485BPOS

Securities Act of 1933 Registration No. 002-11517

Investment Company Act of 1940 Registration No. 811-00215

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 x

o Pre-Effective Amendment No.  ______

x Post-Effective Amendment No.  162

and

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940 x

x Amendment No.  162

Fidelity Hastings Street Trust

 (Exact Name of Registrant as Specified in Charter)

245 Summer Street, Boston, Massachusetts 02210

(Address of Principal Executive Offices)(Zip Code)

Registrant’s Telephone Number: 617-563-7000

Marc Bryant, Secretary

245 Summer Street

Boston, Massachusetts 02210

(Name and Address of Agent for Service)

It is proposed that this filing will become effective immediately upon filing pursuant to paragraph (b).

EXHIBIT INDEX

Exhibit	Exhibit No.
XBRL Instance Document	EX-101.INS
XBRL Taxonomy Extension Schema Document	EX-101.SCH
XBRL Taxonomy Extension Calculation Linkbase Document	EX-101.CAL
XBRL Taxonomy Extension Definition Linkbase Document	EX-101.DEF
XBRL Taxonomy Extension Labels Linkbase Document	EX-101.LAB
XBRL Taxonomy Extension Presentation Linkbase Document	EX-101.PRE

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for the effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this Post-Effective Amendment No.162 to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston, and Commonwealth of Massachusetts, on the 17th day of March 2017.

	Fidelity Hastings Street Trust
	By	/s/Stacie M. Smith
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||		Stacie M. Smith, President

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

(Signature)		(Title)	(Date)
/s/Stacie M. Smith		President and Treasurer	March 17, 2017
Stacie M. Smith		(Principal Executive Officer)
/s/Howard J. Galligan III		Chief Financial Officer	March 17, 2017
Howard J. Galligan III		(Principal Financial Officer)
/s/James C. Curvey	*	Trustee	March 17, 2017
James C. Curvey
/s/Dennis J. Dirks	*	Trustee	March 17, 2017
Dennis J. Dirks
/s/Alan J. Lacy	*	Trustee	March 17, 2017
Alan J. Lacy
/s/Ned C. Lautenbach	*	Trustee	March 17, 2017
Ned C. Lautenbach
/s/Joseph Mauriello	*	Trustee	March 17, 2017
Joseph Mauriello
/s/Charles S. Morrison	*	Trustee	March 17, 2017
Charles S. Morrison
/s/Robert W. Selander	*	Trustee	March 17, 2017
Robert W. Selander
/s/Cornelia M. Small	*	Trustee	March 17, 2017
Cornelia M. Small
/s/William S. Stavropoulos	*	Trustee	March 17, 2017
William S. Stavropoulos
/s/David M. Thomas	*	Trustee	March 17, 2017
David M. Thomas

*	By:	/s/Megan C. Johnson
		Megan C. Johnson, pursuant to a power of attorney dated April 1, 2014 and filed herewith.

POWER OF ATTORNEY

We, the undersigned Directors or Trustees, as the case may be, of the following investment companies:

Fidelity Advisor Series I Fidelity Advisor Series VIII Fidelity Beacon Street Trust Fidelity Capital Trust Fidelity Central Investment Portfolios LLC Fidelity Commonwealth Trust Fidelity Concord Street Trust Fidelity Congress Street Fund Fidelity Contrafund Fidelity Destiny Portfolios Fidelity Devonshire Trust Fidelity Exchange Fund Fidelity Financial Trust Fidelity Hanover Street Trust Fidelity Hastings Street Trust Fidelity Investment Trust Fidelity Magellan Fund Fidelity Mt. Vernon Street Trust Fidelity Puritan Trust Fidelity Securities Fund Fidelity Summer Street Trust Fidelity Trend Fund Variable Insurance Products Fund Variable Insurance Products Fund II Variable Insurance Products Fund III

in addition to any other investment company for which Fidelity Management & Research Company (“FMR”) or an affiliate acts as investment adviser and for which the undersigned individuals serve as Directors or Trustees (collectively, the “Funds”), hereby revoke all previous powers of attorney we have given to sign and otherwise act in our names and behalf in matters involving any investment company for which FMR or an affiliate acts as investment adviser and hereby constitute and appoint Thomas C. Bogle, Joseph R. Fleming, John V. O’Hanlon, Robert W. Helm, Megan C. Johnson, and Anthony H. Zacharski, each of them singly, our true and lawful attorneys-in-fact, with full power of substitution, and with full power to each of them, to sign for us and in our names in the appropriate capacities, all Registration Statements of the Funds on Form N-1A, or any successors thereto, any and all subsequent Amendments, Pre-Effective Amendments, or Post-Effective Amendments to said Registration Statements or any successors thereto, and any supplements or other instruments in connection therewith, and generally to do all such things in our names and behalf in connection therewith as said attorneys–in-fact deem necessary or appropriate, to comply with the provisions of the Securities Act of 1933 and the Investment Company Act of 1940, and all related requirements of the Securities and Exchange Commission.  We hereby ratify and confirm all that said attorneys-in-fact or their substitutes may do or cause to be done by virtue hereof.  This power of attorney is effective for all documents filed on or after April 1, 2014.

WITNESS our hands on this first day of April 2014.

/s/James C. Curvey	/s/Charles S. Morrison
James C. Curvey	Charles S. Morrison
/s/Dennis J. Dirks	/s/Robert W. Selander
Dennis J. Dirks	Robert W. Selander
/s/Alan J. Lacy	/s/Cornelia M. Small
Alan J. Lacy	Cornelia M. Small
/s/Ned C. Lautenbach	/s/William S. Stavropoulos
Ned C. Lautenbach	William S. Stavropoulos
/s/Joseph Mauriello	/s/David M. Thomas
Joseph Mauriello	David M. Thomas

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Dec. 31, 2016
Registrant Name	dei_EntityRegistrantName	FIDELITY HASTINGS STREET TRUST
Central Index Key	dei_EntityCentralIndexKey	0000035348
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Feb. 27, 2017
Document Effective Date	dei_DocumentEffectiveDate	Mar. 01, 2017
Prospectus Date	rr_ProspectusDate	Mar. 01, 2017

XML

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund

Fund Summary

Fund/Class:
Fidelity® Series Emerging Markets Debt Fund/F

Investment Objective

The fund seeks high total return.

Fee Table

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder fees

Shareholder Fees {- Fidelity® Series Emerging Markets Debt Fund}	12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 Fidelity® Series Emerging Markets Debt Fund USD ($)
(fees paid directly from your investment)	none

Annual Operating Expenses

(expenses that you pay each year as a % of the value of your investment)

Annual Operating Expenses {- Fidelity® Series Emerging Markets Debt Fund}	12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 Fidelity® Series Emerging Markets Debt Fund Fidelity Series Emerging Markets Debt Fund-Class F Fidelity
Management fee	0.66%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.05%
Total annual operating expenses	0.71%

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 your shareholder 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:

Sell All Shares

Expense Example {- Fidelity® Series Emerging Markets Debt Fund}	12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 Fidelity® Series Emerging Markets Debt Fund Fidelity Series Emerging Markets Debt Fund-Class F Fidelity USD ($)
1 year	$ 73
3 years	227
5 years	395
10 years	$ 883

Portfolio Turnover

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 47% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing at least 80% of assets in debt securities of issuers in emerging markets (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 with similar emerging characteristics) and other debt investments that are tied economically to emerging markets.

• Potentially investing in other types of securities, including debt securities of non-emerging market foreign issuers and lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) of U.S. issuers.

• Allocating investments across different emerging market countries.

• Analyzing a security's structural features and current pricing, trading opportunities, and the credit, currency, and economic risks of the security and its issuer to select investments.

Principal Investment Risks

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign and Emerging Market Risk. Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Emerging markets can be subject to greater social, economic, regulatory, and political uncertainties and can be extremely volatile. Foreign exchange rates also can be extremely volatile.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. Lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) and certain types of other securities involve greater risk of default or price changes due to changes in the credit quality of the issuer. The value of lower-quality debt securities and certain types of other securities can be more volatile due to increased sensitivity to adverse issuer, political, regulatory, market, or economic developments and can be difficult to resell.

In addition, the fund is considered non-diversified and can invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Performance

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.401k.com and log in for more recent performance information.

Year-by-Year Returns

Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	7.78%	September 30, 2012
Lowest Quarter Return	-5.19%	June 30, 2013

Average Annual Returns

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.

For the periods ended December 31, 2016

Average Annual Total Returns{- Fidelity® Series Emerging Markets Debt Fund} - 12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 - Fidelity® Series Emerging Markets Debt Fund	Past 1 year	Past 5 years	Since Inception	[1]	Inception Date
Fidelity Series Emerging Markets Debt Fund-Class F Fidelity					Mar. 17, 2011
Fidelity Series Emerging Markets Debt Fund-Class F Fidelity | Return Before Taxes	15.82%	6.54%	6.17%
Fidelity Series Emerging Markets Debt Fund-Class F Fidelity | After Taxes on Distributions	12.69%	3.83%	3.60%		Mar. 17, 2011
Fidelity Series Emerging Markets Debt Fund-Class F Fidelity | After Taxes on Distributions and Sales	8.88%	3.82%	3.62%		Mar. 17, 2011
J.P. Morgan Emerging Markets Bond Index Global(reflects no deduction for fees, expenses, or taxes)	10.19%	5.44%	6.06%

[1] From March 17, 2011

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Mar. 01, 2017

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity® Series Emerging Markets Debt Fund/F

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks high total return.

Expense [Heading]

rr_ExpenseHeading

Fee Table

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees

(fees paid directly from your investment)

rr_ShareholderFeeOther

none

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Operating Expenses

(expenses that you pay each year as a % of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 47% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

47.00%

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 your shareholder 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:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Sell All Shares

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing at least 80% of assets in debt securities of issuers in emerging markets (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 with similar emerging characteristics) and other debt investments that are tied economically to emerging markets.

• Potentially investing in other types of securities, including debt securities of non-emerging market foreign issuers and lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) of U.S. issuers.

• Allocating investments across different emerging market countries.

• Analyzing a security's structural features and current pricing, trading opportunities, and the credit, currency, and economic risks of the security and its issuer to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign and Emerging Market Risk. Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Emerging markets can be subject to greater social, economic, regulatory, and political uncertainties and can be extremely volatile. Foreign exchange rates also can be extremely volatile.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. Lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) and certain types of other securities involve greater risk of default or price changes due to changes in the credit quality of the issuer. The value of lower-quality debt securities and certain types of other securities can be more volatile due to increased sensitivity to adverse issuer, political, regulatory, market, or economic developments and can be difficult to resell.

In addition, the fund is considered non-diversified and can invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money by investing in the fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

In addition, the fund is considered non-diversified and can invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

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.401k.com and log in for more recent performance information.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

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]

rr_PerformanceAvailabilityWebSiteAddress

www.401k.com and log in

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance (before and after taxes) is not an indication of future performance.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-Year Returns

Calendar Years

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	7.78%	September 30, 2012
Lowest Quarter Return	-5.19%	June 30, 2013

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Returns

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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

rr_PerformanceTableNotRelevantToTaxDeferred

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

rr_PerformanceTableExplanationAfterTaxHigher

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

rr_PerformanceTableNarrativeTextBlock

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.

For the periods ended December 31, 2016

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund | Fidelity Series Emerging Markets Debt Fund-Class F Fidelity

Risk/Return:

rr_RiskReturnAbstract

Management fee

rr_ManagementFeesOverAssets

0.66%

Distribution and/or Service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.05%

Total annual operating expenses

rr_ExpensesOverAssets

0.71%

1 year

rr_ExpenseExampleYear01

$ 73

3 years

rr_ExpenseExampleYear03

227

5 years

rr_ExpenseExampleYear05

395

10 years

rr_ExpenseExampleYear10

$ 883

2012

rr_AnnualReturn2012

19.24%

2013

rr_AnnualReturn2013

(4.11%)

2014

rr_AnnualReturn2014

1.98%

2015

rr_AnnualReturn2015

1.62%

2016

rr_AnnualReturn2016

15.82%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

7.78%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2013

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(5.19%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 17, 2011

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund | Return Before Taxes | Fidelity Series Emerging Markets Debt Fund-Class F Fidelity

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Emerging Markets Debt Fund

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

15.82%

Past 5 years

rr_AverageAnnualReturnYear05

6.54%

Since Inception

rr_AverageAnnualReturnSinceInception

6.17%

^[1]

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund | After Taxes on Distributions | Fidelity Series Emerging Markets Debt Fund-Class F Fidelity

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Emerging Markets Debt Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

12.69%

Past 5 years

rr_AverageAnnualReturnYear05

3.83%

Since Inception

rr_AverageAnnualReturnSinceInception

3.60%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 17, 2011

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund | After Taxes on Distributions and Sales | Fidelity Series Emerging Markets Debt Fund-Class F Fidelity

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Emerging Markets Debt Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

8.88%

Past 5 years

rr_AverageAnnualReturnYear05

3.82%

Since Inception

rr_AverageAnnualReturnSinceInception

3.62%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 17, 2011

12.31 Fidelity Series Emerging Markets Debt Fund F PRO-02 | Fidelity® Series Emerging Markets Debt Fund | J.P. Morgan Emerging Markets Bond Index Global(reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Past 1 year

rr_AverageAnnualReturnYear01

10.19%

Past 5 years

rr_AverageAnnualReturnYear05

5.44%

Since Inception

rr_AverageAnnualReturnSinceInception

6.06%

^[1]

[1] From March 17, 2011

XML

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund

Fund Summary

Fund/Class:
Fidelity® Series Emerging Markets Debt Fund/Fidelity® Series Emerging Markets Debt Fund

Investment Objective

The fund seeks high total return.

Fee Table

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder fees

Shareholder Fees {- Fidelity® Series Emerging Markets Debt Fund}	12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 Fidelity® Series Emerging Markets Debt Fund USD ($)
(fees paid directly from your investment)	none

Annual Operating Expenses

(expenses that you pay each year as a % of the value of your investment)

Annual Operating Expenses {- Fidelity® Series Emerging Markets Debt Fund}	12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 Fidelity® Series Emerging Markets Debt Fund Fidelity Series Emerging Markets Debt Fund-Series Class
Management fee	0.66%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.16%
Total annual operating expenses	0.82%

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 your shareholder 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:

Sell All Shares

Expense Example {- Fidelity® Series Emerging Markets Debt Fund}	12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 Fidelity® Series Emerging Markets Debt Fund Fidelity Series Emerging Markets Debt Fund-Series Class USD ($)
1 year	$ 84
3 years	262
5 years	455
10 years	$ 1,014

Portfolio Turnover

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 47% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing at least 80% of assets in debt securities of issuers in emerging markets (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 with similar emerging characteristics) and other debt investments that are tied economically to emerging markets.

• Potentially investing in other types of securities, including debt securities of non-emerging market foreign issuers and lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) of U.S. issuers.

• Allocating investments across different emerging market countries.

• Analyzing a security's structural features and current pricing, trading opportunities, and the credit, currency, and economic risks of the security and its issuer to select investments.

Principal Investment Risks

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign and Emerging Market Risk. Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Emerging markets can be subject to greater social, economic, regulatory, and political uncertainties and can be extremely volatile. Foreign exchange rates also can be extremely volatile.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. Lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) and certain types of other securities involve greater risk of default or price changes due to changes in the credit quality of the issuer. The value of lower-quality debt securities and certain types of other securities can be more volatile due to increased sensitivity to adverse issuer, political, regulatory, market, or economic developments and can be difficult to resell.

In addition, the fund is considered non-diversified and can invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Performance

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.

Year-by-Year Returns

Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	7.75%	September 30, 2012
Lowest Quarter Return	-5.21%	June 30, 2013

Average Annual Returns

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.

For the periods ended December 31, 2016

Average Annual Total Returns{- Fidelity® Series Emerging Markets Debt Fund} - 12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 - Fidelity® Series Emerging Markets Debt Fund	Past 1 year	Past 5 years	Since Inception	[1]	Inception Date
Fidelity Series Emerging Markets Debt Fund-Series Class					Mar. 17, 2011
Fidelity Series Emerging Markets Debt Fund-Series Class | Return Before Taxes	15.70%	6.42%	6.05%
Fidelity Series Emerging Markets Debt Fund-Series Class | After Taxes on Distributions	12.63%	3.76%	3.52%		Mar. 17, 2011
Fidelity Series Emerging Markets Debt Fund-Series Class | After Taxes on Distributions and Sales	8.82%	3.75%	3.55%		Mar. 17, 2011
J.P. Morgan Emerging Markets Bond Index Global(reflects no deduction for fees, expenses, or taxes)	10.19%	5.44%	6.06%

[1] From March 17, 2011

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Mar. 01, 2017

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity® Series Emerging Markets Debt Fund/Fidelity® Series Emerging Markets Debt Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks high total return.

Expense [Heading]

rr_ExpenseHeading

Fee Table

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees

(fees paid directly from your investment)

rr_ShareholderFeeOther

none

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Operating Expenses

(expenses that you pay each year as a % of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

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 47% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

47.00%

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

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 your shareholder 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:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Sell All Shares

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing at least 80% of assets in debt securities of issuers in emerging markets (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 with similar emerging characteristics) and other debt investments that are tied economically to emerging markets.

• Potentially investing in other types of securities, including debt securities of non-emerging market foreign issuers and lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) of U.S. issuers.

• Allocating investments across different emerging market countries.

• Analyzing a security's structural features and current pricing, trading opportunities, and the credit, currency, and economic risks of the security and its issuer to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

• Foreign and Emerging Market Risk. Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Emerging markets can be subject to greater social, economic, regulatory, and political uncertainties and can be extremely volatile. Foreign exchange rates also can be extremely volatile.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. Lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) and certain types of other securities involve greater risk of default or price changes due to changes in the credit quality of the issuer. The value of lower-quality debt securities and certain types of other securities can be more volatile due to increased sensitivity to adverse issuer, political, regulatory, market, or economic developments and can be difficult to resell.

In addition, the fund is considered non-diversified and can invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money by investing in the fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

In addition, the fund is considered non-diversified and can invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

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]

rr_PerformanceInformationIllustratesVariabilityOfReturns

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]

rr_PerformanceAvailabilityWebSiteAddress

www.fidelity.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance (before and after taxes) is not an indication of future performance.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-Year Returns

Calendar Years

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	7.75%	September 30, 2012
Lowest Quarter Return	-5.21%	June 30, 2013

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Returns

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

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

rr_PerformanceTableNotRelevantToTaxDeferred

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

rr_PerformanceTableExplanationAfterTaxHigher

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

rr_PerformanceTableNarrativeTextBlock

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.

For the periods ended December 31, 2016

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund | Fidelity Series Emerging Markets Debt Fund-Series Class

Risk/Return:

rr_RiskReturnAbstract

Management fee

rr_ManagementFeesOverAssets

0.66%

Distribution and/or Service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual operating expenses

rr_ExpensesOverAssets

0.82%

1 year

rr_ExpenseExampleYear01

$ 84

3 years

rr_ExpenseExampleYear03

262

5 years

rr_ExpenseExampleYear05

455

10 years

rr_ExpenseExampleYear10

$ 1,014

2012

rr_AnnualReturn2012

19.09%

2013

rr_AnnualReturn2013

(4.22%)

2014

rr_AnnualReturn2014

1.87%

2015

rr_AnnualReturn2015

1.51%

2016

rr_AnnualReturn2016

15.70%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

7.75%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2013

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(5.21%)

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 17, 2011

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund | Return Before Taxes | Fidelity Series Emerging Markets Debt Fund-Series Class

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Emerging Markets Debt Fund

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

15.70%

Past 5 years

rr_AverageAnnualReturnYear05

6.42%

Since Inception

rr_AverageAnnualReturnSinceInception

6.05%

^[1]

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund | After Taxes on Distributions | Fidelity Series Emerging Markets Debt Fund-Series Class

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Emerging Markets Debt Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

12.63%

Past 5 years

rr_AverageAnnualReturnYear05

3.76%

Since Inception

rr_AverageAnnualReturnSinceInception

3.52%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 17, 2011

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund | After Taxes on Distributions and Sales | Fidelity Series Emerging Markets Debt Fund-Series Class

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity® Series Emerging Markets Debt Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

8.82%

Past 5 years

rr_AverageAnnualReturnYear05

3.75%

Since Inception

rr_AverageAnnualReturnSinceInception

3.55%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 17, 2011

12.31 Fidelity Series Emerging Markets Debt Fund Series PRO-02 | Fidelity® Series Emerging Markets Debt Fund | J.P. Morgan Emerging Markets Bond Index Global(reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Past 1 year

rr_AverageAnnualReturnYear01

10.19%

Past 5 years

rr_AverageAnnualReturnYear05

5.44%

Since Inception

rr_AverageAnnualReturnSinceInception

6.06%

^[1]

[1] From March 17, 2011

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	FIDELITY HASTINGS STREET TRUST
Prospectus Date	rr_ProspectusDate	Mar. 01, 2017
Document Creation Date	dei_DocumentCreationDate	Feb. 27, 2017