Risk/Return Detail Data - FidelityIntermediateBondFund-RetailPRO - USD ($)			12 Months Ended											36 Months Ended		60 Months Ended		84 Months Ended		108 Months Ended		120 Months Ended
		Oct. 30, 2025	Oct. 30, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 30, 2025		Oct. 30, 2025		Oct. 30, 2025		Oct. 30, 2025		Oct. 30, 2025
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | Fidelity Advisor Investment Grade Bond Fund - Class A
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		4.00%
Maximum Deferred Sales Charge (as a percentage)	[1]	0.00%
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.25%
Other Expenses (as a percentage of Assets):		0.22%
Expenses (as a percentage of Assets)		0.75%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		0.75%
Expense Example, with Redemption, 1 Year		$ 474
Expense Example, with Redemption, 3 Years		630
Expense Example, with Redemption, 5 Years		800
Expense Example, with Redemption, 10 Years		1,293
Expense Example, No Redemption, 1 Year		474
Expense Example, No Redemption, 3 Years		630
Expense Example, No Redemption, 5 Years		800
Expense Example, No Redemption, 10 Years		$ 1,293
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			(2.77%)													(0.71%)						1.14%
Annual Return [Percent]				1.28%	6.16%	(13.64%)	(1.19%)	9.58%	9.33%	(0.55%)	3.45%	5.14%	(1.89%)
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | Fidelity Advisor Investment Grade Bond Fund - Class M
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		4.00%
Maximum Deferred Sales Charge (as a percentage)	[1]	0.00%
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.25%
Other Expenses (as a percentage of Assets):		0.22%
Expenses (as a percentage of Assets)		0.75%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		0.75%
Expense Example, with Redemption, 1 Year		$ 474
Expense Example, with Redemption, 3 Years		630
Expense Example, with Redemption, 5 Years		800
Expense Example, with Redemption, 10 Years		1,293
Expense Example, No Redemption, 1 Year		474
Expense Example, No Redemption, 3 Years		630
Expense Example, No Redemption, 5 Years		800
Expense Example, No Redemption, 10 Years		$ 1,293
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			(2.76%)													(0.70%)						1.12%
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | Fidelity Advisor Investment Grade Bond Fund - Class C
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)	[2]	1.00%
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		1.00%
Other Expenses (as a percentage of Assets):		0.24%
Expenses (as a percentage of Assets)		1.52%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		1.52%
Expenses Deferred Charges [Text Block]		On Class C shares redeemed less than one year after purchase.
Expense Example, with Redemption, 1 Year		$ 255
Expense Example, with Redemption, 3 Years		480
Expense Example, with Redemption, 5 Years		829
Expense Example, with Redemption, 10 Years		1,604
Expense Example, No Redemption, 1 Year		155
Expense Example, No Redemption, 3 Years		480
Expense Example, No Redemption, 5 Years		829
Expense Example, No Redemption, 10 Years		$ 1,604
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			(0.46%)													(0.66%)						0.93%
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | Fidelity Advisor Investment Grade Bond Fund - Class I
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)		0.00%
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.22%
Expenses (as a percentage of Assets)		0.50%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		0.50%
Expense Example, with Redemption, 1 Year		$ 51
Expense Example, with Redemption, 3 Years		160
Expense Example, with Redemption, 5 Years		280
Expense Example, with Redemption, 10 Years		628
Expense Example, No Redemption, 1 Year		51
Expense Example, No Redemption, 3 Years		160
Expense Example, No Redemption, 5 Years		280
Expense Example, No Redemption, 10 Years		$ 628
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.54%													0.37%						1.81%
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | Fidelity Advisor Investment Grade Bond Fund - Class Z
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)		0.00%
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.12%
Expenses (as a percentage of Assets)		0.40%
Fee Waiver or Reimbursement	[3]	(0.04%)
Net Expenses (as a percentage of Assets)		0.36%
Expense Example, with Redemption, 1 Year		$ 37
Expense Example, with Redemption, 3 Years		123
Expense Example, with Redemption, 5 Years		219
Expense Example, with Redemption, 10 Years		500
Expense Example, No Redemption, 1 Year		37
Expense Example, No Redemption, 3 Years		123
Expense Example, No Redemption, 5 Years		219
Expense Example, No Redemption, 10 Years		$ 500
Annual Return, Inception Date		Oct. 02, 2018
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.69%													0.51%		2.11%	[4]
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund /Class: Fidelity® Investment Grade Bond Fund /Fidelity Advisor® Investment Grade Bond Fund A, M, C, I, Z
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Investment Grade Bond Fund seeks a high level of current income.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 35 of the prospectus and in the sales charge waiver appendix to the prospectus.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 196 % of the average value of its portfolio.
Portfolio Turnover, Rate		196.00%
Expenses Deferred Charges [Text Block]		Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 0.75% and 0.25%, respectively.
Expense Breakpoint Discounts [Text]		You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 35 of the prospectus
Expense Breakpoint, Minimum Investment Required [Amount]		$ 50,000
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated and if you hold your shares:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. Aggregate Bond Index. Allocating assets across different market sectors and maturities. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Investing in lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds). Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit institutional.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.
Performance Availability Website Address [Text]		institutional.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Bar Chart Narrative [Text Block]		The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.
Bar Chart Does Not Reflect Sales Loads [Text]		The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		6.06%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		6.81%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(5.86%)
Performance Table Heading		Average Annual Returns
Performance Table Does Reflect Sales Loads		Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges.
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table One Class of after Tax Shown [Text]		After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary.
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | After Taxes on Distributions | Fidelity Advisor Investment Grade Bond Fund - Class A
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			(4.11%)													(1.87%)						0.06%
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | After Taxes on Distributions and Sales | Fidelity Advisor Investment Grade Bond Fund - Class A
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			(1.55%)													(0.98%)						0.42%
FidelityInvestmentGradeBondFund-AMCIZPRO | Fidelity Investment Grade Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)						1.35%
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | Fidelity Advisor Short-Term Bond Fund - Class A
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		1.50%
Maximum Deferred Sales Charge (as a percentage)	[5]	0.00%
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.15%
Other Expenses (as a percentage of Assets):		0.15%
Expenses (as a percentage of Assets)		0.50%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		0.50%
Expenses Deferred Charges [Text Block]		Purchases of $250,000 or more will not be subject to a front-end sales charge, but may be subject to a 0.50% contingent deferred sales charge (CDSC) if the intermediary firm has elected an upfront finder's fee at the time the shares are purchased, or a 0.75% CDSC if the shares purchased are recordkept in a Fidelity Advisor ® 401(k) Retirement Plan.
Expense Example, with Redemption, 1 Year		$ 200
Expense Example, with Redemption, 3 Years		308
Expense Example, with Redemption, 5 Years		425
Expense Example, with Redemption, 10 Years		769
Expense Example, No Redemption, 1 Year		200
Expense Example, No Redemption, 3 Years		308
Expense Example, No Redemption, 5 Years		425
Expense Example, No Redemption, 10 Years		$ 769
Annual Return, Inception Date		Jul. 12, 2016
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			3.06%													1.34%				1.45%	[6]
Annual Return [Percent]				4.63%	5.00%	(3.80%)	(0.93%)	3.62%	3.99%	0.99%	0.95%
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | Fidelity Advisor Short-Term Bond Fund - Class M
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		1.50%
Maximum Deferred Sales Charge (as a percentage)	[7]	0.00%
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.15%
Other Expenses (as a percentage of Assets):		0.16%
Expenses (as a percentage of Assets)		0.51%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		0.51%
Expenses Deferred Charges [Text Block]		Purchases of $250,000 or more will not be subject to a front-end sales charge but may be subject to a 0.25% CDSC if a finder's fee is paid at the time the shares are purchased.
Expense Example, with Redemption, 1 Year		$ 201
Expense Example, with Redemption, 3 Years		311
Expense Example, with Redemption, 5 Years		431
Expense Example, with Redemption, 10 Years		781
Expense Example, No Redemption, 1 Year		201
Expense Example, No Redemption, 3 Years		311
Expense Example, No Redemption, 5 Years		431
Expense Example, No Redemption, 10 Years		$ 781
Annual Return, Inception Date		Jul. 12, 2016
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			3.05%													1.33%				1.44%	[8]
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | Fidelity Advisor Short-Term Bond Fund - Class C
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)	[9]	1.00%
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		1.00%
Other Expenses (as a percentage of Assets):		0.16%
Expenses (as a percentage of Assets)		1.36%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		1.36%
Expenses Deferred Charges [Text Block]		On Class C shares redeemed less than one year after purchase.
Expense Example, with Redemption, 1 Year		$ 238
Expense Example, with Redemption, 3 Years		431
Expense Example, with Redemption, 5 Years		745
Expense Example, with Redemption, 10 Years		1,399
Expense Example, No Redemption, 1 Year		138
Expense Example, No Redemption, 3 Years		431
Expense Example, No Redemption, 5 Years		745
Expense Example, No Redemption, 10 Years		$ 1,399
Annual Return, Inception Date		Jul. 12, 2016
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			2.74%													0.77%				0.81%	[10]
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | Fidelity Advisor Short-Term Bond Fund - Class I
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)		0.00%
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.15%
Expenses (as a percentage of Assets)		0.35%
Fee Waiver or Reimbursement	[11]	(0.05%)
Net Expenses (as a percentage of Assets)		0.30%
Expense Example, with Redemption, 1 Year		$ 31
Expense Example, with Redemption, 3 Years		106
Expense Example, with Redemption, 5 Years		190
Expense Example, with Redemption, 10 Years		437
Expense Example, No Redemption, 1 Year		31
Expense Example, No Redemption, 3 Years		106
Expense Example, No Redemption, 5 Years		190
Expense Example, No Redemption, 10 Years		$ 437
Annual Return, Inception Date		Jul. 12, 2016
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			4.83%													1.81%				1.79%	[12]
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | Fidelity Advisor Short-Term Bond Fund - Class Z
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)		0.00%
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.05%
Expenses (as a percentage of Assets)		0.25%
Fee Waiver or Reimbursement		(0.00%)
Net Expenses (as a percentage of Assets)		0.25%
Expense Example, with Redemption, 1 Year		$ 26
Expense Example, with Redemption, 3 Years		80
Expense Example, with Redemption, 5 Years		141
Expense Example, with Redemption, 10 Years		318
Expense Example, No Redemption, 1 Year		26
Expense Example, No Redemption, 3 Years		80
Expense Example, No Redemption, 5 Years		141
Expense Example, No Redemption, 10 Years		$ 318
Annual Return, Inception Date		Oct. 02, 2018
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			4.76%													1.92%		2.32%	[13]
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund /Class: Fidelity® Short-Term Bond Fund /Fidelity Advisor® Short-Term Bond Fund A, M, C, I, Z
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Short-Term Bond Fund seeks to obtain a high level of current income consistent with preservation of capital.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 250,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 35 of the prospectus   and in the sales charge waiver appendix to the prospectus.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 59 % of the average value of its portfolio.
Portfolio Turnover, Rate		59.00%
Expense Breakpoint Discounts [Text]		You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 250,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 35 of the prospectus
Expense Breakpoint, Minimum Investment Required [Amount]		$ 250,000
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated and if you hold your shares:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. 1-3 Year Government/Credit Bond Index. Normally maintaining a dollar-weighted average maturity of three years or less. Allocating assets across different market sectors and maturities. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit institutional.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		institutional.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Bar Chart Narrative [Text Block]		The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.
Bar Chart Does Not Reflect Sales Loads [Text]		The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		4.14%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Jun. 30, 2020
Highest Quarterly Return		2.93%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(2.66%)
Performance Table Heading		Average Annual Returns
Performance Table Does Reflect Sales Loads		Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges.
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table One Class of after Tax Shown [Text]		After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary.
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | After Taxes on Distributions | Fidelity Advisor Short-Term Bond Fund - Class A
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			1.51%													0.45%				0.68%	[6]
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | After Taxes on Distributions and Sales | Fidelity Advisor Short-Term Bond Fund - Class A
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			1.83%													0.65%				0.78%	[6]
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | LB013
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. 1-3 Year Government/Credit Bond Index
Average Annual Return, Percent			4.36%													1.58%				1.66%
FidelityShort-TermBondFund-AMCIZPRO | Fidelity Short-Term Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)				0.87%
FidelityShort-TermBondFund-RetailPRO | Fidelity Short-Term Bond Fund | Fidelity Short-Term Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.10%
Expenses (as a percentage of Assets)		0.30%
Expense Example, with Redemption, 1 Year		$ 31
Expense Example, with Redemption, 3 Years		97
Expense Example, with Redemption, 5 Years		169
Expense Example, with Redemption, 10 Years		$ 381
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			4.71%													1.82%						1.77%
Annual Return [Percent]				4.71%	5.34%	(3.62%)	(0.73%)	3.70%	4.20%	1.19%	1.15%	1.45%	0.67%
FidelityShort-TermBondFund-RetailPRO | Fidelity Short-Term Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund /Class: Fidelity® Short-Term Bond Fund /Fidelity® Short-Term Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Short-Term Bond Fund seeks to obtain a high level of current income consistent with preservation of capital.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 59 % of the average value of its portfolio.
Portfolio Turnover, Rate		59.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. 1-3 Year Government/Credit Bond Index. Normally maintaining a dollar-weighted average maturity of three years or less. Allocating assets across different market sectors and maturities. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		4.30%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Jun. 30, 2020
Highest Quarterly Return		2.98%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(2.50%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityShort-TermBondFund-RetailPRO | Fidelity Short-Term Bond Fund | After Taxes on Distributions | Fidelity Short-Term Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			3.04%													0.85%						0.98%
FidelityShort-TermBondFund-RetailPRO | Fidelity Short-Term Bond Fund | After Taxes on Distributions and Sales | Fidelity Short-Term Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			2.79%													0.99%						1.02%
FidelityShort-TermBondFund-RetailPRO | Fidelity Short-Term Bond Fund | LB013
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. 1-3 Year Government/Credit Bond Index
Average Annual Return, Percent			4.36%													1.58%						1.63%
FidelityShort-TermBondFund-RetailPRO | Fidelity Short-Term Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)						1.35%
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Low Duration Bond Fund | Fidelity SAI Low Duration Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.01%
Expenses (as a percentage of Assets)		0.21%
Fee Waiver or Reimbursement	[14]	(0.01%)
Net Expenses (as a percentage of Assets)		0.20%
Expense Example, with Redemption, 1 Year		$ 20
Expense Example, with Redemption, 3 Years		66
Expense Example, with Redemption, 5 Years		117
Expense Example, with Redemption, 10 Years		$ 266
Annual Return, Inception Date		Sep. 15, 2020
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			5.56%													2.79%	[15]
Annual Return [Percent]				5.56%	5.70%	0.73%	(0.01%)
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Low Duration Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® SAI Low Duration Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® SAI Low Duration Bond Fund seeks to obtain a high level of current income consistent with preservation of capital.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 80 % of the average value of its portfolio.
Portfolio Turnover, Rate		80.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Normally maintaining a duration of 1 year or less. Managing the fund to have similar overall interest rate risk to the Bloomberg US Treasury Bill: 6-9 Months Index. Normally maintaining a dollar-weighted average maturity of two years or less. Allocating assets across different market sectors and maturities. Investing more than 25% of total assets in the financial services industries. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		3.61%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Sep. 30, 2024
Highest Quarterly Return		1.83%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(0.53%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Low Duration Bond Fund | After Taxes on Distributions | Fidelity SAI Low Duration Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			3.45%													1.74%	[15]
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Low Duration Bond Fund | After Taxes on Distributions and Sales | Fidelity SAI Low Duration Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			3.33%													1.69%	[15]
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Low Duration Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(1.94%)
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Low Duration Bond Fund | IXXXY
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg US Treasury Bill: 6-9 Months Index
Average Annual Return, Percent			4.88%													2.24%
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Short-Term Bond Fund | Fidelity SAI Short-Term Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.01%
Expenses (as a percentage of Assets)		0.21%
Expense Example, with Redemption, 1 Year		$ 22
Expense Example, with Redemption, 3 Years		68
Expense Example, with Redemption, 5 Years		118
Expense Example, with Redemption, 10 Years		$ 268
Annual Return, Inception Date		Sep. 15, 2020
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			4.70%													1.39%	[16]
Annual Return [Percent]				4.70%	5.20%	(3.47%)	(0.65%)
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Short-Term Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® SAI Short-Term Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® SAI Short-Term Bond Fund seeks to obtain a high level of current income consistent with preservation of capital.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 87 % of the average value of its portfolio.
Portfolio Turnover, Rate		87.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. 1-3 Year Government/Credit Bond Index. Normally maintaining a dollar-weighted average maturity of three years or less. Allocating assets across different market sectors and maturities. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		4.40%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Sep. 30, 2024
Highest Quarterly Return		2.96%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(2.51%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Short-Term Bond Fund | After Taxes on Distributions | Fidelity SAI Short-Term Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			3.03%													0.54%	[16]
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Short-Term Bond Fund | After Taxes on Distributions and Sales | Fidelity SAI Short-Term Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			2.90%													0.72%	[16]
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Short-Term Bond Fund | LB013
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. 1-3 Year Government/Credit Bond Index
Average Annual Return, Percent			4.36%													1.11%
FidelitySAILowDurationBondFund-ComboPRO | Fidelity SAI Short-Term Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(1.94%)
FidelitySAISustainableCorePlusBondFund-PRO | Fidelity SAI Sustainable Core Plus Bond Fund | Fidelity SAI Sustainable Core Plus Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.21%
Expenses (as a percentage of Assets)		0.49%
Fee Waiver or Reimbursement	[17]	(0.13%)
Net Expenses (as a percentage of Assets)		0.36%
Expense Example, with Redemption, 1 Year		$ 37
Expense Example, with Redemption, 3 Years		139
Expense Example, with Redemption, 5 Years		257
Expense Example, with Redemption, 10 Years		$ 599
Annual Return, Inception Date		Apr. 13, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.29%											0.23%	[18]
Annual Return [Percent]				1.29%	6.20%
FidelitySAISustainableCorePlusBondFund-PRO | Fidelity SAI Sustainable Core Plus Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® SAI Sustainable Core Plus Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® SAI Sustainable Core Plus Bond Fund seeks a high level of current income.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 210 % of the average value of its portfolio.
Portfolio Turnover, Rate		210.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in debt securities of all types that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have positive environmental, social and governance (ESG) characteristics and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Evaluating each security in which the fund invests using both a traditional bond credit, structure and relative value analysis and a consideration of the Adviser's judgment about the security's ESG characteristics. When assessing a security's ESG characteristics and its eligibility for purchase, the Adviser considers the following, where available: (i) the sustainability practices of the security's issuer or sponsor, as applicable (each, an "issuer"), based on an evaluation of such issuer's individual ESG profile; (ii) ESG factors related to the security's underlying pool of assets; and (iii) any third-party designation as a green, sustainable or sustainability-linked bond. A security's positive ESG characteristics can be determined under any of those three factors. Using the Adviser's proprietary ESG ratings process to evaluate the current state of an issuer's sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provide a qualitative forward-looking assessment of an issuer's sustainability outlook provided by the Adviser's fundamental research analysts and ESG team. The Adviser's ESG ratings of issuers are derived from multiple factors, including an issuer's environmental profile, which may include, but is not limited to, carbon and toxic emissions, water management, waste management, vulnerability to the physical impacts of climate change, and research and investment into products, services, and energies that reduce emissions and/or provide opportunities to transition to less carbon-intensive products or operations. An assessment of an issuer's social profile includes, but is not limited to, its approach to diversity and inclusion, human capital management, data privacy, product safety and human rights. With respect to governance, the independence and diversity of an issuer's board, its compensation practices and board oversight of critical ESG issues are considered as part of the assessment. These factors are weighted based on how material the Adviser believes each factor is to an issuer's financial outlook, and not all factors may be applicable to all issuers. Issuers with an above average ESG rating as determined by the Adviser are considered to have positive ESG characteristics and well-managed ESG risks. Investing in debt securities of issuers that the Adviser believes deliver tangible environmental or social impact through core business operations. An assessment of the impact characteristics of an issuer may involve corporate engagement and an analysis of issuer alignment with the United Nations Sustainable Development Goals using qualitative analysis as well as proprietary or third-party data. For example, issuers that provide access to clean water, education, or clean energy through their core business may be considered to deliver tangible impact. When evaluating securitized debt securities (including mortgage-backed securities, commercial mortgage-backed securities, and other asset-backed securities), generally considering the issuer's ESG rating along with ESG factors related to the underlying pool of assets, such as energy efficiency and environmental impact of the underlying assets; providing access to affordable housing or opportunities for first time home ownership; and compliance with fair lending laws. In addition to its focus on debt securities with positive ESG characteristics, analyzing the credit quality of the issuer, the issuer's potential for success, the credit, currency, and economic risks of the security and its issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Allocating assets across investment-grade, high yield, and emerging market debt securities. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics. Investing up to 20% of assets in lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds). Managing the fund to have similar overall interest rate risk to the Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index. Investing in domestic and foreign issuers. Allocating assets across different asset classes, market sectors, and maturities. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Employing sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Sustainable Investing Exclusions" for additional information.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		6.26%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		6.73%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Dec. 31, 2024
Lowest Quarterly Return		(3.16%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelitySAISustainableCorePlusBondFund-PRO | Fidelity SAI Sustainable Core Plus Bond Fund | After Taxes on Distributions | Fidelity SAI Sustainable Core Plus Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			(0.33%)											(1.28%)	[18]
FidelitySAISustainableCorePlusBondFund-PRO | Fidelity SAI Sustainable Core Plus Bond Fund | After Taxes on Distributions and Sales | Fidelity SAI Sustainable Core Plus Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			0.78%											(0.46%)	[18]
FidelitySAISustainableCorePlusBondFund-PRO | Fidelity SAI Sustainable Core Plus Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%											0.36%
FidelitySAISustainableCorePlusBondFund-PRO | Fidelity SAI Sustainable Core Plus Bond Fund | IXYQV
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index
Average Annual Return, Percent			1.27%											0.39%
FidelitySAITotalBondFund-PRO | Fidelity SAI Total Bond Fund | Fidelity SAI Total Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.01%
Expenses (as a percentage of Assets)		0.29%
Expense Example, with Redemption, 1 Year		$ 30
Expense Example, with Redemption, 3 Years		93
Expense Example, with Redemption, 5 Years		163
Expense Example, with Redemption, 10 Years		$ 368
Annual Return, Inception Date		Oct. 25, 2018
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			2.91%													1.05%		2.56%	[19]
Annual Return [Percent]				2.91%	7.31%	(12.61%)	0.10%	9.05%	9.87%
FidelitySAITotalBondFund-PRO | Fidelity SAI Total Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® SAI Total Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® SAI Total Bond Fund seeks a high level of current income.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 214 % of the average value of its portfolio.
Portfolio Turnover, Rate		214.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in debt securities of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Allocating assets across investment-grade, high yield, and emerging markets debt securities. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics. Investing up to 20% of assets in lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds). Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. Aggregate Bond Index. Investing in domestic and foreign issuers. Allocating assets across different asset classes, market sectors, and maturities. Analyzing the credit quality of the issuer, the issuer's potential for success, the credit, currency, and economic risks of the security and its issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		6.52%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		6.83%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Jun. 30, 2022
Lowest Quarterly Return		(5.78%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelitySAITotalBondFund-PRO | Fidelity SAI Total Bond Fund | After Taxes on Distributions | Fidelity SAI Total Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			1.15%													(0.60%)		0.84%	[19]
FidelitySAITotalBondFund-PRO | Fidelity SAI Total Bond Fund | After Taxes on Distributions and Sales | Fidelity SAI Total Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			1.88%													0.18%		1.29%	[19]
FidelitySAITotalBondFund-PRO | Fidelity SAI Total Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)		1.45%
FidelityIntermediateBondFund-RetailPRO | Fidelity Intermediate Bond Fund | Fidelity Intermediate Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.17%
Expenses (as a percentage of Assets)		0.45%
Expense Example, with Redemption, 1 Year		$ 46
Expense Example, with Redemption, 3 Years		144
Expense Example, with Redemption, 5 Years		252
Expense Example, with Redemption, 10 Years		$ 567
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			3.25%													1.02%						1.84%
Annual Return [Percent]				3.25%	5.54%	(8.73%)	(1.33%)	7.21%	7.19%	0.51%	2.31%	2.76%	0.68%
FidelityIntermediateBondFund-RetailPRO | Fidelity Intermediate Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® Intermediate Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Intermediate Bond Fund seeks a high level of current income.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 33 % of the average value of its portfolio.
Portfolio Turnover, Rate		33.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. Intermediate Government/Credit Bond Index. Normally maintaining a dollar-weighted average maturity between three and 10 years. Allocating assets across different market sectors and maturities. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Investing in lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds). Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		5.77%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Jun. 30, 2020
Highest Quarterly Return		4.65%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(4.66%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityIntermediateBondFund-RetailPRO | Fidelity Intermediate Bond Fund | After Taxes on Distributions | Fidelity Intermediate Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			1.81%													(0.11%)						0.76%
FidelityIntermediateBondFund-RetailPRO | Fidelity Intermediate Bond Fund | After Taxes on Distributions and Sales | Fidelity Intermediate Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			1.93%													0.34%						0.95%
FidelityIntermediateBondFund-RetailPRO | Fidelity Intermediate Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)						1.35%
FidelityIntermediateBondFund-RetailPRO | Fidelity Intermediate Bond Fund | LB007
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Intermediate Government/Credit Bond Index
Average Annual Return, Percent			3.00%													0.86%						1.71%
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | Fidelity Advisor Tactical Bond Fund - Class A
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		4.00%
Maximum Deferred Sales Charge (as a percentage)	[20]	0.00%
Management Fees (as a percentage of Assets)		0.68%
Distribution and Service (12b-1) Fees		0.25%
Other Expenses (as a percentage of Assets):		0.35%
Expenses (as a percentage of Assets)		1.28%
Fee Waiver or Reimbursement	[21]	(0.33%)
Net Expenses (as a percentage of Assets)		0.95%
Expense Example, with Redemption, 1 Year		$ 493
Expense Example, with Redemption, 3 Years		747
Expense Example, with Redemption, 5 Years		1,033
Expense Example, with Redemption, 10 Years		1,846
Expense Example, No Redemption, 1 Year		493
Expense Example, No Redemption, 3 Years		747
Expense Example, No Redemption, 5 Years		1,033
Expense Example, No Redemption, 10 Years		$ 1,846
Annual Return, Inception Date		Feb. 10, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			(2.83%)											(2.15%)	[22]
Annual Return [Percent]				1.22%	6.78%
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | Fidelity Advisor Tactical Bond Fund - Class M
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		4.00%
Maximum Deferred Sales Charge (as a percentage)	[20]	0.00%
Management Fees (as a percentage of Assets)		0.71%
Distribution and Service (12b-1) Fees		0.25%
Other Expenses (as a percentage of Assets):		0.35%
Expenses (as a percentage of Assets)		1.31%
Fee Waiver or Reimbursement	[21]	(0.36%)
Net Expenses (as a percentage of Assets)		0.95%
Expense Example, with Redemption, 1 Year		$ 493
Expense Example, with Redemption, 3 Years		753
Expense Example, with Redemption, 5 Years		1,045
Expense Example, with Redemption, 10 Years		1,875
Expense Example, No Redemption, 1 Year		493
Expense Example, No Redemption, 3 Years		753
Expense Example, No Redemption, 5 Years		1,045
Expense Example, No Redemption, 10 Years		$ 1,875
Annual Return, Inception Date		Feb. 10, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			(2.83%)											(2.15%)	[23]
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | Fidelity Advisor Tactical Bond Fund - Class C
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)	[24]	1.00%
Management Fees (as a percentage of Assets)		0.71%
Distribution and Service (12b-1) Fees		1.00%
Other Expenses (as a percentage of Assets):		0.35%
Expenses (as a percentage of Assets)		2.06%
Fee Waiver or Reimbursement	[21]	(0.36%)
Net Expenses (as a percentage of Assets)		1.70%
Expenses Deferred Charges [Text Block]		On Class C shares redeemed less than one year after purchase.
Expense Example, with Redemption, 1 Year		$ 273
Expense Example, with Redemption, 3 Years		599
Expense Example, with Redemption, 5 Years		1,064
Expense Example, with Redemption, 10 Years		2,150
Expense Example, No Redemption, 1 Year		173
Expense Example, No Redemption, 3 Years		599
Expense Example, No Redemption, 5 Years		1,064
Expense Example, No Redemption, 10 Years		$ 2,150
Annual Return, Inception Date		Feb. 10, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			(0.51%)											(1.49%)	[25]
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | Fidelity Advisor Tactical Bond Fund - Class I
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)		0.00%
Management Fees (as a percentage of Assets)		0.71%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.40%
Expenses (as a percentage of Assets)		1.11%
Fee Waiver or Reimbursement	[21]	(0.40%)
Net Expenses (as a percentage of Assets)	[26]	0.71%
Expense Example, with Redemption, 1 Year		$ 73
Expense Example, with Redemption, 3 Years		299
Expense Example, with Redemption, 5 Years		559
Expense Example, with Redemption, 10 Years		1,303
Expense Example, No Redemption, 1 Year		73
Expense Example, No Redemption, 3 Years		299
Expense Example, No Redemption, 5 Years		559
Expense Example, No Redemption, 10 Years		$ 1,303
Annual Return, Inception Date		Feb. 10, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.47%											(0.51%)	[27]
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | Fidelity Advisor Tactical Bond Fund - Class Z
Prospectus Line Items
Maximum Cumulative Sales Charge (as a percentage of Offering Price)		0.00%
Maximum Deferred Sales Charge (as a percentage)		0.00%
Management Fees (as a percentage of Assets)		0.61%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.36%
Expenses (as a percentage of Assets)		0.97%
Fee Waiver or Reimbursement	[21]	(0.35%)
Net Expenses (as a percentage of Assets)	[26]	0.62%
Expense Example, with Redemption, 1 Year		$ 63
Expense Example, with Redemption, 3 Years		262
Expense Example, with Redemption, 5 Years		490
Expense Example, with Redemption, 10 Years		1,147
Expense Example, No Redemption, 1 Year		63
Expense Example, No Redemption, 3 Years		262
Expense Example, No Redemption, 5 Years		490
Expense Example, No Redemption, 10 Years		$ 1,147
Annual Return, Inception Date		Feb. 10, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.56%											(0.42%)	[28]
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund /Class: Fidelity® Tactical Bond Fund /Fidelity Advisor® Tactical Bond Fund A, M, C, I, Z
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Tactical Bond Fund seeks a high level of current income. Growth of capital may also be considered.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 39 of the prospectus and in the sales charge waiver appendix to the prospectus.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 30 % of the average value of its portfolio.
Portfolio Turnover, Rate		30.00%
Expenses Deferred Charges [Text Block]		Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 0.75% and 0.25%, respectively.
Expense Breakpoint Discounts [Text]		You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $ 50,000 in the fund or certain other Fidelity ® funds. More information about these and other discounts is available from your investment professional and in the "Fund Distribution" section beginning on page 39 of the prospectus
Expense Breakpoint, Minimum Investment Required [Amount]		$ 50,000
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]		Differs from the ratios of expenses to average net assets in the Financial Highlights section of the prospectus because of acquired fund fees and expenses. For the period, acquired fund fees and expenses are less than 0.01% and are included in other expenses. As a result, the total annual operating expenses after fee waiver and/or expense reimbursement in the fee table exceed the contractual expense limitation of the class.
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated and if you hold your shares:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in debt securities of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Allocating assets across the full spectrum of the debt market, including investment-grade (those of medium and high quality), high yield and emerging markets debt securities across different maturities. In addition to the debt securities listed above, investments also will normally include lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds), investment-grade securitized debt securities, floating rate loans and other floating rate securities, inflation-protected debt securities, preferred securities, contingent convertible securities, and securities of foreign issuers, including securities of issuers located in emerging markets. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics. Investing in both U.S. dollar-denominated and non-U.S. dollar-denominated securities, and generally hedging the fund's foreign currency exposures utilizing forward foreign currency exchange contracts. Investing in collateralized loan obligations (CLO). Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit institutional.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.
Performance Availability Website Address [Text]		institutional.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Bar Chart Narrative [Text Block]		The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.
Bar Chart Does Not Reflect Sales Loads [Text]		The returns in the bar chart do not reflect any applicable sales charges; if sales charges were reflected, returns would be lower than those shown.
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		6.58%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		6.83%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Dec. 31, 2024
Lowest Quarterly Return		(3.30%)
Performance Table Heading		Average Annual Returns
Performance Table Does Reflect Sales Loads		Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges.
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table One Class of after Tax Shown [Text]		After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary.
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges. After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. After-tax returns for Class A are shown in the table below and after-tax returns for other classes will vary. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | After Taxes on Distributions | Fidelity Advisor Tactical Bond Fund - Class A
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			(4.52%)											(3.79%)	[22]
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | After Taxes on Distributions and Sales | Fidelity Advisor Tactical Bond Fund - Class A
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			(1.65%)											(2.31%)	[22]
FidelityTacticalBondFund-AMCIZPRO | Fidelity Tactical Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%											(1.09%)
FidelityFlexConservativeIncomeBondFund-PRO | Fidelity Flex Conservative Income Bond Fund | Fidelity Flex Conservative Income Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.00%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.00%
Expenses (as a percentage of Assets)	[29]	0.00%
Expense Example, with Redemption, 1 Year		$ 0
Expense Example, with Redemption, 3 Years		0
Expense Example, with Redemption, 5 Years		0
Expense Example, with Redemption, 10 Years		$ 0
Annual Return, Inception Date		May 31, 2018
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			5.66%													2.90%		2.87%	[30]
Annual Return [Percent]				5.66%	5.93%	1.47%	0.25%	1.35%	3.20%
FidelityFlexConservativeIncomeBondFund-PRO | Fidelity Flex Conservative Income Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity Flex® Conservative Income Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity Flex® Conservative Income Bond Fund seeks to obtain a high level of current income consistent with preservation of capital.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 71 % of the average value of its portfolio.
Portfolio Turnover, Rate		71.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. This example does not include any fees paid at the fee-based account or plan level. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in U.S. dollar-denominated money market and high quality investment-grade debt securities of all types, and repurchase agreements for those securities. Debt securities, including money market securities, are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, and mortgage and other asset-backed securities. Money market securities include bank certificates of deposit, bankers' acceptances, bank time deposits, notes, commercial paper, and U.S. Government securities. High quality investment grade securities in which the fund invests include securities or issuers (i) rated at least A- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO) or similarly rated by the Adviser, and (ii) for securities with a credit maturity within one year, rated at least BBB or its equivalent by all NRSROs that rate the security and similarly rated by the Adviser. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Potentially entering into reverse repurchase agreements. Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. 3-6 Month Treasury Bill Index. Normally maintaining a dollar-weighted average maturity of one year or less. Normally investing in securities with a maximum maturity of four years. Allocating assets across different market sectors and maturities. Investing more than 25% of total assets in the financial services industries. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level. Visit www.401k.com and log in or www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text]		www.401k.com and log in or www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		3.63%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		1.79%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2020
Lowest Quarterly Return		(0.79%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityFlexConservativeIncomeBondFund-PRO | Fidelity Flex Conservative Income Bond Fund | After Taxes on Distributions | Fidelity Flex Conservative Income Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			3.49%													1.75%		1.74%	[30]
FidelityFlexConservativeIncomeBondFund-PRO | Fidelity Flex Conservative Income Bond Fund | After Taxes on Distributions and Sales | Fidelity Flex Conservative Income Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			3.45%													1.74%		1.72%	[30]
FidelityFlexConservativeIncomeBondFund-PRO | Fidelity Flex Conservative Income Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)		1.26%
FidelityFlexConservativeIncomeBondFund-PRO | Fidelity Flex Conservative Income Bond Fund | LB151
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. 3-6 Month Treasury Bill Index
Average Annual Return, Percent			5.33%													2.52%		2.47%
FidelityTacticalBondFund-RetailPRO | Fidelity Tactical Bond Fund | Fidelity Tactical Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.63%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.35%
Expenses (as a percentage of Assets)		0.98%
Fee Waiver or Reimbursement	[31]	(0.28%)
Net Expenses (as a percentage of Assets)		0.70%
Expense Example, with Redemption, 1 Year		$ 72
Expense Example, with Redemption, 3 Years		274
Expense Example, with Redemption, 5 Years		505
Expense Example, with Redemption, 10 Years		$ 1,167
Annual Return, Inception Date		Feb. 10, 2022
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.47%											(0.51%)	[32]
Annual Return [Percent]				1.47%	7.04%
FidelityTacticalBondFund-RetailPRO | Fidelity Tactical Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund /Class: Fidelity® Tactical Bond Fund /Fidelity® Tactical Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Tactical Bond Fund seeks a high level of current income. Growth of capital may also be considered.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 30 % of the average value of its portfolio.
Portfolio Turnover, Rate		30.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in debt securities of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Allocating assets across the full spectrum of the debt market, including investment-grade (those of medium and high quality), high yield and emerging markets debt securities across different maturities. In addition to the debt securities listed above, investments also will normally include lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds), investment-grade securitized debt securities, floating rate loans and other floating rate securities, inflation-protected debt securities, preferred securities, contingent convertible securities, and securities of foreign issuers, including securities of issuers located in emerging markets. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics. Investing in both U.S. dollar-denominated and non-U.S. dollar-denominated securities, and generally hedging the fund's foreign currency exposures utilizing forward foreign currency exchange contracts. Investing in collateralized loan obligations (CLO). Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		6.78%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		6.90%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Dec. 31, 2024
Lowest Quarterly Return		(3.24%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityTacticalBondFund-RetailPRO | Fidelity Tactical Bond Fund | After Taxes on Distributions | Fidelity Tactical Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			(0.33%)											(2.26%)	[32]
FidelityTacticalBondFund-RetailPRO | Fidelity Tactical Bond Fund | After Taxes on Distributions and Sales | Fidelity Tactical Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			0.96%											(1.11%)	[32]
FidelityTacticalBondFund-RetailPRO | Fidelity Tactical Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%											(1.09%)
FidelitySAIEnhancedCoreBondFund-PRO | Fidelity SAI Enhanced Core Bond Fund | Fidelity SAI Enhanced Core Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.20%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):	[33]	0.04%
Expenses (as a percentage of Assets)		0.24%
Fee Waiver or Reimbursement	[34]	(0.09%)
Net Expenses (as a percentage of Assets)		0.15%
Expense Example, with Redemption, 1 Year		$ 15
Expense Example, with Redemption, 3 Years		$ 65
FidelitySAIEnhancedCoreBondFund-PRO | Fidelity SAI Enhanced Core Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund: Fidelity® SAI Enhanced Core Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® SAI Enhanced Core Bond Fund seeks a high level of current income.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Fee Waiver or Reimbursement over Assets, Date of Termination		Dec. 31, 2026
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. For the period from March 18, 2025 to August 31, 2025, the fund's portfolio turnover rate was 180 % of the average value of its portfolio.
Portfolio Turnover, Rate		180.00%
Other Expenses, New Fund, Based on Estimates [Text]		Based on estimated amounts for the current fiscal year.
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Using the Bloomberg U.S. Aggregate Bond Index as a guide in structuring the fund and selecting its investments as it relates to credit quality distribution and risk characteristics. Investing in domestic and foreign issuers. Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Generally utilizing a research-driven approach identifying long-term drivers of debt security returns that may include, but are not limited to, valuation, quality, momentum, and other factors. The research is systematically applied alongside a proprietary portfolio construction and risk management framework to select a broadly diversified group of debt securities that may have the potential to provide a higher total return than that of the Bloomberg U.S. Aggregate Bond Index.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		Performance history will be available for the fund after the fund has been in operation for one calendar year.
Performance One Year or Less [Text]		Performance history will be available for the fund after the fund has been in operation for one calendar year.
FidelityInvestmentGradeBondFund-RetailPRO | Fidelity Investment Grade Bond Fund | Fidelity Investment Grade Bond Fund
Prospectus Line Items
Management Fees (as a percentage of Assets)		0.28%
Distribution and Service (12b-1) Fees		0.00%
Other Expenses (as a percentage of Assets):		0.17%
Expenses (as a percentage of Assets)		0.45%
Expense Example, with Redemption, 1 Year		$ 46
Expense Example, with Redemption, 3 Years		144
Expense Example, with Redemption, 5 Years		252
Expense Example, with Redemption, 10 Years		$ 567
Average Annual Return, Label [Optional Text]			Return Before Taxes
Average Annual Return, Percent			1.59%													0.39%						1.86%
Annual Return [Percent]				1.59%	6.49%	(13.48%)	(0.89%)	9.90%	9.81%	(0.36%)	3.91%	5.33%	(1.57%)
FidelityInvestmentGradeBondFund-RetailPRO | Fidelity Investment Grade Bond Fund
Prospectus Line Items
Risk/Return [Heading]		Fund Summary Fund /Class: Fidelity® Investment Grade Bond Fund /Fidelity® Investment Grade Bond Fund
Objective [Heading]		Investment Objective
Objective, Primary [Text Block]		Fidelity® Investment Grade Bond Fund seeks a high level of current income.
Expense Heading [Optional Text]		Fee Table
Expense Narrative [Text Block]		The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees Caption [Optional Text]		Shareholder fees
Shareholder Fee, Other		$ 0
Operating Expenses Caption [Optional Text]		Annual Operating Expenses
Portfolio Turnover [Heading]		Portfolio Turnover
Portfolio Turnover [Text Block]		The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 196 % of the average value of its portfolio.
Portfolio Turnover, Rate		196.00%
Expense Example Narrative [Text Block]		This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading]		Principal Investment Strategies
Strategy Narrative [Text Block]		Normally investing at least 80% of assets in investment-grade debt securities (those of medium and high quality) of all types and repurchase agreements for those securities. Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities, such as hybrids and synthetic securities, believed to have debt-like characteristics (e.g., securities classified as Tier 2 Regulatory capital, securities that rank above share capital in an insolvency waterfall, securities with maturity dates and non-cancellable interest payment structures).  Investment grade securities in which the fund invests include securities or issuers rated at least BBB- or its equivalent by at least one nationally recognized statistical ratings organization (NRSRO), or, if unrated, determined by the Adviser to be of comparable quality. A repurchase agreement is an agreement to buy a security at one price and a simultaneous agreement to sell it back at an agreed-upon price. Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.   Managing the fund to have similar overall interest rate risk to the Bloomberg U.S. Aggregate Bond Index. Allocating assets across different market sectors and maturities. Investing in domestic and foreign issuers. Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments. Investing in lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds). Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default), options, and futures contracts - and forward-settling securities, to adjust the fund's risk exposure. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above.
Bar Chart and Performance Table [Heading]		Performance
Performance Narrative [Text Block]		The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text]		The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.
Performance Availability Website Address [Text]		www.fidelity.com
Performance Past Does Not Indicate Future [Text]		Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]		Year-by-Year Returns
Year to Date Return, Label [Optional Text]		Year-to-Date Return
Bar Chart, Year to Date Return, Date		Sep. 30, 2025
Bar Chart, Year to Date Return		6.44%
Highest Quarterly Return, Label [Optional Text]		Highest Quarter Return
Highest Quarterly Return, Date		Dec. 31, 2023
Highest Quarterly Return		6.89%
Lowest Quarterly Return, Label [Optional Text]		Lowest Quarter Return
Lowest Quarterly Return, Date		Mar. 31, 2022
Lowest Quarterly Return		(5.78%)
Performance Table Heading		Average Annual Returns
Performance Table Uses Highest Federal Rate		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred		The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher		Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative		After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityInvestmentGradeBondFund-RetailPRO | Fidelity Investment Grade Bond Fund | After Taxes on Distributions | Fidelity Investment Grade Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions
Average Annual Return, Percent			0.19%													(0.89%)						0.65%
FidelityInvestmentGradeBondFund-RetailPRO | Fidelity Investment Grade Bond Fund | After Taxes on Distributions and Sales | Fidelity Investment Grade Bond Fund
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return, Percent			1.15%													(0.19%)						0.92%
FidelityInvestmentGradeBondFund-RetailPRO | Fidelity Investment Grade Bond Fund | LB001
Prospectus Line Items
Average Annual Return, Label [Optional Text]			Bloomberg U.S. Aggregate Bond Index
Average Annual Return, Percent			1.25%													(0.33%)						1.35%
Document Type		485BPOS
Registrant Name		Fidelity Salem Street Trust

[1] A Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 0.75% and 0.25%, respectively.

[2] B On Class C shares redeemed less than one year after purchase.

[3] A Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse Class Z of the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.36% (the Expense Cap). If at any time during the current fiscal year expenses for Class Z of the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through December 31, 2026 . FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.

[4] A From October 2, 2018 .

[5] A Purchases of $250,000 or more will not be subject to a front-end sales charge, but may be subject to a 0.50% contingent deferred sales charge (CDSC) if the intermediary firm has elected an upfront finder's fee at the time the shares are purchased, or a 0.75% CDSC if the shares purchased are recordkept in a Fidelity Advisor ® 401(k) Retirement Plan.

[6] A From July 12, 2016 .

[7] B Purchases of $250,000 or more will not be subject to a front-end sales charge but may be subject to a 0.25% CDSC if a finder's fee is paid at the time the shares are purchased.

[8] B From July 12, 2016 .

[9] C On Class C shares redeemed less than one year after purchase.

[10] C From July 12, 2016 .

[11] A Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse Class I of the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.30% (the Expense Cap). If at any time during the current fiscal year expenses for Class I of the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through December 31, 2026 . FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.

[12] D From July 12, 2016 .

[13] E From October 2, 2018 .

[14] A Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.20% (the Expense Cap). If at any time during the current fiscal year expenses for the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through December 31, 2026 . FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.

[15] A From September 15, 2020 .

[16] A From September 15, 2020 .

[17] A Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.36% (the Expense Cap). If at any time during the current fiscal year expenses for the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through December 31, 2026 . FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.

[18] A From April 13, 2022 .

[19] A From October 25, 2018 .

[20] A Class A and Class M purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class M purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 0.75% and 0.25%, respectively.

[21] A Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse Class A, Class M, Class C, Class I, and Class Z of the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of their respective average net assets, exceed 0.95%, 0.95%, 1.70%, 0.70%, and 0.61% (the Expense Caps). If at any time during the current fiscal year expenses for Class A, Class M, Class C, Class I, or Class Z of the fund fall below the Expense Caps, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Caps. These arrangements will remain in effect through December 31, 2026 . FMR may not terminate these arrangements before the expiration date without the approval of the Board of Trustees and may extend them in its discretion after that date.

[22] A From February 10, 2022 .

[23] B From February 10, 2022 .

[24] B On Class C shares redeemed less than one year after purchase.

[25] C From February 10, 2022 .

[26] B Differs from the ratios of expenses to average net assets in the Financial Highlights section of the prospectus because of acquired fund fees and expenses. For the period, acquired fund fees and expenses are less than 0.01% and are included in other expenses. As a result, the total annual operating expenses after fee waiver and/or expense reimbursement in the fee table exceed the contractual expense limitation of the class.

[27] D From February 10, 2022 .

[28] E From February 10, 2022 .

[29] A The fund is available only to certain fee-based accounts and advisory programs offered by Fidelity. Advisory account clients, retirement plans, plan sponsors and/or plan participants typically pay an advisory fee that generally covers investment advisory and administrative services.

[30] A From May 31, 2018 .

[31] A Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse the class of shares of the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.70% (the Expense Cap). If at any time during the current fiscal year expenses for the class of shares of the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through December 31, 2026 . FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.

[32] A From February 10, 2022 .

[33] A Based on estimated amounts for the current fiscal year.

[34] B Fidelity Management & Research Company LLC (FMR) has contractually agreed to reimburse the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses (including fees and expenses associated with a wholly owned subsidiary), if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.15% (the Expense Cap). If at any time during the current fiscal year expenses for the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through December 31, 2026 . FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.