485BPOS

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM N-1A
REGISTRATION STATEMENT (No. 002-11517)
		UNDER THE SECURITIES ACT OF 1933	[X]
		Pre-Effective Amendment No. ____	[ ]
		Post-Effective Amendment No. 133	[X]
and
REGISTRATION STATEMENT (No. 811-00215)
		UNDER THE INVESTMENT COMPANY ACT OF 1940	[X]
		Amendment No. 133	[X]
Fidelity Hastings Street Trust
(Exact Name of Registrant as Specified in Charter)
82 Devonshire St., Boston, Massachusetts 02109
(Address Of Principal Executive Offices) (Zip Code)
Registrant's Telephone Number: 617-563-7000
Scott C. Goebel, Secretary
82 Devonshire Street
Boston, Massachusetts 02109
(Name and Address of Agent for Service)
It is proposed that this filing will become effective
	(X)	immediately upon filing pursuant to paragraph (b).
	( )	on ( ) pursuant to paragraph (b) at 5:30 p.m. Eastern Time.
	( )	60 days after filing pursuant to paragraph (a)(1) at 5:30 p.m. Eastern Time.
	( )	on ( ) pursuant to paragraph (a)(1) of Rule 485 at 5:30 p.m. Eastern Time.
	( )	75 days after filing pursuant to paragraph (a)(2) at 5:30 p.m. Eastern Time.
	( )	on ( ) pursuant to paragraph (a)(2) of Rule 485 at 5:30 p.m. Eastern Time.
If appropriate, check the following box:
	( )	this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

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. 133 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 September 2012.

	Fidelity Hastings Street Trust
	By	/s/Kenneth B. Robins
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||		Kenneth B. Robins, 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/Kenneth B. Robins		President and Treasurer	September 17, 2012
Kenneth B. Robins		(Principal Executive Officer)
/s/Christine Reynolds		Chief Financial Officer	September 17, 2012
Christine Reynolds		(Principal Financial Officer)
/s/James C. Curvey	*	Trustee	September 17, 2012
James C. Curvey
/s/Dennis J. Dirks	*	Trustee	September 17, 2012
Dennis J. Dirks
/s/Alan J. Lacy	*	Trustee	September 17, 2012
Alan J. Lacy
/s/Ned C. Lautenbach	*	Trustee	September 17, 2012
Ned C. Lautenbach
/s/Joseph Mauriello	*	Trustee	September 17, 2012
Joseph Mauriello
/s/Ronald P. O'Hanley	*	Trustee	September 17, 2012
Ronald P. O'Hanley
/s/Robert W. Selander	*	Trustee	September 17, 2012
Robert W. Selander
/s/Cornelia M. Small	*	Trustee	September 17, 2012
Cornelia M. Small
/s/William S. Stavropoulos	*	Trustee	September 17, 2012
William S. Stavropoulos
/s/David M. Thomas	*	Trustee	September 17, 2012
David M. Thomas
/s/Michael E. Wiley	*	Trustee	September 17, 2012
Michael E. Wiley

*	By:	/s/Joseph R. Fleming
		Joseph R. Fleming, pursuant to a power of attorney dated December 1, 2011 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 VII 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 Covington Trust 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 Select Portfolios Fidelity Summer Street Trust Fidelity Trend Fund Variable Insurance Products Fund Variable Insurance Products Fund II Variable Insurance Products Fund III Variable Insurance Products Fund IV

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 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 December 1, 2011.

WITNESS our hands on this first day of December 1, 2011.

/s/James C. Curvey	/s/Robert W. Selander
James C. Curvey	Robert W. Selander
/s/Ronald P. O'Hanley	/s/Cornelia M. Small
Ronald P. O'Hanley	Cornelia M. Small
/s/Dennis J. Dirks	/s/William S. Stavropoulos
Dennis J. Dirks	William S. Stavropoulos
/s/Alan J. Lacy	/s/David M. Thomas
Alan J. Lacy	David M. Thomas
/s/Ned C. Lautenbach	/s/Michael E. Wiley
Ned C. Lautenbach	Michael E. Wiley
/s/Joseph Mauriello
Joseph Mauriello

XML

K | Fidelity Fund

Fund Summary

Fund/Class:
Fidelity^® Fund/K

Investment Objective

The fund seeks long-term capital growth.

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
(fees paid directly from your investment)

Shareholder Fees (USD $)	K Fidelity Fund Class K
Shareholder fees (fees paid directly from your investment)	none

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

Annual Class Operating Expenses	K Fidelity Fund Class K
Management fee	0.35%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.08%
Total annual operating expenses	0.43%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	K Fidelity Fund Class K
1 year	44
3 years	138
5 years	241
10 years	542

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 102% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing primarily in common stocks.
• Potentially investing a portion of assets in bonds, including lower-quality debt securities.
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.
• Foreign Exposure. Foreign 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.
• 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) 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.

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 Information about the Index section of the prospectus. Past performance is not an indication of future performance.

Visit www.401k.com and log in for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	16.20%	June 30, 2009
Lowest Quarter Return	-15.04%	September 30, 2011
Year-to-Date Return	10.85%	June 30, 2012

Average Annual Returns
For the periods ended
December 31, 2011

Average Annual Total Returns K Fidelity Fund	Past 1 year	Life of class		Inception Date
Class K	(2.19%)	(2.82%)	[1]	May 09, 2008
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	2.11%	(0.47%)	[1]	May 09, 2008

[1] From May 9, 2008.

XML

Inst | Fidelity Mega Cap Stock Fund

Fund Summary

Fund/Class:
Fidelity^® Mega Cap Stock Fund/Fidelity Advisor^® Mega Cap Stock Fund Institutional

Investment Objective

The fund seeks high total return through a combination of current income and capital appreciation.

Fee Table

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

Shareholder fees
(fees paid directly from your investment)

Shareholder Fees (USD $)	Inst Fidelity Mega Cap Stock Fund Institutional Class
Shareholder fees (fees paid directly from your investment)	none

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

Annual Class Operating Expenses	Inst Fidelity Mega Cap Stock Fund Institutional Class
Management fee	0.46%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.32%
Total annual operating expenses	0.78%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	Inst Fidelity Mega Cap Stock Fund Institutional Class
1 year	80
3 years	249
5 years	433
10 years	966

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 57% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing at least 80% of assets in common stocks of companies with mega market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell Top 200^® Index or the S&P 100^® Index).
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.advisor.fidelity.com for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	18.36%	June 30, 2009
Lowest Quarter Return	-13.08%	September 30, 2011
Year-to-Date Return	10.03%	June 30, 2012

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. 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, 2011

Average Annual Total Returns Inst Fidelity Mega Cap Stock Fund	Past 1 year	Life of class		Inception Date
Institutional Class Return Before Taxes	2.28%	0.07%	[1]	Feb. 05, 2008
Institutional Class Return After Taxes on Distributions	2.10%	(0.14%)	[1]	Feb. 05, 2008
Institutional Class Return After Taxes on Distributions and Sale of Fund Shares	1.70%	0.03%	[1]	Feb. 05, 2008
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	2.11%	0.68%	[1]	Feb. 05, 2008
Russell Top 200 Index (reflects no deduction for fees, expenses, or taxes)	2.83%	0.20%	[1]	Feb. 05, 2008

[1] From February 5, 2008.

XML

Fidelity Fifty

Fund Summary

Fund:
Fidelity Fifty^®

Investment Objective

The fund seeks capital appreciation.

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
(fees paid directly from your investment)

Shareholder Fees (USD $)	Fidelity Fifty Class: Fidelity Fifty
Shareholder fees (fees paid directly from your investment)	none

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

Annual Fund Operating Expenses	Fidelity Fifty Class: Fidelity Fifty
Management fee (fluctuates based on the fund's performance relative to a securities market index)	0.61%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.33%
Total annual fund operating expenses	0.94%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	Fidelity Fifty Class: Fidelity Fifty
1 year	96
3 years	300
5 years	520
10 years	1,155

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 277% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing primarily in common stocks of companies that Fidelity Management & Research Company (FMR) believes have the greatest potential for growth.
• Normally investing in 50-60 stocks.
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 Information about the Index section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	21.29%	June 30, 2009
Lowest Quarter Return	-27.58%	December 31, 2008
Year-to-Date Return	9.46%	June 30, 2012

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. 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, 2011

Average Annual Total Returns Fidelity Fifty	Past 1 year	Past 5 years	Past 10 years
Class: Fidelity Fifty Return Before Taxes	(0.78%)	(1.69%)	3.93%
Class: Fidelity Fifty Return After Taxes on Distributions	(0.83%)	(2.58%)	3.24%
Class: Fidelity Fifty Return After Taxes on Distributions and Sale of Fund Shares	(0.45%)	(1.68%)	3.22%
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	2.11%	(0.25%)	2.92%

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

K | Fidelity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Fund/K

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term capital growth.

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)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 102% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

102.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing primarily in common stocks.
• Potentially investing a portion of assets in bonds, including lower-quality debt securities.
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.
• Foreign Exposure. Foreign 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.
• 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) 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.

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 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 Information about the Index section of the prospectus. Past performance is not an indication of future performance.

Visit www.401k.com and log in for updated return 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 for updated return information

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance 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	16.20%	June 30, 2009
Lowest Quarter Return	-15.04%	September 30, 2011
Year-to-Date Return	10.85%	June 30, 2012

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Returns
For the periods ended
December 31, 2011

K | Fidelity Fund | Class K

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee

rr_ManagementFeesOverAssets

0.35%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.08%

Total annual operating expenses

rr_ExpensesOverAssets

0.43%

1 year

rr_ExpenseExampleYear01

44

3 years

rr_ExpenseExampleYear03

138

5 years

rr_ExpenseExampleYear05

241

10 years

rr_ExpenseExampleYear10

542

2009

rr_AnnualReturn2009

26.95%

2010

rr_AnnualReturn2010

14.74%

2011

rr_AnnualReturn2011

(2.19%)

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

10.85%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.20%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(15.04%)

Label

rr_AverageAnnualReturnLabel

Class K

Past 1 year

rr_AverageAnnualReturnYear01

(2.19%)

Life of class

rr_AverageAnnualReturnSinceInception

(2.82%)

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

May 09, 2008

K | Fidelity Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.11%

Life of class

rr_AverageAnnualReturnSinceInception

(0.47%)

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

May 09, 2008

[1] From May 9, 2008.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

Retail | Fidelity Growth Discovery Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Growth Discovery Fund/Fidelity Growth Discovery Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks capital appreciation.

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)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 74% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

74.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing primarily in common stocks.
• Investing in companies that Fidelity Management & Research Company (FMR) believes have above-average growth potential (stocks of these companies are often called "growth" stocks).
• Investing in domestic and foreign issuers.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.
• "Growth" Investing. "Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.

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 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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Prior to February 1, 2007, the fund operated under certain different investment policies and compared its performance to a different index. The fund's historical performance may not represent its current investment policies. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return 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 and an additional 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	16.04%	September 30, 2009
Lowest Quarter Return	-27.00%	December 31, 2008
Year-to-Date Return	10.47%	June 30, 2012

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.

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. 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, 2011

Retail | Fidelity Growth Discovery Fund | Class: Fidelity Growth Discovery Fund

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee (fluctuates based on the fund's performance relative to a securities market index)

rr_ManagementFeesOverAssets

0.53%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.28%

Total annual operating expenses

rr_ExpensesOverAssets

0.81%

1 year

rr_ExpenseExampleYear01

83

3 years

rr_ExpenseExampleYear03

259

5 years

rr_ExpenseExampleYear05

450

10 years

rr_ExpenseExampleYear10

1,002

2002

rr_AnnualReturn2002

(15.94%)

2003

rr_AnnualReturn2003

19.87%

2004

rr_AnnualReturn2004

10.62%

2005

rr_AnnualReturn2005

2.14%

2006

rr_AnnualReturn2006

13.94%

2007

rr_AnnualReturn2007

26.84%

2008

rr_AnnualReturn2008

(46.72%)

2009

rr_AnnualReturn2009

29.33%

2010

rr_AnnualReturn2010

24.04%

2011

rr_AnnualReturn2011

0.50%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

10.47%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.04%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(27.00%)

Retail | Fidelity Growth Discovery Fund | Return Before Taxes | Class: Fidelity Growth Discovery Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Growth Discovery Fund

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

0.50%

Past 5 years

rr_AverageAnnualReturnYear05

1.73%

Past 10 years

rr_AverageAnnualReturnYear10

3.52%

Retail | Fidelity Growth Discovery Fund | Return After Taxes on Distributions | Class: Fidelity Growth Discovery Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Growth Discovery Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

0.32%

Past 5 years

rr_AverageAnnualReturnYear05

1.64%

Past 10 years

rr_AverageAnnualReturnYear10

3.40%

Retail | Fidelity Growth Discovery Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class: Fidelity Growth Discovery Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Growth Discovery Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

0.37%

Past 5 years

rr_AverageAnnualReturnYear05

1.45%

Past 10 years

rr_AverageAnnualReturnYear10

3.02%

Retail | Fidelity Growth Discovery Fund | Russell 3000 Growth Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Russell 3000^® Growth Index

Past 1 year

rr_AverageAnnualReturnYear01

2.18%

Past 5 years

rr_AverageAnnualReturnYear05

2.46%

Past 10 years

rr_AverageAnnualReturnYear10

2.74%

Retail | Fidelity Growth Discovery Fund | Fidelity Growth Discovery Fund Linked Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Fidelity Growth Discovery Fund Linked Index

Past 1 year

rr_AverageAnnualReturnYear01

2.18%

Past 5 years

rr_AverageAnnualReturnYear05

2.26%

Past 10 years

rr_AverageAnnualReturnYear10

4.21%

XML

A T B C | Fidelity Mega Cap Stock Fund

Fund Summary

Fund/Class:
Fidelity^® Mega Cap Stock Fund/Fidelity Advisor^® Mega Cap Stock Fund A, T, B, C

Investment Objective

The fund seeks high total return through a combination of current income and capital appreciation.

Fee Table

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

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 (Click Here) of the prospectus.

Shareholder fees
(fees paid directly from your investment)

Shareholder Fees A T B C Fidelity Mega Cap Stock Fund	Class A		Class T		Class B		Class C
Maximum sales charge (load) on purchases (as a % of offering price)	5.75%		3.50%		none		none
Maximum contingent deferred sales charge (as a % of the lesser of original purchase price or redemption proceeds)	none	[1]	none	[1]	5.00%	[2]	1.00%	[3]

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

Annual Class Operating Expenses A T B C Fidelity Mega Cap Stock Fund	Class A	Class T	Class B	Class C
Management fee	0.46%	0.46%	0.46%	0.46%
Distribution and/or Service (12b-1) fees	0.25%	0.50%	1.00%	1.00%
Other expenses	0.31%	0.36%	0.36%	0.33%
Total annual operating expenses	1.02%	1.32%	1.82%	1.79%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 and if you hold your shares:

Sell All Shares

Expense Example A T B C Fidelity Mega Cap Stock Fund (USD $)	Class A	Class T	Class B	Class C
1 year	673	480	685	282
3 years	881	754	873	563
5 years	1,106	1,048	1,185	970
10 years	1,751	1,885	1,829	2,105

Hold Shares

Expense Example, No Redemption A T B C Fidelity Mega Cap Stock Fund (USD $)	Class A	Class T	Class B	Class C
1 year	673	480	185	182
3 years	881	754	573	563
5 years	1,106	1,048	985	970
10 years	1,751	1,885	1,829	2,105

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 57% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing at least 80% of assets in common stocks of companies with mega market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell Top 200^® Index or the S&P 100^® Index).
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.advisor.fidelity.com for updated return information.

Year-by-Year Returns

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.

Calendar Years

During the periods shown in the chart for Class A:	Returns	Quarter ended
Highest Quarter Return	18.23%	June 30, 2009
Lowest Quarter Return	-13.14%	September 30, 2011
Year-to-Date Return	9.95%	June 30, 2012

Average Annual Returns

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. 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, 2011

Average Annual Total Returns A T B C Fidelity Mega Cap Stock Fund	Past 1 year	Life of class		Inception Date
Class A Return Before Taxes	(3.89%)	(1.72%)	[1]	Feb. 05, 2008
Class A Return After Taxes on Distributions	(4.03%)	(1.89%)	[1]	Feb. 05, 2008
Class A Return After Taxes on Distributions and Sale of Fund Shares	(2.36%)	(1.48%)	[1]	Feb. 05, 2008
Class T Return Before Taxes	(1.86%)	(1.37%)	[1]	Feb. 05, 2008
Class B Return Before Taxes	(3.78%)	(1.71%)	[1]	Feb. 05, 2008
Class C Return Before Taxes	0.21%	(0.95%)	[1]	Feb. 05, 2008
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	2.11%	0.68%	[1]	Feb. 05, 2008
Russell Top 200 Index (reflects no deduction for fees, expenses, or taxes)	2.83%	0.20%	[1]	Feb. 05, 2008

[1] Class A and Class T purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class T purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% or 0.25%, respectively.

[2] Declines over 6 years from 5.00% to 0%.

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

[1] From February 5, 2008.

XML

K | Fidelity Growth Discovery Fund

Fund Summary

Fund/Class:
Fidelity^® Growth Discovery Fund/K

Investment Objective

The fund seeks capital appreciation.

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
(fees paid directly from your investment)

Shareholder Fees (USD $)	K Fidelity Growth Discovery Fund Class K
Shareholder fees (fees paid directly from your investment)	none

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

Annual Class Operating Expenses	K Fidelity Growth Discovery Fund Class K
Management fee (fluctuates based on the fund's performance relative to a securities market index)	0.53%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.11%
Total annual operating expenses	0.64%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	K Fidelity Growth Discovery Fund Class K
1 year	65
3 years	205
5 years	357
10 years	798

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 74% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing primarily in common stocks.
• Investing in companies that Fidelity Management & Research Company (FMR) believes have above-average growth potential (stocks of these companies are often called "growth" stocks).
• Investing in domestic and foreign issuers.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.
• "Growth" Investing. "Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.

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 Information about the Index section of the prospectus. Past performance is not an indication of future performance.

Visit www.401k.com and log in for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	16.07%	September 30, 2009
Lowest Quarter Return	-15.48%	September 30, 2011
Year-to-Date Return	10.55%	June 30, 2012

Average Annual Returns
For the periods ended
December 31, 2011

Average Annual Total Returns K Fidelity Growth Discovery Fund	Past 1 year	Life of class		Inception Date
Class K	0.70%	(1.62%)	[1]	May 09, 2008
Russell 3000 Growth Index (reflects no deduction for fees, expenses, or taxes)	2.18%	1.70%	[1]	May 09, 2008

[1] From May 9, 2008.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

Retail | Fidelity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Fund/Fidelity Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks long-term capital growth.

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)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 102% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

102.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing primarily in common stocks.
• Potentially investing a portion of assets in bonds, including lower-quality debt securities.
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.
• Foreign Exposure. Foreign 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.
• 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) 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.

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 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 Information about the Index section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return 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	16.14%	June 30, 2009
Lowest Quarter Return	-22.64%	December 31, 2008
Year-to-Date Return	10.79%	June 30, 2012

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.

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. 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, 2011

Retail | Fidelity Fund | Class: Fidelity Fund

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee

rr_ManagementFeesOverAssets

0.35%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual operating expenses

rr_ExpensesOverAssets

0.58%

1 year

rr_ExpenseExampleYear01

59

3 years

rr_ExpenseExampleYear03

186

5 years

rr_ExpenseExampleYear05

324

10 years

rr_ExpenseExampleYear10

726

2002

rr_AnnualReturn2002

(22.25%)

2003

rr_AnnualReturn2003

27.26%

2004

rr_AnnualReturn2004

7.84%

2005

rr_AnnualReturn2005

7.52%

2006

rr_AnnualReturn2006

13.67%

2007

rr_AnnualReturn2007

16.81%

2008

rr_AnnualReturn2008

(40.33%)

2009

rr_AnnualReturn2009

26.75%

2010

rr_AnnualReturn2010

14.55%

2011

rr_AnnualReturn2011

(2.36%)

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

10.79%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.14%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(22.64%)

Retail | Fidelity Fund | Return Before Taxes | Class: Fidelity Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Fund

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

(2.36%)

Past 5 years

rr_AverageAnnualReturnYear05

(0.24%)

Past 10 years

rr_AverageAnnualReturnYear10

2.57%

Retail | Fidelity Fund | Return After Taxes on Distributions | Class: Fidelity Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

(2.47%)

Past 5 years

rr_AverageAnnualReturnYear05

(0.62%)

Past 10 years

rr_AverageAnnualReturnYear10

2.28%

Retail | Fidelity Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class: Fidelity Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

(1.38%)

Past 5 years

rr_AverageAnnualReturnYear05

(0.20%)

Past 10 years

rr_AverageAnnualReturnYear10

2.19%

Retail | Fidelity Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.11%

Past 5 years

rr_AverageAnnualReturnYear05

(0.25%)

Past 10 years

rr_AverageAnnualReturnYear10

2.92%

XML

Retail | Fidelity Fund

Fund Summary

Fund/Class:
Fidelity^® Fund/Fidelity Fund

Investment Objective

The fund seeks long-term capital growth.

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
(fees paid directly from your investment)

Shareholder Fees (USD $)	Retail Fidelity Fund Class: Fidelity Fund
Shareholder fees (fees paid directly from your investment)	none

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

Annual Class Operating Expenses	Retail Fidelity Fund Class: Fidelity Fund
Management fee	0.35%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.23%
Total annual operating expenses	0.58%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	Retail Fidelity Fund Class: Fidelity Fund
1 year	59
3 years	186
5 years	324
10 years	726

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 102% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing primarily in common stocks.
• Potentially investing a portion of assets in bonds, including lower-quality debt securities.
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.
• Foreign Exposure. Foreign 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.
• 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) 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.

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 Information about the Index section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	16.14%	June 30, 2009
Lowest Quarter Return	-22.64%	December 31, 2008
Year-to-Date Return	10.79%	June 30, 2012

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. 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, 2011

Average Annual Total Returns Retail Fidelity Fund	Past 1 year	Past 5 years	Past 10 years
Class: Fidelity Fund Return Before Taxes	(2.36%)	(0.24%)	2.57%
Class: Fidelity Fund Return After Taxes on Distributions	(2.47%)	(0.62%)	2.28%
Class: Fidelity Fund Return After Taxes on Distributions and Sale of Fund Shares	(1.38%)	(0.20%)	2.19%
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	2.11%	(0.25%)	2.92%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	FIDELITY HASTINGS STREET TRUST
Prospectus Date	rr_ProspectusDate	Aug. 29, 2012
Document Creation Date	dei_DocumentCreationDate	Aug. 28, 2012

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

Retail | Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Mega Cap Stock Fund/Fidelity Mega Cap Stock Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks high total return through a combination of current income and capital appreciation.

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, hold, or sell shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees
(fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 57% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

57.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing at least 80% of assets in common stocks of companies with mega market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell Top 200^® Index or the S&P 100^® Index).
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Prior to December 1, 2007, the fund operated under certain different investment policies. The fund's historical performance may not represent its current investment policies. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return 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 and an additional 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	18.52%	June 30, 2009
Lowest Quarter Return	-21.33%	December 31, 2008
Year-to-Date Return	10.00%	June 30, 2012

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.

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. 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, 2011

Retail | Fidelity Mega Cap Stock Fund | Class: Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.30%

Total annual operating expenses

rr_ExpensesOverAssets

0.76%

1 year

rr_ExpenseExampleYear01

78

3 years

rr_ExpenseExampleYear03

243

5 years

rr_ExpenseExampleYear05

422

10 years

rr_ExpenseExampleYear10

942

2002

rr_AnnualReturn2002

(17.06%)

2003

rr_AnnualReturn2003

23.16%

2004

rr_AnnualReturn2004

5.75%

2005

rr_AnnualReturn2005

7.48%

2006

rr_AnnualReturn2006

12.84%

2007

rr_AnnualReturn2007

11.05%

2008

rr_AnnualReturn2008

(39.41%)

2009

rr_AnnualReturn2009

28.61%

2010

rr_AnnualReturn2010

14.41%

2011

rr_AnnualReturn2011

2.34%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

10.00%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.52%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(21.33%)

Retail | Fidelity Mega Cap Stock Fund | Return Before Taxes | Class: Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Mega Cap Stock Fund

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

2.34%

Past 5 years

rr_AverageAnnualReturnYear05

0.26%

Past 10 years

rr_AverageAnnualReturnYear10

2.87%

Retail | Fidelity Mega Cap Stock Fund | Return After Taxes on Distributions | Class: Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Mega Cap Stock Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

2.16%

Past 5 years

rr_AverageAnnualReturnYear05

(0.12%)

Past 10 years

rr_AverageAnnualReturnYear10

2.53%

Retail | Fidelity Mega Cap Stock Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class: Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Mega Cap Stock Fund

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

1.76%

Past 5 years

rr_AverageAnnualReturnYear05

0.16%

Past 10 years

rr_AverageAnnualReturnYear10

2.41%

Retail | Fidelity Mega Cap Stock Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.11%

Past 5 years

rr_AverageAnnualReturnYear05

(0.25%)

Past 10 years

rr_AverageAnnualReturnYear10

2.92%

Retail | Fidelity Mega Cap Stock Fund | Russell Top 200 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Russell Top 200^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.83%

Past 5 years

rr_AverageAnnualReturnYear05

(0.56%)

Past 10 years

rr_AverageAnnualReturnYear10

2.06%

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

K | Fidelity Growth Discovery Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Growth Discovery Fund/K

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks capital appreciation.

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)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 74% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

74.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing primarily in common stocks.
• Investing in companies that Fidelity Management & Research Company (FMR) believes have above-average growth potential (stocks of these companies are often called "growth" stocks).
• Investing in domestic and foreign issuers.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.
• "Growth" Investing. "Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.

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 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 Information about the Index section of the prospectus. Past performance is not an indication of future performance.

Visit www.401k.com and log in for updated return 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 for updated return information

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance 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	16.07%	September 30, 2009
Lowest Quarter Return	-15.48%	September 30, 2011
Year-to-Date Return	10.55%	June 30, 2012

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Returns
For the periods ended
December 31, 2011

K | Fidelity Growth Discovery Fund | Class K

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee (fluctuates based on the fund's performance relative to a securities market index)

rr_ManagementFeesOverAssets

0.53%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.11%

Total annual operating expenses

rr_ExpensesOverAssets

0.64%

1 year

rr_ExpenseExampleYear01

65

3 years

rr_ExpenseExampleYear03

205

5 years

rr_ExpenseExampleYear05

357

10 years

rr_ExpenseExampleYear10

798

2009

rr_AnnualReturn2009

29.70%

2010

rr_AnnualReturn2010

24.33%

2011

rr_AnnualReturn2011

0.70%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

10.55%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.07%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(15.48%)

Label

rr_AverageAnnualReturnLabel

Class K

Past 1 year

rr_AverageAnnualReturnYear01

0.70%

Life of class

rr_AverageAnnualReturnSinceInception

(1.62%)

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

May 09, 2008

K | Fidelity Growth Discovery Fund | Russell 3000 Growth Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Russell 3000^® Growth Index

Past 1 year

rr_AverageAnnualReturnYear01

2.18%

Life of class

rr_AverageAnnualReturnSinceInception

1.70%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

May 09, 2008

[1] From May 9, 2008.

XML

Document and Entity Information	12 Months Ended
	Aug. 29, 2012
Risk/Return:
Document Type	485BPOS
Document Period End Date	Jun. 30, 2012
Registrant Name	FIDELITY HASTINGS STREET TRUST
Central Index Key	0000035348
Amendment Flag	false
Document Creation Date	Aug. 28, 2012
Document Effective Date	Aug. 29, 2012
Prospectus Date	Aug. 29, 2012

XML

Retail | Fidelity Growth Discovery Fund

Fund Summary

Fund/Class:
Fidelity^® Growth Discovery Fund/Fidelity Growth Discovery Fund

Investment Objective

The fund seeks capital appreciation.

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
(fees paid directly from your investment)

Shareholder Fees (USD $)	Retail Fidelity Growth Discovery Fund Class: Fidelity Growth Discovery Fund
Shareholder fees (fees paid directly from your investment)	none

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

Annual Class Operating Expenses	Retail Fidelity Growth Discovery Fund Class: Fidelity Growth Discovery Fund
Management fee (fluctuates based on the fund's performance relative to a securities market index)	0.53%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.28%
Total annual operating expenses	0.81%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	Retail Fidelity Growth Discovery Fund Class: Fidelity Growth Discovery Fund
1 year	83
3 years	259
5 years	450
10 years	1,002

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 74% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing primarily in common stocks.
• Investing in companies that Fidelity Management & Research Company (FMR) believes have above-average growth potential (stocks of these companies are often called "growth" stocks).
• Investing in domestic and foreign issuers.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.
• "Growth" Investing. "Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.

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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Prior to February 1, 2007, the fund operated under certain different investment policies and compared its performance to a different index. The fund's historical performance may not represent its current investment policies. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	16.04%	September 30, 2009
Lowest Quarter Return	-27.00%	December 31, 2008
Year-to-Date Return	10.47%	June 30, 2012

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. 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, 2011

Average Annual Total Returns Retail Fidelity Growth Discovery Fund	Past 1 year	Past 5 years	Past 10 years
Class: Fidelity Growth Discovery Fund Return Before Taxes	0.50%	1.73%	3.52%
Class: Fidelity Growth Discovery Fund Return After Taxes on Distributions	0.32%	1.64%	3.40%
Class: Fidelity Growth Discovery Fund Return After Taxes on Distributions and Sale of Fund Shares	0.37%	1.45%	3.02%
Russell 3000 Growth Index (reflects no deduction for fees, expenses, or taxes)	2.18%	2.46%	2.74%
Fidelity Growth Discovery Fund Linked Index (reflects no deduction for fees, expenses, or taxes)	2.18%	2.26%	4.21%

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

Fidelity Fifty

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund:
Fidelity Fifty^®

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks capital appreciation.

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)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund 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 277% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

277.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing primarily in common stocks of companies that Fidelity Management & Research Company (FMR) believes have the greatest potential for growth.
• Normally investing in 50-60 stocks.
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 Information about the Index section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return 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	21.29%	June 30, 2009
Lowest Quarter Return	-27.58%	December 31, 2008
Year-to-Date Return	9.46%	June 30, 2012

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.

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. 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, 2011

Fidelity Fifty | Class: Fidelity Fifty

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee (fluctuates based on the fund's performance relative to a securities market index)

rr_ManagementFeesOverAssets

0.61%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.33%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.94%

1 year

rr_ExpenseExampleYear01

96

3 years

rr_ExpenseExampleYear03

300

5 years

rr_ExpenseExampleYear05

520

10 years

rr_ExpenseExampleYear10

1,155

2002

rr_AnnualReturn2002

0.32%

2003

rr_AnnualReturn2003

20.41%

2004

rr_AnnualReturn2004

7.42%

2005

rr_AnnualReturn2005

11.00%

2006

rr_AnnualReturn2006

11.13%

2007

rr_AnnualReturn2007

12.63%

2008

rr_AnnualReturn2008

(49.11%)

2009

rr_AnnualReturn2009

37.05%

2010

rr_AnnualReturn2010

17.84%

2011

rr_AnnualReturn2011

(0.78%)

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

9.46%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

21.29%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(27.58%)

Fidelity Fifty | Return Before Taxes | Class: Fidelity Fifty

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Fifty

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

(0.78%)

Past 5 years

rr_AverageAnnualReturnYear05

(1.69%)

Past 10 years

rr_AverageAnnualReturnYear10

3.93%

Fidelity Fifty | Return After Taxes on Distributions | Class: Fidelity Fifty

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Fifty

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

(0.83%)

Past 5 years

rr_AverageAnnualReturnYear05

(2.58%)

Past 10 years

rr_AverageAnnualReturnYear10

3.24%

Fidelity Fifty | Return After Taxes on Distributions and Sale of Fund Shares | Class: Fidelity Fifty

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Fidelity Fifty

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

(0.45%)

Past 5 years

rr_AverageAnnualReturnYear05

(1.68%)

Past 10 years

rr_AverageAnnualReturnYear10

3.22%

Fidelity Fifty | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.11%

Past 5 years

rr_AverageAnnualReturnYear05

(0.25%)

Past 10 years

rr_AverageAnnualReturnYear10

2.92%

XML

Retail | Fidelity Mega Cap Stock Fund

Fund Summary

Fund/Class:
Fidelity^® Mega Cap Stock Fund/Fidelity Mega Cap Stock Fund

Investment Objective

The fund seeks high total return through a combination of current income and capital appreciation.

Fee Table

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

Shareholder fees
(fees paid directly from your investment)

Shareholder Fees (USD $)	Retail Fidelity Mega Cap Stock Fund Class: Fidelity Mega Cap Stock Fund
Shareholder fees (fees paid directly from your investment)	none

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

Annual Class Operating Expenses	Retail Fidelity Mega Cap Stock Fund Class: Fidelity Mega Cap Stock Fund
Management fee	0.46%
Distribution and/or Service (12b-1) fees	none
Other expenses	0.30%
Total annual operating expenses	0.76%

This example helps compare the cost of investing in the fund with the cost of investing in other mutual 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 (USD $)	Retail Fidelity Mega Cap Stock Fund Class: Fidelity Mega Cap Stock Fund
1 year	78
3 years	243
5 years	422
10 years	942

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 57% of the average value of its portfolio.

Principal Investment Strategies

• Normally investing at least 80% of assets in common stocks of companies with mega market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell Top 200^® Index or the S&P 100^® Index).
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Principal Investment Risks

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Prior to December 1, 2007, the fund operated under certain different investment policies. The fund's historical performance may not represent its current investment policies. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for updated return information.

Year-by-Year Returns
Calendar Years

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	18.52%	June 30, 2009
Lowest Quarter Return	-21.33%	December 31, 2008
Year-to-Date Return	10.00%	June 30, 2012

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. 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, 2011

Average Annual Total Returns Retail Fidelity Mega Cap Stock Fund	Past 1 year	Past 5 years	Past 10 years
Class: Fidelity Mega Cap Stock Fund Return Before Taxes	2.34%	0.26%	2.87%
Class: Fidelity Mega Cap Stock Fund Return After Taxes on Distributions	2.16%	(0.12%)	2.53%
Class: Fidelity Mega Cap Stock Fund Return After Taxes on Distributions and Sale of Fund Shares	1.76%	0.16%	2.41%
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	2.11%	(0.25%)	2.92%
Russell Top 200 Index (reflects no deduction for fees, expenses, or taxes)	2.83%	(0.56%)	2.06%

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

A T B C | Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Mega Cap Stock Fund/Fidelity Advisor^® Mega Cap Stock Fund A, T, B, C

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks high total return through a combination of current income and capital appreciation.

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, hold, or sell shares of the fund.

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 (Click Here) of the prospectus.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees
(fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 57% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

57.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

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.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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 mutual 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 and if you hold your shares:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Sell All Shares

Expense Example, No Redemption, By Year, Caption [Text]

rr_ExpenseExampleNoRedemptionByYearCaption

Hold Shares

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing at least 80% of assets in common stocks of companies with mega market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell Top 200^® Index or the S&P 100^® Index).
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.advisor.fidelity.com for updated return 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 and an additional index over various periods of time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.advisor.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

Bar Chart Does Not Reflect Sales Loads [Text]

rr_BarChartDoesNotReflectSalesLoads

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.

Calendar Years

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

During the periods shown in the chart for Class A:	Returns	Quarter ended
Highest Quarter Return	18.23%	June 30, 2009
Lowest Quarter Return	-13.14%	September 30, 2011
Year-to-Date Return	9.95%	June 30, 2012

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Returns

Performance Table Does Reflect Sales Loads

rr_PerformanceTableDoesReflectSalesLoads

Unlike the returns in the bar chart, the returns in the table reflect the maximum applicable sales charges.

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.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

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

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

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. 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, 2011

A T B C | Fidelity Mega Cap Stock Fund | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum contingent deferred sales charge (as a % of the lesser of original purchase price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

Management fee

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.31%

Total annual operating expenses

rr_ExpensesOverAssets

1.02%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

Class A and Class T purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class T purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% or 0.25%, respectively.

1 year

rr_ExpenseExampleYear01

673

3 years

rr_ExpenseExampleYear03

881

5 years

rr_ExpenseExampleYear05

1,106

10 years

rr_ExpenseExampleYear10

1,751

1 year

rr_ExpenseExampleNoRedemptionYear01

673

3 years

rr_ExpenseExampleNoRedemptionYear03

881

5 years

rr_ExpenseExampleNoRedemptionYear05

1,106

10 years

rr_ExpenseExampleNoRedemptionYear10

1,751

2009

rr_AnnualReturn2009

28.14%

2010

rr_AnnualReturn2010

14.10%

2011

rr_AnnualReturn2011

1.97%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

9.95%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.23%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(13.14%)

A T B C | Fidelity Mega Cap Stock Fund | Class T

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

3.50%

Maximum contingent deferred sales charge (as a % of the lesser of original purchase price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

none

^[1]

Management fee

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

0.50%

Other expenses

rr_OtherExpensesOverAssets

0.36%

Total annual operating expenses

rr_ExpensesOverAssets

1.32%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

Class A and Class T purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class T purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% or 0.25%, respectively.

1 year

rr_ExpenseExampleYear01

480

3 years

rr_ExpenseExampleYear03

754

5 years

rr_ExpenseExampleYear05

1,048

10 years

rr_ExpenseExampleYear10

1,885

1 year

rr_ExpenseExampleNoRedemptionYear01

480

3 years

rr_ExpenseExampleNoRedemptionYear03

754

5 years

rr_ExpenseExampleNoRedemptionYear05

1,048

10 years

rr_ExpenseExampleNoRedemptionYear10

1,885

A T B C | Fidelity Mega Cap Stock Fund | Class B

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (as a % of the lesser of original purchase price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

5.00%

^[2]

Management fee

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.36%

Total annual operating expenses

rr_ExpensesOverAssets

1.82%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

Declines over 6 years from 5.00% to 0%.

1 year

rr_ExpenseExampleYear01

685

3 years

rr_ExpenseExampleYear03

873

5 years

rr_ExpenseExampleYear05

1,185

10 years

rr_ExpenseExampleYear10

1,829

1 year

rr_ExpenseExampleNoRedemptionYear01

185

3 years

rr_ExpenseExampleNoRedemptionYear03

573

5 years

rr_ExpenseExampleNoRedemptionYear05

985

10 years

rr_ExpenseExampleNoRedemptionYear10

1,829

A T B C | Fidelity Mega Cap Stock Fund | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (as a % of the lesser of original purchase price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[3]

Management fee

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.33%

Total annual operating expenses

rr_ExpensesOverAssets

1.79%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

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

1 year

rr_ExpenseExampleYear01

282

3 years

rr_ExpenseExampleYear03

563

5 years

rr_ExpenseExampleYear05

970

10 years

rr_ExpenseExampleYear10

2,105

1 year

rr_ExpenseExampleNoRedemptionYear01

182

3 years

rr_ExpenseExampleNoRedemptionYear03

563

5 years

rr_ExpenseExampleNoRedemptionYear05

970

10 years

rr_ExpenseExampleNoRedemptionYear10

2,105

A T B C | Fidelity Mega Cap Stock Fund | Return Before Taxes | Class A

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Class A - Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

(3.89%)

Life of class

rr_AverageAnnualReturnSinceInception

(1.72%)

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | Return Before Taxes | Class T

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Class T - Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

(1.86%)

Life of class

rr_AverageAnnualReturnSinceInception

(1.37%)

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | Return Before Taxes | Class B

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Class B - Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

(3.78%)

Life of class

rr_AverageAnnualReturnSinceInception

(1.71%)

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | Return Before Taxes | Class C

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Class C - Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

0.21%

Life of class

rr_AverageAnnualReturnSinceInception

(0.95%)

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | Return After Taxes on Distributions | Class A

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Class A - Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

(4.03%)

Life of class

rr_AverageAnnualReturnSinceInception

(1.89%)

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class A

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Class A - Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

(2.36%)

Life of class

rr_AverageAnnualReturnSinceInception

(1.48%)

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.11%

Life of class

rr_AverageAnnualReturnSinceInception

0.68%

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

A T B C | Fidelity Mega Cap Stock Fund | Russell Top 200 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Russell Top 200^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.83%

Life of class

rr_AverageAnnualReturnSinceInception

0.20%

^[4]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

[1] Class A and Class T purchases of $1 million or more will not be subject to a front-end sales charge. Such Class A and Class T purchases may be subject, upon redemption, to a contingent deferred sales charge (CDSC) of 1.00% or 0.25%, respectively.

[2] Declines over 6 years from 5.00% to 0%.

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

[4] From February 5, 2008.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

FIDELITY HASTINGS STREET TRUST

Prospectus Date

rr_ProspectusDate

Aug. 29, 2012

Inst | Fidelity Mega Cap Stock Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Fund Summary

Fund/Class:
Fidelity^® Mega Cap Stock Fund/Fidelity Advisor^® Mega Cap Stock Fund Institutional

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The fund seeks high total return through a combination of current income and capital appreciation.

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, hold, or sell shares of the fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees
(fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual class 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 57% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

57.00%

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 mutual 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:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

• Normally investing at least 80% of assets in common stocks of companies with mega market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell Top 200^® Index or the S&P 100^® Index).
• Investing in domestic and foreign issuers.
• Investing in either "growth" stocks or "value" stocks or both.
• Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

Risk [Heading]

rr_RiskHeading

Principal Investment Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

• Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market can react differently to these developments.
• Foreign Exposure. Foreign 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.
• 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.

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 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 and an additional index over various periods of time. The indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the Additional Information about the Indexes section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.advisor.fidelity.com for updated return 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 and an additional index over various periods of time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.advisor.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	18.36%	June 30, 2009
Lowest Quarter Return	-13.08%	September 30, 2011
Year-to-Date Return	10.03%	June 30, 2012

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.

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. 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, 2011

Inst | Fidelity Mega Cap Stock Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Shareholder fees (fees paid directly from your investment)

rr_ShareholderFeeOther

none

Management fee

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.32%

Total annual operating expenses

rr_ExpensesOverAssets

0.78%

1 year

rr_ExpenseExampleYear01

80

3 years

rr_ExpenseExampleYear03

249

5 years

rr_ExpenseExampleYear05

433

10 years

rr_ExpenseExampleYear10

966

2009

rr_AnnualReturn2009

28.55%

2010

rr_AnnualReturn2010

14.35%

2011

rr_AnnualReturn2011

2.28%

Year to Date Return, Label

rr_YearToDateReturnLabel

Year-to-Date Return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

10.03%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest Quarter Return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.36%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest Quarter Return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(13.08%)

Inst | Fidelity Mega Cap Stock Fund | Return Before Taxes | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Institutional Class

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

Past 1 year

rr_AverageAnnualReturnYear01

2.28%

Life of class

rr_AverageAnnualReturnSinceInception

0.07%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

Inst | Fidelity Mega Cap Stock Fund | Return After Taxes on Distributions | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Institutional Class

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

Past 1 year

rr_AverageAnnualReturnYear01

2.10%

Life of class

rr_AverageAnnualReturnSinceInception

(0.14%)

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

Inst | Fidelity Mega Cap Stock Fund | Return After Taxes on Distributions and Sale of Fund Shares | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Column

rr_AverageAnnualReturnColumnName

Institutional Class

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

Past 1 year

rr_AverageAnnualReturnYear01

1.70%

Life of class

rr_AverageAnnualReturnSinceInception

0.03%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

Inst | Fidelity Mega Cap Stock Fund | S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.11%

Life of class

rr_AverageAnnualReturnSinceInception

0.68%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

Inst | Fidelity Mega Cap Stock Fund | Russell Top 200 Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Russell Top 200^® Index

Past 1 year

rr_AverageAnnualReturnYear01

2.83%

Life of class

rr_AverageAnnualReturnSinceInception

0.20%

^[1]

Inception Date

rr_AverageAnnualReturnInceptionDate

Feb. 05, 2008

[1] From February 5, 2008.