Fidelity Real Estate Index Fund (FSRNX) N-CSRS22 Aug 24Certified semi-annual shareholder report (management investment company)Financial data

Company Profile

Form N-CSR Cover

Form N-CSR Cover	6 Months Ended
Form N-CSR Cover	Jun. 30, 2024
Shareholder Report [Line Items]
Document Type	N-CSRS
Amendment Flag	false
Registrant Name	Fidelity Salem Street Trust
Entity Central Index Key	0000035315
Entity Investment Company Type	N-1A
Document Period End Date	Jun. 30, 2024

Shareholder Report

Shareholder Report	6 Months Ended
Shareholder Report	Jun. 30, 2024 USD ($) shares
Shareholder Report [Line Items]
Document Type	N-CSRS
Amendment Flag	false
Registrant Name	Fidelity Salem Street Trust
Entity Central Index Key	0000035315
Entity Investment Company Type	N-1A
Document Period End Date	Jun. 30, 2024
Fidelity Inflation-Protected Bond Index Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Inflation-Protected Bond Index Fund
Class Name	Fidelity® Inflation-Protected Bond Index Fund
Trading Symbol	FIPDX
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains information about Fidelity® Inflation-Protected Bond Index Fund for the period January 1, 2024 to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number	1-800-544-8544
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Inflation-Protected Bond Index Fund $ 0.05 %
Expenses Paid, Amount	$ 3
Expense Ratio, Percent	0.05%
Net Assets	$ 9,175,415,932
Holdings Count \| shares	50
Investment Company Portfolio Turnover	22%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 50 Portfolio Turnover 22 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) 0.01 - 0.99% 62.0 1 - 1.99% 20.2 2 - 2.99% 12.6 3 - 3.99% 4.5 U.S. Treasury Obligations 99.3 Short-Term Investments and Net Other Assets (Liabilities) 0.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 74.9 US Treasury Bonds 24.4 99.3
Fidelity SAI International Credit Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® SAI International Credit Fund
Class Name	Fidelity® SAI International Credit Fund
Trading Symbol	FSNDX
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains information about Fidelity® SAI International Credit Fund for the period January 1, 2024 to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number	1-800-544-3455
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® SAI International Credit Fund $ 0.41 %
Expenses Paid, Amount	$ 21
Expense Ratio, Percent	0.41%
Net Assets	$ 389,358,067
Holdings Count \| shares	232
Investment Company Portfolio Turnover	73%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 232 Portfolio Turnover 73 %
Holdings [Text Block]	U.S. Government and U.S. Government Agency Obligations 25.2 AAA 6.3 AA 0.3 A 12.2 BBB 34.9 BB 4.3 B 0.7 CCC,CC,C 0.6 D 0.1 Not Rated 9.6 Short-Term Investments and Net Other Assets (Liabilities) 5.8 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. Corporate Bonds 53.4 U.S. Treasury Obligations 25.2 Foreign Government and Government Agency Obligations 11.3 Preferred Securities 4.3 Short-Term Investments and Net Other Assets (Liabilities) 5.8 ASSET ALLOCATION (% of Fund's net assets) United States 34.3 United Kingdom 17.4 Germany 15.5 France 4.6 Netherlands 4.1 Switzerland 3.7 Luxembourg 2.9 Japan 2.4 Denmark 2.1 Others 13.0 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 12.9 US Treasury Bonds 12.3 German Federal Republic 6.8 Japan Government 2.4 Canadian Government 2.1 UBS Group AG 2.0 HSBC Holdings PLC 2.0 Lloyds Banking Group PLC 1.9 NatWest Group PLC 1.9 Danske Bank A/S 1.7 46.0
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Series 0-5 Year Inflation-Protected Bond Index Fund
Class Name	Fidelity® Series 0-5 Year Inflation-Protected Bond Index Fund
Trading Symbol	FSTZX
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains information about Fidelity® Series 0-5 Year Inflation-Protected Bond Index Fund for the period January 1, 2024 to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544.
Additional Information Phone Number	1-800-544-8544
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Series 0-5 Year Inflation-Protected Bond Index Fund $ A 0.00 % B A Amount represents less than $.50 B Amount represents less than 0.005%
Expenses Paid, Amount	$ 0
Expense Ratio, Percent	0%
Net Assets	$ 7,539,073,797
Holdings Count \| shares	28
Investment Company Portfolio Turnover	24%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 28 Portfolio Turnover 24 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) 0.01 - 0.99% 66.3 1 - 1.99% 13.2 2 - 2.99% 18.2 3 - 3.99% 1.6 U.S. Treasury Obligations 99.3 Short-Term Investments and Net Other Assets (Liabilities) 0.7 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 88.0 US Treasury Bonds 11.3 99.3
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® Series 5+ Year Inflation-Protected Bond Index Fund
Class Name	Fidelity® Series 5+ Year Inflation-Protected Bond Index Fund
Trading Symbol	FSTDX
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains information about Fidelity® Series 5+ Year Inflation-Protected Bond Index Fund for the period January 1, 2024 to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544.
Additional Information Phone Number	1-800-544-8544
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® Series 5+ Year Inflation-Protected Bond Index Fund $ A 0.00 % B A Amount represents less than $.50 B Amount represents less than 0.005%
Expenses Paid, Amount	$ 0
Expense Ratio, Percent	0%
Net Assets	$ 10,496,299,874
Holdings Count \| shares	27
Investment Company Portfolio Turnover	32%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 27 Portfolio Turnover 32 %
Holdings [Text Block]	COUPON DISTRIBUTION (% of Fund's net assets) 0.01 - 0.99% 59.2 1 - 1.99% 33.5 2 - 2.99% 5.0 3 - 3.99% 1.9 U.S. Treasury Obligations 99.6 Short-Term Investments and Net Other Assets (Liabilities) 0.4 ASSET ALLOCATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) US Treasury Notes 68.0 US Treasury Bonds 31.6 99.6
Fidelity SAI Municipal Income Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® SAI Municipal Income Fund
Class Name	Fidelity® SAI Municipal Income Fund
Trading Symbol	FSMNX
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains information about Fidelity® SAI Municipal Income Fund for the period January 1, 2024 to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number	1-800-544-3455
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® SAI Municipal Income Fund $ 0.34 %
Expenses Paid, Amount	$ 17
Expense Ratio, Percent	0.34%
Net Assets	$ 2,103,556,992
Holdings Count \| shares	1,862
Investment Company Portfolio Turnover	7%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 1,862 Portfolio Turnover 7 %
Holdings [Text Block]	REVENUE SOURCES (% of Fund's net assets) General Obligations 20.0 Transportation 16.5 Health Care 14.8 Education 8.1 Special Tax 8.0 Housing 7.7 State G.O. 6.5 Water & Sewer 5.4 Others(Individually Less Than 5%) 13.0 100.0 AAA 10.8 AA 33.2 A 37.2 BBB 7.9 BB 1.1 B 0.2 CCC,CC,C 0.0 Not Rated 4.1 Short-Term Investments and Net Other Assets (Liabilities) 5.5 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. TOP STATES (% of Fund's net assets) Illinois 10.0 New York 8.1 New Jersey 7.2 Texas 7.2 Pennsylvania 6.0
Fidelity International Bond Index Fund
Shareholder Report [Line Items]
Fund Name	Fidelity® International Bond Index Fund
Class Name	Fidelity® International Bond Index Fund
Trading Symbol	FBIIX
Annual or Semi-Annual Statement [Text Block]	This semi-annual shareholder report contains information about Fidelity® International Bond Index Fund for the period January 1, 2024 to June 30, 2024.
Shareholder Report Annual or Semi-Annual	semi-annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.
Additional Information Phone Number	1-800-544-8544
Additional Information Email	fidfunddocuments@fidelity.com
Additional Information Website	fundresearch.fidelity.com/prospectus/sec
Expenses [Text Block]	What were your Fund costs for the last six months? (based on hypothetical $10,000 investment) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Fidelity® International Bond Index Fund $ 0.06 %
Expenses Paid, Amount	$ 3
Expense Ratio, Percent	0.06%
Net Assets	$ 802,782,572
Holdings Count \| shares	1,785
Investment Company Portfolio Turnover	22%
Additional Fund Statistics [Text Block]	Key Fund Statistics (as of June 30, 2024) KEY FACTS Fund Size $ Number of Holdings 1,785 Portfolio Turnover 22 %
Holdings [Text Block]	AAA 16.7 AA 11.8 A 12.2 BBB 11.2 BB 0.2 B 0.0 CCC,CC,C 0.0 Not Rated 46.6 Short-Term Investments and Net Other Assets (Liabilities) 1.3 QUALITY DIVERSIFICATION (% of Fund's net assets) We have used ratings from Moody's Investors Service, Inc. Where Moody's® ratings are not available, we have used S&P® ratings. All ratings are as of the date indicated and do not reflect subsequent changes. Foreign Government and Government Agency Obligations 64.5 Corporate Bonds 33.8 Preferred Securities 0.4 U.S. Treasury Obligations 0.0 Short-Term Investments and Net Other Assets (Liabilities) 1.3 ASSET ALLOCATION (% of Fund's net assets) China 19.4 France 10.0 Japan 9.6 Germany 8.9 Italy 6.3 Canada 5.9 United States 5.3 United Kingdom 4.2 Spain 4.2 Others 26.2 GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)
Largest Holdings [Text Block]	TOP HOLDINGS (% of Fund's net assets) Peoples Republic of China 11.5 Japan Government 9.2 Italian Republic 5.6 French Government 5.6 German Federal Republic 5.0 China Development Bank 4.2 Spanish Kingdom 3.5 United Kingdom of Great Britain and Northern Ireland 2.6 Korean Republic 2.1 Agricultural Development Bank of China 2.1 51.4

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Jun. 30, 2024
Fidelity Inflation-Protected Bond Index Fund \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	74.90%
Fidelity Inflation-Protected Bond Index Fund \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	24.40%
Fidelity Inflation-Protected Bond Index Fund \| CD0Member
Holdings [Line Items]
Percent of Net Asset Value	62%
Fidelity Inflation-Protected Bond Index Fund \| CD1Member
Holdings [Line Items]
Percent of Net Asset Value	20.20%
Fidelity Inflation-Protected Bond Index Fund \| CD2Member
Holdings [Line Items]
Percent of Net Asset Value	12.60%
Fidelity Inflation-Protected Bond Index Fund \| CD3Member
Holdings [Line Items]
Percent of Net Asset Value	4.50%
Fidelity Inflation-Protected Bond Index Fund \| AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	99.30%
Fidelity Inflation-Protected Bond Index Fund \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity SAI International Credit Fund \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	12.90%
Fidelity SAI International Credit Fund \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	12.30%
Fidelity SAI International Credit Fund \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	6.80%
Fidelity SAI International Credit Fund \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity SAI International Credit Fund \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity SAI International Credit Fund \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity SAI International Credit Fund \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	2%
Fidelity SAI International Credit Fund \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity SAI International Credit Fund \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity SAI International Credit Fund \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	1.70%
Fidelity SAI International Credit Fund \| QDUSGovernmentandUSGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	25.20%
Fidelity SAI International Credit Fund \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	12.20%
Fidelity SAI International Credit Fund \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	34.90%
Fidelity SAI International Credit Fund \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity SAI International Credit Fund \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity SAI International Credit Fund \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0.60%
Fidelity SAI International Credit Fund \| QDDMember
Holdings [Line Items]
Percent of Net Asset Value	0.10%
Fidelity SAI International Credit Fund \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	9.60%
Fidelity SAI International Credit Fund \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	5.80%
Fidelity SAI International Credit Fund \| United States
Holdings [Line Items]
Percent of Net Asset Value	34.30%
Fidelity SAI International Credit Fund \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	17.40%
Fidelity SAI International Credit Fund \| Germany
Holdings [Line Items]
Percent of Net Asset Value	15.50%
Fidelity SAI International Credit Fund \| France
Holdings [Line Items]
Percent of Net Asset Value	4.60%
Fidelity SAI International Credit Fund \| Netherlands
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity SAI International Credit Fund \| Switzerland
Holdings [Line Items]
Percent of Net Asset Value	3.70%
Fidelity SAI International Credit Fund \| Luxembourg
Holdings [Line Items]
Percent of Net Asset Value	2.90%
Fidelity SAI International Credit Fund \| Japan
Holdings [Line Items]
Percent of Net Asset Value	2.40%
Fidelity SAI International Credit Fund \| Denmark
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity SAI International Credit Fund \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	13%
Fidelity SAI International Credit Fund \| AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	25.20%
Fidelity SAI International Credit Fund \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	5.80%
Fidelity SAI International Credit Fund \| AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	53.40%
Fidelity SAI International Credit Fund \| AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	11.30%
Fidelity SAI International Credit Fund \| AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	4.30%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	88%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	11.30%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| CD0Member
Holdings [Line Items]
Percent of Net Asset Value	66.30%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| CD1Member
Holdings [Line Items]
Percent of Net Asset Value	13.20%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| CD2Member
Holdings [Line Items]
Percent of Net Asset Value	18.20%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| CD3Member
Holdings [Line Items]
Percent of Net Asset Value	1.60%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	99.30%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.70%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	68%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	31.60%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| CD0Member
Holdings [Line Items]
Percent of Net Asset Value	59.20%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| CD1Member
Holdings [Line Items]
Percent of Net Asset Value	33.50%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| CD2Member
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| CD3Member
Holdings [Line Items]
Percent of Net Asset Value	1.90%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	99.60%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%
Fidelity SAI Municipal Income Fund \| TS0Member
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity SAI Municipal Income Fund \| TS1Member
Holdings [Line Items]
Percent of Net Asset Value	8.10%
Fidelity SAI Municipal Income Fund \| TS2Member
Holdings [Line Items]
Percent of Net Asset Value	7.20%
Fidelity SAI Municipal Income Fund \| TS3Member
Holdings [Line Items]
Percent of Net Asset Value	7.20%
Fidelity SAI Municipal Income Fund \| TS4Member
Holdings [Line Items]
Percent of Net Asset Value	6%
Fidelity SAI Municipal Income Fund \| RS0Member
Holdings [Line Items]
Percent of Net Asset Value	20%
Fidelity SAI Municipal Income Fund \| RS1Member
Holdings [Line Items]
Percent of Net Asset Value	16.50%
Fidelity SAI Municipal Income Fund \| RS2Member
Holdings [Line Items]
Percent of Net Asset Value	14.80%
Fidelity SAI Municipal Income Fund \| RS3Member
Holdings [Line Items]
Percent of Net Asset Value	8.10%
Fidelity SAI Municipal Income Fund \| RS4Member
Holdings [Line Items]
Percent of Net Asset Value	8%
Fidelity SAI Municipal Income Fund \| RS5Member
Holdings [Line Items]
Percent of Net Asset Value	7.70%
Fidelity SAI Municipal Income Fund \| RS6Member
Holdings [Line Items]
Percent of Net Asset Value	6.50%
Fidelity SAI Municipal Income Fund \| RS7Member
Holdings [Line Items]
Percent of Net Asset Value	5.40%
Fidelity SAI Municipal Income Fund \| RS8Member
Holdings [Line Items]
Percent of Net Asset Value	13%
Fidelity SAI Municipal Income Fund \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	37.20%
Fidelity SAI Municipal Income Fund \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	7.90%
Fidelity SAI Municipal Income Fund \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	1.10%
Fidelity SAI Municipal Income Fund \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity SAI Municipal Income Fund \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity SAI Municipal Income Fund \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	4.10%
Fidelity SAI Municipal Income Fund \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	5.50%
Fidelity International Bond Index Fund \| TH0Member
Holdings [Line Items]
Percent of Net Asset Value	11.50%
Fidelity International Bond Index Fund \| TH1Member
Holdings [Line Items]
Percent of Net Asset Value	9.20%
Fidelity International Bond Index Fund \| TH2Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity International Bond Index Fund \| TH3Member
Holdings [Line Items]
Percent of Net Asset Value	5.60%
Fidelity International Bond Index Fund \| TH4Member
Holdings [Line Items]
Percent of Net Asset Value	5%
Fidelity International Bond Index Fund \| TH5Member
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity International Bond Index Fund \| TH6Member
Holdings [Line Items]
Percent of Net Asset Value	3.50%
Fidelity International Bond Index Fund \| TH7Member
Holdings [Line Items]
Percent of Net Asset Value	2.60%
Fidelity International Bond Index Fund \| TH8Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity International Bond Index Fund \| TH9Member
Holdings [Line Items]
Percent of Net Asset Value	2.10%
Fidelity International Bond Index Fund \| QDAMember
Holdings [Line Items]
Percent of Net Asset Value	12.20%
Fidelity International Bond Index Fund \| QDBBBMember
Holdings [Line Items]
Percent of Net Asset Value	11.20%
Fidelity International Bond Index Fund \| QDBBMember
Holdings [Line Items]
Percent of Net Asset Value	0.20%
Fidelity International Bond Index Fund \| QDBMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity International Bond Index Fund \| QDCCCCCCMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity International Bond Index Fund \| QDNotRatedMember
Holdings [Line Items]
Percent of Net Asset Value	46.60%
Fidelity International Bond Index Fund \| QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity International Bond Index Fund \| United States
Holdings [Line Items]
Percent of Net Asset Value	5.30%
Fidelity International Bond Index Fund \| United Kingdom
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity International Bond Index Fund \| Germany
Holdings [Line Items]
Percent of Net Asset Value	8.90%
Fidelity International Bond Index Fund \| France
Holdings [Line Items]
Percent of Net Asset Value	10%
Fidelity International Bond Index Fund \| Japan
Holdings [Line Items]
Percent of Net Asset Value	9.60%
Fidelity International Bond Index Fund \| OtherMember
Holdings [Line Items]
Percent of Net Asset Value	26.20%
Fidelity International Bond Index Fund \| China
Holdings [Line Items]
Percent of Net Asset Value	19.40%
Fidelity International Bond Index Fund \| Italy
Holdings [Line Items]
Percent of Net Asset Value	6.30%
Fidelity International Bond Index Fund \| Canada
Holdings [Line Items]
Percent of Net Asset Value	5.90%
Fidelity International Bond Index Fund \| Spain
Holdings [Line Items]
Percent of Net Asset Value	4.20%
Fidelity International Bond Index Fund \| AAUSTreasuryObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	0%
Fidelity International Bond Index Fund \| AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember
Holdings [Line Items]
Percent of Net Asset Value	1.30%
Fidelity International Bond Index Fund \| AACorporateBondsMember
Holdings [Line Items]
Percent of Net Asset Value	33.80%
Fidelity International Bond Index Fund \| AAForeignGovernmentandGovernmentAgencyObligationsMember
Holdings [Line Items]
Percent of Net Asset Value	64.50%
Fidelity International Bond Index Fund \| AAPreferredSecuritiesMember
Holdings [Line Items]
Percent of Net Asset Value	0.40%

Uncategorized Items - filing779

Label	Element	Value
C000241080 [Member] \| QDAAMember [Member]
Percent of Net Asset Value	oef_PctOfNav	0.30%
C000241080 [Member] \| QDAAAMember [Member]
Percent of Net Asset Value	oef_PctOfNav	6.30%
C000200824 [Member] \| QDAAMember [Member]
Percent of Net Asset Value	oef_PctOfNav	33.20%
C000200824 [Member] \| QDAAAMember [Member]
Percent of Net Asset Value	oef_PctOfNav	10.80%
C000214977 [Member] \| QDAAMember [Member]
Percent of Net Asset Value	oef_PctOfNav	11.80%
C000214977 [Member] \| QDAAAMember [Member]
Percent of Net Asset Value	oef_PctOfNav	16.70%