485BPOS

As filed with the Securities and Exchange Commission on November 21, 2018

Securities Act File No. 333-173276

Investment Company Act of 1940 File No. 811-22542

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	☒
Pre-Effective Amendment No.
Post-Effective Amendment No. 143	☒

and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940	☒
Amendment No. 149	☒

SSGA Active Trust

(Exact Name of Registrant as Specified in Charter)

One Iron Street

Boston, Massachusetts 02210

(Address of Principal Executive Offices)

Registrant’s Telephone Number: (617) 664-7037

Joshua A. Weinberg, Esq.

Managing Director and Managing Counsel

c/o SSGA Funds Management, Inc.

One Iron Street

Boston, Massachusetts 02210

(Name and Address of Agent for Service)

Copies to:

W. John McGuire

Morgan, Lewis & Bockius LLP

1111 Pennsylvania Avenue, NW

Washington, DC 20004

It is proposed that this filing will become effective:

☒ immediately upon filing pursuant to Rule 485, paragraph (b)

☐ on _________________ pursuant to Rule 485, paragraph (b)

☐ 60 days after filing pursuant to Rule 485, paragraph (a)(1)

☐ on _________________ pursuant to Rule 485, paragraph (a)(1)

☐ 75 days after filing pursuant to Rule 485, paragraph (a)(2)

☐ on _________________ pursuant to Rule 485, paragraph (a)(2)

☐ As soon as practicable after the effective date of this registration statement.

SSGA MASTER TRUST HAS ALSO EXECUTED THIS REGISTRATION STATEMENT

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, SSGA Active Trust, the Registrant, certifies that it meets all of the requirements for effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933, as amended, and has duly caused this Amendment to the Registration Statement to be signed on its behalf by the undersigned, thereunder duly authorized, in the City of Boston and the Commonwealth of Massachusetts on the 21^st day of November, 2018.

	SSGA Active Trust
By:	/s/ Ellen M. Needham
	Ellen M. Needham
	President

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, this Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated:

SIGNATURES	TITLE	DATE
/s/ Bonny E. Boatman* Bonny E. Boatman	Trustee	November 21, 2018
/s/ Dwight D. Churchill* Dwight D. Churchill	Trustee	November 21, 2018
/s/ Frank Nesvet* Frank Nesvet	Trustee	November 21, 2018
/s/ Clare Richer* Clare Richer	Trustee	November 21, 2018
/s/ Sandra G. Sponem* Sandra G. Sponem	Trustee	November 21, 2018
/s/ Carl G. Verboncoeur* Carl G. Verboncoeur	Trustee	November 21, 2018
/s/ James E. Ross* James E. Ross	Trustee	November 21, 2018
/s/ Ellen M. Needham Ellen M. Needham	President and Principal Executive Officer	November 21, 2018
/s/ Bruce S. Rosenberg Bruce S. Rosenberg	Treasurer and Principal Financial Officer	November 21, 2018
*By: /s/ Jesse D. Hallee
Jesse D. Hallee
As Attorney-in-Fact   Pursuant to Power of Attorney

SIGNATURES

SSGA Master Trust has duly caused this Post-Effective Amendment No. 143 to the Registration Statement on Form N-1A of the SSGA Active Trust (the “Registrant”) to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston and the Commonwealth of Massachusetts on November 21, 2018.

SSGA MASTER TRUST
By:	/s/ Ellen M. Needham
	Ellen M. Needham
	President

This Registration Statement on Form N-1A of the Registrant has been signed below by the following persons, solely in the capacities indicated, on November 21, 2018.

SIGNATURE	TITLE
/s/ Bonny E. Boatman* Bonny E. Boatman	Trustee
/s/ Dwight D. Churchill* Dwight D. Churchill	Trustee
/s/ Frank Nesvet* Frank Nesvet	Trustee
/s/ Clare Richer* Clare Richer	Trustee
/s/ Sandra G. Sponem* Sandra G. Sponem	Trustee
/s/ Carl G. Verboncoeur* Carl G. Verboncoeur	Trustee
/s/James E. Ross* James E. Ross	Trustee
/s/ Ellen M. Needham Ellen M. Needham	President and Principal Executive Officer
/s/ Bruce S. Rosenberg Bruce S. Rosenberg	Treasurer and Principal Financial Officer
*By: /s/ Jesse D. Hallee
Jesse D. Hallee
As Attorney-in-Fact   Pursuant to Power of Attorney

Exhibit Index

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

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Jun. 30, 2018
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Central Index Key	dei_EntityCentralIndexKey	0001516212
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Oct. 29, 2018
Document Effective Date	dei_DocumentEffectiveDate	Oct. 31, 2018
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A

XML

SPDR SSGA Multi-Asset Real Return ETF

FUND SUMMARIES <br/><br/> <b>SPDR^® SSGA Multi-Asset Real Return ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR SSGA Multi-Asset Real Return ETF (the “Fund”) seeks to achieve real return consisting of capital appreciation and current income.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR SSGA Multi-Asset Real Return ETF SPDR SSGA Multi-Asset Real Return ETF
Management fees	0.50%	[1]
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.50%	[1]

<b>EXAMPLE: </b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR SSGA Multi-Asset Real Return ETF | SPDR SSGA Multi-Asset Real Return ETF | USD ($)	51	160	280	628

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 44% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>

Under normal circumstances, SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) invests at least 80% of the net assets of the Fund among exchange traded products (“ETPs”) that provide exposure to the following primary asset classes: (i) inflation protected securities issued by the United States government, its agencies and/or instrumentalities, as well as inflation protected securities issued by foreign governments, agencies, and/or instrumentalities; (ii) domestic and international real estate securities; (iii) commodities; and (iv) publicly-traded companies in natural resources and/or commodities businesses. Publicly-traded companies in natural resources and/or commodities businesses may include agriculture, energy, and metals and mining companies. In addition, the Fund may also invest in ETPs that provide exposure to the publicly-traded domestic and international infrastructure companies asset class. The Fund's allocation among these asset classes will be in proportions consistent with the Adviser's evaluation of the expected returns and risks of each asset class as well as the allocation that, in the Adviser's view, will best meet the Fund's investment objective. The Adviser's investment process relies on proprietary quantitative models as well as the Adviser's fundamental views regarding qualitative factors that may not be captured by the quantitative models. The allocations to each asset class will change over time as the Adviser's expectations of each asset class shift. The Fund's indirect holdings by virtue of investing in ETPs representing those asset classes will consist of a diversified mix of domestic and international equity securities, including emerging markets, government bonds, inflation protected securities, commodities and real estate investment trusts (“REITs”) and master limited partnerships (“MLPs”). The Fund may invest in ETPs that gain exposure to commodities through the use of derivatives. The Adviser considers real return to be a rate of return above the rate of inflation over a market cycle.

ETPs in which the Fund invests include exchange-traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”), exchange traded commodity trusts; and exchange traded notes (“ETNs”). The Fund may invest in ETPs that are qualified publicly traded partnerships (“QPTPs”). In addition, the Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. In addition, the Fund may invest in cash and cash equivalents or money market instruments, such as money market funds (including money market funds advised by the Adviser).

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Asset Allocation Risk: The Fund's investment performance depends upon the successful allocation by the Adviser of the Fund's assets among asset classes, geographical regions, industry sectors, and specific issuers and investments. There is no guarantee that the Adviser's allocation techniques and decisions will produce the desired results.

Cash Position Risk: If the Fund holds a significant position in cash or cash equivalents, its investment returns may be adversely affected, and the Fund may not achieve its investment objective.

Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. The Fund is subject to the following risks indirectly through its investments in ETPs:

Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund.

Agriculture Companies Risk: Economic forces, including forces affecting agricultural markets, as well as government policies and regulations affecting agriculture companies, could adversely impact the Fund's investments. Agricultural and livestock production and trade flows are significantly affected by government policies and regulations. Governmental policies affecting agriculture companies, such as taxes, tariffs, duties, subsidies and import and export restrictions on agricultural commodities, commodity products and livestock, can influence agriculture company profitability, the planting/raising of certain crops/livestock versus other uses of resources, the location and size of crop and livestock production, whether unprocessed or processed commodity products are traded and the volume and types of imports and exports. In addition, companies in the agriculture sector must comply with a broad range of environmental laws and regulations. Additional or more stringent environmental laws and regulations may be enacted in the future and such changes could have a material adverse effect on the business of such companies. In addition, agriculture companies may be significantly affected by adverse weather, pollution and/or disease which could limit or halt production.

Commodities Risk: Commodity prices can have significant volatility, and exposure to commodities can cause the net asset value of Fund Shares to decline or fluctuate in a rapid and unpredictable manner. A liquid secondary market may not exist for certain commodity investments, which may make it difficult for the Fund to sell them at a desirable price or at the price at which it is carrying them.

Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based.

Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and it may be difficult to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return margin, or otherwise honor its obligations. A derivatives transaction may not have the effect or behave in the manner anticipated.

Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries.

Energy Sector Risk: Issuers in energy-related industries can be significantly affected by fluctuations in energy prices and supply and demand of energy fuels. Markets for various energy-related commodities can have significant volatility, and are subject to control or manipulation by large producers or purchasers. Companies in the energy sector may need to make substantial expenditures, and to incur significant amounts of debt, in order to maintain or expand their reserves. Oil and gas exploration and production can be significantly affected by natural disasters as well as changes in exchange rates, interest rates, government regulation, world events and economic conditions. These companies may be at risk for environmental damage claims.

In addition, energy MLPs may be subject to regulation by the Federal Energy Regulatory Commission (“FERC”) with respect to tariff rates that these companies may charge for interstate pipeline transportation services. An adverse determination by FERC with respect to tariff rates of a pipeline MLP could have a material adverse effect on the financial condition of that pipeline MLP and its ability to make cash distributions to its equity owners.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Adviser.

Infrastructure-Related Companies Risk: Infrastructure-related companies include companies that primarily own, manage, develop and/or operate infrastructure assets, including transportation, utility, energy and/or telecommunications assets. Investment in infrastructure-related securities entails exposure to adverse economic, regulatory, political, legal, and other conditions or events affecting the issuers of such securities. Certain infrastructure-related entities, particularly telecommunications and utilities companies, are subject to extensive regulation by various governmental authorities. The costs of complying with governmental regulations, delays or failure to receive required regulatory approvals or the enactment of new adverse regulatory requirements may adversely affect infrastructure-related companies. Infrastructure-related companies may also be affected by service interruption and/or legal challenges due to environmental, operational or other conditions or events, and the imposition of special tariffs and changes in tax laws, regulatory policies and accounting standards.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Master Limited Partnership Risk: Investments in securities of MLPs involve certain risks different from or in addition to the risks of investing in common stocks. MLP common units can be affected by macro-economic factors and other factors unique to the partnership or company and the industry or industries in which the MLP operates. Certain MLP securities may trade in relatively low volumes due to their smaller capitalizations or other factors, which may cause them to have a high degree of price volatility and illiquidity. The structures of MLPs create certain risks, including, for example, risks related to the limited ability of investors to control an MLP and to vote on matters affecting the MLP, risks related to potential conflicts of interest between an MLP and the MLP's general partner, the risk that an MLP will generate insufficient cash flow to meet its current operating requirements, the risk that an MLP will issue additional securities or engage in other transactions that will have the effect of diluting the interests of existing investors, and risks related to the general partner's right to require unit-holders to sell their common units at an undesirable time or price.

MLP Tax Risk: A change in current tax law, or a change in the underlying business mix of a given MLP, could result in an MLP being treated as a corporation for U.S. federal income tax purposes, which would result in such MLP being required to pay U.S. federal income tax on its taxable income. The classification of an MLP as a corporation for U.S. federal income tax purposes would likely have a significant adverse impact on the value of an investment in the MLP.

Metals and Mining Companies Risk: Metals and mining companies can be significantly affected by events relating to international political and economic developments, energy conservation, the success of exploration projects, commodity prices, and tax and other government regulations. Investments in metals and mining companies may be speculative and may be subject to greater price volatility than investments in other types of companies. Risks of metals and mining investments include: changes in international monetary policies or economic and political conditions that can affect the supply of precious metals and consequently the value of metals and mining company investments; the United States or foreign governments may pass laws or regulations limiting metals investments for strategic or other policy reasons; and increased environmental or labor costs may depress the value of metals and mining investments.

Mid-Capitalization Securities Risk: The securities of mid-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of mid-sized companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of mid-sized issuers may be illiquid or may be restricted as to resale, and their values may be volatile.

Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds.

Natural Resources Risk: Investments in companies in natural resources industries can be significantly affected by (often rapid) changes in supply of, or demand for, various natural resources. They may also be affected by changes in energy prices, international political and economic developments, environmental incidents, energy conservation, the success of exploration projects, changes in commodity prices, and tax and other government regulations.

Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Real Estate Sector Risk: An investment in a real property company may be subject to risks similar to those associated with direct ownership of real estate, including, by way of example, the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property.

REIT Risk: REITs are subject to the risks associated with investing in the real estate sector in general. In particular, a REIT may be affected by changes in the values of the properties that the REIT owns or operates or that underlie the mortgages or similar real estate interests in which the REIT invests. In addition, REITs may be affected by changes to interest rates or property taxes. Further, REITs are dependent upon specialized management skills, and their investments may be concentrated in relatively few properties, or in a small geographic area or a single property type. REITs are also subject to heavy cash flow dependency and, as a result, are particularly reliant on the proper functioning of capital markets. In addition, a REIT could fail to qualify for favorable tax or regulatory treatment. Smaller capitalization REITs may be more volatile and may involve more risk than larger capitalization REITs. Equity REITs earn income from leasing properties and realize gains and losses from the sale of properties, and are therefore subject to the risk of extended vacancies, limitations on rents, the failure to collect rents, and the costs of obtaining financing for purchasing real estate. Mortgage REITs receive principal and interest payments from the owners of mortgage properties and are therefore subject to the credit risk of borrowers, lack of mortgage funds, and prepayment on underlying mortgage loans.

Small-Capitalization Securities Risk: The securities of small-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of smaller companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of smaller issuers may be illiquid or may be restricted as to resale, and their values may have significant volatility. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. Returns on investments in securities of small-capitalization companies could trail the returns on investments in securities of larger companies.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

Tax Risk-Qualifying Income: Regulated investment companies are subject to favorable tax treatment under the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). To qualify as a regulated investment company, the Fund must derive at least 90% of its gross income for each taxable year from sources generating “qualifying income.” Income derived from direct and certain indirect investments in commodities is not qualifying income. Thus, income from the Fund's investments in certain commodities-related investments may cause the Fund not to qualify as a regulated investment company. The Fund may also invest up to 25% of its total assets in one or more QPTPs, including ETPs that are QPTPs and whose principal activities are the buying and selling of commodities or options, futures, or forwards with respect to commodities. Although income from QPTPs is generally qualifying income, if an ETP intending to qualify as a QPTP fails to qualify as a QPTP, the income generated from the Fund's investment in the ETP may not be qualifying income.

U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)

Highest Quarterly Return: 5.58% (Q4, 2017)
Lowest Quarterly Return: -11.98% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR SSGA Multi-Asset Real Return ETF	One Year	Five Years	Since Inception	Inception Date
SPDR SSGA Multi-Asset Real Return ETF	10.22%	(1.05%)	(0.25%)	Apr. 25, 2012
SPDR SSGA Multi-Asset Real Return ETF | Return After Taxes on Distributions	9.58%	(1.63%)	(0.88%)	Apr. 25, 2012
SPDR SSGA Multi-Asset Real Return ETF | Return After Taxes on Distributions and Sale of Fund Shares	6.03%	(0.94%)	(0.36%)	Apr. 25, 2012
Bloomberg Barclays U.S. Government Inflation-Linked Bond Index (reflects no deduction for fees, expenses or taxes)	3.30%	0.17%	0.95%	Apr. 25, 2012
DBIQ Optimum Yield Diversified Commodity Index Excess Return (reflects no deduction for fees, expenses or taxes)	5.17%	(8.80%)	(7.93%)	Apr. 25, 2012

[1] The Fund's “Management fees” and “Total annual Fund operating expenses” have been restated to reflect current fees.

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 1.81%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR SSGA Multi-Asset Real Return ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	FUND SUMMARIES <br/><br/> <b>SPDR<sup>®</sup> SSGA Multi-Asset Real Return ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR SSGA Multi-Asset Real Return ETF (the “Fund”) seeks to achieve real return consisting of capital appreciation and current income.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 44% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	44.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	The Fund's “Management fees” and “Total annual Fund operating expenses” have been restated to reflect current fees.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE: </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) invests at least 80% of the net assets of the Fund among exchange traded products (“ETPs”) that provide exposure to the following primary asset classes: (i) inflation protected securities issued by the United States government, its agencies and/or instrumentalities, as well as inflation protected securities issued by foreign governments, agencies, and/or instrumentalities; (ii) domestic and international real estate securities; (iii) commodities; and (iv) publicly-traded companies in natural resources and/or commodities businesses. Publicly-traded companies in natural resources and/or commodities businesses may include agriculture, energy, and metals and mining companies. In addition, the Fund may also invest in ETPs that provide exposure to the publicly-traded domestic and international infrastructure companies asset class. The Fund's allocation among these asset classes will be in proportions consistent with the Adviser's evaluation of the expected returns and risks of each asset class as well as the allocation that, in the Adviser's view, will best meet the Fund's investment objective. The Adviser's investment process relies on proprietary quantitative models as well as the Adviser's fundamental views regarding qualitative factors that may not be captured by the quantitative models. The allocations to each asset class will change over time as the Adviser's expectations of each asset class shift. The Fund's indirect holdings by virtue of investing in ETPs representing those asset classes will consist of a diversified mix of domestic and international equity securities, including emerging markets, government bonds, inflation protected securities, commodities and real estate investment trusts (“REITs”) and master limited partnerships (“MLPs”). The Fund may invest in ETPs that gain exposure to commodities through the use of derivatives. The Adviser considers real return to be a rate of return above the rate of inflation over a market cycle. ETPs in which the Fund invests include exchange-traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”), exchange traded commodity trusts; and exchange traded notes (“ETNs”). The Fund may invest in ETPs that are qualified publicly traded partnerships (“QPTPs”). In addition, the Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. In addition, the Fund may invest in cash and cash equivalents or money market instruments, such as money market funds (including money market funds advised by the Adviser).
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Asset Allocation Risk: The Fund's investment performance depends upon the successful allocation by the Adviser of the Fund's assets among asset classes, geographical regions, industry sectors, and specific issuers and investments. There is no guarantee that the Adviser's allocation techniques and decisions will produce the desired results. Cash Position Risk: If the Fund holds a significant position in cash or cash equivalents, its investment returns may be adversely affected, and the Fund may not achieve its investment objective. Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. The Fund is subject to the following risks indirectly through its investments in ETPs: Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund. Agriculture Companies Risk: Economic forces, including forces affecting agricultural markets, as well as government policies and regulations affecting agriculture companies, could adversely impact the Fund's investments. Agricultural and livestock production and trade flows are significantly affected by government policies and regulations. Governmental policies affecting agriculture companies, such as taxes, tariffs, duties, subsidies and import and export restrictions on agricultural commodities, commodity products and livestock, can influence agriculture company profitability, the planting/raising of certain crops/livestock versus other uses of resources, the location and size of crop and livestock production, whether unprocessed or processed commodity products are traded and the volume and types of imports and exports. In addition, companies in the agriculture sector must comply with a broad range of environmental laws and regulations. Additional or more stringent environmental laws and regulations may be enacted in the future and such changes could have a material adverse effect on the business of such companies. In addition, agriculture companies may be significantly affected by adverse weather, pollution and/or disease which could limit or halt production. Commodities Risk: Commodity prices can have significant volatility, and exposure to commodities can cause the net asset value of Fund Shares to decline or fluctuate in a rapid and unpredictable manner. A liquid secondary market may not exist for certain commodity investments, which may make it difficult for the Fund to sell them at a desirable price or at the price at which it is carrying them. Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based. Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and it may be difficult to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return margin, or otherwise honor its obligations. A derivatives transaction may not have the effect or behave in the manner anticipated. Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries. Energy Sector Risk: Issuers in energy-related industries can be significantly affected by fluctuations in energy prices and supply and demand of energy fuels. Markets for various energy-related commodities can have significant volatility, and are subject to control or manipulation by large producers or purchasers. Companies in the energy sector may need to make substantial expenditures, and to incur significant amounts of debt, in order to maintain or expand their reserves. Oil and gas exploration and production can be significantly affected by natural disasters as well as changes in exchange rates, interest rates, government regulation, world events and economic conditions. These companies may be at risk for environmental damage claims. In addition, energy MLPs may be subject to regulation by the Federal Energy Regulatory Commission (“FERC”) with respect to tariff rates that these companies may charge for interstate pipeline transportation services. An adverse determination by FERC with respect to tariff rates of a pipeline MLP could have a material adverse effect on the financial condition of that pipeline MLP and its ability to make cash distributions to its equity owners. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Adviser. Infrastructure-Related Companies Risk: Infrastructure-related companies include companies that primarily own, manage, develop and/or operate infrastructure assets, including transportation, utility, energy and/or telecommunications assets. Investment in infrastructure-related securities entails exposure to adverse economic, regulatory, political, legal, and other conditions or events affecting the issuers of such securities. Certain infrastructure-related entities, particularly telecommunications and utilities companies, are subject to extensive regulation by various governmental authorities. The costs of complying with governmental regulations, delays or failure to receive required regulatory approvals or the enactment of new adverse regulatory requirements may adversely affect infrastructure-related companies. Infrastructure-related companies may also be affected by service interruption and/or legal challenges due to environmental, operational or other conditions or events, and the imposition of special tariffs and changes in tax laws, regulatory policies and accounting standards. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Master Limited Partnership Risk: Investments in securities of MLPs involve certain risks different from or in addition to the risks of investing in common stocks. MLP common units can be affected by macro-economic factors and other factors unique to the partnership or company and the industry or industries in which the MLP operates. Certain MLP securities may trade in relatively low volumes due to their smaller capitalizations or other factors, which may cause them to have a high degree of price volatility and illiquidity. The structures of MLPs create certain risks, including, for example, risks related to the limited ability of investors to control an MLP and to vote on matters affecting the MLP, risks related to potential conflicts of interest between an MLP and the MLP's general partner, the risk that an MLP will generate insufficient cash flow to meet its current operating requirements, the risk that an MLP will issue additional securities or engage in other transactions that will have the effect of diluting the interests of existing investors, and risks related to the general partner's right to require unit-holders to sell their common units at an undesirable time or price. MLP Tax Risk: A change in current tax law, or a change in the underlying business mix of a given MLP, could result in an MLP being treated as a corporation for U.S. federal income tax purposes, which would result in such MLP being required to pay U.S. federal income tax on its taxable income. The classification of an MLP as a corporation for U.S. federal income tax purposes would likely have a significant adverse impact on the value of an investment in the MLP. Metals and Mining Companies Risk: Metals and mining companies can be significantly affected by events relating to international political and economic developments, energy conservation, the success of exploration projects, commodity prices, and tax and other government regulations. Investments in metals and mining companies may be speculative and may be subject to greater price volatility than investments in other types of companies. Risks of metals and mining investments include: changes in international monetary policies or economic and political conditions that can affect the supply of precious metals and consequently the value of metals and mining company investments; the United States or foreign governments may pass laws or regulations limiting metals investments for strategic or other policy reasons; and increased environmental or labor costs may depress the value of metals and mining investments. Mid-Capitalization Securities Risk: The securities of mid-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of mid-sized companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of mid-sized issuers may be illiquid or may be restricted as to resale, and their values may be volatile. Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds. Natural Resources Risk: Investments in companies in natural resources industries can be significantly affected by (often rapid) changes in supply of, or demand for, various natural resources. They may also be affected by changes in energy prices, international political and economic developments, environmental incidents, energy conservation, the success of exploration projects, changes in commodity prices, and tax and other government regulations. Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Real Estate Sector Risk: An investment in a real property company may be subject to risks similar to those associated with direct ownership of real estate, including, by way of example, the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property. REIT Risk: REITs are subject to the risks associated with investing in the real estate sector in general. In particular, a REIT may be affected by changes in the values of the properties that the REIT owns or operates or that underlie the mortgages or similar real estate interests in which the REIT invests. In addition, REITs may be affected by changes to interest rates or property taxes. Further, REITs are dependent upon specialized management skills, and their investments may be concentrated in relatively few properties, or in a small geographic area or a single property type. REITs are also subject to heavy cash flow dependency and, as a result, are particularly reliant on the proper functioning of capital markets. In addition, a REIT could fail to qualify for favorable tax or regulatory treatment. Smaller capitalization REITs may be more volatile and may involve more risk than larger capitalization REITs. Equity REITs earn income from leasing properties and realize gains and losses from the sale of properties, and are therefore subject to the risk of extended vacancies, limitations on rents, the failure to collect rents, and the costs of obtaining financing for purchasing real estate. Mortgage REITs receive principal and interest payments from the owners of mortgage properties and are therefore subject to the credit risk of borrowers, lack of mortgage funds, and prepayment on underlying mortgage loans. Small-Capitalization Securities Risk: The securities of small-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of smaller companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of smaller issuers may be illiquid or may be restricted as to resale, and their values may have significant volatility. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. Returns on investments in securities of small-capitalization companies could trail the returns on investments in securities of larger companies. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. Tax Risk-Qualifying Income: Regulated investment companies are subject to favorable tax treatment under the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). To qualify as a regulated investment company, the Fund must derive at least 90% of its gross income for each taxable year from sources generating “qualifying income.” Income derived from direct and certain indirect investments in commodities is not qualifying income. Thus, income from the Fund's investments in certain commodities-related investments may cause the Fund not to qualify as a regulated investment company. The Fund may also invest up to 25% of its total assets in one or more QPTPs, including ETPs that are QPTPs and whose principal activities are the buying and selling of commodities or options, futures, or forwards with respect to commodities. Although income from QPTPs is generally qualifying income, if an ETP intending to qualify as a QPTP fails to qualify as a QPTP, the income generated from the Fund's investment in the ETP may not be qualifying income. U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 5.58% (Q4, 2017) Lowest Quarterly Return: -11.98% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR SSGA Multi-Asset Real Return ETF | SPDR SSGA Multi-Asset Real Return ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.50%	[1]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.50%	[1]
Year 1	rr_ExpenseExampleYear01	$ 51
Year 3	rr_ExpenseExampleYear03	160
Year 5	rr_ExpenseExampleYear05	280
Year 10	rr_ExpenseExampleYear10	$ 628
2013	rr_AnnualReturn2013	(3.08%)	[2]
2014	rr_AnnualReturn2014	(6.52%)	[2]
2015	rr_AnnualReturn2015	(15.21%)	[2]
2016	rr_AnnualReturn2016	12.03%	[2]
2017	rr_AnnualReturn2017	10.22%	[2]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	1.81%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	5.58%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(11.98%)
One Year	rr_AverageAnnualReturnYear01	10.22%
Five Years	rr_AverageAnnualReturnYear05	(1.05%)
Since Inception	rr_AverageAnnualReturnSinceInception	(0.25%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Multi-Asset Real Return ETF | Return After Taxes on Distributions | SPDR SSGA Multi-Asset Real Return ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	9.58%
Five Years	rr_AverageAnnualReturnYear05	(1.63%)
Since Inception	rr_AverageAnnualReturnSinceInception	(0.88%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Multi-Asset Real Return ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR SSGA Multi-Asset Real Return ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	6.03%
Five Years	rr_AverageAnnualReturnYear05	(0.94%)
Since Inception	rr_AverageAnnualReturnSinceInception	(0.36%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Multi-Asset Real Return ETF | Bloomberg Barclays U.S. Government Inflation-Linked Bond Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	3.30%
Five Years	rr_AverageAnnualReturnYear05	0.17%
Since Inception	rr_AverageAnnualReturnSinceInception	0.95%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Multi-Asset Real Return ETF | DBIQ Optimum Yield Diversified Commodity Index Excess Return (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	5.17%
Five Years	rr_AverageAnnualReturnYear05	(8.80%)
Since Inception	rr_AverageAnnualReturnSinceInception	(7.93%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012

[1] The Fund's “Management fees” and “Total annual Fund operating expenses” have been restated to reflect current fees.

[2] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 1.81%.

XML

SPDR SSGA Income Allocation ETF

<b>SPDR^® SSGA Income Allocation ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR SSGA Income Allocation ETF (the “Fund”) seeks to provide total return by focusing on investments in income and yield-generating assets.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR SSGA Income Allocation ETF SPDR SSGA Income Allocation ETF
Management fees	0.50%	[1]
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.50%	[1]

<b>EXAMPLE: </b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR SSGA Income Allocation ETF | SPDR SSGA Income Allocation ETF | USD ($)	51	160	280	628

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 29% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>

SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) primarily invests the assets of the Fund among exchange traded products (“ETPs”) that provide exposure to five primary asset classes: (i) domestic and international equity securities; (ii) domestic and international investment-grade and high yield debt securities (commonly known as “junk bonds”); (iii) hybrid equity/debt securities (such as preferred stock and convertible securities); (iv) first lien senior secured floating rate bank loans, commonly referred to as “Senior Loans”; and (v) real estate investment trusts (“REITs”), including equity REITs and mortgage REITs. The Fund's allocation among those asset classes will be in proportions consistent with the Adviser's evaluation of the expected returns and risks of each asset class as well as the allocation that, in the Adviser's view, will best meet the Fund's investment objective. The Adviser's investment process relies on proprietary quantitative models as well as the Adviser's fundamental views regarding factors that may not be captured by the quantitative models. The allocations to each asset class will change over time as the Adviser's expectations of each asset class shift. The Fund's indirect holdings by virtue of investing in ETPs representing these asset classes will consist of a diversified mix of domestic and international, including emerging markets, equity securities, investment-grade and high yield government and corporate bonds, hybrid securities such as preferred stock and convertible securities, inflation protected securities, Senior Loans and REITs.

ETPs in which the Fund invests include exchange-traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”), and exchange traded notes (“ETNs”). The Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. In addition, the Fund may invest in cash and cash equivalents or money market instruments, such as money market funds (including money market funds advised by the Adviser).

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Asset Allocation Risk: The Fund's investment performance depends upon the successful allocation by the Adviser of the Fund's assets among asset classes, geographical regions, industry sectors, and specific issuers and investments. There is no guarantee that the Adviser's allocation techniques and decisions will produce the desired results.

Cash Position Risk: If the Fund holds a significant position in cash or cash equivalents, its investment returns may be adversely affected, and the Fund may not achieve its investment objective.

Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. The Fund is subject to the following risks indirectly through its investments in ETPs:

Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund.

Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general.

Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible.

Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based.

Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Adviser.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Mid-Capitalization Securities Risk: The securities of mid-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of mid-sized companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of mid-sized issuers may be illiquid or may be restricted as to resale, and their values may be volatile.

Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds.

Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund and, therefore, the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield.

Real Estate Sector Risk: An investment in a real property company may be subject to risks similar to those associated with direct ownership of real estate, including, by way of example, the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property.

REIT Risk: REITs are subject to the risks associated with investing in the real estate sector in general. In particular, a REIT may be affected by changes in the values of the properties that the REIT owns or operates or that underlie the mortgages or similar real estate interests in which the REIT invests. In addition, REITs may be affected by changes to interest rates or property taxes. Further, REITs are dependent upon specialized management skills, and their investments may be concentrated in relatively few properties, or in a small geographic area or a single property type. REITs are also subject to heavy cash flow dependency and, as a result, are particularly reliant on the proper functioning of capital markets. In addition, a REIT could fail to qualify for favorable tax or regulatory treatment. Smaller capitalization REITs may be more volatile and may involve more risk than larger capitalization REITs. Equity REITs earn income from leasing properties and realize gains and losses from the sale of properties, and are therefore subject to the risk of extended vacancies, limitations on rents, the failure to collect rents, and the costs of obtaining financing for purchasing real estate. Mortgage REITs receive principal and interest payments from the owners of mortgage properties and are therefore subject to the credit risk of borrowers, lack of mortgage funds, and prepayment on underlying mortgage loans.

Senior Loan Risk: Investments in Senior Loans are subject to credit risk and general investment risk. Credit risk refers to the possibility that the borrower of a Senior Loan will be unable and/or unwilling to make timely interest payments and/or repay the principal on its obligation. Default in the payment of interest or principal on a Senior Loan will result in a reduction in the value of the Senior Loan and consequently a reduction in the value of the Fund's investments and a potential decrease in the net asset value (“NAV”) of the Fund. Senior Loans are also subject to the risk that the value of the collateral securing a Senior Loan may decline, be insufficient to meet the obligations of the borrower or be difficult to liquidate. In addition, the Fund's access to the collateral may be limited by bankruptcy or other insolvency laws. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some Senior Loans are subject to the risk that a court, pursuant to fraudulent conveyance or other similar laws, could subordinate the Senior Loans to presently existing or future indebtedness of the borrower or take other action detrimental to lenders, including the Fund, such as invalidation of Senior Loans or causing interest previously paid to be refunded to the borrower. Senior Loans are also subject to high yield securities risks and liquidity risks described above. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans.

Small-Capitalization Securities Risk: The securities of small-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of smaller companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of smaller issuers may be illiquid or may be restricted as to resale, and their values may have significant volatility. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. Returns on investments in securities of small-capitalization companies could trail the returns on investments in securities of larger companies.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)

Highest Quarterly Return: 4.99% (Q2, 2014)
Lowest Quarterly Return: -4.45% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR SSGA Income Allocation ETF	One Year	Five Years	Since Inception	Inception Date
SPDR SSGA Income Allocation ETF	13.63%	5.23%	5.82%	Apr. 25, 2012
SPDR SSGA Income Allocation ETF | Return After Taxes on Distributions	12.38%	3.91%	4.42%	Apr. 25, 2012
SPDR SSGA Income Allocation ETF | Return After Taxes on Distributions and Sale of Fund Shares	7.97%	3.52%	3.96%	Apr. 25, 2012
MSCI World Index (reflects no deduction for fees, expenses or taxes other than withholding taxes on reinvested dividends)	22.40%	11.64%	11.26%	Apr. 25, 2012
Bloomberg Barclays US Long Government/Credit Bond Index (reflects no deduction for fees, expenses or taxes)	10.71%	4.43%	5.37%	Apr. 25, 2012

[1] The Fund's “Management fees” and “Total annual Fund operating expenses” have been restated to reflect current fees.

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was -1.32%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR SSGA Income Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> SSGA Income Allocation ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR SSGA Income Allocation ETF (the “Fund”) seeks to provide total return by focusing on investments in income and yield-generating assets.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 29% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	29.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	The Fund's “Management fees” and “Total annual Fund operating expenses” have been restated to reflect current fees.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE: </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) primarily invests the assets of the Fund among exchange traded products (“ETPs”) that provide exposure to five primary asset classes: (i) domestic and international equity securities; (ii) domestic and international investment-grade and high yield debt securities (commonly known as “junk bonds”); (iii) hybrid equity/debt securities (such as preferred stock and convertible securities); (iv) first lien senior secured floating rate bank loans, commonly referred to as “Senior Loans”; and (v) real estate investment trusts (“REITs”), including equity REITs and mortgage REITs. The Fund's allocation among those asset classes will be in proportions consistent with the Adviser's evaluation of the expected returns and risks of each asset class as well as the allocation that, in the Adviser's view, will best meet the Fund's investment objective. The Adviser's investment process relies on proprietary quantitative models as well as the Adviser's fundamental views regarding factors that may not be captured by the quantitative models. The allocations to each asset class will change over time as the Adviser's expectations of each asset class shift. The Fund's indirect holdings by virtue of investing in ETPs representing these asset classes will consist of a diversified mix of domestic and international, including emerging markets, equity securities, investment-grade and high yield government and corporate bonds, hybrid securities such as preferred stock and convertible securities, inflation protected securities, Senior Loans and REITs. ETPs in which the Fund invests include exchange-traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”), and exchange traded notes (“ETNs”). The Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. In addition, the Fund may invest in cash and cash equivalents or money market instruments, such as money market funds (including money market funds advised by the Adviser).
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Asset Allocation Risk: The Fund's investment performance depends upon the successful allocation by the Adviser of the Fund's assets among asset classes, geographical regions, industry sectors, and specific issuers and investments. There is no guarantee that the Adviser's allocation techniques and decisions will produce the desired results. Cash Position Risk: If the Fund holds a significant position in cash or cash equivalents, its investment returns may be adversely affected, and the Fund may not achieve its investment objective. Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. The Fund is subject to the following risks indirectly through its investments in ETPs: Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund. Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general. Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible. Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based. Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Adviser. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Mid-Capitalization Securities Risk: The securities of mid-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of mid-sized companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of mid-sized issuers may be illiquid or may be restricted as to resale, and their values may be volatile. Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds. Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund and, therefore, the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield. Real Estate Sector Risk: An investment in a real property company may be subject to risks similar to those associated with direct ownership of real estate, including, by way of example, the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property. REIT Risk: REITs are subject to the risks associated with investing in the real estate sector in general. In particular, a REIT may be affected by changes in the values of the properties that the REIT owns or operates or that underlie the mortgages or similar real estate interests in which the REIT invests. In addition, REITs may be affected by changes to interest rates or property taxes. Further, REITs are dependent upon specialized management skills, and their investments may be concentrated in relatively few properties, or in a small geographic area or a single property type. REITs are also subject to heavy cash flow dependency and, as a result, are particularly reliant on the proper functioning of capital markets. In addition, a REIT could fail to qualify for favorable tax or regulatory treatment. Smaller capitalization REITs may be more volatile and may involve more risk than larger capitalization REITs. Equity REITs earn income from leasing properties and realize gains and losses from the sale of properties, and are therefore subject to the risk of extended vacancies, limitations on rents, the failure to collect rents, and the costs of obtaining financing for purchasing real estate. Mortgage REITs receive principal and interest payments from the owners of mortgage properties and are therefore subject to the credit risk of borrowers, lack of mortgage funds, and prepayment on underlying mortgage loans. Senior Loan Risk: Investments in Senior Loans are subject to credit risk and general investment risk. Credit risk refers to the possibility that the borrower of a Senior Loan will be unable and/or unwilling to make timely interest payments and/or repay the principal on its obligation. Default in the payment of interest or principal on a Senior Loan will result in a reduction in the value of the Senior Loan and consequently a reduction in the value of the Fund's investments and a potential decrease in the net asset value (“NAV”) of the Fund. Senior Loans are also subject to the risk that the value of the collateral securing a Senior Loan may decline, be insufficient to meet the obligations of the borrower or be difficult to liquidate. In addition, the Fund's access to the collateral may be limited by bankruptcy or other insolvency laws. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some Senior Loans are subject to the risk that a court, pursuant to fraudulent conveyance or other similar laws, could subordinate the Senior Loans to presently existing or future indebtedness of the borrower or take other action detrimental to lenders, including the Fund, such as invalidation of Senior Loans or causing interest previously paid to be refunded to the borrower. Senior Loans are also subject to high yield securities risks and liquidity risks described above. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans. Small-Capitalization Securities Risk: The securities of small-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of smaller companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of smaller issuers may be illiquid or may be restricted as to resale, and their values may have significant volatility. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. Returns on investments in securities of small-capitalization companies could trail the returns on investments in securities of larger companies. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 4.99% (Q2, 2014) Lowest Quarterly Return: -4.45% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR SSGA Income Allocation ETF | SPDR SSGA Income Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.50%	[1]
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.50%	[1]
Year 1	rr_ExpenseExampleYear01	$ 51
Year 3	rr_ExpenseExampleYear03	160
Year 5	rr_ExpenseExampleYear05	280
Year 10	rr_ExpenseExampleYear10	$ 628
2013	rr_AnnualReturn2013	3.01%	[2]
2014	rr_AnnualReturn2014	8.45%	[2]
2015	rr_AnnualReturn2015	(4.64%)	[2]
2016	rr_AnnualReturn2016	6.61%	[2]
2017	rr_AnnualReturn2017	13.63%	[2]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(1.32%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2014
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	4.99%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(4.45%)
One Year	rr_AverageAnnualReturnYear01	13.63%
Five Years	rr_AverageAnnualReturnYear05	5.23%
Since Inception	rr_AverageAnnualReturnSinceInception	5.82%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Income Allocation ETF | Return After Taxes on Distributions | SPDR SSGA Income Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	12.38%
Five Years	rr_AverageAnnualReturnYear05	3.91%
Since Inception	rr_AverageAnnualReturnSinceInception	4.42%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Income Allocation ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR SSGA Income Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	7.97%
Five Years	rr_AverageAnnualReturnYear05	3.52%
Since Inception	rr_AverageAnnualReturnSinceInception	3.96%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Income Allocation ETF | MSCI World Index (reflects no deduction for fees, expenses or taxes other than withholding taxes on reinvested dividends)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	22.40%
Five Years	rr_AverageAnnualReturnYear05	11.64%
Since Inception	rr_AverageAnnualReturnSinceInception	11.26%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Income Allocation ETF | Bloomberg Barclays US Long Government/Credit Bond Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	10.71%
Five Years	rr_AverageAnnualReturnYear05	4.43%
Since Inception	rr_AverageAnnualReturnSinceInception	5.37%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012

[1] The Fund's “Management fees” and “Total annual Fund operating expenses” have been restated to reflect current fees.

[2] As of 9/30/2018, the Fund's Calendar Year-To-Date return was -1.32%.

XML

SPDR SSGA Global Allocation ETF

<b>SPDR^® SSGA Global Allocation ETF </b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR SSGA Global Allocation ETF (the “Fund”) seeks to provide capital appreciation.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR SSGA Global Allocation ETF SPDR SSGA Global Allocation ETF
Management fees	0.35%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.35%

<b>EXAMPLE: </b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR SSGA Global Allocation ETF | SPDR SSGA Global Allocation ETF | USD ($)	36	113	197	443

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 43% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>

SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) primarily invests the assets of the Fund among exchange traded products (“ETPs”) that provide balanced exposure to domestic and international debt and equity securities. The Fund typically allocates approximately 60% of its assets to equity securities, though this percentage can vary based on the Adviser's tactical decisions. The Adviser's investment process relies on proprietary quantitative models as well as the Adviser's fundamental views regarding factors that may not be captured by the quantitative models. The allocations to each asset class will change over time as the Adviser's expectations of each asset class shift. The Fund's indirect holdings by virtue of investing in ETPs representing these asset classes consist of a diversified mix of domestic and international, including emerging market, equity securities across all market capitalizations, investment-grade and high yield government and corporate bonds (high yield bonds are commonly known as “junk bonds”), inflation protected securities, mortgage pass through securities, commercial mortgage backed securities, asset backed securities, commodities and real estate investment trusts (“REITs”). The Fund, through its investments in ETPs, will generally invest at least 30% of its assets in securities of issuers economically tied to countries other than the U.S. and will generally hold securities of issuers economically tied to at least three countries, including the U.S. In determining if a security is economically tied to a non-U.S. country, the Fund generally looks to the country of incorporation of the issuer as listed on Bloomberg L.P., a widely recognized provider of market information. However, the Adviser may determine a security is economically tied to a non-U.S. country based on other factors, such as an issuer's country of domicile, where more than 50% of an issuer's revenues are generated or where an issuer's primary exchange is located. As a result, a security may be economically tied to more than one country.

ETPs in which the Fund invests include exchange-traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”), exchange traded commodity trusts; and exchange traded notes (“ETNs”). The Fund may invest in ETPs that are qualified publicly traded partnerships (“QPTPs”). In addition, the Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. In addition, the Fund may invest in cash and cash equivalents or money market instruments, such as money market funds (including money market funds advised by the Adviser).

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Asset Allocation Risk: The Fund's investment performance depends upon the successful allocation by the Adviser of the Fund's assets among asset classes, geographical regions, industry sectors, and specific issuers and investments. There is no guarantee that the Adviser's allocation techniques and decisions will produce the desired results.

Cash Position Risk: If the Fund holds a significant position in cash or cash equivalents, its investment returns may be adversely affected, and the Fund may not achieve its investment objective.

Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. The Fund is subject to the following risks indirectly through its investments in ETPs:

Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund.

Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general.

Commodities Risk: Commodity prices can have significant volatility, and exposure to commodities can cause the net asset value of Fund Shares to decline or fluctuate in a rapid and unpredictable manner. A liquid secondary market may not exist for certain commodity investments, which may make it difficult for the Fund to sell them at a desirable price or at the price at which it is carrying them.

Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based.

Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Adviser.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Mid-Capitalization Securities Risk: The securities of mid-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of mid-sized companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of mid-sized issuers may be illiquid or may be restricted as to resale, and their values may be volatile.

Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds.

Mortgage-Related and Other Asset-Backed Securities Risk: Investments in mortgage-related and other asset-backed securities are subject to the risk of significant credit downgrades, illiquidity, and defaults to a greater extent than many other types of fixed-income investments. The liquidity of mortgage-related and asset-backed securities may change over time. During periods of falling interest rates, mortgage- and asset-backed securities may be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of mortgage- and asset-backed securities may extend, which may lock in a below-market interest rate, increase the security's duration and interest rate sensitivity, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, and the underlying assets or collateral may be insufficient if the issuer defaults.

Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund and, therefore, the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Real Estate Sector Risk: An investment in a real property company may be subject to risks similar to those associated with direct ownership of real estate, including, by way of example, the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property.

REIT Risk: REITs are subject to the risks associated with investing in the real estate sector in general. In particular, a REIT may be affected by changes in the values of the properties that the REIT owns or operates or that underlie the mortgages or similar real estate interests in which the REIT invests. In addition, REITs may be affected by changes to interest rates or property taxes. Further, REITs are dependent upon specialized management skills, and their investments may be concentrated in relatively few properties, or in a small geographic area or a single property type. REITs are also subject to heavy cash flow dependency and, as a result, are particularly reliant on the proper functioning of capital markets. In addition, a REIT could fail to qualify for favorable tax or regulatory treatment. Smaller capitalization REITs may be more volatile and may involve more risk than larger capitalization REITs. Equity REITs earn income from leasing properties and realize gains and losses from the sale of properties, and are therefore subject to the risk of extended vacancies, limitations on rents, the failure to collect rents, and the costs of obtaining financing for purchasing real estate. Mortgage REITs receive principal and interest payments from the owners of mortgage properties and are therefore subject to the credit risk of borrowers, lack of mortgage funds, and prepayment on underlying mortgage loans.

Small-Capitalization Securities Risk: The securities of small-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of smaller companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of smaller issuers may be illiquid or may be restricted as to resale, and their values may have significant volatility. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. Returns on investments in securities of small-capitalization companies could trail the returns on investments in securities of larger companies.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

Tax Risk-Qualifying Income: Regulated investment companies are subject to favorable tax treatment under the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). To qualify as a regulated investment company, the Fund must derive at least 90% of its gross income for each taxable year from sources generating “qualifying income.” Income derived from direct and certain indirect investments in commodities is not qualifying income. Thus, income from the Fund's investments in certain commodities-related investments may cause the Fund not to qualify as a regulated investment company. The Fund may also invest up to 25% of its total assets in one or more QPTPs, including ETPs that are QPTPs and whose principal activities are the buying and selling of commodities or options, futures, or forwards with respect to commodities. Although income from QPTPs is generally qualifying income, if an ETP intending to qualify as a QPTP fails to qualify as a QPTP, the income generated from the Fund's investment in the ETP may not be qualifying income.

U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

When-Issued, TBA and Delayed Delivery Securities Risk: The Fund may purchase securities on a when-issued, to-be-announced (“TBA”) or delayed delivery basis and may purchase securities on a forward commitment basis. The purchase price of the securities is typically fixed at the time of the commitment, but delivery and payment can take place a month or more after the date of the commitment. At the time of delivery of the securities, the value may be more or less than the purchase or sale price. Purchase of securities on a when-issued, TBA, delayed delivery, or forward commitment basis may give rise to investment leverage, and may result in increased volatility of the Fund's net asset value. Default by, or bankruptcy of, a counterparty to a when-issued, TBA or delayed delivery transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools specified in such transaction. Recently finalized rules of the Financial Industry Regulatory Authority, Inc. would impose mandatory margin requirements for certain types of when-issued, TBA delayed delivery or forward commitment transactions, with limited exceptions. Such transactions historically have not been required to be collateralized, and, if those rules are implemented, mandatory collateralization could increase the cost of such transactions and impose added operational complexity.

<b>FUND PERFORMANCE</b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)

Highest Quarterly Return: 5.61% (Q3, 2013)
Lowest Quarterly Return: -5.63% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR SSGA Global Allocation ETF	One Year	Five Years	Since Inception	Inception Date
SPDR SSGA Global Allocation ETF	18.38%	7.19%	7.37%	Apr. 25, 2012
SPDR SSGA Global Allocation ETF | Return After Taxes on Distributions	17.47%	6.14%	6.28%	Apr. 25, 2012
SPDR SSGA Global Allocation ETF | Return After Taxes on Distributions and Sale of Fund Shares	10.65%	5.20%	5.34%	Apr. 25, 2012
MSCI ACWI IMI Index (reflects no deduction for fees, expenses or taxes other than withholding taxes on reinvested dividends)	23.95%	11.00%	10.72%	Apr. 25, 2012
Bloomberg Barclays U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)	3.54%	2.10%	2.38%	Apr. 25, 2012

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 2.14%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR SSGA Global Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> SSGA Global Allocation ETF </b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR SSGA Global Allocation ETF (the “Fund”) seeks to provide capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 43% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	43.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE: </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) primarily invests the assets of the Fund among exchange traded products (“ETPs”) that provide balanced exposure to domestic and international debt and equity securities. The Fund typically allocates approximately 60% of its assets to equity securities, though this percentage can vary based on the Adviser's tactical decisions. The Adviser's investment process relies on proprietary quantitative models as well as the Adviser's fundamental views regarding factors that may not be captured by the quantitative models. The allocations to each asset class will change over time as the Adviser's expectations of each asset class shift. The Fund's indirect holdings by virtue of investing in ETPs representing these asset classes consist of a diversified mix of domestic and international, including emerging market, equity securities across all market capitalizations, investment-grade and high yield government and corporate bonds (high yield bonds are commonly known as “junk bonds”), inflation protected securities, mortgage pass through securities, commercial mortgage backed securities, asset backed securities, commodities and real estate investment trusts (“REITs”). The Fund, through its investments in ETPs, will generally invest at least 30% of its assets in securities of issuers economically tied to countries other than the U.S. and will generally hold securities of issuers economically tied to at least three countries, including the U.S. In determining if a security is economically tied to a non-U.S. country, the Fund generally looks to the country of incorporation of the issuer as listed on Bloomberg L.P., a widely recognized provider of market information. However, the Adviser may determine a security is economically tied to a non-U.S. country based on other factors, such as an issuer's country of domicile, where more than 50% of an issuer's revenues are generated or where an issuer's primary exchange is located. As a result, a security may be economically tied to more than one country. ETPs in which the Fund invests include exchange-traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”), exchange traded commodity trusts; and exchange traded notes (“ETNs”). The Fund may invest in ETPs that are qualified publicly traded partnerships (“QPTPs”). In addition, the Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. In addition, the Fund may invest in cash and cash equivalents or money market instruments, such as money market funds (including money market funds advised by the Adviser).
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Asset Allocation Risk: The Fund's investment performance depends upon the successful allocation by the Adviser of the Fund's assets among asset classes, geographical regions, industry sectors, and specific issuers and investments. There is no guarantee that the Adviser's allocation techniques and decisions will produce the desired results. Cash Position Risk: If the Fund holds a significant position in cash or cash equivalents, its investment returns may be adversely affected, and the Fund may not achieve its investment objective. Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. The Fund is subject to the following risks indirectly through its investments in ETPs: Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund. Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general. Commodities Risk: Commodity prices can have significant volatility, and exposure to commodities can cause the net asset value of Fund Shares to decline or fluctuate in a rapid and unpredictable manner. A liquid secondary market may not exist for certain commodity investments, which may make it difficult for the Fund to sell them at a desirable price or at the price at which it is carrying them. Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based. Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Adviser. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Mid-Capitalization Securities Risk: The securities of mid-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of mid-sized companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of mid-sized issuers may be illiquid or may be restricted as to resale, and their values may be volatile. Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds. Mortgage-Related and Other Asset-Backed Securities Risk: Investments in mortgage-related and other asset-backed securities are subject to the risk of significant credit downgrades, illiquidity, and defaults to a greater extent than many other types of fixed-income investments. The liquidity of mortgage-related and asset-backed securities may change over time. During periods of falling interest rates, mortgage- and asset-backed securities may be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of mortgage- and asset-backed securities may extend, which may lock in a below-market interest rate, increase the security's duration and interest rate sensitivity, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, and the underlying assets or collateral may be insufficient if the issuer defaults. Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund and, therefore, the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Real Estate Sector Risk: An investment in a real property company may be subject to risks similar to those associated with direct ownership of real estate, including, by way of example, the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property. REIT Risk: REITs are subject to the risks associated with investing in the real estate sector in general. In particular, a REIT may be affected by changes in the values of the properties that the REIT owns or operates or that underlie the mortgages or similar real estate interests in which the REIT invests. In addition, REITs may be affected by changes to interest rates or property taxes. Further, REITs are dependent upon specialized management skills, and their investments may be concentrated in relatively few properties, or in a small geographic area or a single property type. REITs are also subject to heavy cash flow dependency and, as a result, are particularly reliant on the proper functioning of capital markets. In addition, a REIT could fail to qualify for favorable tax or regulatory treatment. Smaller capitalization REITs may be more volatile and may involve more risk than larger capitalization REITs. Equity REITs earn income from leasing properties and realize gains and losses from the sale of properties, and are therefore subject to the risk of extended vacancies, limitations on rents, the failure to collect rents, and the costs of obtaining financing for purchasing real estate. Mortgage REITs receive principal and interest payments from the owners of mortgage properties and are therefore subject to the credit risk of borrowers, lack of mortgage funds, and prepayment on underlying mortgage loans. Small-Capitalization Securities Risk: The securities of small-capitalization companies may be more volatile and may involve more risk than the securities of larger companies. These companies may have limited product lines, markets or financial resources, may lack the competitive strength of larger companies, and may depend on a few key employees. In addition, these companies may have been recently organized and may have little or no track record of success. The securities of smaller companies may trade less frequently and in smaller volumes than more widely held securities. Some securities of smaller issuers may be illiquid or may be restricted as to resale, and their values may have significant volatility. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. Returns on investments in securities of small-capitalization companies could trail the returns on investments in securities of larger companies. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. Tax Risk-Qualifying Income: Regulated investment companies are subject to favorable tax treatment under the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). To qualify as a regulated investment company, the Fund must derive at least 90% of its gross income for each taxable year from sources generating “qualifying income.” Income derived from direct and certain indirect investments in commodities is not qualifying income. Thus, income from the Fund's investments in certain commodities-related investments may cause the Fund not to qualify as a regulated investment company. The Fund may also invest up to 25% of its total assets in one or more QPTPs, including ETPs that are QPTPs and whose principal activities are the buying and selling of commodities or options, futures, or forwards with respect to commodities. Although income from QPTPs is generally qualifying income, if an ETP intending to qualify as a QPTP fails to qualify as a QPTP, the income generated from the Fund's investment in the ETP may not be qualifying income. U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology. When-Issued, TBA and Delayed Delivery Securities Risk: The Fund may purchase securities on a when-issued, to-be-announced (“TBA”) or delayed delivery basis and may purchase securities on a forward commitment basis. The purchase price of the securities is typically fixed at the time of the commitment, but delivery and payment can take place a month or more after the date of the commitment. At the time of delivery of the securities, the value may be more or less than the purchase or sale price. Purchase of securities on a when-issued, TBA, delayed delivery, or forward commitment basis may give rise to investment leverage, and may result in increased volatility of the Fund's net asset value. Default by, or bankruptcy of, a counterparty to a when-issued, TBA or delayed delivery transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools specified in such transaction. Recently finalized rules of the Financial Industry Regulatory Authority, Inc. would impose mandatory margin requirements for certain types of when-issued, TBA delayed delivery or forward commitment transactions, with limited exceptions. Such transactions historically have not been required to be collateralized, and, if those rules are implemented, mandatory collateralization could increase the cost of such transactions and impose added operational complexity.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 5.61% (Q3, 2013) Lowest Quarterly Return: -5.63% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR SSGA Global Allocation ETF | SPDR SSGA Global Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.35%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.35%
Year 1	rr_ExpenseExampleYear01	$ 36
Year 3	rr_ExpenseExampleYear03	113
Year 5	rr_ExpenseExampleYear05	197
Year 10	rr_ExpenseExampleYear10	$ 443
2013	rr_AnnualReturn2013	12.68%	[1]
2014	rr_AnnualReturn2014	5.23%	[1]
2015	rr_AnnualReturn2015	(2.29%)	[1]
2016	rr_AnnualReturn2016	3.18%	[1]
2017	rr_AnnualReturn2017	18.38%	[1]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	2.14%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2013
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	5.61%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(5.63%)
One Year	rr_AverageAnnualReturnYear01	18.38%
Five Years	rr_AverageAnnualReturnYear05	7.19%
Since Inception	rr_AverageAnnualReturnSinceInception	7.37%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Global Allocation ETF | Return After Taxes on Distributions | SPDR SSGA Global Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	17.47%
Five Years	rr_AverageAnnualReturnYear05	6.14%
Since Inception	rr_AverageAnnualReturnSinceInception	6.28%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Global Allocation ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR SSGA Global Allocation ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	10.65%
Five Years	rr_AverageAnnualReturnYear05	5.20%
Since Inception	rr_AverageAnnualReturnSinceInception	5.34%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Global Allocation ETF | MSCI ACWI IMI Index (reflects no deduction for fees, expenses or taxes other than withholding taxes on reinvested dividends)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	23.95%
Five Years	rr_AverageAnnualReturnYear05	11.00%
Since Inception	rr_AverageAnnualReturnSinceInception	10.72%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012
SPDR SSGA Global Allocation ETF | Bloomberg Barclays U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	3.54%
Five Years	rr_AverageAnnualReturnYear05	2.10%
Since Inception	rr_AverageAnnualReturnSinceInception	2.38%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 25, 2012

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 2.14%.

XML

SPDR SSGA Ultra Short Term Bond ETF

<b>SPDR^® SSGA Ultra Short Term Bond ETF </b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR SSGA Ultra Short Term Bond ETF (the “Fund”) seeks to provide current income consistent with preservation of capital and daily liquidity through short duration high quality investments.

<b>FEES AND EXPENSES OF THE FUND</b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR SSGA Ultra Short Term Bond ETF SPDR SSGA Ultra Short Term Bond ETF
Management fees	0.20%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.20%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR SSGA Ultra Short Term Bond ETF | SPDR SSGA Ultra Short Term Bond ETF | USD ($)	20	64	113	255

<b>PORTFOLIO TURNOVER:</b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 76% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>

SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) invests, under normal circumstances, at least 80% of the Fund's net assets (plus the amount of borrowings for investment purposes) in a diversified portfolio of U.S. dollar-denominated investment-grade fixed income securities. The Fund primarily invests in investment-grade fixed income securities that are rated at the time of purchase a minimum of A- or higher by Standard & Poor's Financial Services LLC and/or Fitch Inc., or A3 or higher by Moody's Investors Service, Inc., or, if unrated, determined by the management team to be of equivalent quality. The Fund invests in fixed and floating rate securities of varying maturities, such as corporate obligations (including commercial paper of U.S. and foreign entities, master notes, and medium term notes); government bonds (including U.S. Treasury Bills, notes, and bonds); agency securities; privately-issued securities; asset-backed and mortgage-backed securities; money market instruments (including U.S. and foreign bank time deposits, certificates of deposit, and banker acceptances) and other investment companies. The Fund may also invest in exchange traded products (“ETPs”). ETPs include exchange traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”) and exchange traded notes (“ETNs”). In addition, the Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services.

Under normal circumstances, the effective duration of the Fund is expected to be between three and nine months. Effective duration is a measure of the Fund's price sensitivity to changes in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and may not reliably predict a particular security's price sensitivity to changes in yield or interest rates. In addition, the Fund expects to maintain a weighted average maturity between six and eighteen months. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Fund. For the purposes of determining the Fund's weighted average maturity, a security's final maturity date, or for amortizing securities such as asset-backed and mortgage-backed securities, its weighted average life will be used for calculation purposes. The Adviser buys and sells securities for the Fund based on its analysis of credit quality and overall portfolio duration. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the financial and industrial sectors, although this may change from time to time. The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations.

Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Industrial Sector Risk: Industrial companies are affected by supply and demand both for their specific product or service and for industrial sector products in general. Government regulation, world events, exchange rates and economic conditions, technological developments and liabilities for environmental damage and general civil liabilities will likewise affect the performance of these companies. Aerospace and defense companies, a component of the industrial sector, can be significantly affected by government spending policies because companies involved in this industry rely, to a significant extent, on U.S. and foreign government demand for their products and services. Thus, the financial condition of, and investor interest in, aerospace and defense companies are heavily influenced by governmental defense spending policies which are typically under pressure from efforts to control the U.S. (and other) government budgets. Transportation securities, a component of the industrial sector, are cyclical and have occasional sharp price movements which may result from changes in the economy, fuel prices, labor agreements and insurance costs.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds.

Mortgage-Related and Other Asset-Backed Securities Risk: Investments in mortgage-related and other asset-backed securities are subject to the risk of significant credit downgrades, illiquidity, and defaults to a greater extent than many other types of fixed-income investments. The liquidity of mortgage-related and asset-backed securities may change over time. During periods of falling interest rates, mortgage- and asset-backed securities may be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of mortgage- and asset-backed securities may extend, which may lock in a below-market interest rate, increase the security's duration and interest rate sensitivity, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, and the underlying assets or collateral may be insufficient if the issuer defaults.

Non-Diversification Risk: As a “non-diversified” fund, the Fund may hold a smaller number of portfolio securities than many other funds. To the extent the Fund invests in a relatively small number of issuers, a decline in the market value of a particular security held by the Fund may affect its value more than if it invested in a larger number of issuers. The value of Fund Shares may be more volatile than the values of shares of more diversified funds.

Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund and, therefore, the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks.

U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield.  Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such securities.

<b>FUND PERFORMANCE</b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS </b>(years ended 12/31)

Highest Quarterly Return: 0.53% (Q3, 2016)
Lowest Quarterly Return: -0.07% (Q4, 2014)

<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR SSGA Ultra Short Term Bond ETF	One Year	Since Inception	Inception Date
SPDR SSGA Ultra Short Term Bond ETF	1.39%	0.82%	Oct. 09, 2013
SPDR SSGA Ultra Short Term Bond ETF | Return After Taxes on Distributions	0.86%	0.53%	Oct. 09, 2013
SPDR SSGA Ultra Short Term Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	0.79%	0.50%	Oct. 09, 2013
Bloomberg Barclays US Treasury Bellwether 3 Month Index (reflects no deduction for fees, expenses or taxes)	0.87%	0.32%	Oct. 09, 2013

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 1.59%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR SSGA Ultra Short Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> SSGA Ultra Short Term Bond ETF </b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR SSGA Ultra Short Term Bond ETF (the “Fund”) seeks to provide current income consistent with preservation of capital and daily liquidity through short duration high quality investments.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER:</b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 76% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	76.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	SSGA Funds Management, Inc. (the “Adviser” or “SSGA FM”) invests, under normal circumstances, at least 80% of the Fund's net assets (plus the amount of borrowings for investment purposes) in a diversified portfolio of U.S. dollar-denominated investment-grade fixed income securities. The Fund primarily invests in investment-grade fixed income securities that are rated at the time of purchase a minimum of A- or higher by Standard & Poor's Financial Services LLC and/or Fitch Inc., or A3 or higher by Moody's Investors Service, Inc., or, if unrated, determined by the management team to be of equivalent quality. The Fund invests in fixed and floating rate securities of varying maturities, such as corporate obligations (including commercial paper of U.S. and foreign entities, master notes, and medium term notes); government bonds (including U.S. Treasury Bills, notes, and bonds); agency securities; privately-issued securities; asset-backed and mortgage-backed securities; money market instruments (including U.S. and foreign bank time deposits, certificates of deposit, and banker acceptances) and other investment companies. The Fund may also invest in exchange traded products (“ETPs”). ETPs include exchange traded funds registered under the Investment Company Act of 1940, as amended (the “1940 Act”) (“Underlying ETFs”) and exchange traded notes (“ETNs”). In addition, the Fund may invest in certain ETPs that pay fees to the Adviser and its affiliates for management, marketing or other services. Under normal circumstances, the effective duration of the Fund is expected to be between three and nine months. Effective duration is a measure of the Fund's price sensitivity to changes in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and may not reliably predict a particular security's price sensitivity to changes in yield or interest rates. In addition, the Fund expects to maintain a weighted average maturity between six and eighteen months. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Fund. For the purposes of determining the Fund's weighted average maturity, a security's final maturity date, or for amortizing securities such as asset-backed and mortgage-backed securities, its weighted average life will be used for calculation purposes. The Adviser buys and sells securities for the Fund based on its analysis of credit quality and overall portfolio duration. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the financial and industrial sectors, although this may change from time to time. The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Affiliated ETP Risk: The Adviser may receive management or other fees from the ETPs (“Affiliated ETPs”) in which the Fund may invest, as well as a management fee for managing the Fund. It is possible that a conflict of interest among the Fund and the Affiliated ETPs could affect how the Adviser fulfills its fiduciary duties to the Fund and the Affiliated ETPs. Because the amount of the investment management fees to be retained by the Adviser may differ depending upon the Affiliated ETPs in which the Fund invests, there is a conflict of interest for the Adviser in selecting the Affiliated ETPs. In addition, the Adviser may have an incentive to take into account the effect on an Affiliated ETP in which the Fund may invest in determining whether, and under what circumstances, to purchase or sell shares in that Affiliated ETP. Although the Adviser takes steps to address the conflicts of interest, it is possible that the conflicts could impact the Fund. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an ETF's shares) for a number of reasons. For example, supply and demand for shares of an Underlying ETF or market disruptions may cause the market price of the Underlying ETF to deviate from the value of the Underlying ETF's investments, which may be exacerbated in less liquid markets. The value of an ETN may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, the Fund indirectly bears the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund and its shareholders directly bear in connection with the Fund's own operations. Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Industrial Sector Risk: Industrial companies are affected by supply and demand both for their specific product or service and for industrial sector products in general. Government regulation, world events, exchange rates and economic conditions, technological developments and liabilities for environmental damage and general civil liabilities will likewise affect the performance of these companies. Aerospace and defense companies, a component of the industrial sector, can be significantly affected by government spending policies because companies involved in this industry rely, to a significant extent, on U.S. and foreign government demand for their products and services. Thus, the financial condition of, and investor interest in, aerospace and defense companies are heavily influenced by governmental defense spending policies which are typically under pressure from efforts to control the U.S. (and other) government budgets. Transportation securities, a component of the industrial sector, are cyclical and have occasional sharp price movements which may result from changes in the economy, fuel prices, labor agreements and insurance costs. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Management Risk: The Fund is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Money Market Risk: An investment in a money market fund is not a deposit of any bank and is not insured or guaranteed by the FDIC or any other government agency. Certain money market funds seek to preserve the value of their shares at $1.00 per share, although there can be no assurance that they will do so, and it is possible to lose money by investing in such a money market fund. A major or unexpected increase in interest rates or a decline in the credit quality of an issuer or entity providing credit support, an inactive trading market for money market instruments, or adverse market, economic, industry, political, regulatory, geopolitical, and other conditions could cause the share price of such a money market fund to fall below $1.00. Other money market funds price and transact at a “floating” NAV that will fluctuate along with changes in the market-based value of fund assets. Shares sold utilizing a floating NAV may be worth more or less than their original purchase price. Recent changes in the regulation of money market funds may affect the operations and structures of money market funds. Mortgage-Related and Other Asset-Backed Securities Risk: Investments in mortgage-related and other asset-backed securities are subject to the risk of significant credit downgrades, illiquidity, and defaults to a greater extent than many other types of fixed-income investments. The liquidity of mortgage-related and asset-backed securities may change over time. During periods of falling interest rates, mortgage- and asset-backed securities may be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of mortgage- and asset-backed securities may extend, which may lock in a below-market interest rate, increase the security's duration and interest rate sensitivity, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, and the underlying assets or collateral may be insufficient if the issuer defaults. Non-Diversification Risk: As a “non-diversified” fund, the Fund may hold a smaller number of portfolio securities than many other funds. To the extent the Fund invests in a relatively small number of issuers, a decline in the market value of a particular security held by the Fund may affect its value more than if it invested in a larger number of issuers. The value of Fund Shares may be more volatile than the values of shares of more diversified funds. Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund and, therefore, the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks. U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology. Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield.  Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such securities.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	<blockquote><b>Non-Diversification Risk:</b> As a “non-diversified” fund, the Fund may hold a smaller number of portfolio securities than many other funds. To the extent the Fund invests in a relatively small number of issuers, a decline in the market value of a particular security held by the Fund may affect its value more than if it invested in a larger number of issuers. The value of Fund Shares may be more volatile than the values of shares of more diversified funds.</blockquote>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS </b>(years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 0.53% (Q3, 2016) Lowest Quarterly Return: -0.07% (Q4, 2014)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR SSGA Ultra Short Term Bond ETF | SPDR SSGA Ultra Short Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.20%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.20%
Year 1	rr_ExpenseExampleYear01	$ 20
Year 3	rr_ExpenseExampleYear03	64
Year 5	rr_ExpenseExampleYear05	113
Year 10	rr_ExpenseExampleYear10	$ 255
2014	rr_AnnualReturn2014	0.28%	[1]
2015	rr_AnnualReturn2015	0.12%	[1]
2016	rr_AnnualReturn2016	1.52%	[1]
2017	rr_AnnualReturn2017	1.39%	[1]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	1.59%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.53%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2014
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(0.07%)
One Year	rr_AverageAnnualReturnYear01	1.39%
Since Inception	rr_AverageAnnualReturnSinceInception	0.82%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 09, 2013
SPDR SSGA Ultra Short Term Bond ETF | Return After Taxes on Distributions | SPDR SSGA Ultra Short Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.86%
Since Inception	rr_AverageAnnualReturnSinceInception	0.53%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 09, 2013
SPDR SSGA Ultra Short Term Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR SSGA Ultra Short Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.79%
Since Inception	rr_AverageAnnualReturnSinceInception	0.50%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 09, 2013
SPDR SSGA Ultra Short Term Bond ETF | Bloomberg Barclays US Treasury Bellwether 3 Month Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.87%
Since Inception	rr_AverageAnnualReturnSinceInception	0.32%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 09, 2013

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 1.59%.

XML

SPDR DoubleLine Total Return Tactical ETF

<b>SPDR^® DoubleLine Total Return Tactical ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR DoubleLine Total Return Tactical ETF (the “Fund”) seeks to maximize total return.

<b>FEES AND EXPENSES OF THE FUND</b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR DoubleLine Total Return Tactical ETF SPDR DoubleLine Total Return Tactical ETF
Management fees	0.65%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.65%
Less contractual fee waiver	(0.10%)	[1]
Net annual Fund operating expenses	0.55%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the Fund's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR DoubleLine Total Return Tactical ETF | SPDR DoubleLine Total Return Tactical ETF | USD ($)	56	198	352	801

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 34% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>

Under normal circumstances, DoubleLine Capital LP (the “Sub-Adviser” or “DoubleLine”) will invest at least 80% of the Fund's net assets in a portfolio of fixed income securities of any credit quality. Fixed income securities in which the Fund principally invests include securities issued or guaranteed by the U.S. government or its agencies, instrumentalities or sponsored corporations; inflation protected public obligations of the U.S. Treasury; agency and non-agency residential mortgage-backed securities (“RMBS”); agency and non-agency commercial mortgage-backed securities (“CMBS”); agency and non-agency asset-backed securities (“ABS”); domestic corporate bonds; fixed income securities issued by foreign corporations and foreign governments including emerging markets; bank loans (primarily senior loans, including loan participations or assignments whose loan syndication exceeds $300 million) municipal bonds; and other securities (such as perpetual bonds) bearing fixed interest rates of any maturity. The Fund may also invest in collateralized loan obligations, floating rate securities (including floating rate loans), variable rate securities, Rule 144A securities, and repurchase agreements and may enter into reverse repurchase agreements. The Fund may conduct foreign currency transactions on a spot (i.e., cash) or forward basis (i.e., by entering into forward contracts to purchase or sell foreign currencies).

The Fund intends to invest at least 20% of its net assets in mortgage-backed securities of any maturity or type guaranteed by, or secured by collateral that is guaranteed by, the U.S. Government, its agencies, instrumentalities or sponsored corporations, or in privately issued mortgage-backed securities rated at the time of investment Aa3 or higher by Moody's Investors Service, Inc. (“Moody's”) or AA- or higher by Standard & Poor's Rating Service (“S&P”) or the equivalent by any other nationally recognized statistical rating organization (“NRSRO”) or, if unrated by an NRSRO, securities that are determined by the Sub-Adviser to be of comparable quality. The Fund may invest up to 20% of the fixed income portion of its portfolio, in the aggregate, in non-agency RMBS, CMBS and ABS. The Fund may invest a substantial portion of its assets in U.S. agency mortgage pass-through securities. The term “U.S. agency mortgage pass-through security” refers to a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. Government-sponsored enterprises: Ginnie Mae, Fannie Mae or Freddie Mac. The Fund will seek to obtain exposure to U.S. agency mortgage pass-through securities primarily through the use of “to-be-announced” or “TBA Transactions”. “TBA” refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed securities. Most transactions in mortgage pass-through securities occur through the use of TBA Transactions. TBA Transactions generally are conducted in accordance with widely-accepted guidelines which establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA Transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined prior to settlement date.

The Fund may invest up to 25% of its net assets in corporate high yield securities (commonly known as “junk bonds”). Under normal circumstances, the combined total of corporate, sovereign, non-agency and all other debt rated below investment-grade will not exceed 40% of the Fund's net assets. The Sub-Adviser strives to allocate below investment-grade securities broadly by industry and issuer in an attempt to reduce the impact of negative events on an industry or issuer. Below investment-grade securities are instruments that are rated BB+ or lower by S&P or Fitch Inc. or Ba1 or lower by Moody's or equivalent ratings by another registered NRSRO, or, if unrated by an NRSRO, of comparable quality in the opinion of the Sub-Adviser.

The Fund may invest up to 15% of its net assets in securities denominated in foreign currencies, and may invest beyond this limit in U.S. dollar-denominated securities of foreign issuers. The Fund may invest up to 25% of its net assets in securities and instruments that are economically tied to emerging market countries. The Fund generally considers an issuer to be economically tied to an emerging market country if: (i) the issuer is organized under the laws of an emerging country; (ii) the issuer's securities are traded principally in an emerging country; or (iii) during the issuer's most recent fiscal year it derived at least 50% of its revenues, earnings before interest, taxes, depreciation, and amortization, or profits from goods produced or sold by, investments made in, or services performed in emerging countries, or it had at least 50% of its assets in emerging countries.

The Sub-Adviser monitors the duration of the securities held by the Fund to seek to mitigate exposure to interest rate risk. Under normal circumstances, the Sub-Adviser seeks to maintain an investment portfolio with a weighted average effective duration of no less than 1 year and no more than 8 years. The duration of the portfolio may vary materially from its target, from time to time. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The longer a security's duration, the more sensitive it will be to changes in interest rates.

The Sub-Adviser actively manages the Fund's asset class exposure using a top-down approach based on analysis of sector fundamentals and rotates Fund assets among sectors in various markets to attempt to maximize return. Individual securities within asset classes are selected using a bottom-up approach. Under normal circumstances, the Sub-Adviser uses a controlled risk approach in managing the Fund's investments. The techniques of this approach attempt to control the principal risk components of the fixed income markets and include consideration of:

• Security selection within a given sector;

• Relative performance of the various market sectors;

• The shape of the yield curve; and

• Fluctuations in the overall level of interest rates.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND</b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Asset-Backed and Mortgage-Backed Securities Risk: Asset-backed and mortgage-backed securities (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. These securities, in most cases, are not backed by the full faith and credit of the U.S. government, and there can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. These securities may be subject to liquidity risk as well as the risk of illiquidity and default on the underlying asset or mortgage, particularly during periods of economic downturn. The liquidity of mortgage-related and asset-backed securities may change over time. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain asset-backed and mortgage-backed securities. In particular, during periods of falling interest rates, mortgage-backed securities will be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of a mortgage-backed security may extend, which may lock in a below-market interest rate, increase the security's duration, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, or the underlying assets or collateral may be insufficient if the issuer defaults. The values of certain types of mortgage-backed securities, such as inverse floaters and interest-only and principal-only securities, may be extremely sensitive to changes in interest rates and prepayment rates.

Bank Loan Risk: The Fund may invest in secured and unsecured participations in bank loans and assignments of such loans. In making investments in such loans, which are made by banks or other financial intermediaries to borrowers, the Fund will depend primarily upon the creditworthiness of the borrower for payment of principal and interest which will expose the Fund to the credit risk of both the financial institution and the underlying borrower. The market for bank loans may not be highly liquid and the Fund may have difficulty selling them. The Fund may also experience settlement delays with respect to bank loan trades. Participations by the Fund in a lender's portion of a bank loan typically will result in the Fund having a contractual relationship only with such lender, not with the borrower. The Fund may have the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling a loan participation and only upon receipt by such lender of such payments from the borrower. In connection with purchasing participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other lenders through set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund may assume the credit risk of both the borrower and the lender selling the participation. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans.

Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general.

Collateralized Loan Obligation Risk: The risks of an investment in a collateralized loan obligation depend largely on the type of the collateral securities and the class of the debt obligation in which the Fund invests. Collateralized loan obligations are generally subject to credit, interest rate, valuation, liquidity, prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. Collateralized loan obligations carry additional risks including, but not limited to, (i) the possibility that distributions from collateral securities will not be adequate to make interest of other payments, (ii) the collateral may decline in value or default, (iii) the Fund may invest in obligations that are subordinate to other classes, and (iv) the complex structure of the security may not be fully understood at the time of investment and produce disputes with the issuer or unexpected investment results.

Counterparty Risk: The Fund will be subject to credit risk with respect to the counterparties with which the Fund enters into derivatives contracts, repurchase agreements, reverse repurchase agreements, and other transactions. If a counterparty fails to meet its contractual obligations, the Fund may be unable to terminate or realize any gain on the investment or transaction, or to recover collateral posted to the counterparty, resulting in a loss to the Fund. If the Fund holds collateral posted by its counterparty, it may be delayed or prevented from realizing on the collateral in the event of a bankruptcy or insolvency proceeding relating to the counterparty.

Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and the Fund may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Fund's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Sub-Adviser or may not have the effect on the Fund anticipated by the Sub-Adviser.

Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Sub-Adviser.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Mortgage Pass-Through Securities Risk: Most transactions in mortgage pass through securities occur through the use of TBA Transactions, as described above. Default by, or bankruptcy of, a counterparty to a TBA Transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA Transaction.

Municipal Obligations Risk: Issuers, including governmental issuers, may be unable to pay their obligations as they come due. The values of municipal obligations that depend on a specific revenue source to fund their payment obligations may fluctuate as a result of actual or anticipated changes in the cash flows generated by the revenue source or changes in the priority of the municipal obligation to receive the cash flows generated by the revenue source. In addition, changes in federal tax laws or the activity of an issuer may adversely affect the tax-exempt status of municipal obligations. Loss of tax-exempt status may cause interest received and distributed by the Fund to shareholders to be taxable and may result in a significant decline in the values of such municipal obligations.

Non-Diversification Risk: As a “non-diversified” fund, the Fund may hold a smaller number of portfolio securities than many other funds. To the extent the Fund invests in a relatively small number of issuers, a decline in the market value of a particular security held by the Fund may affect its value more than if it invested in a larger number of issuers. The value of Fund Shares may be more volatile than the values of shares of more diversified funds.

Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Perpetual Bond Risk: Perpetual bonds offer a fixed return with no maturity date. Because they never mature, perpetual bonds can be more volatile than other types of bonds that have a maturity date and may have heightened sensitivity to changes in interest rates. If market interest rates rise significantly, the interest rate paid by a perpetual bond may be much lower than the prevailing interest rate.  Perpetual bonds are also subject to credit risk with respect to the issuer.  In addition, because perpetual bonds may be callable after a set period of time, there is the risk that the issuer may recall the bond.

Repurchase Agreement Risk: Repurchase agreements may be viewed as loans made by the Fund which are collateralized by the securities subject to repurchase. If the Fund's counterparty should default on its obligations and the Fund is delayed or prevented from recovering the collateral, or if the value of the collateral is insufficient, the Fund may realize a loss.

Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility.

Reverse Repurchase Agreement Risk: Reverse repurchase agreements involve both counterparty risk and the risk that the value of securities that the Fund is obligated to repurchase under the agreement may decline below the repurchase price. Reverse repurchase agreements involve leverage risk; the Fund may lose money as a result of declines in the values both of the security subject to the reverse repurchase agreement and the instruments in which the Fund invested the proceeds of the reverse repurchase agreement.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks.

U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield. In addition, investment in derivative variable rate securities, such as inverse floaters, whose rates vary inversely with market rates of interest, or range floaters or capped floaters, whose rates are subject to periodic or lifetime caps, or in securities that pay a rate of interest determined by applying a multiple to the variable rate involves special risks as compared to investment in a fixed-rate security and may involve leverage. Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade frequently, and their value may be impaired when the Fund needs to liquidate such securities.

When-Issued, TBA and Delayed Delivery Securities Risk: The Fund may purchase securities on a when-issued, to-be-announced (“TBA”) or delayed delivery basis and may purchase securities on a forward commitment basis. The purchase price of the securities is typically fixed at the time of the commitment, but delivery and payment can take place a month or more after the date of the commitment. At the time of delivery of the securities, the value may be more or less than the purchase or sale price. Purchase of securities on a when-issued, TBA, delayed delivery, or forward commitment basis may give rise to investment leverage, and may result in increased volatility of the Fund's net asset value. Default by, or bankruptcy of, a counterparty to a when-issued, TBA or delayed delivery transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools specified in such transaction. Recently finalized rules of the Financial Industry Regulatory Authority, Inc. would impose mandatory margin requirements for certain types of when-issued, TBA delayed delivery or forward commitment transactions, with limited exceptions. Such transactions historically have not been required to be collateralized, and, if those rules are implemented, mandatory collateralization could increase the cost of such transactions and impose added operational complexity.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURN </b>(years ended 12/31)

Highest Quarterly Return: 2.00% (Q1, 2016)
Lowest Quarterly Return: -1.95% (Q4, 2016)

<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR DoubleLine Total Return Tactical ETF	One Year	Since Inception	Inception Date
SPDR DoubleLine Total Return Tactical ETF	3.42%	2.16%	Feb. 23, 2015
SPDR DoubleLine Total Return Tactical ETF | Return After Taxes on Distributions	2.09%	0.81%	Feb. 23, 2015
SPDR DoubleLine Total Return Tactical ETF | Return After Taxes on Distributions and Sale of Fund Shares	1.93%	1.03%	Feb. 23, 2015
Bloomberg Barclays U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)	3.54%	2.07%	Feb. 23, 2015

[1] SSGA Funds Management, Inc. ("SSGA FM" or "Adviser") has contractually agreed to waive a portion of its management fee and/or reimburse certain expenses, until October 31, 2019, so that the net annual Fund operating expenses, before application of any fees and expenses not paid by the Adviser pursuant to the Investment Advisory Agreement, if any, are limited to 0.55% of the Fund's average daily net assets. The contractual fee waiver and/or reimbursement does not provide for the recoupment by the Adviser of any fees the Adviser previously waived. The Adviser may continue the waiver and/or reimbursement from year to year, but there is no guarantee that the Adviser will do so and after October 31, 2019, the waiver and/or reimbursement may be cancelled or modified at any time. This waiver and/or reimbursement may not be terminated prior to October 31, 2019 except with the approval of the SSGA Active Trust's Board of Trustees.

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was -0.69%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR DoubleLine Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> DoubleLine Total Return Tactical ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR DoubleLine Total Return Tactical ETF (the “Fund”) seeks to maximize total return.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	October 31, 2019
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 34% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	34.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the Fund's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, DoubleLine Capital LP (the “Sub-Adviser” or “DoubleLine”) will invest at least 80% of the Fund's net assets in a portfolio of fixed income securities of any credit quality. Fixed income securities in which the Fund principally invests include securities issued or guaranteed by the U.S. government or its agencies, instrumentalities or sponsored corporations; inflation protected public obligations of the U.S. Treasury; agency and non-agency residential mortgage-backed securities (“RMBS”); agency and non-agency commercial mortgage-backed securities (“CMBS”); agency and non-agency asset-backed securities (“ABS”); domestic corporate bonds; fixed income securities issued by foreign corporations and foreign governments including emerging markets; bank loans (primarily senior loans, including loan participations or assignments whose loan syndication exceeds $300 million) municipal bonds; and other securities (such as perpetual bonds) bearing fixed interest rates of any maturity. The Fund may also invest in collateralized loan obligations, floating rate securities (including floating rate loans), variable rate securities, Rule 144A securities, and repurchase agreements and may enter into reverse repurchase agreements. The Fund may conduct foreign currency transactions on a spot (i.e., cash) or forward basis (i.e., by entering into forward contracts to purchase or sell foreign currencies). The Fund intends to invest at least 20% of its net assets in mortgage-backed securities of any maturity or type guaranteed by, or secured by collateral that is guaranteed by, the U.S. Government, its agencies, instrumentalities or sponsored corporations, or in privately issued mortgage-backed securities rated at the time of investment Aa3 or higher by Moody's Investors Service, Inc. (“Moody's”) or AA- or higher by Standard & Poor's Rating Service (“S&P”) or the equivalent by any other nationally recognized statistical rating organization (“NRSRO”) or, if unrated by an NRSRO, securities that are determined by the Sub-Adviser to be of comparable quality. The Fund may invest up to 20% of the fixed income portion of its portfolio, in the aggregate, in non-agency RMBS, CMBS and ABS. The Fund may invest a substantial portion of its assets in U.S. agency mortgage pass-through securities. The term “U.S. agency mortgage pass-through security” refers to a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. Government-sponsored enterprises: Ginnie Mae, Fannie Mae or Freddie Mac. The Fund will seek to obtain exposure to U.S. agency mortgage pass-through securities primarily through the use of “to-be-announced” or “TBA Transactions”. “TBA” refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed securities. Most transactions in mortgage pass-through securities occur through the use of TBA Transactions. TBA Transactions generally are conducted in accordance with widely-accepted guidelines which establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA Transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined prior to settlement date. The Fund may invest up to 25% of its net assets in corporate high yield securities (commonly known as “junk bonds”). Under normal circumstances, the combined total of corporate, sovereign, non-agency and all other debt rated below investment-grade will not exceed 40% of the Fund's net assets. The Sub-Adviser strives to allocate below investment-grade securities broadly by industry and issuer in an attempt to reduce the impact of negative events on an industry or issuer. Below investment-grade securities are instruments that are rated BB+ or lower by S&P or Fitch Inc. or Ba1 or lower by Moody's or equivalent ratings by another registered NRSRO, or, if unrated by an NRSRO, of comparable quality in the opinion of the Sub-Adviser. The Fund may invest up to 15% of its net assets in securities denominated in foreign currencies, and may invest beyond this limit in U.S. dollar-denominated securities of foreign issuers. The Fund may invest up to 25% of its net assets in securities and instruments that are economically tied to emerging market countries. The Fund generally considers an issuer to be economically tied to an emerging market country if: (i) the issuer is organized under the laws of an emerging country; (ii) the issuer's securities are traded principally in an emerging country; or (iii) during the issuer's most recent fiscal year it derived at least 50% of its revenues, earnings before interest, taxes, depreciation, and amortization, or profits from goods produced or sold by, investments made in, or services performed in emerging countries, or it had at least 50% of its assets in emerging countries. The Sub-Adviser monitors the duration of the securities held by the Fund to seek to mitigate exposure to interest rate risk. Under normal circumstances, the Sub-Adviser seeks to maintain an investment portfolio with a weighted average effective duration of no less than 1 year and no more than 8 years. The duration of the portfolio may vary materially from its target, from time to time. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The longer a security's duration, the more sensitive it will be to changes in interest rates. The Sub-Adviser actively manages the Fund's asset class exposure using a top-down approach based on analysis of sector fundamentals and rotates Fund assets among sectors in various markets to attempt to maximize return. Individual securities within asset classes are selected using a bottom-up approach. Under normal circumstances, the Sub-Adviser uses a controlled risk approach in managing the Fund's investments. The techniques of this approach attempt to control the principal risk components of the fixed income markets and include consideration of: Security selection within a given sector; Relative performance of the various market sectors; The shape of the yield curve; and Fluctuations in the overall level of interest rates.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Asset-Backed and Mortgage-Backed Securities Risk: Asset-backed and mortgage-backed securities (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. These securities, in most cases, are not backed by the full faith and credit of the U.S. government, and there can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. These securities may be subject to liquidity risk as well as the risk of illiquidity and default on the underlying asset or mortgage, particularly during periods of economic downturn. The liquidity of mortgage-related and asset-backed securities may change over time. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain asset-backed and mortgage-backed securities. In particular, during periods of falling interest rates, mortgage-backed securities will be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of a mortgage-backed security may extend, which may lock in a below-market interest rate, increase the security's duration, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, or the underlying assets or collateral may be insufficient if the issuer defaults. The values of certain types of mortgage-backed securities, such as inverse floaters and interest-only and principal-only securities, may be extremely sensitive to changes in interest rates and prepayment rates. Bank Loan Risk: The Fund may invest in secured and unsecured participations in bank loans and assignments of such loans. In making investments in such loans, which are made by banks or other financial intermediaries to borrowers, the Fund will depend primarily upon the creditworthiness of the borrower for payment of principal and interest which will expose the Fund to the credit risk of both the financial institution and the underlying borrower. The market for bank loans may not be highly liquid and the Fund may have difficulty selling them. The Fund may also experience settlement delays with respect to bank loan trades. Participations by the Fund in a lender's portion of a bank loan typically will result in the Fund having a contractual relationship only with such lender, not with the borrower. The Fund may have the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling a loan participation and only upon receipt by such lender of such payments from the borrower. In connection with purchasing participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other lenders through set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund may assume the credit risk of both the borrower and the lender selling the participation. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans. Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general. Collateralized Loan Obligation Risk: The risks of an investment in a collateralized loan obligation depend largely on the type of the collateral securities and the class of the debt obligation in which the Fund invests. Collateralized loan obligations are generally subject to credit, interest rate, valuation, liquidity, prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. Collateralized loan obligations carry additional risks including, but not limited to, (i) the possibility that distributions from collateral securities will not be adequate to make interest of other payments, (ii) the collateral may decline in value or default, (iii) the Fund may invest in obligations that are subordinate to other classes, and (iv) the complex structure of the security may not be fully understood at the time of investment and produce disputes with the issuer or unexpected investment results. Counterparty Risk: The Fund will be subject to credit risk with respect to the counterparties with which the Fund enters into derivatives contracts, repurchase agreements, reverse repurchase agreements, and other transactions. If a counterparty fails to meet its contractual obligations, the Fund may be unable to terminate or realize any gain on the investment or transaction, or to recover collateral posted to the counterparty, resulting in a loss to the Fund. If the Fund holds collateral posted by its counterparty, it may be delayed or prevented from realizing on the collateral in the event of a bankruptcy or insolvency proceeding relating to the counterparty. Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and the Fund may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Fund's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Sub-Adviser or may not have the effect on the Fund anticipated by the Sub-Adviser. Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Sub-Adviser. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Mortgage Pass-Through Securities Risk: Most transactions in mortgage pass through securities occur through the use of TBA Transactions, as described above. Default by, or bankruptcy of, a counterparty to a TBA Transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA Transaction. Municipal Obligations Risk: Issuers, including governmental issuers, may be unable to pay their obligations as they come due. The values of municipal obligations that depend on a specific revenue source to fund their payment obligations may fluctuate as a result of actual or anticipated changes in the cash flows generated by the revenue source or changes in the priority of the municipal obligation to receive the cash flows generated by the revenue source. In addition, changes in federal tax laws or the activity of an issuer may adversely affect the tax-exempt status of municipal obligations. Loss of tax-exempt status may cause interest received and distributed by the Fund to shareholders to be taxable and may result in a significant decline in the values of such municipal obligations. Non-Diversification Risk: As a “non-diversified” fund, the Fund may hold a smaller number of portfolio securities than many other funds. To the extent the Fund invests in a relatively small number of issuers, a decline in the market value of a particular security held by the Fund may affect its value more than if it invested in a larger number of issuers. The value of Fund Shares may be more volatile than the values of shares of more diversified funds. Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Perpetual Bond Risk: Perpetual bonds offer a fixed return with no maturity date. Because they never mature, perpetual bonds can be more volatile than other types of bonds that have a maturity date and may have heightened sensitivity to changes in interest rates. If market interest rates rise significantly, the interest rate paid by a perpetual bond may be much lower than the prevailing interest rate.  Perpetual bonds are also subject to credit risk with respect to the issuer.  In addition, because perpetual bonds may be callable after a set period of time, there is the risk that the issuer may recall the bond. Repurchase Agreement Risk: Repurchase agreements may be viewed as loans made by the Fund which are collateralized by the securities subject to repurchase. If the Fund's counterparty should default on its obligations and the Fund is delayed or prevented from recovering the collateral, or if the value of the collateral is insufficient, the Fund may realize a loss. Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility. Reverse Repurchase Agreement Risk: Reverse repurchase agreements involve both counterparty risk and the risk that the value of securities that the Fund is obligated to repurchase under the agreement may decline below the repurchase price. Reverse repurchase agreements involve leverage risk; the Fund may lose money as a result of declines in the values both of the security subject to the reverse repurchase agreement and the instruments in which the Fund invested the proceeds of the reverse repurchase agreement. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks. U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology. Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield. In addition, investment in derivative variable rate securities, such as inverse floaters, whose rates vary inversely with market rates of interest, or range floaters or capped floaters, whose rates are subject to periodic or lifetime caps, or in securities that pay a rate of interest determined by applying a multiple to the variable rate involves special risks as compared to investment in a fixed-rate security and may involve leverage. Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade frequently, and their value may be impaired when the Fund needs to liquidate such securities. When-Issued, TBA and Delayed Delivery Securities Risk: The Fund may purchase securities on a when-issued, to-be-announced (“TBA”) or delayed delivery basis and may purchase securities on a forward commitment basis. The purchase price of the securities is typically fixed at the time of the commitment, but delivery and payment can take place a month or more after the date of the commitment. At the time of delivery of the securities, the value may be more or less than the purchase or sale price. Purchase of securities on a when-issued, TBA, delayed delivery, or forward commitment basis may give rise to investment leverage, and may result in increased volatility of the Fund's net asset value. Default by, or bankruptcy of, a counterparty to a when-issued, TBA or delayed delivery transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools specified in such transaction. Recently finalized rules of the Financial Industry Regulatory Authority, Inc. would impose mandatory margin requirements for certain types of when-issued, TBA delayed delivery or forward commitment transactions, with limited exceptions. Such transactions historically have not been required to be collateralized, and, if those rules are implemented, mandatory collateralization could increase the cost of such transactions and impose added operational complexity.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	<blockquote><b>Non-Diversification Risk:</b> As a “non-diversified” fund, the Fund may hold a smaller number of portfolio securities than many other funds. To the extent the Fund invests in a relatively small number of issuers, a decline in the market value of a particular security held by the Fund may affect its value more than if it invested in a larger number of issuers. The value of Fund Shares may be more volatile than the values of shares of more diversified funds.</blockquote>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURN </b>(years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 2.00% (Q1, 2016) Lowest Quarterly Return: -1.95% (Q4, 2016)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR DoubleLine Total Return Tactical ETF | SPDR DoubleLine Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.65%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.65%
Less contractual fee waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.10%)	[1]
Net annual Fund operating expenses	rr_NetExpensesOverAssets	0.55%
Year 1	rr_ExpenseExampleYear01	$ 56
Year 3	rr_ExpenseExampleYear03	198
Year 5	rr_ExpenseExampleYear05	352
Year 10	rr_ExpenseExampleYear10	$ 801
2016	rr_AnnualReturn2016	3.02%	[2]
2017	rr_AnnualReturn2017	3.42%	[2]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(0.69%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	2.00%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2016
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(1.95%)
One Year	rr_AverageAnnualReturnYear01	3.42%
Since Inception	rr_AverageAnnualReturnSinceInception	2.16%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 23, 2015
SPDR DoubleLine Total Return Tactical ETF | Return After Taxes on Distributions | SPDR DoubleLine Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	2.09%
Since Inception	rr_AverageAnnualReturnSinceInception	0.81%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 23, 2015
SPDR DoubleLine Total Return Tactical ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR DoubleLine Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.93%
Since Inception	rr_AverageAnnualReturnSinceInception	1.03%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 23, 2015
SPDR DoubleLine Total Return Tactical ETF | Bloomberg Barclays U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	3.54%
Since Inception	rr_AverageAnnualReturnSinceInception	2.07%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 23, 2015

[1] SSGA Funds Management, Inc. ("SSGA FM" or "Adviser") has contractually agreed to waive a portion of its management fee and/or reimburse certain expenses, until October 31, 2019, so that the net annual Fund operating expenses, before application of any fees and expenses not paid by the Adviser pursuant to the Investment Advisory Agreement, if any, are limited to 0.55% of the Fund's average daily net assets. The contractual fee waiver and/or reimbursement does not provide for the recoupment by the Adviser of any fees the Adviser previously waived. The Adviser may continue the waiver and/or reimbursement from year to year, but there is no guarantee that the Adviser will do so and after October 31, 2019, the waiver and/or reimbursement may be cancelled or modified at any time. This waiver and/or reimbursement may not be terminated prior to October 31, 2019 except with the approval of the SSGA Active Trust's Board of Trustees.

[2] As of 9/30/2018, the Fund's Calendar Year-To-Date return was -0.69%.

XML

SPDR MFS Systematic Core Equity ETF

<b>SPDR^® MFS Systematic Core Equity ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR MFS Systematic Core Equity ETF's (the “Fund”) investment objective is to seek capital appreciation.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR MFS Systematic Core Equity ETF SPDR MFS Systematic Core Equity ETF
Management fees	0.60%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.60%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR MFS Systematic Core Equity ETF | SPDR MFS Systematic Core Equity ETF | USD ($)	61	192	335	750

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 67% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes) in equity securities. Equity securities in which the Fund invests include common stocks, preferred stocks, and securities convertible into stocks.

In selecting securities for the Fund, Massachusetts Financial Services Company (the “Sub-Adviser” or “MFS”) utilizes a bottom-up approach to buying and selling investments for the Fund. Investments are selected primarily based on fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition, and market, economic, political, and regulatory conditions to identify potential investments. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. From the universe of issuers with fundamental research, MFS then uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, as well as issuer, industry, and sector weightings and other factors, to determine periodically, typically not more frequently than once every two to five weeks, which investments to buy and sell.

While MFS may invest the Fund's assets in securities of companies of any size, MFS primarily invests in securities of companies with large market capitalizations. In selecting investments for the Fund, MFS invests the Fund's assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies), in the stocks of companies it believes are undervalued compared to their perceived worth (value companies), or in a combination of growth and value companies. MFS normally invests the Fund's assets across different industries and sectors, but MFS may invest a significant percentage of the Fund's assets in a single or small number of industries or sectors. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the technology sector, although this may change from time to time.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, political, regulatory, geopolitical, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical and other conditions can adversely affect the price of an investment. The price of securities of smaller, less well-known issuers can be more volatile than the price of securities of larger issuers or the market in general.

Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Growth Stock Risk: The prices of growth stocks may be based largely on expectations of future earnings, and their prices can decline rapidly and significantly in reaction to negative news. Growth stocks may underperform value stocks and stocks in other broad style categories (and the stock market as a whole) over any period of time and may shift in and out of favor with investors generally, sometimes rapidly, depending on changes in market, economic, and other factors.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Sub-Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Sub-Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield.

Technology Sector Risk: Market or economic factors impacting technology companies and companies that rely heavily on technological advances could have a major effect on the value of the Fund's investments. The value of stocks of technology companies and companies that rely heavily on technology is particularly vulnerable to rapid changes in technology product cycles, rapid product obsolescence, government regulation and competition, both domestically and internationally, including competition from foreign competitors with lower production costs. Stocks of technology companies and companies that rely heavily on technology, especially those of smaller, less-seasoned companies, tend to be more volatile than the overall market. Technology companies are heavily dependent on patent and intellectual property rights, the loss or impairment of which may adversely affect profitability. Additionally, companies in the technology sector may face dramatic and often unpredictable changes in growth rates and competition for the services of qualified personnel.

Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.

Value Stock Risk: A “value” style of investing is subject to the risk that the returns on “value” equity securities are less than returns on other styles of investing or the overall stock market. Value stocks present the risk that they may decline in price or never reach their expected full market value, either because the market fails to recognize a stock's intrinsic worth or the Sub-Adviser overestimates the stock's expected value.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)

Highest Quarterly Return: 6.57% (Q4, 2015)
Lowest Quarterly Return: -5.16% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR MFS Systematic Core Equity ETF	One Year	Since Inception	Inception Date
SPDR MFS Systematic Core Equity ETF	21.12%	13.45%	Jan. 08, 2014
SPDR MFS Systematic Core Equity ETF | Return After Taxes on Distributions	20.43%	12.58%	Jan. 08, 2014
SPDR MFS Systematic Core Equity ETF | Return After Taxes on Distributions and Sale of Fund Shares	12.51%	10.40%	Jan. 08, 2014
S&P 500 Index (reflects no deduction for fees, expenses or taxes)	21.83%	12.20%	Jan. 08, 2014

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 10.82%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR MFS Systematic Core Equity ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> MFS Systematic Core Equity ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR MFS Systematic Core Equity ETF's (the “Fund”) investment objective is to seek capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 67% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	67.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes) in equity securities. Equity securities in which the Fund invests include common stocks, preferred stocks, and securities convertible into stocks. In selecting securities for the Fund, Massachusetts Financial Services Company (the “Sub-Adviser” or “MFS”) utilizes a bottom-up approach to buying and selling investments for the Fund. Investments are selected primarily based on fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition, and market, economic, political, and regulatory conditions to identify potential investments. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. From the universe of issuers with fundamental research, MFS then uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, as well as issuer, industry, and sector weightings and other factors, to determine periodically, typically not more frequently than once every two to five weeks, which investments to buy and sell. While MFS may invest the Fund's assets in securities of companies of any size, MFS primarily invests in securities of companies with large market capitalizations. In selecting investments for the Fund, MFS invests the Fund's assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies), in the stocks of companies it believes are undervalued compared to their perceived worth (value companies), or in a combination of growth and value companies. MFS normally invests the Fund's assets across different industries and sectors, but MFS may invest a significant percentage of the Fund's assets in a single or small number of industries or sectors. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the technology sector, although this may change from time to time.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, political, regulatory, geopolitical, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical and other conditions can adversely affect the price of an investment. The price of securities of smaller, less well-known issuers can be more volatile than the price of securities of larger issuers or the market in general. Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Growth Stock Risk: The prices of growth stocks may be based largely on expectations of future earnings, and their prices can decline rapidly and significantly in reaction to negative news. Growth stocks may underperform value stocks and stocks in other broad style categories (and the stock market as a whole) over any period of time and may shift in and out of favor with investors generally, sometimes rapidly, depending on changes in market, economic, and other factors. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Sub-Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Sub-Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield. Technology Sector Risk: Market or economic factors impacting technology companies and companies that rely heavily on technological advances could have a major effect on the value of the Fund's investments. The value of stocks of technology companies and companies that rely heavily on technology is particularly vulnerable to rapid changes in technology product cycles, rapid product obsolescence, government regulation and competition, both domestically and internationally, including competition from foreign competitors with lower production costs. Stocks of technology companies and companies that rely heavily on technology, especially those of smaller, less-seasoned companies, tend to be more volatile than the overall market. Technology companies are heavily dependent on patent and intellectual property rights, the loss or impairment of which may adversely affect profitability. Additionally, companies in the technology sector may face dramatic and often unpredictable changes in growth rates and competition for the services of qualified personnel. Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly. Value Stock Risk: A “value” style of investing is subject to the risk that the returns on “value” equity securities are less than returns on other styles of investing or the overall stock market. Value stocks present the risk that they may decline in price or never reach their expected full market value, either because the market fails to recognize a stock's intrinsic worth or the Sub-Adviser overestimates the stock's expected value.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 6.57% (Q4, 2015) Lowest Quarterly Return: -5.16% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR MFS Systematic Core Equity ETF | SPDR MFS Systematic Core Equity ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.60%
Year 1	rr_ExpenseExampleYear01	$ 61
Year 3	rr_ExpenseExampleYear03	192
Year 5	rr_ExpenseExampleYear05	335
Year 10	rr_ExpenseExampleYear10	$ 750
2015	rr_AnnualReturn2015	4.78%	[1]
2016	rr_AnnualReturn2016	10.15%	[1]
2017	rr_AnnualReturn2017	21.12%	[1]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	10.82%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2015
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	6.57%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(5.16%)
One Year	rr_AverageAnnualReturnYear01	21.12%
Since Inception	rr_AverageAnnualReturnSinceInception	13.45%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Core Equity ETF | Return After Taxes on Distributions | SPDR MFS Systematic Core Equity ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	20.43%
Since Inception	rr_AverageAnnualReturnSinceInception	12.58%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Core Equity ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR MFS Systematic Core Equity ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	12.51%
Since Inception	rr_AverageAnnualReturnSinceInception	10.40%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Core Equity ETF | S&P 500 Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	21.83%
Since Inception	rr_AverageAnnualReturnSinceInception	12.20%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 10.82%.

XML

SPDR MFS Systematic Growth Equity ETF

<b>SPDR^® MFS Systematic Growth Equity ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR MFS Systematic Growth Equity ETF's (the "Fund") investment objective is to seek capital appreciation.

<b>FEES AND EXPENSES OF THE FUND</b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR MFS Systematic Growth Equity ETF SPDR MFS Systematic Growth Equity ETF
Management fees	0.60%
Distribution and service (12b-1) fees	none
Other expenses	0.01%
Total annual Fund operating expenses	0.61%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR MFS Systematic Growth Equity ETF | SPDR MFS Systematic Growth Equity ETF | USD ($)	62	195	340	762

<b>PORTFOLIO TURNOVER:</b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 76% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes) in equity securities. Equity securities in which the Fund invests include common stocks, preferred stocks, and securities convertible into stocks.

In selecting securities for the Fund, Massachusetts Financial Services Company (the “Sub-Adviser” or “MFS”) utilizes a bottom-up approach to buying and selling investments for the Fund. Investments are selected primarily based on fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition, and market, economic, political, and regulatory conditions to identify potential investments. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. From the universe of issuers with fundamental research, MFS then uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, as well as issuer, industry, and sector weightings and other factors, to determine periodically, typically not more frequently than once every two to five weeks, which investments to buy and sell.

While MFS may invest the Fund's assets in securities of companies of any size, MFS primarily invests in securities of companies with large market capitalizations. In selecting investments for the Fund, MFS invests the Fund's assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies). Growth companies tend to have stock prices that are high relative to their earnings, dividends, book value, or other financial measures. MFS normally invests the Fund's assets across different industries and sectors, but MFS may invest a significant percentage of the Fund's assets in a single or small number of industries or sectors. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the technology, health care and consumer discretionary sectors, although this may change from time to time.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND</b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, political, regulatory, geopolitical, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical and other conditions can adversely affect the price of an investment. The price of securities of smaller, less well-known issuers can be more volatile than the price of securities of larger issuers or the market in general.

Consumer Discretionary Sector Risk: The success of consumer product manufacturers and retailers is tied closely to the performance of the overall global economy, interest rates, competition and consumer confidence. Success depends heavily on disposable household income and consumer spending. Also, companies in the consumer discretionary sector may be subject to severe competition, which may have an adverse impact on their respective profitability. Changes in demographics and consumer tastes can also affect the demand for, and success of, consumer products and services in the marketplace.

Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Growth Stock Risk: The prices of growth stocks may be based largely on expectations of future earnings, and their prices can decline rapidly and significantly in reaction to negative news. Growth stocks may underperform value stocks and stocks in other broad style categories (and the stock market as a whole) over any period of time and may shift in and out of favor with investors generally, sometimes rapidly, depending on changes in market, economic, and other factors.

Health Care Sector Risk: Companies in the health care sector are subject to extensive government regulation and their profitability can be significantly affected by restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure (including price discounting), limited product lines and an increased emphasis on the delivery of healthcare through outpatient services. Companies in the health care sector are heavily dependent on obtaining and defending patents, which may be time consuming and costly, and the expiration of patents may also adversely affect the profitability of these companies. Health care companies are also subject to extensive litigation based on product liability and similar claims. In addition, their products can become obsolete due to industry innovation, changes in technologies or other market developments. Many new products in the health care sector require significant research and development and may be subject to regulatory approvals, all of which may be time consuming and costly with no guarantee that any product will come to market.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Sub-Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Sub-Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield.

Technology Sector Risk: Market or economic factors impacting technology companies and companies that rely heavily on technological advances could have a major effect on the value of the Fund's investments. The value of stocks of technology companies and companies that rely heavily on technology is particularly vulnerable to rapid changes in technology product cycles, rapid product obsolescence, government regulation and competition, both domestically and internationally, including competition from foreign competitors with lower production costs. Stocks of technology companies and companies that rely heavily on technology, especially those of smaller, less-seasoned companies, tend to be more volatile than the overall market. Technology companies are heavily dependent on patent and intellectual property rights, the loss or impairment of which may adversely affect profitability. Additionally, companies in the technology sector may face dramatic and often unpredictable changes in growth rates and competition for the services of qualified personnel.

Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.

<b>FUND PERFORMANCE</b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)

Highest Quarterly Return: 9.21% (Q1, 2017)
Lowest Quarterly Return: -4.63% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR MFS Systematic Growth Equity ETF	One Year	Since Inception	Inception Date
SPDR MFS Systematic Growth Equity ETF	27.83%	15.01%	Jan. 08, 2014
SPDR MFS Systematic Growth Equity ETF | Return After Taxes on Distributions	27.54%	14.20%	Jan. 08, 2014
SPDR MFS Systematic Growth Equity ETF | Return After Taxes on Distributions and Sale of Fund Shares	15.97%	11.65%	Jan. 08, 2014
Russell 1000 Growth Index (reflects no deduction for fees, expenses or taxes)	30.21%	13.88%	Jan. 08, 2014

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 10.00%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR MFS Systematic Growth Equity ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> MFS Systematic Growth Equity ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR MFS Systematic Growth Equity ETF's (the "Fund") investment objective is to seek capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER:</b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 76% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	76.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes) in equity securities. Equity securities in which the Fund invests include common stocks, preferred stocks, and securities convertible into stocks. In selecting securities for the Fund, Massachusetts Financial Services Company (the “Sub-Adviser” or “MFS”) utilizes a bottom-up approach to buying and selling investments for the Fund. Investments are selected primarily based on fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition, and market, economic, political, and regulatory conditions to identify potential investments. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. From the universe of issuers with fundamental research, MFS then uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, as well as issuer, industry, and sector weightings and other factors, to determine periodically, typically not more frequently than once every two to five weeks, which investments to buy and sell. While MFS may invest the Fund's assets in securities of companies of any size, MFS primarily invests in securities of companies with large market capitalizations. In selecting investments for the Fund, MFS invests the Fund's assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies). Growth companies tend to have stock prices that are high relative to their earnings, dividends, book value, or other financial measures. MFS normally invests the Fund's assets across different industries and sectors, but MFS may invest a significant percentage of the Fund's assets in a single or small number of industries or sectors. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the technology, health care and consumer discretionary sectors, although this may change from time to time.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, political, regulatory, geopolitical, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical and other conditions can adversely affect the price of an investment. The price of securities of smaller, less well-known issuers can be more volatile than the price of securities of larger issuers or the market in general. Consumer Discretionary Sector Risk: The success of consumer product manufacturers and retailers is tied closely to the performance of the overall global economy, interest rates, competition and consumer confidence. Success depends heavily on disposable household income and consumer spending. Also, companies in the consumer discretionary sector may be subject to severe competition, which may have an adverse impact on their respective profitability. Changes in demographics and consumer tastes can also affect the demand for, and success of, consumer products and services in the marketplace. Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Growth Stock Risk: The prices of growth stocks may be based largely on expectations of future earnings, and their prices can decline rapidly and significantly in reaction to negative news. Growth stocks may underperform value stocks and stocks in other broad style categories (and the stock market as a whole) over any period of time and may shift in and out of favor with investors generally, sometimes rapidly, depending on changes in market, economic, and other factors. Health Care Sector Risk: Companies in the health care sector are subject to extensive government regulation and their profitability can be significantly affected by restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure (including price discounting), limited product lines and an increased emphasis on the delivery of healthcare through outpatient services. Companies in the health care sector are heavily dependent on obtaining and defending patents, which may be time consuming and costly, and the expiration of patents may also adversely affect the profitability of these companies. Health care companies are also subject to extensive litigation based on product liability and similar claims. In addition, their products can become obsolete due to industry innovation, changes in technologies or other market developments. Many new products in the health care sector require significant research and development and may be subject to regulatory approvals, all of which may be time consuming and costly with no guarantee that any product will come to market. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Sub-Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Sub-Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield. Technology Sector Risk: Market or economic factors impacting technology companies and companies that rely heavily on technological advances could have a major effect on the value of the Fund's investments. The value of stocks of technology companies and companies that rely heavily on technology is particularly vulnerable to rapid changes in technology product cycles, rapid product obsolescence, government regulation and competition, both domestically and internationally, including competition from foreign competitors with lower production costs. Stocks of technology companies and companies that rely heavily on technology, especially those of smaller, less-seasoned companies, tend to be more volatile than the overall market. Technology companies are heavily dependent on patent and intellectual property rights, the loss or impairment of which may adversely affect profitability. Additionally, companies in the technology sector may face dramatic and often unpredictable changes in growth rates and competition for the services of qualified personnel. Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 9.21% (Q1, 2017) Lowest Quarterly Return: -4.63% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR MFS Systematic Growth Equity ETF | SPDR MFS Systematic Growth Equity ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.01%
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.61%
Year 1	rr_ExpenseExampleYear01	$ 62
Year 3	rr_ExpenseExampleYear03	195
Year 5	rr_ExpenseExampleYear05	340
Year 10	rr_ExpenseExampleYear10	$ 762
2015	rr_AnnualReturn2015	8.17%	[1]
2016	rr_AnnualReturn2016	5.24%	[1]
2017	rr_AnnualReturn2017	27.83%	[1]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	10.00%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	9.21%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(4.63%)
One Year	rr_AverageAnnualReturnYear01	27.83%
Since Inception	rr_AverageAnnualReturnSinceInception	15.01%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Growth Equity ETF | Return After Taxes on Distributions | SPDR MFS Systematic Growth Equity ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	27.54%
Since Inception	rr_AverageAnnualReturnSinceInception	14.20%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Growth Equity ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR MFS Systematic Growth Equity ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	15.97%
Since Inception	rr_AverageAnnualReturnSinceInception	11.65%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Growth Equity ETF | Russell 1000 Growth Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	30.21%
Since Inception	rr_AverageAnnualReturnSinceInception	13.88%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 10.00%.

XML

SPDR MFS Systematic Value Equity ETF

<b>SPDR^® MFS Systematic Value Equity ETF</b>

<b>INVESTMENT OBJECTIVE </b>

The SPDR MFS Systematic Value Equity ETF's (the “Fund”) investment objective is to seek capital appreciation.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR MFS Systematic Value Equity ETF SPDR MFS Systematic Value Equity ETF
Management fees	0.60%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.60%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR MFS Systematic Value Equity ETF | SPDR MFS Systematic Value Equity ETF | USD ($)	61	192	335	750

<b>PORTFOLIO TURNOVER:</b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 54% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes) in equity securities. Equity securities in which the Fund invests include common stocks, preferred stocks, and securities convertible into stocks.

In selecting securities for the Fund, Massachusetts Financial Services Company (the “Sub-Adviser” or “MFS”) utilizes a bottom-up approach to buying and selling investments for the Fund. Investments are selected primarily based on fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition, and market, economic, political, and regulatory conditions to identify potential investments. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. From the universe of issuers with fundamental research, MFS then uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, as well as issuer, industry, and sector weightings and other factors, to determine periodically, typically not more frequently than once every two to five weeks, which investments to buy and sell.

While MFS may invest the Fund's assets in securities of companies of any size, MFS primarily invests in securities of companies with large market capitalizations. In selecting investments for the Fund, MFS invests the Fund's assets in the stocks of companies it believes are undervalued compared to their perceived worth (value companies). Value companies tend to have stock prices that are low relative to their earnings, dividends, assets, or other financial measures. MFS normally invests the Fund's assets across different industries and sectors, but MFS may invest a significant percentage of the Fund's assets in a single or small number of industries or sectors. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the financial and health care sectors, although this may change from time to time.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, political, regulatory, geopolitical, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical and other conditions can adversely affect the price of an investment. The price of securities of smaller, less well-known issuers can be more volatile than the price of securities of larger issuers or the market in general.

Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate.

Health Care Sector Risk: Companies in the health care sector are subject to extensive government regulation and their profitability can be significantly affected by restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure (including price discounting), limited product lines and an increased emphasis on the delivery of healthcare through outpatient services. Companies in the health care sector are heavily dependent on obtaining and defending patents, which may be time consuming and costly, and the expiration of patents may also adversely affect the profitability of these companies. Health care companies are also subject to extensive litigation based on product liability and similar claims. In addition, their products can become obsolete due to industry innovation, changes in technologies or other market developments. Many new products in the health care sector require significant research and development and may be subject to regulatory approvals, all of which may be time consuming and costly with no guarantee that any product will come to market.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Sub-Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Sub-Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield.

Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.

Value Stock Risk: A “value” style of investing is subject to the risk that the returns on “value” equity securities are less than returns on other styles of investing or the overall stock market. Value stocks present the risk that they may decline in price or never reach their expected full market value, either because the market fails to recognize a stock's intrinsic worth or the Sub-Adviser overestimates the stock's expected value.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS </b> (years ended 12/31)

Highest Quarterly Return: 7.64% (Q4, 2017)
Lowest Quarterly Return: -7.41% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR MFS Systematic Value Equity ETF	One Year	Since Inception	Inception Date
SPDR MFS Systematic Value Equity ETF	20.39%	12.24%	Jan. 08, 2014
SPDR MFS Systematic Value Equity ETF | Return After Taxes on Distributions	19.38%	10.74%	Jan. 08, 2014
SPDR MFS Systematic Value Equity ETF | Return After Taxes on Distributions and Sale of Fund Shares	12.17%	9.18%	Jan. 08, 2014
Russell 1000 Value Index (reflects no deduction for fees, expenses or taxes)	13.66%	9.96%	Jan. 08, 2014

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 6.24%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR MFS Systematic Value Equity ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> MFS Systematic Value Equity ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE </b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR MFS Systematic Value Equity ETF's (the “Fund”) investment objective is to seek capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER:</b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 54% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	54.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of borrowings for investment purposes) in equity securities. Equity securities in which the Fund invests include common stocks, preferred stocks, and securities convertible into stocks. In selecting securities for the Fund, Massachusetts Financial Services Company (the “Sub-Adviser” or “MFS”) utilizes a bottom-up approach to buying and selling investments for the Fund. Investments are selected primarily based on fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition, and market, economic, political, and regulatory conditions to identify potential investments. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. From the universe of issuers with fundamental research, MFS then uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, as well as issuer, industry, and sector weightings and other factors, to determine periodically, typically not more frequently than once every two to five weeks, which investments to buy and sell. While MFS may invest the Fund's assets in securities of companies of any size, MFS primarily invests in securities of companies with large market capitalizations. In selecting investments for the Fund, MFS invests the Fund's assets in the stocks of companies it believes are undervalued compared to their perceived worth (value companies). Value companies tend to have stock prices that are low relative to their earnings, dividends, assets, or other financial measures. MFS normally invests the Fund's assets across different industries and sectors, but MFS may invest a significant percentage of the Fund's assets in a single or small number of industries or sectors. As of August 31, 2018, a significant portion of the Fund comprised securities of companies in the financial and health care sectors, although this may change from time to time.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, political, regulatory, geopolitical, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical and other conditions can adversely affect the price of an investment. The price of securities of smaller, less well-known issuers can be more volatile than the price of securities of larger issuers or the market in general. Convertible Securities Risk: Convertible securities may be subordinate to other debt securities issued by the same issuer. Issuers of convertible securities are often not as strong financially as issuers with higher credit ratings. Convertible securities typically provide yields lower than comparable non-convertible securities. Their values may be more volatile than those of non-convertible securities, reflecting changes in the values of the securities into which they are convertible. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate. Health Care Sector Risk: Companies in the health care sector are subject to extensive government regulation and their profitability can be significantly affected by restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure (including price discounting), limited product lines and an increased emphasis on the delivery of healthcare through outpatient services. Companies in the health care sector are heavily dependent on obtaining and defending patents, which may be time consuming and costly, and the expiration of patents may also adversely affect the profitability of these companies. Health care companies are also subject to extensive litigation based on product liability and similar claims. In addition, their products can become obsolete due to industry innovation, changes in technologies or other market developments. Many new products in the health care sector require significant research and development and may be subject to regulatory approvals, all of which may be time consuming and costly with no guarantee that any product will come to market. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Sub-Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Fund from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Sub-Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield. Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly. Value Stock Risk: A “value” style of investing is subject to the risk that the returns on “value” equity securities are less than returns on other styles of investing or the overall stock market. Value stocks present the risk that they may decline in price or never reach their expected full market value, either because the market fails to recognize a stock's intrinsic worth or the Sub-Adviser overestimates the stock's expected value.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS </b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 7.64% (Q4, 2017) Lowest Quarterly Return: -7.41% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS </b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR MFS Systematic Value Equity ETF | SPDR MFS Systematic Value Equity ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.60%
Year 1	rr_ExpenseExampleYear01	$ 61
Year 3	rr_ExpenseExampleYear03	192
Year 5	rr_ExpenseExampleYear05	335
Year 10	rr_ExpenseExampleYear10	$ 750
2015	rr_AnnualReturn2015	2.83%	[1]
2016	rr_AnnualReturn2016	11.97%	[1]
2017	rr_AnnualReturn2017	20.39%	[1]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	6.24%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	7.64%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(7.41%)
One Year	rr_AverageAnnualReturnYear01	20.39%
Since Inception	rr_AverageAnnualReturnSinceInception	12.24%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Value Equity ETF | Return After Taxes on Distributions | SPDR MFS Systematic Value Equity ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	19.38%
Since Inception	rr_AverageAnnualReturnSinceInception	10.74%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Value Equity ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR MFS Systematic Value Equity ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	12.17%
Since Inception	rr_AverageAnnualReturnSinceInception	9.18%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014
SPDR MFS Systematic Value Equity ETF | Russell 1000 Value Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	13.66%
Since Inception	rr_AverageAnnualReturnSinceInception	9.96%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jan. 08, 2014

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 6.24%.

XML

SPDR Blackstone / GSO Senior Loan ETF

FUND SUMMARY <br/><br/> <b>SPDR^® Blackstone / GSO Senior Loan ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The investment objective of the SPDR Blackstone / GSO Senior Loan ETF (the “Fund”) is to provide current income consistent with the preservation of capital.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of both the Fund and the Portfolio (as defined below) and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR Blackstone / GSO Senior Loan ETF SPDR Blackstone / GSO Senior Loan ETF
Management fees	0.70%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.70%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR Blackstone / GSO Senior Loan ETF | SPDR Blackstone / GSO Senior Loan ETF | USD ($)	72	224	390	871

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate (based on the Portfolio's turnover rate) was 90% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>

Under normal circumstances, the Fund invests substantially all of its assets in the Blackstone / GSO Senior Loan Portfolio (the “Portfolio”), a separate series of the SSGA Master Trust with an identical investment objective as the Fund. As a result, the Fund invests indirectly through the Portfolio.

In pursuing its investment objective, the Portfolio seeks to outperform the Markit iBoxx USD Liquid Leveraged Loan Index (the “Primary Index”) and the S&P/LSTA U.S. Leveraged Loan 100 Index (the “Secondary Index”) by normally investing at least 80% of its net assets (plus any borrowings for investment purposes) in Senior Loans. For purposes of this 80% test, “Senior Loans” are first lien senior secured floating rate bank loans. A Senior Loan is an advance or commitment of funds made by one or more banks or similar financial institutions, including the Portfolio, to one or more corporations, partnerships or other business entities and pays interest at a floating or adjusting rate that is determined periodically at a designated premium above a base lending rate, most commonly the London Interbank Offered Rate (“LIBOR”). A Senior Loan is senior to all unsecured claims against the borrower and senior or equal to all other secured claims, meaning that, in the event of a bankruptcy, the Senior Loan, together with other first lien claims, is entitled to be the first to be repaid out of proceeds of the assets securing the loans, before other existing claims or interests receive repayment. However, in bankruptcy proceedings, there may be other claims, such as taxes or additional advances that take precedence. The Primary Index is composed of the 100 most liquid Senior Loans in the market, while the Secondary Index is composed of the 100 largest Senior Loans in the market, as measured by the borrowed amounts outstanding. The Portfolio intends to hold a large percentage of the components of the Primary and Secondary Indexes. It is anticipated that the Portfolio will invest approximately 50% to 75% of its net assets in Senior Loans that are eligible for inclusion in the Primary and/or Secondary Indexes. Each of the Portfolio's Senior Loan investments is expected to have no less than $250 million par outstanding.

The Portfolio invests in Senior Loans that are made predominantly to businesses operating in North America, but may also invest in Senior Loans made to businesses operating outside of North America. The Portfolio may invest in Senior Loans directly, either from the borrower as part of a primary issuance or in the secondary market through assignments of portions of Senior Loans from third parties, or participations in Senior Loans, which are contractual relationships with an existing lender in a loan facility whereby the Portfolio purchases the right to receive principal and interest payments on a loan but the existing lender remains the record holder of the loan. Under normal market conditions, it is expected that the Portfolio's Senior Loan investments will maintain an average interest rate duration of less than 90 days.

In selecting securities for the Portfolio, the Portfolio's sub-adviser, GSO / Blackstone Debt Funds Management LLC (the “Sub-Adviser” or “GSO / Blackstone”), seeks to construct a portfolio of loans that it believes is less volatile than the general loan market. In addition, when making investments, the Sub-Adviser seeks to maintain appropriate liquidity and price transparency for the Portfolio. On an on-going basis, the Sub-Adviser adds or removes those individual loans that it believes will cause the Portfolio to outperform or underperform, respectively, the Primary and Secondary Indexes.

When identifying prospective investment opportunities in Senior Loans, the Sub-Adviser currently intends to invest principally in Senior Loans that are below investment-grade quality and will rely on fundamental credit analysis in an effort to attempt to minimize the loss of the Portfolio's capital. While credit ratings assigned by Moody's Investors Service, Inc., Standard & Poor's Financial Services, LLC and/or Fitch Inc. (the “SROs” (statistical rating agencies)) will be considered, such ratings will not be determinative in the Sub-Adviser's process in the selection of specific debt securities (including Senior Loans). The Senior Loans and other securities that the Sub-Adviser is likely to select for investment in by the Portfolio will typically be rated below investment-grade quality by one or more of the SROs or, if unrated, will typically, in the opinion of the Sub-Adviser, be of similar credit quality. If circumstances cause the Sub-Adviser to take a negative credit view on an existing investment the Portfolio may, if the Sub-Adviser believes that circumstances require, exit the investment. The circumstances giving rise to the Sub-Adviser's negative credit view may, but will not necessarily, coincide with a downgrade of the Senior Loan or other security's credit rating. The Sub-Adviser expects to invest in Senior Loans, other loans and bonds of companies, including high yield securities (commonly known as “junk”) and Rule 144A securities, possessing the following attributes, which it believes will help generate higher risk adjusted total returns:

Leading, defensible market positions. The Sub-Adviser intends to invest in companies that it believes have developed strong positions within their respective markets and exhibit the potential to maintain sufficient cash flows and profitability to service their obligations in a range of economic environments. The Sub-Adviser will seek companies that it believes possess advantages in scale, scope, customer loyalty, product pricing, or product quality versus their competitors, thereby minimizing business risk and protecting profitability.

Investing in companies with positive cash flow. The Sub-Adviser intends to invest primarily in established companies which have demonstrated a record of profitability and cash flows over several economic cycles. The Sub-Adviser believes such companies are well-positioned to maintain consistent cash flow to service and repay their obligations and maintain growth in their businesses or market share. The Sub-Adviser does not intend to invest in primarily start-up companies, companies in turnaround situations or companies with speculative business plans.

Proven management teams. The Sub-Adviser intends to focus on investments in which the target company has an experienced management team with an established track record of success. The Sub-Adviser will typically require companies to have in place proper incentives to align management's goals with the Portfolio's goals.

Private equity sponsorship. Often the Sub-Adviser will seek to participate in transactions sponsored by what it believes to be high-quality private equity firms. The Sub-Adviser believes that a private equity sponsor's willingness to invest significant sums of equity capital into a company is an implicit endorsement of the quality of the investment. Further, private equity sponsors of companies with significant investments at risk have the ability and a strong incentive to contribute additional capital in difficult economic times should operational issues arise.

Diversification, concentration and reliance on other lenders. The Sub-Adviser will seek to invest broadly among companies and industries, thereby potentially reducing the risk of a downturn in any one company or industry having a disproportionate impact on the value of the Portfolio's portfolio. While the Portfolio does not treat banks originating loans as the issuers of such loans, it is possible that under a different interpretation the Portfolio may be deemed to concentrate its investments in the financial services industries. Loans, and the collateral securing them, are typically monitored by agents for the lenders, which may be the originating bank or banks. The Portfolio may be affected by the creditworthiness of the agent bank and other intermediate participants in a Senior Loan, in addition to the borrower, since rights that may exist under the loan against the borrower if the borrower defaults are typically asserted by or through the agent bank or intermediate participant. Agents are typically large commercial banks, although for Senior Loans that are not broadly syndicated they can also include thrift institutions, insurance companies or finance companies (or their affiliates). Such companies may be especially susceptible to the effects of changes in interest rates resulting from changes in U.S. or foreign fiscal or monetary policies, governmental regulations affecting capital raising activities or other economic or market fluctuations.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Because the Fund invests substantially all of its assets in the Portfolio, it is subject to substantially the same risks as those associated with the direct ownership of the securities in which the Portfolio invests.

Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Portfolio's fixed income securities to decrease, an adverse impact on the liquidity of the Portfolio's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Portfolio may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate.

Income Risk: The Portfolio's income may decline due to falling interest rates or other factors. Issuers of securities held by the Portfolio may call or redeem the securities during periods of falling interest rates, and the Portfolio would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Portfolio is prepaid, the Portfolio may have to reinvest the prepayment in other obligations paying income at lower rates.

Liquidity Risk: There is no organized exchange on which loans are traded and reliable market quotations may not be readily available. A majority of the Portfolio's assets are likely to be invested in loans that are less liquid than securities traded on national exchanges. Illiquidity of the Portfolio's holdings may limit the ability of the Portfolio and the Fund to obtain cash to meet redemptions on a timely basis. Loans with reduced liquidity involve greater risk than securities with more liquid markets. Available market quotations for such loans may vary over time, and if the credit quality of a loan unexpectedly declines, secondary trading of that loan may decline for a period of time. During periods of infrequent trading, valuing a loan can be more difficult and buying and selling a loan at an acceptable price can be more difficult and delayed. In the event that the Portfolio voluntarily or involuntarily liquidates portfolio assets during periods of infrequent trading, it may not receive full value for those assets. Therefore, elements of judgment may play a greater role in valuation of loans. To the extent that a secondary market exists for certain loans, the market may be subject to irregular trading activity, wide bid/ask spreads and extended trade settlement periods.

Management Risk: The Portfolio is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Portfolio and, therefore, the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Portfolio's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Portfolio and, therefore, the Fund are subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Non-Senior Loans and Other Debt Securities Risk: Secured loans that are not first lien, loans that are unsecured and debt securities are subject to many of the same risks that affect Senior Loans; however they are often unsecured and/or lower in the issuer's capital structure than Senior Loans, and thus may be exposed to greater risk of default and lower recoveries in the event of a default. This risk can be further heightened in the case of below investment-grade instruments. Additionally, most fixed-income securities are fixed-rate and thus are generally more susceptible than floating rate loans to price volatility related to changes in prevailing interest rates.

Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Portfolio buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Portfolio and, therefore, the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Restricted Securities Risk: The Portfolio may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Portfolio from disposing of them promptly at reasonable prices. The Portfolio may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility.

Senior Loan Risk: Investments in Senior Loans are subject to credit risk and general investment risk. Credit risk refers to the possibility that the borrower of a Senior Loan will be unable and/or unwilling to make timely interest payments and/or repay the principal on its obligation. Default in the payment of interest or principal on a Senior Loan will result in a reduction in the value of the Senior Loan and consequently a reduction in the value of the Portfolio's investments and a potential decrease in the net asset value (“NAV”) of the Portfolio. Senior Loans are also subject to the risk that the value of the collateral securing a Senior Loan may decline, be insufficient to meet the obligations of the borrower or be difficult to liquidate. In addition, the Portfolio's access to the collateral may be limited by bankruptcy or other insolvency laws. Further, loans held by the Portfolio may not be considered securities and, therefore, purchasers, such as the Portfolio, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some Senior Loans are subject to the risk that a court, pursuant to fraudulent conveyance or other similar laws, could subordinate the Senior Loans to presently existing or future indebtedness of the borrower or take other action detrimental to lenders, including the Portfolio, such as invalidation of Senior Loans or causing interest previously paid to be refunded to the borrower. Senior Loans are also subject to high yield securities risks and liquidity risks described above. Some of the loans in which the Portfolio may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Portfolio may experience delays in enforcing its rights on its holdings of covenant-lite loans.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Portfolio could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Portfolio would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Portfolio at that time. Investors who purchase or redeem Fund Shares on days when the Portfolio is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Portfolio had not fair-valued the holding(s) or had used a different valuation methodology.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)

Highest Quarterly Return: 2.35% (Q3, 2016)
Lowest Quarterly Return: -2.04% (Q3, 2015)

<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR Blackstone / GSO Senior Loan ETF	One Year	Since Inception	Inception Date
SPDR Blackstone / GSO Senior Loan ETF	3.60%	2.55%	Apr. 03, 2013
SPDR Blackstone / GSO Senior Loan ETF | Return After Taxes on Distributions	1.83%	0.91%	Apr. 03, 2013
SPDR Blackstone / GSO Senior Loan ETF | Return After Taxes on Distributions and Sale of Fund Shares	2.02%	1.19%	Apr. 03, 2013
Markit iBoxx USD Liquid Leveraged Loan Index (reflects no deduction for fees, expenses or taxes)	2.01%	2.52%	Apr. 03, 2013
S&P/LSTA U.S. Leveraged Loan 100 Index (reflects no deduction for fees, expenses or taxes)	3.31%	3.11%	Apr. 03, 2013

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 3.38%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR Blackstone / GSO Senior Loan ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	FUND SUMMARY <br/><br/> <b>SPDR<sup>®</sup> Blackstone / GSO Senior Loan ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of the SPDR Blackstone / GSO Senior Loan ETF (the “Fund”) is to provide current income consistent with the preservation of capital.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of both the Fund and the Portfolio (as defined below) and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate (based on the Portfolio's turnover rate) was 90% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	90.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of both the Fund and the Portfolio (as defined below) and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests substantially all of its assets in the Blackstone / GSO Senior Loan Portfolio (the “Portfolio”), a separate series of the SSGA Master Trust with an identical investment objective as the Fund. As a result, the Fund invests indirectly through the Portfolio. In pursuing its investment objective, the Portfolio seeks to outperform the Markit iBoxx USD Liquid Leveraged Loan Index (the “Primary Index”) and the S&P/LSTA U.S. Leveraged Loan 100 Index (the “Secondary Index”) by normally investing at least 80% of its net assets (plus any borrowings for investment purposes) in Senior Loans. For purposes of this 80% test, “Senior Loans” are first lien senior secured floating rate bank loans. A Senior Loan is an advance or commitment of funds made by one or more banks or similar financial institutions, including the Portfolio, to one or more corporations, partnerships or other business entities and pays interest at a floating or adjusting rate that is determined periodically at a designated premium above a base lending rate, most commonly the London Interbank Offered Rate (“LIBOR”). A Senior Loan is senior to all unsecured claims against the borrower and senior or equal to all other secured claims, meaning that, in the event of a bankruptcy, the Senior Loan, together with other first lien claims, is entitled to be the first to be repaid out of proceeds of the assets securing the loans, before other existing claims or interests receive repayment. However, in bankruptcy proceedings, there may be other claims, such as taxes or additional advances that take precedence. The Primary Index is composed of the 100 most liquid Senior Loans in the market, while the Secondary Index is composed of the 100 largest Senior Loans in the market, as measured by the borrowed amounts outstanding. The Portfolio intends to hold a large percentage of the components of the Primary and Secondary Indexes. It is anticipated that the Portfolio will invest approximately 50% to 75% of its net assets in Senior Loans that are eligible for inclusion in the Primary and/or Secondary Indexes. Each of the Portfolio's Senior Loan investments is expected to have no less than $250 million par outstanding. The Portfolio invests in Senior Loans that are made predominantly to businesses operating in North America, but may also invest in Senior Loans made to businesses operating outside of North America. The Portfolio may invest in Senior Loans directly, either from the borrower as part of a primary issuance or in the secondary market through assignments of portions of Senior Loans from third parties, or participations in Senior Loans, which are contractual relationships with an existing lender in a loan facility whereby the Portfolio purchases the right to receive principal and interest payments on a loan but the existing lender remains the record holder of the loan. Under normal market conditions, it is expected that the Portfolio's Senior Loan investments will maintain an average interest rate duration of less than 90 days. In selecting securities for the Portfolio, the Portfolio's sub-adviser, GSO / Blackstone Debt Funds Management LLC (the “Sub-Adviser” or “GSO / Blackstone”), seeks to construct a portfolio of loans that it believes is less volatile than the general loan market. In addition, when making investments, the Sub-Adviser seeks to maintain appropriate liquidity and price transparency for the Portfolio. On an on-going basis, the Sub-Adviser adds or removes those individual loans that it believes will cause the Portfolio to outperform or underperform, respectively, the Primary and Secondary Indexes. When identifying prospective investment opportunities in Senior Loans, the Sub-Adviser currently intends to invest principally in Senior Loans that are below investment-grade quality and will rely on fundamental credit analysis in an effort to attempt to minimize the loss of the Portfolio's capital. While credit ratings assigned by Moody's Investors Service, Inc., Standard & Poor's Financial Services, LLC and/or Fitch Inc. (the “SROs” (statistical rating agencies)) will be considered, such ratings will not be determinative in the Sub-Adviser's process in the selection of specific debt securities (including Senior Loans). The Senior Loans and other securities that the Sub-Adviser is likely to select for investment in by the Portfolio will typically be rated below investment-grade quality by one or more of the SROs or, if unrated, will typically, in the opinion of the Sub-Adviser, be of similar credit quality. If circumstances cause the Sub-Adviser to take a negative credit view on an existing investment the Portfolio may, if the Sub-Adviser believes that circumstances require, exit the investment. The circumstances giving rise to the Sub-Adviser's negative credit view may, but will not necessarily, coincide with a downgrade of the Senior Loan or other security's credit rating. The Sub-Adviser expects to invest in Senior Loans, other loans and bonds of companies, including high yield securities (commonly known as “junk”) and Rule 144A securities, possessing the following attributes, which it believes will help generate higher risk adjusted total returns: Leading, defensible market positions. The Sub-Adviser intends to invest in companies that it believes have developed strong positions within their respective markets and exhibit the potential to maintain sufficient cash flows and profitability to service their obligations in a range of economic environments. The Sub-Adviser will seek companies that it believes possess advantages in scale, scope, customer loyalty, product pricing, or product quality versus their competitors, thereby minimizing business risk and protecting profitability. Investing in companies with positive cash flow. The Sub-Adviser intends to invest primarily in established companies which have demonstrated a record of profitability and cash flows over several economic cycles. The Sub-Adviser believes such companies are well-positioned to maintain consistent cash flow to service and repay their obligations and maintain growth in their businesses or market share. The Sub-Adviser does not intend to invest in primarily start-up companies, companies in turnaround situations or companies with speculative business plans. Proven management teams. The Sub-Adviser intends to focus on investments in which the target company has an experienced management team with an established track record of success. The Sub-Adviser will typically require companies to have in place proper incentives to align management's goals with the Portfolio's goals. Private equity sponsorship. Often the Sub-Adviser will seek to participate in transactions sponsored by what it believes to be high-quality private equity firms. The Sub-Adviser believes that a private equity sponsor's willingness to invest significant sums of equity capital into a company is an implicit endorsement of the quality of the investment. Further, private equity sponsors of companies with significant investments at risk have the ability and a strong incentive to contribute additional capital in difficult economic times should operational issues arise. Diversification, concentration and reliance on other lenders. The Sub-Adviser will seek to invest broadly among companies and industries, thereby potentially reducing the risk of a downturn in any one company or industry having a disproportionate impact on the value of the Portfolio's portfolio. While the Portfolio does not treat banks originating loans as the issuers of such loans, it is possible that under a different interpretation the Portfolio may be deemed to concentrate its investments in the financial services industries. Loans, and the collateral securing them, are typically monitored by agents for the lenders, which may be the originating bank or banks. The Portfolio may be affected by the creditworthiness of the agent bank and other intermediate participants in a Senior Loan, in addition to the borrower, since rights that may exist under the loan against the borrower if the borrower defaults are typically asserted by or through the agent bank or intermediate participant. Agents are typically large commercial banks, although for Senior Loans that are not broadly syndicated they can also include thrift institutions, insurance companies or finance companies (or their affiliates). Such companies may be especially susceptible to the effects of changes in interest rates resulting from changes in U.S. or foreign fiscal or monetary policies, governmental regulations affecting capital raising activities or other economic or market fluctuations.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Because the Fund invests substantially all of its assets in the Portfolio, it is subject to substantially the same risks as those associated with the direct ownership of the securities in which the Portfolio invests. Below Investment-Grade Securities Risk: Lower-quality debt securities (“high yield” or “junk” bonds) are considered predominantly speculative, and can involve a substantially greater risk of default than higher quality debt securities. Issuers of lower-quality debt securities may have substantially greater risk of insolvency or bankruptcy than issuers of higher-quality debt securities. They can be illiquid, and their values can have significant volatility and may decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Portfolio's fixed income securities to decrease, an adverse impact on the liquidity of the Portfolio's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Portfolio may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate. Income Risk: The Portfolio's income may decline due to falling interest rates or other factors. Issuers of securities held by the Portfolio may call or redeem the securities during periods of falling interest rates, and the Portfolio would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Portfolio is prepaid, the Portfolio may have to reinvest the prepayment in other obligations paying income at lower rates. Liquidity Risk: There is no organized exchange on which loans are traded and reliable market quotations may not be readily available. A majority of the Portfolio's assets are likely to be invested in loans that are less liquid than securities traded on national exchanges. Illiquidity of the Portfolio's holdings may limit the ability of the Portfolio and the Fund to obtain cash to meet redemptions on a timely basis. Loans with reduced liquidity involve greater risk than securities with more liquid markets. Available market quotations for such loans may vary over time, and if the credit quality of a loan unexpectedly declines, secondary trading of that loan may decline for a period of time. During periods of infrequent trading, valuing a loan can be more difficult and buying and selling a loan at an acceptable price can be more difficult and delayed. In the event that the Portfolio voluntarily or involuntarily liquidates portfolio assets during periods of infrequent trading, it may not receive full value for those assets. Therefore, elements of judgment may play a greater role in valuation of loans. To the extent that a secondary market exists for certain loans, the market may be subject to irregular trading activity, wide bid/ask spreads and extended trade settlement periods. Management Risk: The Portfolio is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Portfolio and, therefore, the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Portfolio's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Portfolio and, therefore, the Fund are subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Non-Senior Loans and Other Debt Securities Risk: Secured loans that are not first lien, loans that are unsecured and debt securities are subject to many of the same risks that affect Senior Loans; however they are often unsecured and/or lower in the issuer's capital structure than Senior Loans, and thus may be exposed to greater risk of default and lower recoveries in the event of a default. This risk can be further heightened in the case of below investment-grade instruments. Additionally, most fixed-income securities are fixed-rate and thus are generally more susceptible than floating rate loans to price volatility related to changes in prevailing interest rates. Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, to the extent the Portfolio buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Portfolio and, therefore, the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Restricted Securities Risk: The Portfolio may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Portfolio from disposing of them promptly at reasonable prices. The Portfolio may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility. Senior Loan Risk: Investments in Senior Loans are subject to credit risk and general investment risk. Credit risk refers to the possibility that the borrower of a Senior Loan will be unable and/or unwilling to make timely interest payments and/or repay the principal on its obligation. Default in the payment of interest or principal on a Senior Loan will result in a reduction in the value of the Senior Loan and consequently a reduction in the value of the Portfolio's investments and a potential decrease in the net asset value (“NAV”) of the Portfolio. Senior Loans are also subject to the risk that the value of the collateral securing a Senior Loan may decline, be insufficient to meet the obligations of the borrower or be difficult to liquidate. In addition, the Portfolio's access to the collateral may be limited by bankruptcy or other insolvency laws. Further, loans held by the Portfolio may not be considered securities and, therefore, purchasers, such as the Portfolio, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some Senior Loans are subject to the risk that a court, pursuant to fraudulent conveyance or other similar laws, could subordinate the Senior Loans to presently existing or future indebtedness of the borrower or take other action detrimental to lenders, including the Portfolio, such as invalidation of Senior Loans or causing interest previously paid to be refunded to the borrower. Senior Loans are also subject to high yield securities risks and liquidity risks described above. Some of the loans in which the Portfolio may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Portfolio may experience delays in enforcing its rights on its holdings of covenant-lite loans. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Portfolio could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Portfolio would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Portfolio at that time. Investors who purchase or redeem Fund Shares on days when the Portfolio is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Portfolio had not fair-valued the holding(s) or had used a different valuation methodology.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of indexes measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURNS</b> (years ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 2.35% (Q3, 2016) Lowest Quarterly Return: -2.04% (Q3, 2015)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR Blackstone / GSO Senior Loan ETF | SPDR Blackstone / GSO Senior Loan ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.70%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.70%
Year 1	rr_ExpenseExampleYear01	$ 72
Year 3	rr_ExpenseExampleYear03	224
Year 5	rr_ExpenseExampleYear05	390
Year 10	rr_ExpenseExampleYear10	$ 871
2014	rr_AnnualReturn2014	0.90%	[1]
2015	rr_AnnualReturn2015	(0.86%)	[1]
2016	rr_AnnualReturn2016	6.84%	[1]
2017	rr_AnnualReturn2017	3.60%	[1]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	3.38%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	2.35%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(2.04%)
One Year	rr_AverageAnnualReturnYear01	3.60%
Since Inception	rr_AverageAnnualReturnSinceInception	2.55%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 03, 2013
SPDR Blackstone / GSO Senior Loan ETF | Return After Taxes on Distributions | SPDR Blackstone / GSO Senior Loan ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.83%
Since Inception	rr_AverageAnnualReturnSinceInception	0.91%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 03, 2013
SPDR Blackstone / GSO Senior Loan ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR Blackstone / GSO Senior Loan ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	2.02%
Since Inception	rr_AverageAnnualReturnSinceInception	1.19%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 03, 2013
SPDR Blackstone / GSO Senior Loan ETF | Markit iBoxx USD Liquid Leveraged Loan Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	2.01%
Since Inception	rr_AverageAnnualReturnSinceInception	2.52%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 03, 2013
SPDR Blackstone / GSO Senior Loan ETF | S&P/LSTA U.S. Leveraged Loan 100 Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	3.31%
Since Inception	rr_AverageAnnualReturnSinceInception	3.11%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 03, 2013

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 3.38%.

XML

SPDR DoubleLine Emerging Markets Fixed Income ETF

FUND SUMMARIES <br/><br/> <b>SPDR^® DoubleLine^® Emerging Markets Fixed Income ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR DoubleLine Emerging Markets Fixed Income ETF (the “Fund”) seeks to provide high total return from current income and capital appreciation.

<b>FEES AND EXPENSES OF THE FUND </b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR DoubleLine Emerging Markets Fixed Income ETF SPDR DoubleLine Emerging Markets Fixed Income ETF
Management fees	0.75%
Distribution and service (12b-1) fees	none
Other expenses	0.01%
Total annual Fund operating expenses	0.76%
Less contractual fee waiver	(0.11%)	[1]
Net annual Fund operating expenses	0.65%

<b>EXAMPLE: </b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the Fund's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR DoubleLine Emerging Markets Fixed Income ETF | SPDR DoubleLine Emerging Markets Fixed Income ETF | USD ($)	66	232	412	932

<b>PORTFOLIO TURNOVER: </b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 55% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>

Under normal circumstances, DoubleLine Capital LP (the “Sub-Adviser” or “DoubleLine”) will invest at least 80% of the Fund's net assets (plus the amount of borrowings for investment purposes) in emerging market fixed income securities. The Fund will provide shareholders with at least 60 days' notice prior to any change in this 80% investment policy. Fixed income securities are defined as fixed income securities issued or guaranteed by foreign corporations or foreign governments, including securities issued or guaranteed by companies (including hybrid securities), financial institutions, or government entities in emerging market countries; corporate or government bonds; sovereign debt; structured securities; foreign currency transactions; certain derivatives; preferred securities; zero coupon bonds; credit-linked notes; pass through notes; bank loans; and perpetual maturity bonds. Fixed income securities may have fixed or variable interest rates and any maturity. The Fund may also invest in exchange-traded foreign equity securities and depositary receipts. The Fund will generally invest in securities and/or instruments from at least five emerging market countries, with no more than 20% allocated to a single country. An “emerging market country” is a country that, at the time the Fund invests in the related security or instrument, is classified as an emerging or developing economy by any supranational organization such as the World Bank or the United Nations, or related entities, or is considered an emerging market country for purposes of constructing a major emerging market securities index. A security or instrument is considered to be from an emerging market country if the issuer or guarantor of the security or instrument is either domiciled in an emerging market country or derives a majority of its cash flow or revenue from an emerging market country. Certain fixed income securities held by the Fund may not be registered under the Securities Act of 1933, as amended (“1933 Act”), including securities that are typically purchased pursuant to Rule 144A or Regulation S promulgated under the 1933 Act. These securities are expected to be liquid.

The Fund may invest in fixed income securities of any credit quality, but seeks to invest no more than 20%, at the time of investment, in fixed income securities that are unrated, rated BB+ or lower by Standard & Poor's Rating Service or Ba1 or lower by Moody's Investors Service, Inc. or the equivalent by any other nationally recognized statistical rating organization. Corporate bonds and certain other fixed income securities rated below investment-grade, or such instruments that are unrated and are determined by the Sub-Adviser to be of comparable quality, are high yield, high risk bonds, commonly known as junk bonds. The Fund may invest in hybrid securities relating to emerging market countries. A hybrid security may be created by combining an income-producing debt security and the right to receive payment based on the change in the price of an equity security.

The Fund may conduct foreign currency transactions on a spot (i.e., cash) or forward basis (i.e., by entering into forward contracts to purchase or sell foreign currencies). The Fund may also invest in the following derivatives: foreign currency futures; credit default swaps; and options, swaps, futures, and forward contracts on securities. These practices may be used to hedge the Fund's portfolio (e.g., to hedge against currency fluctuations), as well as for investment purposes (e.g., to gain exposure to certain issuers or emerging markets); however, such practices sometimes may reduce returns or increase volatility. All such derivatives will be exchange traded or centrally cleared.

In allocating investments among various emerging market countries, the Sub-Adviser attempts to analyze internal political, market and economic factors. These factors may include public finances, monetary policy, external accounts, financial markets, foreign investment regulations, stability of exchange rate policy, and labor conditions.

In managing the Fund's investments, under normal market conditions, the Sub-Adviser intends to seek to construct an investment portfolio with a weighted average effective duration of no less than two years and no more than eight years. Duration is a measure of the expected life of a fixed income instrument that is used to determine the sensitivity of a security's price to changes in interest rates. Effective duration is a measure of the Fund's portfolio duration adjusted for the anticipated effect of interest rate changes on bond and mortgage pre-payment rates. The effective duration of the Fund's investment portfolio may vary materially from its target, from time to time, and there is no assurance that the effective duration of the Fund's investment portfolio will not exceed its target. The Fund may invest without limit in investments denominated in any currency, but expects to invest a portion of its assets in investments denominated in the U.S. dollar. Securities held by the Fund may be sold at any time. By way of example, sales may occur when the Sub-Adviser perceives deterioration in the credit fundamentals of the issuer, when the Sub-Adviser believes there are negative macro geo-political considerations that may affect the issuer, when the Sub-Adviser determines to take advantage of a better investment opportunity, or the individual security has reached the Sub-Adviser's sell target.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bank Loan Risk: The Fund may invest in secured and unsecured participations in bank loans and assignments of such loans. In making investments in such loans, which are made by banks or other financial intermediaries to borrowers, the Fund will depend primarily upon the creditworthiness of the borrower for payment of principal and interest which will expose the Fund to the credit risk of both the financial institution and the underlying borrower. The market for bank loans may not be highly liquid and the Fund may have difficulty selling them. The Fund may also experience settlement delays with respect to bank loan trades. Participations by the Fund in a lender's portion of a bank loan typically will result in the Fund having a contractual relationship only with such lender, not with the borrower. The Fund may have the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling a loan participation and only upon receipt by such lender of such payments from the borrower. In connection with purchasing participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other lenders through set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund may assume the credit risk of both the borrower and the lender selling the participation. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans.

Counterparty Risk: The Fund will be subject to credit risk with respect to the counterparties with which the Fund enters into derivatives contracts, repurchase agreements, reverse repurchase agreements, and other transactions. If a counterparty fails to meet its contractual obligations, the Fund may be unable to terminate or realize any gain on the investment or transaction, or to recover collateral posted to the counterparty, resulting in a loss to the Fund. If the Fund holds collateral posted by its counterparty, it may be delayed or prevented from realizing on the collateral in the event of a bankruptcy or insolvency proceeding relating to the counterparty.

Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies.

Currency Hedging Risk: If the Fund enters into currency hedging transactions, any loss generated by those transactions generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the hedging transaction and the risk sought to be hedged. There can be no assurance that the Fund's hedging transactions will be effective.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based.

Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and the Fund may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Fund's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Sub-Adviser or may not have the effect on the Fund anticipated by the Sub-Adviser.

Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries.

Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate.

Geographic Focus Risk: The performance of a fund that is less diversified across countries or geographic regions will be closely tied to market, currency, economic, political, environmental, or regulatory conditions and developments in the countries or regions in which the fund invests, and may be more volatile than the performance of a more geographically-diversified fund.

Latin America: Latin American economies are generally considered emerging markets and are generally characterized by high interest, inflation, and unemployment rates. Currency devaluations in any one Latin American country can have a significant effect on the entire Latin American region. Because commodities such as oil and gas, minerals, and metals represent a significant percentage of the region's exports, the economies of Latin American countries are particularly sensitive to fluctuations in commodity prices. A relatively small number of Latin American companies represents a large portion of Latin America's total market and thus may be more sensitive to adverse political or economic circumstances and market movements.

High Yield Securities Risk: Securities rated below investment-grade, commonly referred to as “junk bonds,” include bonds that are rated Ba1/BB+/BB+ or below by Moody's Investors Service, Inc., Fitch Inc., or Standard & Poor's Financial Services, LLC, respectively, or unrated securities considered to be of equivalent quality by the Sub-Adviser, and may involve greater risks than securities in higher rating categories. Such bonds are regarded as speculative in nature, involve greater risk of default by the issuing entity and may be subject to greater market fluctuations than higher rated debt securities. They are usually issued by entities without long track records of sales and earnings, or by entities with questionable credit strength. The retail secondary market for these “junk bonds” may be less liquid than that of higher rated securities and adverse conditions could make it difficult at times to sell certain securities or could result in lower prices than those used in calculating the Fund's net asset value. High yield securities also may present greater credit risk because such securities may be issued in connection with corporate restructuring by highly leveraged issuers or may not be current in the payment of interest or principal or in default.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Leveraging Risk: Use of leverage by the Fund may have the effect of increasing the volatility of the value of the Fund's portfolio, and may entail risk of loss in excess of the Fund's invested capital. To the extent the Fund uses leverage, the Fund's losses (and gains) may be greater than if the Fund had not used leverage.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, when the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Pass-Through Securities Risk: Pass-through securities are debt obligations backed by a pool of assets, such as mortgages. In addition to the risks associated with investing in debt securities generally, pass-through securities are subject to changes in the payment patterns of borrowers of the underlying debt. When interest rates fall, borrowers are more likely to refinance or prepay their debt before its stated maturity. This may result in the Fund having to reinvest the proceeds in lower yielding securities, effectively reducing the Fund's income. Conversely, if interest rates rise and borrowers repay their debt more slowly than expected, the time in which pass-through securities are paid off could be extended, reducing the Fund's cash available for reinvestment in higher yielding securities.

Perpetual Bond Risk: Perpetual bonds offer a fixed return with no maturity date. Because they never mature, perpetual bonds can be more volatile than other types of bonds that have a maturity date and may have heightened sensitivity to changes in interest rates. If market interest rates rise significantly, the interest rate paid by a perpetual bond may be much lower than the prevailing interest rate.  Perpetual bonds are also subject to credit risk with respect to the issuer.  In addition, because perpetual bonds may be callable after a set period of time, there is the risk that the issuer may recall the bond.

Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield.

Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

Structured Securities Risk: Structured securities generally include privately-issued and publicly-issued structured securities, including certain publicly-issued structured securities that are not agency securities. An investment in a structured product may decline in value due to changes in the underlying instruments on which the product is based. The cash flow or rate of return on a structured investment may be determined by applying a multiplier to the rate of total return on the underlying investments or referenced indicator. Application of a multiplier is comparable to the use of financial leverage, a speculative technique. Holders of structured products indirectly bear risks associated with the underlying investments, index or reference obligation, and are subject to counterparty risk. Structured products are generally privately offered and sold, and thus, are not registered under the securities laws. Certain structured products may be thinly traded or have a limited trading market and may have the effect of increasing the Fund's illiquidity to the extent that the Fund, at a particular point in time, may be unable to find qualified buyers for these securities. Structured notes are derivative securities for which the amount of principal repayment and/or interest payments is based on the movement of one or more “factors.” Investments in structured notes, including credit-linked notes, involve risks including interest rate risk, credit risk and market risk. Where the Fund's investments in structured notes are based upon the movement of one or more factors, depending on the factor used and the use of multipliers or deflators, changes in interest rates and movement of the factor may cause significant price fluctuations.

Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield. In addition, investment in derivative variable rate securities, such as inverse floaters, whose rates vary inversely with market rates of interest, or range floaters or capped floaters, whose rates are subject to periodic or lifetime caps, or in securities that pay a rate of interest determined by applying a multiple to the variable rate involves special risks as compared to investment in a fixed-rate security and may involve leverage. Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such securities.

Zero-Coupon Bond Risk: Zero-coupon bonds usually trade at a deep discount from their face or par values and are subject to greater market value fluctuations from changing interest rates than debt obligations of comparable maturities that make current distributions of interest.

<b>FUND PERFORMANCE </b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURN</b> (year ended 12/31)

Highest Quarterly Return: 2.95% (Q1, 2017)
Lowest Quarterly Return: 0.09% (Q4, 2017)

<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR DoubleLine Emerging Markets Fixed Income ETF	One Year	Since Inception	Inception Date
SPDR DoubleLine Emerging Markets Fixed Income ETF	7.60%	7.86%	Apr. 13, 2016
SPDR DoubleLine Emerging Markets Fixed Income ETF | Return After Taxes on Distributions	5.70%	4.51%	Apr. 13, 2016
SPDR DoubleLine Emerging Markets Fixed Income ETF | Return After Taxes on Distributions and Sale of Fund Shares	4.31%	4.46%	Apr. 13, 2016
JP Morgan Corporate Emerging Market Bond Index Broad Diversified (reflects no deduction for fees, expenses or taxes)	7.96%	7.44%	Apr. 13, 2016

[1] SSGA Funds Management, Inc. (“SSGA FM” or “Adviser”) has contractually agreed to waive a portion of its management fee and/or reimburse certain expenses, until October 31, 2019, so that the net annual Fund operating expenses, before application of any fees and expenses not paid by the Adviser pursuant to the Investment Advisory Agreement, if any, are limited to 0.65% of the Fund's average daily net assets. The contractual fee waiver and/or reimbursement does not provide for the recoupment by the Adviser of any fees the Adviser previously waived. The Adviser may continue the waiver and/or reimbursement from year to year, but there is no guarantee that the Adviser will do so and after October 31, 2019, the waiver and/or reimbursement may be cancelled or modified at any time. This waiver and/or reimbursement may not be terminated prior to October 31, 2019 except with the approval of the SSGA Active Trust's Board of Trustees.

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was -1.64%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR DoubleLine Emerging Markets Fixed Income ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	FUND SUMMARIES <br/><br/> <b>SPDR<sup>®</sup> DoubleLine<sup>®</sup> Emerging Markets Fixed Income ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR DoubleLine Emerging Markets Fixed Income ETF (the “Fund”) seeks to provide high total return from current income and capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	October 31, 2019
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER: </b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 55% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	55.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE: </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the Fund's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, DoubleLine Capital LP (the “Sub-Adviser” or “DoubleLine”) will invest at least 80% of the Fund's net assets (plus the amount of borrowings for investment purposes) in emerging market fixed income securities. The Fund will provide shareholders with at least 60 days' notice prior to any change in this 80% investment policy. Fixed income securities are defined as fixed income securities issued or guaranteed by foreign corporations or foreign governments, including securities issued or guaranteed by companies (including hybrid securities), financial institutions, or government entities in emerging market countries; corporate or government bonds; sovereign debt; structured securities; foreign currency transactions; certain derivatives; preferred securities; zero coupon bonds; credit-linked notes; pass through notes; bank loans; and perpetual maturity bonds. Fixed income securities may have fixed or variable interest rates and any maturity. The Fund may also invest in exchange-traded foreign equity securities and depositary receipts. The Fund will generally invest in securities and/or instruments from at least five emerging market countries, with no more than 20% allocated to a single country. An “emerging market country” is a country that, at the time the Fund invests in the related security or instrument, is classified as an emerging or developing economy by any supranational organization such as the World Bank or the United Nations, or related entities, or is considered an emerging market country for purposes of constructing a major emerging market securities index. A security or instrument is considered to be from an emerging market country if the issuer or guarantor of the security or instrument is either domiciled in an emerging market country or derives a majority of its cash flow or revenue from an emerging market country. Certain fixed income securities held by the Fund may not be registered under the Securities Act of 1933, as amended (“1933 Act”), including securities that are typically purchased pursuant to Rule 144A or Regulation S promulgated under the 1933 Act. These securities are expected to be liquid. The Fund may invest in fixed income securities of any credit quality, but seeks to invest no more than 20%, at the time of investment, in fixed income securities that are unrated, rated BB+ or lower by Standard & Poor's Rating Service or Ba1 or lower by Moody's Investors Service, Inc. or the equivalent by any other nationally recognized statistical rating organization. Corporate bonds and certain other fixed income securities rated below investment-grade, or such instruments that are unrated and are determined by the Sub-Adviser to be of comparable quality, are high yield, high risk bonds, commonly known as junk bonds. The Fund may invest in hybrid securities relating to emerging market countries. A hybrid security may be created by combining an income-producing debt security and the right to receive payment based on the change in the price of an equity security. The Fund may conduct foreign currency transactions on a spot (i.e., cash) or forward basis (i.e., by entering into forward contracts to purchase or sell foreign currencies). The Fund may also invest in the following derivatives: foreign currency futures; credit default swaps; and options, swaps, futures, and forward contracts on securities. These practices may be used to hedge the Fund's portfolio (e.g., to hedge against currency fluctuations), as well as for investment purposes (e.g., to gain exposure to certain issuers or emerging markets); however, such practices sometimes may reduce returns or increase volatility. All such derivatives will be exchange traded or centrally cleared. In allocating investments among various emerging market countries, the Sub-Adviser attempts to analyze internal political, market and economic factors. These factors may include public finances, monetary policy, external accounts, financial markets, foreign investment regulations, stability of exchange rate policy, and labor conditions. In managing the Fund's investments, under normal market conditions, the Sub-Adviser intends to seek to construct an investment portfolio with a weighted average effective duration of no less than two years and no more than eight years. Duration is a measure of the expected life of a fixed income instrument that is used to determine the sensitivity of a security's price to changes in interest rates. Effective duration is a measure of the Fund's portfolio duration adjusted for the anticipated effect of interest rate changes on bond and mortgage pre-payment rates. The effective duration of the Fund's investment portfolio may vary materially from its target, from time to time, and there is no assurance that the effective duration of the Fund's investment portfolio will not exceed its target. The Fund may invest without limit in investments denominated in any currency, but expects to invest a portion of its assets in investments denominated in the U.S. dollar. Securities held by the Fund may be sold at any time. By way of example, sales may occur when the Sub-Adviser perceives deterioration in the credit fundamentals of the issuer, when the Sub-Adviser believes there are negative macro geo-political considerations that may affect the issuer, when the Sub-Adviser determines to take advantage of a better investment opportunity, or the individual security has reached the Sub-Adviser's sell target.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Bank Loan Risk: The Fund may invest in secured and unsecured participations in bank loans and assignments of such loans. In making investments in such loans, which are made by banks or other financial intermediaries to borrowers, the Fund will depend primarily upon the creditworthiness of the borrower for payment of principal and interest which will expose the Fund to the credit risk of both the financial institution and the underlying borrower. The market for bank loans may not be highly liquid and the Fund may have difficulty selling them. The Fund may also experience settlement delays with respect to bank loan trades. Participations by the Fund in a lender's portion of a bank loan typically will result in the Fund having a contractual relationship only with such lender, not with the borrower. The Fund may have the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling a loan participation and only upon receipt by such lender of such payments from the borrower. In connection with purchasing participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other lenders through set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund may assume the credit risk of both the borrower and the lender selling the participation. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans. Counterparty Risk: The Fund will be subject to credit risk with respect to the counterparties with which the Fund enters into derivatives contracts, repurchase agreements, reverse repurchase agreements, and other transactions. If a counterparty fails to meet its contractual obligations, the Fund may be unable to terminate or realize any gain on the investment or transaction, or to recover collateral posted to the counterparty, resulting in a loss to the Fund. If the Fund holds collateral posted by its counterparty, it may be delayed or prevented from realizing on the collateral in the event of a bankruptcy or insolvency proceeding relating to the counterparty. Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies. Currency Hedging Risk: If the Fund enters into currency hedging transactions, any loss generated by those transactions generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the hedging transaction and the risk sought to be hedged. There can be no assurance that the Fund's hedging transactions will be effective. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Depositary Receipts Risk: Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market. If a depositary receipt is denominated in a different currency than its underlying securities, the Fund will be subject to the currency risk of both the investment in the depositary receipt and the underlying security. Holders of depositary receipts may have limited or no rights to take action with respect to the underlying securities or to compel the issuer of the receipts to take action. The prices of depositary receipts may differ from the prices of securities upon which they are based. Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and the Fund may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Fund's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Sub-Adviser or may not have the effect on the Fund anticipated by the Sub-Adviser. Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries. Equity Investing Risk: The market prices of equity securities owned by the Fund may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate. Geographic Focus Risk: The performance of a fund that is less diversified across countries or geographic regions will be closely tied to market, currency, economic, political, environmental, or regulatory conditions and developments in the countries or regions in which the fund invests, and may be more volatile than the performance of a more geographically-diversified fund. Latin America: Latin American economies are generally considered emerging markets and are generally characterized by high interest, inflation, and unemployment rates. Currency devaluations in any one Latin American country can have a significant effect on the entire Latin American region. Because commodities such as oil and gas, minerals, and metals represent a significant percentage of the region's exports, the economies of Latin American countries are particularly sensitive to fluctuations in commodity prices. A relatively small number of Latin American companies represents a large portion of Latin America's total market and thus may be more sensitive to adverse political or economic circumstances and market movements. High Yield Securities Risk: Securities rated below investment-grade, commonly referred to as “junk bonds,” include bonds that are rated Ba1/BB+/BB+ or below by Moody's Investors Service, Inc., Fitch Inc., or Standard & Poor's Financial Services, LLC, respectively, or unrated securities considered to be of equivalent quality by the Sub-Adviser, and may involve greater risks than securities in higher rating categories. Such bonds are regarded as speculative in nature, involve greater risk of default by the issuing entity and may be subject to greater market fluctuations than higher rated debt securities. They are usually issued by entities without long track records of sales and earnings, or by entities with questionable credit strength. The retail secondary market for these “junk bonds” may be less liquid than that of higher rated securities and adverse conditions could make it difficult at times to sell certain securities or could result in lower prices than those used in calculating the Fund's net asset value. High yield securities also may present greater credit risk because such securities may be issued in connection with corporate restructuring by highly leveraged issuers or may not be current in the payment of interest or principal or in default. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Leveraging Risk: Use of leverage by the Fund may have the effect of increasing the volatility of the value of the Fund's portfolio, and may entail risk of loss in excess of the Fund's invested capital. To the extent the Fund uses leverage, the Fund's losses (and gains) may be greater than if the Fund had not used leverage. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, when the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Pass-Through Securities Risk: Pass-through securities are debt obligations backed by a pool of assets, such as mortgages. In addition to the risks associated with investing in debt securities generally, pass-through securities are subject to changes in the payment patterns of borrowers of the underlying debt. When interest rates fall, borrowers are more likely to refinance or prepay their debt before its stated maturity. This may result in the Fund having to reinvest the proceeds in lower yielding securities, effectively reducing the Fund's income. Conversely, if interest rates rise and borrowers repay their debt more slowly than expected, the time in which pass-through securities are paid off could be extended, reducing the Fund's cash available for reinvestment in higher yielding securities. Perpetual Bond Risk: Perpetual bonds offer a fixed return with no maturity date. Because they never mature, perpetual bonds can be more volatile than other types of bonds that have a maturity date and may have heightened sensitivity to changes in interest rates. If market interest rates rise significantly, the interest rate paid by a perpetual bond may be much lower than the prevailing interest rate.  Perpetual bonds are also subject to credit risk with respect to the issuer.  In addition, because perpetual bonds may be callable after a set period of time, there is the risk that the issuer may recall the bond. Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield. Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. Structured Securities Risk: Structured securities generally include privately-issued and publicly-issued structured securities, including certain publicly-issued structured securities that are not agency securities. An investment in a structured product may decline in value due to changes in the underlying instruments on which the product is based. The cash flow or rate of return on a structured investment may be determined by applying a multiplier to the rate of total return on the underlying investments or referenced indicator. Application of a multiplier is comparable to the use of financial leverage, a speculative technique. Holders of structured products indirectly bear risks associated with the underlying investments, index or reference obligation, and are subject to counterparty risk. Structured products are generally privately offered and sold, and thus, are not registered under the securities laws. Certain structured products may be thinly traded or have a limited trading market and may have the effect of increasing the Fund's illiquidity to the extent that the Fund, at a particular point in time, may be unable to find qualified buyers for these securities. Structured notes are derivative securities for which the amount of principal repayment and/or interest payments is based on the movement of one or more “factors.” Investments in structured notes, including credit-linked notes, involve risks including interest rate risk, credit risk and market risk. Where the Fund's investments in structured notes are based upon the movement of one or more factors, depending on the factor used and the use of multipliers or deflators, changes in interest rates and movement of the factor may cause significant price fluctuations. Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology. Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield. In addition, investment in derivative variable rate securities, such as inverse floaters, whose rates vary inversely with market rates of interest, or range floaters or capped floaters, whose rates are subject to periodic or lifetime caps, or in securities that pay a rate of interest determined by applying a multiple to the variable rate involves special risks as compared to investment in a fixed-rate security and may involve leverage. Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such securities. Zero-Coupon Bond Risk: Zero-coupon bonds usually trade at a deep discount from their face or par values and are subject to greater market value fluctuations from changing interest rates than debt obligations of comparable maturities that make current distributions of interest.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURN</b> (year ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 2.95% (Q1, 2017) Lowest Quarterly Return: 0.09% (Q4, 2017)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR DoubleLine Emerging Markets Fixed Income ETF | SPDR DoubleLine Emerging Markets Fixed Income ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.01%
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.76%
Less contractual fee waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.11%)	[1]
Net annual Fund operating expenses	rr_NetExpensesOverAssets	0.65%
Year 1	rr_ExpenseExampleYear01	$ 66
Year 3	rr_ExpenseExampleYear03	232
Year 5	rr_ExpenseExampleYear05	412
Year 10	rr_ExpenseExampleYear10	$ 932
2017	rr_AnnualReturn2017	7.60%	[2]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(1.64%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	2.95%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2017
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.09%
One Year	rr_AverageAnnualReturnYear01	7.60%
Since Inception	rr_AverageAnnualReturnSinceInception	7.86%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016
SPDR DoubleLine Emerging Markets Fixed Income ETF | Return After Taxes on Distributions | SPDR DoubleLine Emerging Markets Fixed Income ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	5.70%
Since Inception	rr_AverageAnnualReturnSinceInception	4.51%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016
SPDR DoubleLine Emerging Markets Fixed Income ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR DoubleLine Emerging Markets Fixed Income ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	4.31%
Since Inception	rr_AverageAnnualReturnSinceInception	4.46%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016
SPDR DoubleLine Emerging Markets Fixed Income ETF | JP Morgan Corporate Emerging Market Bond Index Broad Diversified (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	7.96%
Since Inception	rr_AverageAnnualReturnSinceInception	7.44%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016

[1] SSGA Funds Management, Inc. (“SSGA FM” or “Adviser”) has contractually agreed to waive a portion of its management fee and/or reimburse certain expenses, until October 31, 2019, so that the net annual Fund operating expenses, before application of any fees and expenses not paid by the Adviser pursuant to the Investment Advisory Agreement, if any, are limited to 0.65% of the Fund's average daily net assets. The contractual fee waiver and/or reimbursement does not provide for the recoupment by the Adviser of any fees the Adviser previously waived. The Adviser may continue the waiver and/or reimbursement from year to year, but there is no guarantee that the Adviser will do so and after October 31, 2019, the waiver and/or reimbursement may be cancelled or modified at any time. This waiver and/or reimbursement may not be terminated prior to October 31, 2019 except with the approval of the SSGA Active Trust's Board of Trustees.

[2] As of 9/30/2018, the Fund's Calendar Year-To-Date return was -1.64%.

XML

SPDR DoubleLine Short Duration Total Return Tactical ETF

<b>SPDR^® DoubleLine^® Short Duration Total Return Tactical ETF</b>

<b>INVESTMENT OBJECTIVE</b>

The SPDR DoubleLine Short Duration Total Return Tactical ETF (the “Fund”) seeks to maximize current income with a dollar-weighted average effective duration between one and three years.

<b>FEES AND EXPENSES OF THE FUND</b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.

<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	SPDR DoubleLine Short Duration Total Return Tactical ETF SPDR DoubleLine Short Duration Total Return Tactical ETF
Management fees	0.50%
Distribution and service (12b-1) fees	none
Other expenses	none
Total annual Fund operating expenses	0.50%
Less contractual fee waiver	(0.05%)	[1]
Net annual Fund operating expenses	0.45%

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the Fund's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
SPDR DoubleLine Short Duration Total Return Tactical ETF | SPDR DoubleLine Short Duration Total Return Tactical ETF | USD ($)	46	155	275	623

<b>PORTFOLIO TURNOVER:</b>

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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 50% of the average value of its portfolio.

<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>

Under normal circumstances, DoubleLine Capital LP (the “Sub-Adviser” or “DoubleLine”) will invest at least 80% of the Fund's net assets (plus the amount of borrowings for investment purposes) in a diversified portfolio of fixed income securities of any credit quality (subject to certain limits described below). The Fund will provide shareholders with at least 60 days' notice prior to any change in this 80% investment policy. Fixed income securities in which the Fund principally invests are defined as securities issued or guaranteed by the U.S. government or its agencies, instrumentalities or sponsored corporations; inflation protected public obligations of the U.S. Treasury (“TIPS”); securities issued or guaranteed by state or local governments or their agencies or instrumentalities (commonly known as municipal bonds) (the Fund may invest up to 20% of its portfolio in municipal bonds); asset-backed securities (“ABS”) (which include the following: agency and non-agency residential mortgage-backed securities (“RMBS”), agency and non-agency commercial mortgage-backed securities (“CMBS”), and any other agency and non-agency asset-backed securities (“NAABS”)); collateralized debt obligations (“CDOs”); collateralized loan obligations (“CLOs”); collateralized bond obligations (“CBOs”); collateralized mortgage obligations (“CMOs”); and Real Estate Mortgage Investment Conduits (“REMICs”) and Re-REMICs (which are REMICs that have been resecuritized); stripped securities (i.e., interest rate only and principal only securities); zero coupon securities; foreign (including emerging markets) and domestic corporate bonds; sovereign debt; bank loans; preferred securities; and exchange-traded products, including exchange-traded funds and exchange-traded notes, that invest in fixed income securities. To the extent applicable, debt instruments that comprise fixed income securities may be either fixed rate securities, floating rate securities, or variable rate securities. The Fund may also invest in cash and other short-term instruments, as well as restricted securities.

The Fund may invest up to 20% of the fixed income portion of its portfolio, in the aggregate, in non-agency ABS, which may include privately issued mortgage-backed securities of any rating assigned by Moody's Investors Service, Inc. (“Moody's”) or by Standard & Poor's Rating Service (“S&P”) or assigned by any other nationally recognized statistical rating organization (“NRSRO”) or in unrated securities that are determined by the Sub-Adviser to be of comparable quality. The Fund intends to invest at least 25% of its net assets in mortgage-backed securities of any maturity or type guaranteed by, or secured by collateral that is guaranteed by, the U.S. government, its agencies, instrumentalities or sponsored corporations. The Fund may invest a substantial portion of its assets in U.S. agency mortgage pass-through securities. The term “U.S. agency mortgage pass-through security” refers to a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. Government-sponsored enterprises: Ginnie Mae, Fannie Mae or Freddie Mac. The Fund may seek to obtain exposure to U.S. agency mortgage pass-through securities through the use of “to-be-announced” or “TBA Transactions.”“TBA” refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed security. Transactions in mortgage pass-through securities may occur through the use of TBA Transactions. TBA Transactions generally are conducted in accordance with widely-accepted guidelines which establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA Transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined prior to settlement date.

The Fund may invest up to 20% of its net assets in corporate high yield securities (commonly known as “junk bonds”). Under normal circumstances, the combined total of corporate, sovereign, non-agency and all other debt rated below investment-grade will not exceed 40% of the Fund's net assets. Below investment-grade securities are instruments that are rated BB+ or lower by S&P or Fitch Inc. or Ba1 or lower by Moody's or equivalent ratings by another registered NRSRO or, if unrated by an NRSRO, of comparable quality in the opinion of the Sub-Adviser. The Sub-Adviser strives to allocate securities broadly by industry and issuer in an attempt to reduce the impact of negative events on an industry or issuer.

The Fund may invest up to 15% of its net assets in securities denominated in foreign currencies, and may invest beyond this limit in U.S. dollar-denominated securities of foreign issuers. The Fund may invest up to 20% of its net assets in securities and instruments that are economically tied to emerging market countries. The Fund generally considers an issuer to be economically tied to an emerging market country if: (i) the issuer is organized under the laws of an emerging country; (ii) the issuer's securities are traded principally in an emerging country; or (iii) during the issuer's most recent fiscal year it derived at least 50% of its revenues, earnings before interest, taxes, depreciation, and amortization, or profits from goods produced or sold by, investments made in, or services performed in emerging countries, or it had at least 50% of its assets in emerging countries.

The Sub-Adviser monitors the duration of the securities held by the Fund to seek to mitigate exposure to interest rate risk. Under normal circumstances, the Sub-Adviser seeks to maintain an investment portfolio with a weighted average effective duration between 1 and 3 years. The duration of the portfolio may vary materially from its target, from time to time. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The longer a security's duration, the more sensitive it will be to changes in interest rates.

The Sub-Adviser actively manages the Fund's asset class exposure using a top-down approach based on analysis of sector fundamentals and rotates Fund assets among sectors in various markets to attempt to maximize return. Individual securities within asset classes are selected using a bottom-up approach. Under normal circumstances, the Sub-Adviser uses a controlled risk approach in managing the Fund's investments. The techniques of this approach attempt to control the principal risk components of the fixed income markets and include consideration of:

• security selection within a given sector;

• relative performance of the various market sectors;

• the shape of the yield curve; and

• fluctuations in the overall level of interest rates.

<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>

As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Asset-Backed and Mortgage-Backed Securities Risk: Asset-backed and mortgage-backed securities (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. These securities, in most cases, are not backed by the full faith and credit of the U.S. government, and there can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. These securities may be subject to liquidity risk as well as the risk of illiquidity and default on the underlying asset or mortgage, particularly during periods of economic downturn. The liquidity of mortgage-related and asset-backed securities may change over time. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain asset-backed and mortgage-backed securities. In particular, during periods of falling interest rates, mortgage-backed securities will be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of a mortgage-backed security may extend, which may lock in a below-market interest rate, increase the security's duration, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, or the underlying assets or collateral may be insufficient if the issuer defaults. The values of certain types of mortgage-backed securities, such as inverse floaters and interest-only and principal-only securities, may be extremely sensitive to changes in interest rates and prepayment rates.

Bank Loan Risk: The Fund may invest in secured and unsecured participations in bank loans and assignments of such loans. In making investments in such loans, which are made by banks or other financial intermediaries to borrowers, the Fund will depend primarily upon the creditworthiness of the borrower for payment of principal and interest which will expose the Fund to the credit risk of both the financial institution and the underlying borrower. The market for bank loans may not be highly liquid and the Fund may have difficulty selling them. The Fund may also experience settlement delays with respect to bank loan trades. Participations by the Fund in a lender's portion of a bank loan typically will result in the Fund having a contractual relationship only with such lender, not with the borrower. The Fund may have the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling a loan participation and only upon receipt by such lender of such payments from the borrower. In connection with purchasing participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other lenders through set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund may assume the credit risk of both the borrower and the lender selling the participation. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans.

Collateralized Debt Obligations Risk: The risks of an investment in a collateralized debt obligation depend largely on the type of the collateral securities and the class of the debt obligation in which the Fund invests. Collateralized debt obligations are generally subject to credit, interest rate, valuation, liquidity, prepayment and extension risks. These securities also are subject to risk of default on the underlying assets, particularly during periods of economic downturn.

Collateralized Loan Obligation Risk: The risks of an investment in a collateralized loan obligation depend largely on the type of the collateral securities and the class of the debt obligation in which the Fund invests. Collateralized loan obligations are generally subject to credit, interest rate, valuation, liquidity, prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. Collateralized loan obligations carry additional risks including, but not limited to, (i) the possibility that distributions from collateral securities will not be adequate to make interest of other payments, (ii) the collateral may decline in value or default, (iii) the Fund may invest in obligations that are subordinate to other classes, and (iv) the complex structure of the security may not be fully understood at the time of investment and produce disputes with the issuer or unexpected investment results.

Collateralized Bond Obligation Risk: The pool of high yield securities underlying collateralized bond obligations is typically separated into groupings called tranches representing different degrees of credit quality. The higher quality tranches have greater degrees of protection and pay lower interest rates. The lower tranches, with greater risk, pay higher interest rates.

Collateralized Mortgage Obligation Risk: The expected average life of collateralized mortgage obligations (“CMOs”) is determined using mathematical models that incorporate prepayment assumptions and other factors that involve estimates of future economic and market conditions. These estimates may vary from actual future results, particularly during periods of extreme market volatility. Further, under certain market conditions, the average weighted life of certain CMOs may not accurately reflect the price volatility of such securities. For example, in periods of supply and demand imbalances in the market for such securities and/or in periods of sharp interest rate movements, the prices of CMOs may fluctuate to a greater extent than would be expected from interest rate movements alone. CMOs issued by private entities are not obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities and are not guaranteed by any government agency, although the securities underlying a CMO may be subject to a guarantee. Therefore, if the collateral securing the CMO, as well as any third party credit support or guarantees, is insufficient to make payments when due, the holder could sustain a loss.

Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies.

Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities.

Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries.

Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an exchange traded fund's (“ETF”) shares) for a number of reasons. For example, supply and demand for shares of an ETF or market disruptions may cause the market price of the ETF to deviate from the value of the ETF's investments, which may be exacerbated in less liquid markets. The value of an exchange traded note may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, Fund shareholders indirectly bear the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund shareholders directly bear in connection with the Fund's operations.

Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate.

High Yield Securities Risk: Securities rated below investment-grade, commonly referred to as “junk bonds,” include bonds that are rated Ba1/BB+/BB+ or below by Moody's Investors Service, Inc., Fitch Inc., or Standard & Poor's Financial Services, LLC, respectively, or unrated securities considered to be of equivalent quality by the Sub-Adviser, and may involve greater risks than securities in higher rating categories. Such bonds are regarded as speculative in nature, involve greater risk of default by the issuing entity and may be subject to greater market fluctuations than higher rated debt securities. They are usually issued by entities without long track records of sales and earnings, or by entities with questionable credit strength. The retail secondary market for these “junk bonds” may be less liquid than that of higher rated securities and adverse conditions could make it difficult at times to sell certain securities or could result in lower prices than those used in calculating the Fund's net asset value. High yield securities also may present greater credit risk because such securities may be issued in connection with corporate restructuring by highly leveraged issuers or may not be current in the payment of interest or principal or in default.

Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates.

Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Sub-Adviser.

Interest Rate Only and Principal Only Securities Risk: Interest rate only and principal only securities are acutely sensitive to interest rate changes and to the rate of principal prepayments. These securities are volatile in price and may have lower liquidity.

Investment in ETNs: The value of an exchanged traded note (“ETN”) may be influenced by time to maturity, supply and demand, volatility and lack of liquidity, changes in interest rates, and economic, legal, political or geographic events that affect the referenced market. Because ETNs are debt securities, they are subject to credit risk. There are typically no periodic interest payments for ETNs, and the amount of principal payable at maturity may decline, depending in part on the performance of an underlying index or asset. A Fund could lose all or some of the amount invested in an ETN.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Mortgage Pass-Through Securities Risk: Most transactions in mortgage pass through securities occur through the use of TBA Transactions, as described above. Default by, or bankruptcy of, a counterparty to a TBA Transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA Transaction.

Municipal Obligations Risk: Issuers, including governmental issuers, may be unable to pay their obligations as they come due. The values of municipal obligations that depend on a specific revenue source to fund their payment obligations may fluctuate as a result of actual or anticipated changes in the cash flows generated by the revenue source or changes in the priority of the municipal obligation to receive the cash flows generated by the revenue source. In addition, changes in federal tax laws or the activity of an issuer may adversely affect the tax-exempt status of municipal obligations. Loss of tax-exempt status may result in a significant decline in the values of such municipal obligations.

Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, when the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity.

Political Risk: A significant restructuring of federal income tax rates or even serious discussion on the topic in Congress could cause municipal bond prices to fall. The demand for municipal securities is strongly influenced by the value of tax-exempt income to investors. Lower income tax rates could reduce the advantage of owning municipals.

Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield.

Privately Issued Securities Risk: The Fund will invest in privately-issued securities, including those which are normally purchased pursuant to Rule 144A or Regulation S promulgated under the Securities Act. Privately-issued securities are securities that have not been registered under the Securities Act and as a result are subject to legal restrictions on resale. Privately-issued securities are not traded on established markets and may be illiquid, difficult to value and subject to wide fluctuations in value. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices.

REMIC Risk: The issuer of a series of mortgage pass-through securities may elect to be treated as a Real Estate Mortgage Investment Conduit (“REMIC”). REMICs include governmental and/or private entities that issue a fixed pool of mortgages secured by an interest in real property. REMICs are similar to collateralized mortgage obligations (“CMOs”) in that they issue multiple classes of securities but, unlike CMOs, which are required to be structured as debt securities, REMICs may be structured as indirect ownership interests in the underlying assets of the REMICs themselves. The risks associated with an investment in a particular CMO or REMIC class vary substantially depending on the combination of rights associated with that class. An investment in the most subordinated classes of a CMO or REMIC bears a disproportionate share of the risks associated with mortgage-backed security generally, be it credit risk, prepayment or extension risk (the risk of a security's expected maturity being reduced or lengthened in duration due to a change of the timing of payment), interest rate risk, income risk, market risk, liquidity risk or any other risk associated with a debt or equity instrument with similar features to the relevant class. As a result, an investment in the most subordinated classes of a CMO or REMIC is often riskier than an investment in other types of mortgage-backed securities.

Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility.

Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly.

U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks.

U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline.

Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology.

Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield. Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such securities.

Zero-Coupon Bond Risk: Zero-coupon bonds usually trade at a deep discount from their face or par values and are subject to greater market value fluctuations from changing interest rates than debt obligations of comparable maturities that make current distributions of interest.

<b>FUND PERFORMANCE</b>

The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.

<b>ANNUAL TOTAL RETURN </b>(year ended 12/31)

Highest Quarterly Return: 0.64% (Q2, 2017)
Lowest Quarterly Return: -0.12% (Q4, 2017)

<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.

Average Annual Total Returns - SPDR DoubleLine Short Duration Total Return Tactical ETF	One Year	Since Inception	Inception Date
SPDR DoubleLine Short Duration Total Return Tactical ETF	1.63%	1.48%	Apr. 13, 2016
SPDR DoubleLine Short Duration Total Return Tactical ETF | Return After Taxes on Distributions	0.77%	0.46%	Apr. 13, 2016
SPDR DoubleLine Short Duration Total Return Tactical ETF | Return After Taxes on Distributions and Sale of Fund Shares	0.92%	0.67%	Apr. 13, 2016
Bloomberg Barclays U.S. Aggregate 1-3 Year Index (reflects no deduction for fees, expenses or taxes)	0.86%	0.67%	Apr. 13, 2016

[1] SSGA Funds Management, Inc. (“SSGA FM” or “Adviser”) has contractually agreed to waive a portion of its management fee and/or reimburse certain expenses, until October 31, 2019, so that the net annual Fund operating expenses, before application of any fees and expenses not paid by the Adviser pursuant to the Investment Advisory Agreement, if any, are limited to 0.45% of the Fund's average daily net assets. The contractual fee waiver and/or reimbursement does not provide for the recoupment by the Adviser of any fees the Adviser previously waived. The Adviser may continue the waiver and/or reimbursement from year to year, but there is no guarantee that the Adviser will do so and after October 31, 2019, the waiver and/or reimbursement may be cancelled or modified at any time. This waiver and/or reimbursement may not be terminated prior to October 31, 2019 except with the approval of the SSGA Active Trust's Board of Trustees.

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 0.41%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
SPDR DoubleLine Short Duration Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<b>SPDR<sup>®</sup> DoubleLine<sup>®</sup> Short Duration Total Return Tactical ETF</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The SPDR DoubleLine Short Duration Total Return Tactical ETF (the “Fund”) seeks to maximize current income with a dollar-weighted average effective duration between one and three years.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE FUND</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund (“Fund Shares”). This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES</b> (expenses that you pay each year as a percentage of the value of your investment):
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	October 31, 2019
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER:</b>
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 Fund Operating Expenses or in the Example, affect the Fund's performance.  During the most recent fiscal year, the Fund's portfolio turnover rate was 50% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	50.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	This table and the Example below reflect the expenses of the Fund and do not reflect brokerage commissions you may pay on purchases and sales of Fund Shares.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the Fund's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE FUND'S PRINCIPAL INVESTMENT STRATEGY</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, DoubleLine Capital LP (the “Sub-Adviser” or “DoubleLine”) will invest at least 80% of the Fund's net assets (plus the amount of borrowings for investment purposes) in a diversified portfolio of fixed income securities of any credit quality (subject to certain limits described below). The Fund will provide shareholders with at least 60 days' notice prior to any change in this 80% investment policy. Fixed income securities in which the Fund principally invests are defined as securities issued or guaranteed by the U.S. government or its agencies, instrumentalities or sponsored corporations; inflation protected public obligations of the U.S. Treasury (“TIPS”); securities issued or guaranteed by state or local governments or their agencies or instrumentalities (commonly known as municipal bonds) (the Fund may invest up to 20% of its portfolio in municipal bonds); asset-backed securities (“ABS”) (which include the following: agency and non-agency residential mortgage-backed securities (“RMBS”), agency and non-agency commercial mortgage-backed securities (“CMBS”), and any other agency and non-agency asset-backed securities (“NAABS”)); collateralized debt obligations (“CDOs”); collateralized loan obligations (“CLOs”); collateralized bond obligations (“CBOs”); collateralized mortgage obligations (“CMOs”); and Real Estate Mortgage Investment Conduits (“REMICs”) and Re-REMICs (which are REMICs that have been resecuritized); stripped securities (i.e., interest rate only and principal only securities); zero coupon securities; foreign (including emerging markets) and domestic corporate bonds; sovereign debt; bank loans; preferred securities; and exchange-traded products, including exchange-traded funds and exchange-traded notes, that invest in fixed income securities. To the extent applicable, debt instruments that comprise fixed income securities may be either fixed rate securities, floating rate securities, or variable rate securities. The Fund may also invest in cash and other short-term instruments, as well as restricted securities. The Fund may invest up to 20% of the fixed income portion of its portfolio, in the aggregate, in non-agency ABS, which may include privately issued mortgage-backed securities of any rating assigned by Moody's Investors Service, Inc. (“Moody's”) or by Standard & Poor's Rating Service (“S&P”) or assigned by any other nationally recognized statistical rating organization (“NRSRO”) or in unrated securities that are determined by the Sub-Adviser to be of comparable quality. The Fund intends to invest at least 25% of its net assets in mortgage-backed securities of any maturity or type guaranteed by, or secured by collateral that is guaranteed by, the U.S. government, its agencies, instrumentalities or sponsored corporations. The Fund may invest a substantial portion of its assets in U.S. agency mortgage pass-through securities. The term “U.S. agency mortgage pass-through security” refers to a category of pass-through securities backed by pools of mortgages and issued by one of several U.S. Government-sponsored enterprises: Ginnie Mae, Fannie Mae or Freddie Mac. The Fund may seek to obtain exposure to U.S. agency mortgage pass-through securities through the use of “to-be-announced” or “TBA Transactions.”“TBA” refers to a commonly used mechanism for the forward settlement of U.S. agency mortgage pass-through securities, and not to a separate type of mortgage-backed security. Transactions in mortgage pass-through securities may occur through the use of TBA Transactions. TBA Transactions generally are conducted in accordance with widely-accepted guidelines which establish commonly observed terms and conditions for execution, settlement and delivery. In a TBA Transaction, the buyer and seller decide on general trade parameters, such as agency, settlement date, par amount, and price. The actual pools delivered generally are determined prior to settlement date. The Fund may invest up to 20% of its net assets in corporate high yield securities (commonly known as “junk bonds”). Under normal circumstances, the combined total of corporate, sovereign, non-agency and all other debt rated below investment-grade will not exceed 40% of the Fund's net assets. Below investment-grade securities are instruments that are rated BB+ or lower by S&P or Fitch Inc. or Ba1 or lower by Moody's or equivalent ratings by another registered NRSRO or, if unrated by an NRSRO, of comparable quality in the opinion of the Sub-Adviser. The Sub-Adviser strives to allocate securities broadly by industry and issuer in an attempt to reduce the impact of negative events on an industry or issuer. The Fund may invest up to 15% of its net assets in securities denominated in foreign currencies, and may invest beyond this limit in U.S. dollar-denominated securities of foreign issuers. The Fund may invest up to 20% of its net assets in securities and instruments that are economically tied to emerging market countries. The Fund generally considers an issuer to be economically tied to an emerging market country if: (i) the issuer is organized under the laws of an emerging country; (ii) the issuer's securities are traded principally in an emerging country; or (iii) during the issuer's most recent fiscal year it derived at least 50% of its revenues, earnings before interest, taxes, depreciation, and amortization, or profits from goods produced or sold by, investments made in, or services performed in emerging countries, or it had at least 50% of its assets in emerging countries. The Sub-Adviser monitors the duration of the securities held by the Fund to seek to mitigate exposure to interest rate risk. Under normal circumstances, the Sub-Adviser seeks to maintain an investment portfolio with a weighted average effective duration between 1 and 3 years. The duration of the portfolio may vary materially from its target, from time to time. Duration is a measure used to determine the sensitivity of a security's price to changes in interest rates. The longer a security's duration, the more sensitive it will be to changes in interest rates. The Sub-Adviser actively manages the Fund's asset class exposure using a top-down approach based on analysis of sector fundamentals and rotates Fund assets among sectors in various markets to attempt to maximize return. Individual securities within asset classes are selected using a bottom-up approach. Under normal circumstances, the Sub-Adviser uses a controlled risk approach in managing the Fund's investments. The techniques of this approach attempt to control the principal risk components of the fixed income markets and include consideration of: security selection within a given sector; relative performance of the various market sectors; the shape of the yield curve; and fluctuations in the overall level of interest rates.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE FUND </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Asset-Backed and Mortgage-Backed Securities Risk: Asset-backed and mortgage-backed securities (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. These securities, in most cases, are not backed by the full faith and credit of the U.S. government, and there can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so. These securities may be subject to liquidity risk as well as the risk of illiquidity and default on the underlying asset or mortgage, particularly during periods of economic downturn. The liquidity of mortgage-related and asset-backed securities may change over time. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain asset-backed and mortgage-backed securities. In particular, during periods of falling interest rates, mortgage-backed securities will be called or prepaid, which may result in the Fund having to reinvest proceeds in other investments at a lower interest rate. During periods of rising interest rates, the average life of a mortgage-backed security may extend, which may lock in a below-market interest rate, increase the security's duration, and reduce the value of the security. Enforcing rights against the underlying assets or collateral may be difficult, or the underlying assets or collateral may be insufficient if the issuer defaults. The values of certain types of mortgage-backed securities, such as inverse floaters and interest-only and principal-only securities, may be extremely sensitive to changes in interest rates and prepayment rates. Bank Loan Risk: The Fund may invest in secured and unsecured participations in bank loans and assignments of such loans. In making investments in such loans, which are made by banks or other financial intermediaries to borrowers, the Fund will depend primarily upon the creditworthiness of the borrower for payment of principal and interest which will expose the Fund to the credit risk of both the financial institution and the underlying borrower. The market for bank loans may not be highly liquid and the Fund may have difficulty selling them. The Fund may also experience settlement delays with respect to bank loan trades. Participations by the Fund in a lender's portion of a bank loan typically will result in the Fund having a contractual relationship only with such lender, not with the borrower. The Fund may have the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling a loan participation and only upon receipt by such lender of such payments from the borrower. In connection with purchasing participations, the Fund generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights with respect to any funds acquired by other lenders through set-off against the borrower, and the Fund may not directly benefit from any collateral supporting the loan in which it has purchased the participation. As a result, the Fund may assume the credit risk of both the borrower and the lender selling the participation. Further, loans held by the Fund may not be considered securities and, therefore, purchasers, such as the Fund, may not be entitled to rely on the strong anti-fraud protections of the federal securities laws. Some of the loans in which the Fund may invest or obtain exposure to may be “covenant-lite” loans. Covenant-lite loans may contain fewer or no maintenance covenants compared to other loans and may not include terms which allow the lender to monitor the performance of the borrower and declare a default if certain criteria are breached. The Fund may experience delays in enforcing its rights on its holdings of covenant-lite loans. Collateralized Debt Obligations Risk: The risks of an investment in a collateralized debt obligation depend largely on the type of the collateral securities and the class of the debt obligation in which the Fund invests. Collateralized debt obligations are generally subject to credit, interest rate, valuation, liquidity, prepayment and extension risks. These securities also are subject to risk of default on the underlying assets, particularly during periods of economic downturn. Collateralized Loan Obligation Risk: The risks of an investment in a collateralized loan obligation depend largely on the type of the collateral securities and the class of the debt obligation in which the Fund invests. Collateralized loan obligations are generally subject to credit, interest rate, valuation, liquidity, prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. Collateralized loan obligations carry additional risks including, but not limited to, (i) the possibility that distributions from collateral securities will not be adequate to make interest of other payments, (ii) the collateral may decline in value or default, (iii) the Fund may invest in obligations that are subordinate to other classes, and (iv) the complex structure of the security may not be fully understood at the time of investment and produce disputes with the issuer or unexpected investment results. Collateralized Bond Obligation Risk: The pool of high yield securities underlying collateralized bond obligations is typically separated into groupings called tranches representing different degrees of credit quality. The higher quality tranches have greater degrees of protection and pay lower interest rates. The lower tranches, with greater risk, pay higher interest rates. Collateralized Mortgage Obligation Risk: The expected average life of collateralized mortgage obligations (“CMOs”) is determined using mathematical models that incorporate prepayment assumptions and other factors that involve estimates of future economic and market conditions. These estimates may vary from actual future results, particularly during periods of extreme market volatility. Further, under certain market conditions, the average weighted life of certain CMOs may not accurately reflect the price volatility of such securities. For example, in periods of supply and demand imbalances in the market for such securities and/or in periods of sharp interest rate movements, the prices of CMOs may fluctuate to a greater extent than would be expected from interest rate movements alone. CMOs issued by private entities are not obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities and are not guaranteed by any government agency, although the securities underlying a CMO may be subject to a guarantee. Therefore, if the collateral securing the CMO, as well as any third party credit support or guarantees, is insufficient to make payments when due, the holder could sustain a loss. Currency Risk: The value of the Fund's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Fund's assets denominated in foreign currencies. Debt Securities Risk: The values of debt securities may increase or decrease as a result of the following: market fluctuations, increases in interest rates, actual or perceived inability or unwillingness of issuers, guarantors or liquidity providers to make scheduled principal or interest payments or illiquidity in debt securities markets; the risk of low rates of return due to reinvestment of securities during periods of falling interest rates or repayment by issuers with higher coupon or interest rates; and/or the risk of low income due to falling interest rates. To the extent that interest rates rise, certain underlying obligations may be paid off substantially slower than originally anticipated and the value of those securities may fall sharply. In recent years, the U.S. has experienced low interest rate levels. However, interest rates have begun to rise. In addition, economic recovery and the ending of the Federal Reserve Board's quantitative easing program increase the likelihood that interest rates will continue to rise in the future. A rising interest rate environment may cause the value of the Fund's fixed income securities to decrease, an adverse impact on the liquidity of the Fund's fixed income securities, and increased volatility of the fixed income markets. If the principal on a debt obligation is prepaid before expected, the prepayments of principal may have to be reinvested in obligations paying interest at lower rates. During periods of falling interest rates, the income received by the Fund may decline. Changes in interest rates will likely have a greater effect on the values of debt securities of longer durations. Returns on investments in debt securities could trail the returns on other investment options, including investments in equity securities. Emerging Markets Risk: Risks of investing in emerging markets include, among others, greater political and economic instability, greater volatility in currency exchange rates, less developed securities markets, possible trade barriers, currency transfer restrictions, a more limited number of potential buyers and issuers, an emerging market country's dependence on revenue from particular commodities or international aid, less governmental supervision and regulation, unavailability of currency hedging techniques, differences in auditing and financial reporting standards, and less developed legal systems. There is also the potential for unfavorable action such as expropriation, nationalization, embargo, and acts of war. The securities of emerging market companies may trade less frequently and in smaller volumes than more widely held securities. Market disruptions or substantial market corrections may limit very significantly the liquidity of securities of certain companies in a particular country or geographic region, or of all companies in the country or region. The Fund may be unable to liquidate its positions in such securities at any time, or at a favorable price, in order to meet the Fund's obligations. These risks are generally greater for investments in frontier market countries, which typically have smaller economies or less developed capital markets than traditional emerging market countries. Exchange Traded Products Risk: The Fund is subject to substantially the same risks as those associated with the direct ownership of the securities represented by the ETPs in which it invests. In addition, the shares of certain ETPs may trade at a premium or discount to their intrinsic value (i.e., the market value may differ from the net asset value of an exchange traded fund's (“ETF”) shares) for a number of reasons. For example, supply and demand for shares of an ETF or market disruptions may cause the market price of the ETF to deviate from the value of the ETF's investments, which may be exacerbated in less liquid markets. The value of an exchange traded note may also differ from the valuation of its reference market due to changes in the issuer's credit rating. By investing in ETPs, Fund shareholders indirectly bear the Fund's proportionate share of any fees and expenses (e.g. management, custody, accounting, and administration) of the ETP, if applicable, in addition to the fees and expenses that the Fund shareholders directly bear in connection with the Fund's operations. Financial Sector Risk: Financial services companies are subject to extensive governmental regulation which may limit both the amounts and types of loans and other financial commitments they can make, the interest rates and fees they can charge, the scope of their activities, the prices they can charge and the amount of capital they must maintain. Profitability is largely dependent on the availability and cost of capital funds and can fluctuate significantly when interest rates change or due to increased competition. In addition, deterioration of the credit markets generally may cause an adverse impact in a broad range of markets, including U.S. and international credit and interbank money markets generally, thereby affecting a wide range of financial institutions and markets. Certain events in the financial sector may cause an unusually high degree of volatility in the financial markets, both domestic and foreign, and cause certain financial services companies to incur large losses. Securities of financial services companies may experience a dramatic decline in value when such companies experience substantial declines in the valuations of their assets, take action to raise capital (such as the issuance of debt or equity securities), or cease operations. Credit losses resulting from financial difficulties of borrowers and financial losses associated with investment activities can negatively impact the sector. Insurance companies may be subject to severe price competition. Adverse economic, business or political developments could adversely affect financial institutions engaged in mortgage finance or other lending or investing activities directly or indirectly connected to the value of real estate. High Yield Securities Risk: Securities rated below investment-grade, commonly referred to as “junk bonds,” include bonds that are rated Ba1/BB+/BB+ or below by Moody's Investors Service, Inc., Fitch Inc., or Standard & Poor's Financial Services, LLC, respectively, or unrated securities considered to be of equivalent quality by the Sub-Adviser, and may involve greater risks than securities in higher rating categories. Such bonds are regarded as speculative in nature, involve greater risk of default by the issuing entity and may be subject to greater market fluctuations than higher rated debt securities. They are usually issued by entities without long track records of sales and earnings, or by entities with questionable credit strength. The retail secondary market for these “junk bonds” may be less liquid than that of higher rated securities and adverse conditions could make it difficult at times to sell certain securities or could result in lower prices than those used in calculating the Fund's net asset value. High yield securities also may present greater credit risk because such securities may be issued in connection with corporate restructuring by highly leveraged issuers or may not be current in the payment of interest or principal or in default. Income Risk: The Fund's income may decline due to falling interest rates or other factors. Issuers of securities held by the Fund may call or redeem the securities during periods of falling interest rates, and the Fund would likely be required to reinvest in securities paying lower interest rates. If an obligation held by the Fund is prepaid, the Fund may have to reinvest the prepayment in other obligations paying income at lower rates. Inflation-Indexed Securities Risk: The principal amount of an inflation-indexed security typically increases with inflation and decreases with deflation, as measured by a specified index. It is possible that, in a period of declining inflation rates, the Fund could receive at maturity less than the initial principal amount of an inflation-indexed security. Changes in the values of inflation-indexed securities may be difficult to predict, and it is possible that an investment in such securities will have an effect different from that anticipated by the Sub-Adviser. Interest Rate Only and Principal Only Securities Risk: Interest rate only and principal only securities are acutely sensitive to interest rate changes and to the rate of principal prepayments. These securities are volatile in price and may have lower liquidity. Investment in ETNs: The value of an exchanged traded note (“ETN”) may be influenced by time to maturity, supply and demand, volatility and lack of liquidity, changes in interest rates, and economic, legal, political or geographic events that affect the referenced market. Because ETNs are debt securities, they are subject to credit risk. There are typically no periodic interest payments for ETNs, and the amount of principal payable at maturity may decline, depending in part on the performance of an underlying index or asset. A Fund could lose all or some of the amount invested in an ETN. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Fund's holdings may limit the ability of the Fund to obtain cash to meet redemptions on a timely basis.  In addition, the Fund, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Management Risk: The Fund is actively managed. The Sub-Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Fund to incur losses. There can be no assurance that the Sub-Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Fund's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Fund is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Mortgage Pass-Through Securities Risk: Most transactions in mortgage pass through securities occur through the use of TBA Transactions, as described above. Default by, or bankruptcy of, a counterparty to a TBA Transaction would expose the Fund to possible losses because of an adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA Transaction. Municipal Obligations Risk: Issuers, including governmental issuers, may be unable to pay their obligations as they come due. The values of municipal obligations that depend on a specific revenue source to fund their payment obligations may fluctuate as a result of actual or anticipated changes in the cash flows generated by the revenue source or changes in the priority of the municipal obligation to receive the cash flows generated by the revenue source. In addition, changes in federal tax laws or the activity of an issuer may adversely affect the tax-exempt status of municipal obligations. Loss of tax-exempt status may result in a significant decline in the values of such municipal obligations. Non-U.S. Securities Risk: Non-U.S. securities are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. To the extent underlying securities held by the Fund trade on foreign exchanges that are closed when the exchange on which the Fund's shares trade is open, there may be deviations between the current price of an underlying security and the last quoted price for the underlying security on the closed foreign market. These deviations could result in the Fund experiencing premiums or discounts greater than those of ETFs that invest in domestic securities. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, when the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Certain countries have recently experienced (or currently are expected to experience) negative interest rates on certain fixed-income securities, and similar interest rate conditions may be experienced in other regions.  Investments in fixed-income securities with very low or negative interest rates may magnify the Fund's susceptibility to interest rate risk and diminish yield and performance, and such investments may be subject to heightened volatility and reduced liquidity. Political Risk: A significant restructuring of federal income tax rates or even serious discussion on the topic in Congress could cause municipal bond prices to fall. The demand for municipal securities is strongly influenced by the value of tax-exempt income to investors. Lower income tax rates could reduce the advantage of owning municipals. Preferred Securities Risk: Generally, preferred security holders have no or limited voting rights with respect to the issuing company. In addition, preferred securities are subordinated to bonds and other debt instruments in a company's capital structure and therefore will be subject to greater credit risk than those debt instruments. Dividend payments on a preferred security typically must be declared by the issuer's board of directors. In the event an issuer of preferred securities experiences economic difficulties, the issuer's preferred securities may lose substantial value due to the reduced likelihood that the issuer's board of directors will declare a dividend and the fact that the preferred security may be subordinated to other securities of the same issuer. Further, because many preferred securities pay dividends at a fixed rate, their market price can be sensitive to changes in interest rates in a manner similar to bonds — that is, as interest rates rise, the value of the preferred securities held by the Fund are likely to decline. In addition, because many preferred securities allow holders to convert the preferred securities into common stock of the issuer, their market price can be sensitive to changes in the value of the issuer's common stock and, therefore, declining common stock values may also cause the value of the Fund's investments to decline. Preferred securities often have call features which allow the issuer to redeem the security at its discretion. The redemption of a preferred security having a higher than average yield may cause a decrease in the Fund's yield. Privately Issued Securities Risk: The Fund will invest in privately-issued securities, including those which are normally purchased pursuant to Rule 144A or Regulation S promulgated under the Securities Act. Privately-issued securities are securities that have not been registered under the Securities Act and as a result are subject to legal restrictions on resale. Privately-issued securities are not traded on established markets and may be illiquid, difficult to value and subject to wide fluctuations in value. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. REMIC Risk: The issuer of a series of mortgage pass-through securities may elect to be treated as a Real Estate Mortgage Investment Conduit (“REMIC”). REMICs include governmental and/or private entities that issue a fixed pool of mortgages secured by an interest in real property. REMICs are similar to collateralized mortgage obligations (“CMOs”) in that they issue multiple classes of securities but, unlike CMOs, which are required to be structured as debt securities, REMICs may be structured as indirect ownership interests in the underlying assets of the REMICs themselves. The risks associated with an investment in a particular CMO or REMIC class vary substantially depending on the combination of rights associated with that class. An investment in the most subordinated classes of a CMO or REMIC bears a disproportionate share of the risks associated with mortgage-backed security generally, be it credit risk, prepayment or extension risk (the risk of a security's expected maturity being reduced or lengthened in duration due to a change of the timing of payment), interest rate risk, income risk, market risk, liquidity risk or any other risk associated with a debt or equity instrument with similar features to the relevant class. As a result, an investment in the most subordinated classes of a CMO or REMIC is often riskier than an investment in other types of mortgage-backed securities. Restricted Securities Risk: The Fund may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Fund from disposing of them promptly at reasonable prices. The Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility. Sovereign Debt Obligations Risk: Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment-grade (“junk” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. Unconstrained Sector Risk: The Fund may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Fund's Shares to decrease, perhaps significantly. U.S. Government Securities Risk: Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks. U.S. Treasury Obligations Risk: U.S. Treasury obligations may differ from other fixed income securities in their interest rates, maturities, times of issuance and other characteristics. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government may cause the value of the Fund's U.S. Treasury obligations to decline. Valuation Risk: Some portfolio holdings, potentially a large portion of the Fund's investment portfolio, may be valued on the basis of factors other than market quotations. This may occur more often in times of market turmoil or reduced liquidity. There are multiple methods that can be used to value a portfolio holding when market quotations are not readily available. The value established for any portfolio holding at a point in time might differ from what would be produced using a different methodology or if it had been priced using market quotations. Portfolio holdings that are valued using techniques other than market quotations, including “fair valued” securities, may be subject to greater fluctuation in their valuations from one day to the next than if market quotations were used. In addition, there is no assurance that the Fund could sell or close out a portfolio position for the value established for it at any time, and it is possible that the Fund would incur a loss because a portfolio position is sold or closed out at a discount to the valuation established by the Fund at that time. Investors who purchase or redeem Fund Shares on days when the Fund is holding fair-valued investments may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the Fund had not fair-valued the holding(s) or had used a different valuation methodology. Variable and Floating Rate Securities Risk: During periods of increasing interest rates, changes in the coupon rates of variable or floating rate securities may lag behind the changes in market rates or may have limits on the maximum increases in coupon rates. Alternatively, during periods of declining interest rates, the coupon rates on such securities will typically readjust downward resulting in a lower yield. Floating rate notes are generally subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such securities. Zero-Coupon Bond Risk: Zero-coupon bonds usually trade at a deep discount from their face or par values and are subject to greater market value fluctuations from changing interest rates than debt obligations of comparable maturities that make current distributions of interest.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Fund. Fund Shares will change in value, and you could lose money by investing in the Fund.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>FUND PERFORMANCE</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.spdrs.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.spdrs.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>ANNUAL TOTAL RETURN </b>(year ended 12/31)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 0.64% (Q2, 2017) Lowest Quarterly Return: -0.12% (Q4, 2017)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS</b> (for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Fund Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Fund Shares.
SPDR DoubleLine Short Duration Total Return Tactical ETF | SPDR DoubleLine Short Duration Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.50%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	none
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.50%
Less contractual fee waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.05%)	[1]
Net annual Fund operating expenses	rr_NetExpensesOverAssets	0.45%
Year 1	rr_ExpenseExampleYear01	$ 46
Year 3	rr_ExpenseExampleYear03	155
Year 5	rr_ExpenseExampleYear05	275
Year 10	rr_ExpenseExampleYear10	$ 623
2017	rr_AnnualReturn2017	1.63%	[2]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.41%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.64%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2017
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(0.12%)
One Year	rr_AverageAnnualReturnYear01	1.63%
Since Inception	rr_AverageAnnualReturnSinceInception	1.48%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016
SPDR DoubleLine Short Duration Total Return Tactical ETF | Return After Taxes on Distributions | SPDR DoubleLine Short Duration Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.77%
Since Inception	rr_AverageAnnualReturnSinceInception	0.46%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016
SPDR DoubleLine Short Duration Total Return Tactical ETF | Return After Taxes on Distributions and Sale of Fund Shares | SPDR DoubleLine Short Duration Total Return Tactical ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.92%
Since Inception	rr_AverageAnnualReturnSinceInception	0.67%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016
SPDR DoubleLine Short Duration Total Return Tactical ETF | Bloomberg Barclays U.S. Aggregate 1-3 Year Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.86%
Since Inception	rr_AverageAnnualReturnSinceInception	0.67%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 13, 2016

[1] SSGA Funds Management, Inc. (“SSGA FM” or “Adviser”) has contractually agreed to waive a portion of its management fee and/or reimburse certain expenses, until October 31, 2019, so that the net annual Fund operating expenses, before application of any fees and expenses not paid by the Adviser pursuant to the Investment Advisory Agreement, if any, are limited to 0.45% of the Fund's average daily net assets. The contractual fee waiver and/or reimbursement does not provide for the recoupment by the Adviser of any fees the Adviser previously waived. The Adviser may continue the waiver and/or reimbursement from year to year, but there is no guarantee that the Adviser will do so and after October 31, 2019, the waiver and/or reimbursement may be cancelled or modified at any time. This waiver and/or reimbursement may not be terminated prior to October 31, 2019 except with the approval of the SSGA Active Trust's Board of Trustees.

[2] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 0.41%.

XML

State Street Disciplined Global Equity Portfolio

PORTFOLIO SUMMARY<br/><br/><b>State Street Disciplined Global Equity Portfolio</b>

<b>INVESTMENT OBJECTIVE</b>

The State Street Disciplined Global Equity Portfolio (the “Portfolio”) seeks to provide competitive long-term returns while maintaining low long-term volatility relative to the broad global equity market.

<b>FEES AND EXPENSES OF THE PORTFOLIO</b>

The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio (“Portfolio Shares”). Portfolio Shares are offered exclusively to investors that pay fees to SSGA Funds Management, Inc. (“SSGA FM” or the “Adviser”), the Portfolio's investment adviser, or its affiliates.

<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):

Annual Fund Operating Expenses	State Street Disciplined Global Equity Portfolio State Street Disciplined Global Equity Portfolio
Management fees	0.25%
Distribution and service (12b-1) fees	none
Other expenses	0.05%
Total annual Fund operating expenses	0.30%
Less contractual fee waiver	(0.30%)	[1]
Net annual Fund operating expenses	none

<b>EXAMPLE:</b>

This Example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Portfolio for the time periods indicated, and then sell all of your Portfolio Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. The Example reflects the Portfolio's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	Year 1	Year 3	Year 5	Year 10
State Street Disciplined Global Equity Portfolio | State Street Disciplined Global Equity Portfolio | USD ($)	none	66	138	351

<b>PORTFOLIO TURNOVER:</b>

The Portfolio 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 Portfolio Shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Portfolio's performance.  During the most recent fiscal year, the Portfolio's portfolio turnover rate was 47% of the average value of its portfolio.

<b>THE PORTFOLIO'S PRINCIPAL INVESTMENT STRATEGY</b>

Under normal circumstances, the Portfolio will invest at least 80% of its net assets (plus borrowings, if any, for investment purposes) in equity securities. The Portfolio will provide shareholders with at least sixty (60) days' notice prior to any change in its 80% policy. The notional value of the Portfolio's investments in derivatives or other synthetic instruments that provide exposure comparable, in the judgment of the Adviser, to the foregoing types of investments may be counted toward satisfaction of the Portfolio's 80% policy. The Adviser seeks to select a portfolio of securities that it expects over the long term to exhibit low volatility both in absolute terms and in comparison with the MSCI World Index (the “Index”) and provide competitive returns as compared with the Index.

In seeking to identify stocks offering the potential for capital growth, the Adviser employs a proprietary quantitative process. The process evaluates the relative attractiveness of eligible securities based on the correlation of certain historical economic and financial factors (such as measures of growth potential, valuation, quality and investor sentiment), and other historical quantitative metrics. Additionally, the process may incorporate an element designed to evaluate the macroeconomic environment and prevailing market conditions. The process is intended to allow the Adviser to evaluate eligible securities and then rank eligible securities in the Portfolio's investment universe in the order of their attractiveness as potential Portfolio investments.

The Adviser also uses a quantitative analysis to determine the expected volatility of a stock's market price. Volatility is a statistical measurement of up and down fluctuations in the value of a security over time. Volatility may result in rapid and dramatic price swings. The Adviser seeks to favor securities with low exposure to market risk factors and low security-specific risk. In determining the exposure of a security to such risk factors, the Adviser may take into account, among other things, such considerations as a security's market capitalization, its price momentum, the security's valuation, the liquidity of the security, the degree to which the issuer is leveraged, and the issuer's growth prospects. The Adviser also implements risk constraints at the overall portfolio level by periodic testing of the Portfolio's composition against proprietary risk models, focusing on such factors as industry and sector exposures, portfolio diversification levels, market capitalization exposure, and geographic exposures.

Through these quantitative processes of security selection and portfolio diversification, the Adviser expects that the Portfolio will be subject to a relatively low level of absolute risk (as defined by statistical measures of volatility, such as standard deviation of returns) and that the Portfolio should exhibit relatively low volatility compared with the Index over the long term. The Adviser will make changes over time in the Portfolio's portfolio to reflect changes in the various risk factors described above. From time to time, the Adviser may make a qualitative judgment not to implement fully the results of the quantitative investment process if it believes that the process did not take into account all of the information relevant to a particular investment or the Portfolio's portfolio in the aggregate, or that a different investment might be more appropriate.

Although the Portfolio targets a low level of volatility in absolute terms and in comparison to the Index, there is no assurance that the Portfolio will achieve its target volatility, and the Portfolio may be subject to significant changes in value over short or longer timeframes. There also can be no assurance that the Portfolio will produce returns in excess of the Index.

The Portfolio will generally invest at least 40% of its assets in securities of issuers economically tied to countries other than the United States and will generally hold securities of issuers economically tied to at least three countries, including the United States. The Portfolio will generally consider an investment in an issuer to be tied to a particular country if (i) the issuer is organized in such country or maintains a principal place of business in such country; (ii) the issuer's securities are traded principally in such country; or (iii) during the issuer's most recent fiscal year, it derived at least 50% of its revenues or profits from goods produced or sold, investments made, or services performed in such country or has at least 50% of its assets in such country.

The Portfolio expects to invest primarily in common stocks. The Portfolio may purchase securities in their initial public offerings, and may hold securities that are restricted as to resale. The Portfolio may invest in other investment companies, including exchange-traded funds, to the extent permitted by applicable law (including those advised by the Adviser). The Portfolio may hold a portion of its assets in cash and cash instruments. While the Portfolio may invest in companies of any market capitalization, it expects to primarily invest in large capitalization companies.

The Portfolio may invest in derivatives, such as futures contracts, in order to gain broad equity market exposures pending investments of cash, or to reduce market exposures pending the sales of securities. The Portfolio reserves the right to enter into foreign currency futures and forward contracts to hedge currency risk, although the Adviser does not currently anticipate that such transactions will play any significant role of the investment process.

<b>PRINCIPAL RISKS OF INVESTING IN THE PORTFOLIO</b>

As with all investments, there are certain risks of investing in the Portfolio. Portfolio Shares will change in value, and you could lose money by investing in the Portfolio. An investment in the Portfolio is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Counterparty Risk: The Portfolio will be subject to credit risk with respect to the counterparties with which the Portfolio enters into derivatives contracts, repurchase agreements, reverse repurchase agreements, and other transactions. If a counterparty fails to meet its contractual obligations, the Portfolio may be unable to terminate or realize any gain on the investment or transaction, or to recover collateral posted to the counterparty, resulting in a loss to the Portfolio. If the Portfolio holds collateral posted by its counterparty, it may be delayed or prevented from realizing on the collateral in the event of a bankruptcy or insolvency proceeding relating to the counterparty.

Currency Hedging Risk: If the Portfolio enters into currency hedging transactions, any loss generated by those transactions generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the hedging transaction and the risk sought to be hedged. There can be no assurance that the Portfolio's hedging transactions will be effective.

Currency Risk: The value of the Portfolio's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Portfolio's assets denominated in foreign currencies.

Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and the Portfolio may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Portfolio's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Adviser or may not have the effect on the Portfolio anticipated by the Adviser.

Equity Investing Risk: The market prices of equity securities owned by the Portfolio may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time.

Futures Contract Risks; Other Exchange-Traded Derivatives: The risk of loss relating to the use of futures contracts and other exchange-traded derivatives is potentially unlimited. There is no assurance that a liquid secondary market on an exchange will exist for any particular futures contract or other exchange-traded derivative or at any particular time. In the event no such market exists for a particular derivative, it might not be possible to effect closing transactions, and the Portfolio will be unable to terminate its exposure to the derivative. If the Portfolio uses futures contracts or other exchange-traded derivatives for hedging purposes, there is a risk of imperfect correlation between movements in the prices of the derivatives and movements in the securities or index underlying the derivatives or movements in the prices of the Portfolio's investments that are the subject of such hedge. Certain foreign futures contracts and other exchange-traded derivatives may be less liquid and more volatile than U.S. contracts. The Portfolio may be delayed or prevented from recovering margin or other amounts deposited with a futures commission merchant or futures clearinghouse.

Geographic Focus Risk: The performance of a fund that is less diversified across countries or geographic regions will be closely tied to market, currency, economic, political, environmental, or regulatory conditions and developments in the countries or regions in which the fund invests, and may be more volatile than the performance of a more geographically-diversified fund.

Growth Stock Risk: The prices of growth stocks may be based largely on expectations of future earnings, and their prices can decline rapidly and significantly in reaction to negative news. Growth stocks may underperform value stocks and stocks in other broad style categories (and the stock market as a whole) over any period of time and may shift in and out of favor with investors generally, sometimes rapidly, depending on changes in market, economic, and other factors.

IPO Risk: The Portfolio may at times have the opportunity to invest in securities offered in initial public offerings ("IPOs"). IPOs involve companies that have no public operating history and therefore entail more risk than established public companies. The prices of securities offered in IPOs can have significant volatility and the Portfolio may lose money on an investment in such securities. IPO investments in which other clients of the Adviser invest may not be made available to the Portfolio.

Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies.

Leveraging Risk: Use of leverage by the Portfolio may have the effect of increasing the volatility of the value of the Portfolio's portfolio, and may entail risk of loss in excess of the Portfolio's invested capital. To the extent the Portfolio uses leverage, the Portfolio's losses (and gains) may be greater than if the Portfolio had not used leverage.

Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Portfolio to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Portfolio's holdings may limit the ability of the Portfolio to obtain cash to meet redemptions on a timely basis.  In addition, the Portfolio, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector.

Management Risk: The Portfolio is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Portfolio to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results.

Market Risk: The Portfolio's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Portfolio is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets.

Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Portfolio from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors.

Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, when the Portfolio buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Portfolio. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market.

Restricted Securities Risk: The Portfolio may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Portfolio from disposing of them promptly at reasonable prices. The Portfolio may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility.

Unconstrained Sector Risk: The Portfolio may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Portfolio's Shares to decrease, perhaps significantly.

Volatility Risk: Because the Portfolio seeks to exhibit relative low volatility and excess returns as compared to the Index over the long term, both its portfolio investments and its returns may differ, potentially greatly, from those of the Index. There can be no assurance that the Portfolio will in fact experience lower volatility than the Index nor can there be any assurance that the Portfolio will produce returns in excess of the benchmark. The application of the Adviser's active stock selection model may lead to a degree of added risk in exchange for the potential outperformance relative to the Index. Because the Portfolio is managed to limit volatility, it is likely that in periods of rapidly rising markets the Portfolio will experience less favorable returns than the Index.

<b>PORTFOLIO PERFORMANCE</b>

The following bar chart and table provide an indication of the risks of investing in the Portfolio by showing changes in the Portfolio's performance from year to year and by showing how the Portfolio's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Portfolio's past performance (before and after taxes) is not necessarily an indication of how the Portfolio will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.ssgafunds.com/resources/materials/mpfDocuments.seam.

Highest Quarterly Return: 7.40% (Q1, 2017)
Lowest Quarterly Return: 3.66% (Q3, 2017)

<b>AVERAGE ANNUAL TOTAL RETURNS </b>(for periods ended 12/31/17)

The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Portfolio Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Portfolio Shares.

Average Annual Total Returns - State Street Disciplined Global Equity Portfolio	One Year	Since Inception	Inception Date
State Street Disciplined Global Equity Portfolio	21.91%	17.28%	Feb. 18, 2016
State Street Disciplined Global Equity Portfolio | Return After Taxes on Distributions	19.84%	15.27%	Feb. 18, 2016
State Street Disciplined Global Equity Portfolio | Return After Taxes on Distributions and Sale of Fund Shares	12.51%	12.42%	Feb. 18, 2016
MSCI World Index (reflects no deduction for fees, expenses or taxes other than withholding taxes on reinvested dividends)	22.40%	20.42%	Feb. 18, 2016

[1] The Adviser has contractually agreed to waive its management fee and/or reimburse expenses in such an amount equal to the “Total annual Fund operating expenses” until the later of April 30, 2020 or such time as the shares of the Portfolio cease to be the only investment security held by the State Street Disciplined Global Equity Fund, a separate series of State Street Institutional Investment Trust. The waiver may be terminated only by the SSGA Active Trust's Board of Trustees.

[1] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 4.49%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
State Street Disciplined Global Equity Portfolio
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	PORTFOLIO SUMMARY<br/><br/><b>State Street Disciplined Global Equity Portfolio</b>
Objective [Heading]	rr_ObjectiveHeading	<b>INVESTMENT OBJECTIVE</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The State Street Disciplined Global Equity Portfolio (the “Portfolio”) seeks to provide competitive long-term returns while maintaining low long-term volatility relative to the broad global equity market.
Expense [Heading]	rr_ExpenseHeading	<b>FEES AND EXPENSES OF THE PORTFOLIO</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio (“Portfolio Shares”). Portfolio Shares are offered exclusively to investors that pay fees to SSGA Funds Management, Inc. (“SSGA FM” or the “Adviser”), the Portfolio's investment adviser, or its affiliates.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>ANNUAL FUND OPERATING EXPENSES </b> (expenses that you pay each year as a percentage of the value of your investment):
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	April 30, 2020
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>PORTFOLIO TURNOVER:</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Portfolio 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 Portfolio Shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Portfolio's performance.  During the most recent fiscal year, the Portfolio's portfolio turnover rate was 47% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	47.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>EXAMPLE:</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Portfolio for the time periods indicated, and then sell all of your Portfolio Shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. The Example reflects the Portfolio's contractual fee waiver and/or expense reimbursement only in the periods for which the contractual fee waiver and/or expense reimbursement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>THE PORTFOLIO'S PRINCIPAL INVESTMENT STRATEGY</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Portfolio will invest at least 80% of its net assets (plus borrowings, if any, for investment purposes) in equity securities. The Portfolio will provide shareholders with at least sixty (60) days' notice prior to any change in its 80% policy. The notional value of the Portfolio's investments in derivatives or other synthetic instruments that provide exposure comparable, in the judgment of the Adviser, to the foregoing types of investments may be counted toward satisfaction of the Portfolio's 80% policy. The Adviser seeks to select a portfolio of securities that it expects over the long term to exhibit low volatility both in absolute terms and in comparison with the MSCI World Index (the “Index”) and provide competitive returns as compared with the Index. In seeking to identify stocks offering the potential for capital growth, the Adviser employs a proprietary quantitative process. The process evaluates the relative attractiveness of eligible securities based on the correlation of certain historical economic and financial factors (such as measures of growth potential, valuation, quality and investor sentiment), and other historical quantitative metrics. Additionally, the process may incorporate an element designed to evaluate the macroeconomic environment and prevailing market conditions. The process is intended to allow the Adviser to evaluate eligible securities and then rank eligible securities in the Portfolio's investment universe in the order of their attractiveness as potential Portfolio investments. The Adviser also uses a quantitative analysis to determine the expected volatility of a stock's market price. Volatility is a statistical measurement of up and down fluctuations in the value of a security over time. Volatility may result in rapid and dramatic price swings. The Adviser seeks to favor securities with low exposure to market risk factors and low security-specific risk. In determining the exposure of a security to such risk factors, the Adviser may take into account, among other things, such considerations as a security's market capitalization, its price momentum, the security's valuation, the liquidity of the security, the degree to which the issuer is leveraged, and the issuer's growth prospects. The Adviser also implements risk constraints at the overall portfolio level by periodic testing of the Portfolio's composition against proprietary risk models, focusing on such factors as industry and sector exposures, portfolio diversification levels, market capitalization exposure, and geographic exposures. Through these quantitative processes of security selection and portfolio diversification, the Adviser expects that the Portfolio will be subject to a relatively low level of absolute risk (as defined by statistical measures of volatility, such as standard deviation of returns) and that the Portfolio should exhibit relatively low volatility compared with the Index over the long term. The Adviser will make changes over time in the Portfolio's portfolio to reflect changes in the various risk factors described above. From time to time, the Adviser may make a qualitative judgment not to implement fully the results of the quantitative investment process if it believes that the process did not take into account all of the information relevant to a particular investment or the Portfolio's portfolio in the aggregate, or that a different investment might be more appropriate. Although the Portfolio targets a low level of volatility in absolute terms and in comparison to the Index, there is no assurance that the Portfolio will achieve its target volatility, and the Portfolio may be subject to significant changes in value over short or longer timeframes. There also can be no assurance that the Portfolio will produce returns in excess of the Index. The Portfolio will generally invest at least 40% of its assets in securities of issuers economically tied to countries other than the United States and will generally hold securities of issuers economically tied to at least three countries, including the United States. The Portfolio will generally consider an investment in an issuer to be tied to a particular country if (i) the issuer is organized in such country or maintains a principal place of business in such country; (ii) the issuer's securities are traded principally in such country; or (iii) during the issuer's most recent fiscal year, it derived at least 50% of its revenues or profits from goods produced or sold, investments made, or services performed in such country or has at least 50% of its assets in such country. The Portfolio expects to invest primarily in common stocks. The Portfolio may purchase securities in their initial public offerings, and may hold securities that are restricted as to resale. The Portfolio may invest in other investment companies, including exchange-traded funds, to the extent permitted by applicable law (including those advised by the Adviser). The Portfolio may hold a portion of its assets in cash and cash instruments. While the Portfolio may invest in companies of any market capitalization, it expects to primarily invest in large capitalization companies. The Portfolio may invest in derivatives, such as futures contracts, in order to gain broad equity market exposures pending investments of cash, or to reduce market exposures pending the sales of securities. The Portfolio reserves the right to enter into foreign currency futures and forward contracts to hedge currency risk, although the Adviser does not currently anticipate that such transactions will play any significant role of the investment process.
Risk [Heading]	rr_RiskHeading	<b>PRINCIPAL RISKS OF INVESTING IN THE PORTFOLIO</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with all investments, there are certain risks of investing in the Portfolio. Portfolio Shares will change in value, and you could lose money by investing in the Portfolio. An investment in the Portfolio is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Counterparty Risk: The Portfolio will be subject to credit risk with respect to the counterparties with which the Portfolio enters into derivatives contracts, repurchase agreements, reverse repurchase agreements, and other transactions. If a counterparty fails to meet its contractual obligations, the Portfolio may be unable to terminate or realize any gain on the investment or transaction, or to recover collateral posted to the counterparty, resulting in a loss to the Portfolio. If the Portfolio holds collateral posted by its counterparty, it may be delayed or prevented from realizing on the collateral in the event of a bankruptcy or insolvency proceeding relating to the counterparty. Currency Hedging Risk: If the Portfolio enters into currency hedging transactions, any loss generated by those transactions generally should be substantially offset by gains on the hedged investment, and vice versa. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the hedging transaction and the risk sought to be hedged. There can be no assurance that the Portfolio's hedging transactions will be effective. Currency Risk: The value of the Portfolio's assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and delays, restrictions or prohibitions on the repatriation of foreign currencies. Foreign currency exchange rates may have significant volatility, and changes in the values of foreign currencies against the U.S. dollar may result in substantial declines in the values of the Portfolio's assets denominated in foreign currencies. Derivatives Risk: Derivative transactions can create investment leverage and may have significant volatility. It is possible that a derivative transaction will result in a much greater loss than the principal amount invested, and the Portfolio may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Portfolio's margin, or otherwise honor its obligations. A derivatives transaction may not behave in the manner anticipated by the Adviser or may not have the effect on the Portfolio anticipated by the Adviser. Equity Investing Risk: The market prices of equity securities owned by the Portfolio may go up or down, sometimes rapidly or unpredictably. The value of a security may decline for a number of reasons that may directly relate to the issuer and also may decline due to general industry or market conditions that are not specifically related to a particular company. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Futures Contract Risks; Other Exchange-Traded Derivatives: The risk of loss relating to the use of futures contracts and other exchange-traded derivatives is potentially unlimited. There is no assurance that a liquid secondary market on an exchange will exist for any particular futures contract or other exchange-traded derivative or at any particular time. In the event no such market exists for a particular derivative, it might not be possible to effect closing transactions, and the Portfolio will be unable to terminate its exposure to the derivative. If the Portfolio uses futures contracts or other exchange-traded derivatives for hedging purposes, there is a risk of imperfect correlation between movements in the prices of the derivatives and movements in the securities or index underlying the derivatives or movements in the prices of the Portfolio's investments that are the subject of such hedge. Certain foreign futures contracts and other exchange-traded derivatives may be less liquid and more volatile than U.S. contracts. The Portfolio may be delayed or prevented from recovering margin or other amounts deposited with a futures commission merchant or futures clearinghouse. Geographic Focus Risk: The performance of a fund that is less diversified across countries or geographic regions will be closely tied to market, currency, economic, political, environmental, or regulatory conditions and developments in the countries or regions in which the fund invests, and may be more volatile than the performance of a more geographically-diversified fund. Growth Stock Risk: The prices of growth stocks may be based largely on expectations of future earnings, and their prices can decline rapidly and significantly in reaction to negative news. Growth stocks may underperform value stocks and stocks in other broad style categories (and the stock market as a whole) over any period of time and may shift in and out of favor with investors generally, sometimes rapidly, depending on changes in market, economic, and other factors. IPO Risk: The Portfolio may at times have the opportunity to invest in securities offered in initial public offerings ("IPOs"). IPOs involve companies that have no public operating history and therefore entail more risk than established public companies. The prices of securities offered in IPOs can have significant volatility and the Portfolio may lose money on an investment in such securities. IPO investments in which other clients of the Adviser invest may not be made available to the Portfolio. Large-Capitalization Securities Risk: Returns on investments in securities of large companies could trail the returns on investments in securities of smaller and mid-sized companies. Larger companies may be unable to respond as quickly as smaller and mid-sized companies to competitive challenges or to changes in business, product, financial, or other market conditions. Larger companies may not be able to maintain growth at the high rates that may be achieved by well-managed smaller and mid-sized companies. Leveraging Risk: Use of leverage by the Portfolio may have the effect of increasing the volatility of the value of the Portfolio's portfolio, and may entail risk of loss in excess of the Portfolio's invested capital. To the extent the Portfolio uses leverage, the Portfolio's losses (and gains) may be greater than if the Portfolio had not used leverage. Liquidity Risk: Lack of a ready market or restrictions on resale may limit the ability of the Portfolio to sell a security at an advantageous time or price or at all. Illiquid securities may trade at a discount from comparable, more liquid investments and may be subject to wide fluctuations in market value. Illiquidity of the Portfolio's holdings may limit the ability of the Portfolio to obtain cash to meet redemptions on a timely basis.  In addition, the Portfolio, due to limitations on investments in any illiquid securities and/or the difficulty in purchasing and selling such investments, may be unable to achieve its desired level of exposure to a certain market or sector. Management Risk: The Portfolio is actively managed. The Adviser's judgments about the attractiveness, relative value, or potential appreciation of a particular sector, security, commodity or investment strategy may prove to be incorrect, and may cause the Portfolio to incur losses. There can be no assurance that the Adviser's investment techniques and decisions will produce the desired results. Market Risk: The Portfolio's investments are subject to changes in general economic conditions, and general market fluctuations and the risks inherent in investment in securities markets. Investment markets can be volatile and prices of investments can change substantially due to various factors including, but not limited to, economic growth or recession, changes in interest rates, changes in the actual or perceived creditworthiness of issuers, and general market liquidity. The Portfolio is subject to the risk that geopolitical events will disrupt securities markets and adversely affect global economies and markets. Modeling Risk: The Adviser uses quantitative models in an effort to enhance returns and manage risk. Any imperfections, errors or limitations in these models could limit any benefit to the Portfolio from the use of the models, or could result in incorrect outputs or in investment outcomes different from or opposite to those expected or desired by the Adviser. There can be no assurance that the models will behave as expected in all market conditions. In addition, computer programming used to create quantitative models, or the data on which such models operate, might contain one or more errors. Non-U.S. Securities Risk: Non-U.S. securities (including depositary receipts) are subject to political, regulatory, and economic risks not present in domestic investments. There may be less information publicly available about a non-U.S. entity than about a U.S. entity, and many non-U.S. entities are not subject to accounting, auditing, legal and financial report standards comparable to those in the United States. Further, such entities and/or their securities may be subject to risks associated with currency controls; expropriation; changes in tax policy; greater market volatility; differing securities market structures; higher transaction costs; and various administrative difficulties, such as delays in clearing and settling portfolio transactions or in receiving payment of dividends. Securities traded on foreign markets may be less liquid (harder to sell) than securities traded domestically. Foreign governments may impose restrictions on the repatriation of capital to the U.S. In addition, when the Portfolio buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent investments are made in a limited number of countries, events in those countries will have a more significant impact on the Portfolio. Investments in depositary receipts may be less liquid and more volatile than the underlying shares in their primary trading market. Restricted Securities Risk: The Portfolio may hold securities that have not been registered for sale to the public under the U.S. federal securities laws. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may have an adverse effect on their marketability, and may prevent the Portfolio from disposing of them promptly at reasonable prices. The Portfolio may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Also, restricted securities may be difficult to value because market quotations may not be readily available, and the securities may have significant volatility. Unconstrained Sector Risk: The Portfolio may invest a substantial portion of its assets within one or more economic sectors or industries, which may change from time to time. Greater investment focus on one or more sectors or industries increases the potential for volatility and the risk that events negatively affecting such sectors or industries could reduce returns, potentially causing the value of the Portfolio's Shares to decrease, perhaps significantly. Volatility Risk: Because the Portfolio seeks to exhibit relative low volatility and excess returns as compared to the Index over the long term, both its portfolio investments and its returns may differ, potentially greatly, from those of the Index. There can be no assurance that the Portfolio will in fact experience lower volatility than the Index nor can there be any assurance that the Portfolio will produce returns in excess of the benchmark. The application of the Adviser's active stock selection model may lead to a degree of added risk in exchange for the potential outperformance relative to the Index. Because the Portfolio is managed to limit volatility, it is likely that in periods of rapidly rising markets the Portfolio will experience less favorable returns than the Index.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with all investments, there are certain risks of investing in the Portfolio. Portfolio Shares will change in value, and you could lose money by investing in the Portfolio.
RIsk Not Insured [Text]	rr_RiskNotInsured	An investment in the Portfolio is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>PORTFOLIO PERFORMANCE</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide an indication of the risks of investing in the Portfolio by showing changes in the Portfolio's performance from year to year and by showing how the Portfolio's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance. The Portfolio's past performance (before and after taxes) is not necessarily an indication of how the Portfolio will perform in the future. Updated performance information is available by calling 1-866-787-2257 or visiting our website at https://www.ssgafunds.com/resources/materials/mpfDocuments.seam.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide an indication of the risks of investing in the Portfolio by showing changes in the Portfolio's performance from year to year and by showing how the Portfolio's average annual returns for certain time periods compare with the average annual returns of an index measuring market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-866-787-2257
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://www.ssgafunds.com/resources/materials/mpfDocuments.seam
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Portfolio's past performance (before and after taxes) is not necessarily an indication of how the Portfolio will perform in the future.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Highest Quarterly Return: 7.40% (Q1, 2017) Lowest Quarterly Return: 3.66% (Q3, 2017)
Performance Table Heading	rr_PerformanceTableHeading	<b>AVERAGE ANNUAL TOTAL RETURNS </b>(for periods ended 12/31/17)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Portfolio Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Portfolio Shares.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold Portfolio Shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. The returns after taxes can exceed the returns before taxes due to an assumed tax benefit for a shareholder from realizing a capital loss on a sale of Portfolio Shares.
State Street Disciplined Global Equity Portfolio | State Street Disciplined Global Equity Portfolio
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.25%
Distribution and service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.05%
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.30%
Less contractual fee waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.30%)	[1]
Net annual Fund operating expenses	rr_NetExpensesOverAssets	none
Year 1	rr_ExpenseExampleYear01	none
Year 3	rr_ExpenseExampleYear03	66
Year 5	rr_ExpenseExampleYear05	138
Year 10	rr_ExpenseExampleYear10	$ 351
2017	rr_AnnualReturn2017	21.91%	[2]
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-To-Date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	4.49%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarterly Return:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	7.40%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarterly Return:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2017
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	3.66%
One Year	rr_AverageAnnualReturnYear01	21.91%
Since Inception	rr_AverageAnnualReturnSinceInception	17.28%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 18, 2016
State Street Disciplined Global Equity Portfolio | Return After Taxes on Distributions | State Street Disciplined Global Equity Portfolio
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	19.84%
Since Inception	rr_AverageAnnualReturnSinceInception	15.27%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 18, 2016
State Street Disciplined Global Equity Portfolio | Return After Taxes on Distributions and Sale of Fund Shares | State Street Disciplined Global Equity Portfolio
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	12.51%
Since Inception	rr_AverageAnnualReturnSinceInception	12.42%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 18, 2016
State Street Disciplined Global Equity Portfolio | MSCI World Index (reflects no deduction for fees, expenses or taxes other than withholding taxes on reinvested dividends)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	22.40%
Since Inception	rr_AverageAnnualReturnSinceInception	20.42%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 18, 2016

[1] The Adviser has contractually agreed to waive its management fee and/or reimburse expenses in such an amount equal to the “Total annual Fund operating expenses” until the later of April 30, 2020 or such time as the shares of the Portfolio cease to be the only investment security held by the State Street Disciplined Global Equity Fund, a separate series of State Street Institutional Investment Trust. The waiver may be terminated only by the SSGA Active Trust's Board of Trustees.

[2] As of 9/30/2018, the Fund's Calendar Year-To-Date return was 4.49%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SSGA Active Trust
Prospectus Date	rr_ProspectusDate	Oct. 31, 2018
Document Creation Date	dei_DocumentCreationDate	Oct. 29, 2018