.60%
Fidelity Environmental Bond Fund | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	23.50%
Fidelity Environmental Bond Fund | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Environmental Bond Fund | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Environmental Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Environmental Bond Fund | United States
Holdings [Line Items]
Percent of Net Asset Value	82.60%
Fidelity Environmental Bond Fund | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	2.20%
Fidelity Environmental Bond Fund | Germany
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity Environmental Bond Fund | Ireland
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Environmental Bond Fund | France
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Environmental Bond Fund | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	4%
Fidelity Environmental Bond Fund | Netherlands
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Environmental Bond Fund | Italy
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Environmental Bond Fund | Japan
Holdings [Line Items]
Percent of Net Asset Value	1.40%
Fidelity Environmental Bond Fund | Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Environmental Bond Fund | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	27%
Fidelity Environmental Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity Environmental Bond Fund | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	21.20%
Fidelity Environmental Bond Fund | AAUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Environmental Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Environmental Bond Fund | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	44%
Fidelity Environmental Bond Fund | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Environmental Bond Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Environmental Bond Fund | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class Z | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	25.40%
Fidelity Advisor Total Bond Fund - Class Z | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.40%
Fidelity Advisor Total Bond Fund - Class Z | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.60%
Fidelity Advisor Total Bond Fund - Class Z | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.20%
Fidelity Advisor Total Bond Fund - Class Z | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class Z | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Total Bond Fund - Class Z | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class Z | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class Z | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Total Bond Fund - Class Z | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Total Bond Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	54.70%
Fidelity Advisor Total Bond Fund - Class Z | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Total Bond Fund - Class Z | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class Z | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Advisor Total Bond Fund - Class Z | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	16.30%
Fidelity Advisor Total Bond Fund - Class Z | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Total Bond Fund - Class Z | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Total Bond Fund - Class Z | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class Z | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class Z | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class Z | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class Z | United States
Holdings [Line Items]
Percent of Net Asset Value	86.30%
Fidelity Advisor Total Bond Fund - Class Z | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Advisor Total Bond Fund - Class Z | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Advisor Total Bond Fund - Class Z | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Total Bond Fund - Class Z | Germany
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class Z | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class Z | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Total Bond Fund - Class Z | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class Z | France
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Advisor Total Bond Fund - Class Z | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Total Bond Fund - Class Z | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Fidelity Advisor Total Bond Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity Advisor Total Bond Fund - Class Z | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	19.90%
Fidelity Advisor Total Bond Fund - Class Z | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	27.70%
Fidelity Advisor Total Bond Fund - Class Z | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	7.40%
Fidelity Advisor Total Bond Fund - Class Z | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Total Bond Fund - Class Z | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class Z | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Total Bond Fund - Class Z | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class Z | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class Z | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class Z | AASupranationalObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class Z | AAPreferredStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class I | TH0Member
Holdings [Line Items]
Percent of Net Asset Value	25.40%
Fidelity Advisor Total Bond Fund - Class I | TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.40%
Fidelity Advisor Total Bond Fund - Class I | TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.60%
Fidelity Advisor Total Bond Fund - Class I | TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.20%
Fidelity Advisor Total Bond Fund - Class I | TH4Member
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class I | TH5Member
Holdings [Line Items]
Percent of Net Asset Value	3.60%
Fidelity Advisor Total Bond Fund - Class I | TH6Member
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class I | TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class I | TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1%
Fidelity Advisor Total Bond Fund - Class I | TH9Member
Holdings [Line Items]
Percent of Net Asset Value	0.90%
Fidelity Advisor Total Bond Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	54.70%
Fidelity Advisor Total Bond Fund - Class I | QDAAAMember
Holdings [Line Items]
Percent of Net Asset Value	8.80%
Fidelity Advisor Total Bond Fund - Class I | QDAAMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class I | QDAMember
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity Advisor Total Bond Fund - Class I | QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	16.30%
Fidelity Advisor Total Bond Fund - Class I | QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity Advisor Total Bond Fund - Class I | QDBMember
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity Advisor Total Bond Fund - Class I | QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class I | QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity Advisor Total Bond Fund - Class I | QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	3.90%
Fidelity Advisor Total Bond Fund - Class I | QDEquitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class I | United States
Holdings [Line Items]
Percent of Net Asset Value	86.30%
Fidelity Advisor Total Bond Fund - Class I | GrandCaymanUKOverseasTerMember
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity Advisor Total Bond Fund - Class I | United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	1.50%
Fidelity Advisor Total Bond Fund - Class I | Mexico
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity Advisor Total Bond Fund - Class I | Germany
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity Advisor Total Bond Fund - Class I | Ireland
Holdings [Line Items]
Percent of Net Asset Value	0.80%
Fidelity Advisor Total Bond Fund - Class I | Switzerland
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Advisor Total Bond Fund - Class I | Canada
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity Advisor Total Bond Fund - Class I | France
Holdings [Line Items]
Percent of Net Asset Value	0.30%
Fidelity Advisor Total Bond Fund - Class I | OtherMember
Holdings [Line Items]
Percent of Net Asset Value	3.20%
Fidelity Advisor Total Bond Fund - Class I | AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	34.80%
Fidelity Advisor Total Bond Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity Advisor Total Bond Fund - Class I | AAUSGovernmentAgencyMortgageSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	19.90%
Fidelity Advisor Total Bond Fund - Class I | AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	27.70%
Fidelity Advisor Total Bond Fund - Class I | AAAssetBackedSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	7.40%
Fidelity Advisor Total Bond Fund - Class I | AABankLoanObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Advisor Total Bond Fund - Class I | AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	1.20%
Fidelity Advisor Total Bond Fund - Class I | AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity Advisor Total Bond Fund - Class I | AACommonStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class I | AAOtherInvestmentsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class I | AAPurchasedSwaptionsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class I | AASupranationalObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity Advisor Total Bond Fund - Class I | AAPreferredStocksMember
Holdings [Line Items]
Percent of Net Asset Value	0%