Pioneer Series Trust VI

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Registrant Name

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Pioneer Series Trust VI

Prospectus Date

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Sep. 13, 2013

Pioneer Multi-Asset Real Return Fund

Objective, Primary [Text Block]

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Risk/Return [Heading]

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PIONEER MULTI-ASSET REAL RETURN FUND

Objective [Heading]

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INVESTMENT OBJECTIVE

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The fund's investment objective is total return.

Expense [Heading]

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FEES AND EXPENSES OF THE FUND

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.

You may qualify for sales charge discounts if you or your family invest, or agree to invest in the future, at least $100,000 in Class A shares of the Pioneer funds. More information about these and other discounts is available from your investment professional and in the "Sales charges" section of the prospectus beginning on page 55 and the "Sales charges" section of the statement of additional information beginning on page 67.

Shareholder Fees Caption [Text]

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SHAREOWNER FEES
(fees paid directly from your investment)

Operating Expenses Caption [Text]

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

Fee Waiver or Reimbursement over Assets, Date of Termination

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May 1, 2014

Portfolio Turnover [Heading]

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PORTFOLIO TURNOVER

Portfolio Turnover [Text Block]

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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 175% of the average value of its portfolio.

Portfolio Turnover, Rate

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175.00%

Expense Breakpoint Discounts [Text]

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You may qualify for sales charge discounts if you or your family invest, or agree to invest in the future, at least $100,000 in Class A shares of the Pioneer funds.

Expense Breakpoint, Minimum Investment Required [Amount]

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$ 100,000

Other Expenses, New Fund, Based on Estimates [Text]

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Other expenses for Class R and Class Z shares are based on estimated amounts for the current fiscal year.

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

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Total annual fund operating expenses in the table, before and after fee waiver and expense reimbursements, may be higher than the corresponding ratio of expenses to average net assets shown in the "Financial Highlights" section which does not include acquired fund fees and expenses.

Expense Example [Heading]

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EXAMPLE

Expense Example Narrative [Text Block]

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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 shown and then, except as indicated, redeem all of your shares at the end of those periods. It also assumes that (a) your investment has a 5% return each year and (b) the fund's total annual operating expenses remain the same except for year one (which considers the effect of the expense limitation). Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example by, Year, Caption [Text]

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IF YOU REDEEM YOUR SHARES
NUMBER OF YEARS YOU OWN YOUR SHARES

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

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IF YOU DO NOT REDEEM YOUR SHARES
NUMBER OF YEARS YOU OWN YOUR SHARES

Strategy [Heading]

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PRINCIPAL INVESTMENT STRATEGIES

Strategy Narrative [Text Block]

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The fund selects investments from a broad spectrum of asset classes, including both traditional investments, such as equity and fixed income securities, and less traditional or alternative investments, such as commodity-oriented investments, real estate related investments, and currencies. The fund seeks "real return" by holding some investments that historically have not moved in step with broad equity and fixed income markets and selecting investments believed to provide total return in consideration of perceived risk and changing market and economic conditions over time. Real return is considered to be a level of total return that exceeds the rate of inflation over the course of different market environments.

Equity securities may include common and preferred stocks, depositary receipts, warrants, rights, equity-linked securities and other equity interests. The fund may invest in securities of issuers of any market capitalization. In addition to direct investment in securities and other instruments, the fund may invest in other funds, including exchange-traded funds ("ETFs"), unit investment trusts, and other pooled investment vehicles that may or may not be registered under the Investment Company Act of 1940 (the "1940 Act"). Some of these funds may be managed by the adviser. The fund may invest in real estate investment trusts ("REITs") and U.S. and non-U.S. real estate companies.

Fixed income securities include those issued by U.S. and non-U.S. governmental, corporate and other issuers, including mortgage-related or mortgage-backed securities (including "sub-prime" mortgages), asset-backed securities and floating rate loans, convertible securities, Treasury Inflation Protected Securities ("TIPS") and other inflation-linked debt securities, subordinated debt securities and event-linked bonds. The fund may invest in debt securities of any credit quality, including those rated below investment grade (known as "junk bonds") or, if unrated, of equivalent credit quality as determined by the fund's investment adviser. The fund may invest in securities with a broad range of maturities.

The fund's investments may have fixed or variable principal payments and all types of interest rate payment and reset terms, including fixed rate, floating rate, inverse floating rate, zero coupon, contingent, deferred and payment in kind and auction rate features. The fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis.

The fund may gain exposure to commodities (such as oil and precious metals) through investment in commodity-linked derivatives, ETFs, and leveraged or unleveraged commodity-linked notes (derivative debt instruments with principal and/or coupon payments linked to the performance of commodity indices). The fund also may invest in equity securities of issuers in commodity-related industries. The fund may gain exposure to commodities through investment in a wholly-owned subsidiary of the fund organized under the laws of the Cayman Islands (the "Subsidiary") that is expected to invest in commodity-oriented investments. The fund may invest up to 25% of its total assets in the Subsidiary. The Subsidiary is advised by the adviser.

The fund may, but is not required to, use derivatives. The fund may use derivatives for a variety of other purposes, including: as a hedge against adverse changes in the market price of securities, interest rates or currency exchange rates; as a substitute for purchasing or selling securities; and to increase the fund's return as a non-hedging strategy that may be considered speculative. The fund may invest without limit in derivative instruments (other than commodity-related derivative instruments). However, the fund may choose not to make use of derivatives for a variety of reasons, and any use may be limited by applicable law and regulations.

The fund may invest up to 100% of its assets in non-U.S. securities, including securities of emerging market issuers. In addition to investing in securities denominated in non-U.S. currencies, the fund may hold non-U.S. currencies and purchase and sell forward currency exchange contracts in non-U.S. currencies.

The fund may take a short position with respect to a security or index for which the adviser has a negative tactical view, either through the short sale of a security or through a derivative position, such as a futures contract or swap agreement.

As part of its investment strategies, the fund may engage in active and frequent trading of portfolio securities.

In selecting investments, the adviser initially constructs an overall asset allocation model based on its expectations for economic growth and inflation on a global basis. In selecting among asset classes, the adviser considers the relative return potential of particular asset classes in view of their expected relative volatility (the variability of returns from one period to the next). The goal of this process is to identify a combination of asset classes with the potential to provide real return due to a favorable overall risk/return profile. In selecting investments within each asset class, the adviser considers the potential to provide incremental return to the portfolio consistent with the expectations for the asset class. When investing in equity and debt securities, the adviser generally favors those securities it perceives to be undervalued. Investments typically are sold when the adviser's overall assessment of market and economic conditions changes or the assessments of the attributes of asset classes or individual holdings change.

The fund is not required to allocate its investments among asset classes in any fixed proportion, nor is it limited by the issuer's geographic location, size or market capitalization. The fund may have none, some or all of its assets invested in each asset class in relative proportions that change over time based upon market and economic conditions.

The fund is not diversified, which means that it can invest a higher percentage of its assets in the securities of any one or more issuers than a diversified fund.

Risk [Heading]

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PRINCIPAL RISKS OF INVESTING IN THE FUND

Risk Narrative [Text Block]

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You could lose money on your investment in the fund. As with any mutual fund, there is no guarantee that the fund will achieve its objective.

MARKET RISK. The values of securities held by the fund may go up or down, sometimes rapidly or unpredictably, due to general market conditions, such as real or perceived adverse economic, political, or regulatory conditions, inflation, changes in interest or currency rates or adverse investor sentiment. Adverse market conditions may be prolonged and may not have the same impact on all types of securities. The values of securities may fall due to factors affecting a particular issuer, industry or the securities market as a whole. The stock market may perform poorly relative to other investments. (This risk may be greater in the short term.) High public debt in the U.S. and other countries creates ongoing systemic and market risks and policymaking uncertainty. The financial crisis that began in 2008 has caused a significant decline in the value and liquidity of many securities of issuers worldwide. Some governmental and non-governmental issuers (notably in Europe) have defaulted on, or been forced to restructure, their debts, and many other issuers have faced difficulties obtaining credit. These market conditions may continue, worsen or spread, including in the U.S., Europe and beyond. Further defaults or restructurings by governments and others of their debt could have additional adverse effects on economies, financial markets and asset valuations around the world. In response to the crisis, the U.S. and other governments and the Federal Reserve and certain foreign central banks have taken steps to support financial markets. The withdrawal of this support, failure of efforts in response to the crisis, or investor perception that these efforts are not succeeding could negatively affect financial markets generally as well as the value and liquidity of certain securities. Whether or not the fund invests in securities of issuers located in or with significant exposure to countries experiencing economic and financial difficulties, the value and liquidity of the fund's investments may be negatively affected by the countries experiencing these difficulties. In addition, policy and legislative changes in the U.S. and in other countries are affecting many aspects of financial regulation. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time. The fund may experience a substantial or complete loss on any individual security.

NON-DIVERSIFICATION RISK. The fund is not diversified, which means that it can invest a higher percentage of its assets in the securities of any one or more issuers than a diversified fund. Being non-diversified may magnify the fund's losses from adverse events affecting a particular issuer.

INTEREST RATE RISK. Interest rates may go up, causing the value of the fund's investments to decline (this risk generally will be greater for securities with longer maturities). Interest rates in the U.S. recently have been historically low.

CREDIT RISK. If an issuer or guarantor of a security held by the fund or a counterparty to a financial contract with the fund defaults on its obligation to pay principal and/or interest, has its credit rating downgraded or is perceived to be less creditworthy, or the credit quality or value of any underlying assets declines, the value of your investment will decline. Credit risk is broadly gauged by the credit ratings of the securities in which the fund invests. However, ratings are only the opinions of the companies issuing them and are not guarantees as to quality. Junk bonds have a higher risk of default or are already in default and are considered speculative.

PREPAYMENT OR CALL RISK. Many issuers have a right to prepay their securities. If interest rates fall, an issuer may exercise this right. If this happens, the fund will be forced to reinvest prepayment proceeds at a time when yields on securities available in the market are lower than the yield on the prepaid security. The fund also may lose any premium it paid on the security.

EXTENSION RISK. During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected principal payments. This may lock in a below market interest rate, increase the security's duration (the estimated period until the security is paid in full) and reduce the value of the security.

INFLATION-LINKED SECURITIES RISK. The principal or interest of inflation-linked securities such as TIPS is adjusted periodically to a specified rate of inflation. The inflation index used may not accurately measure the real rate of inflation. Inflation-linked securities may lose value or interest payments on such securities may decline in the event that the actual rate of inflation is different than the rate of the inflation index.

U.S. GOVERNMENT AGENCY OBLIGATIONS RISK. The fund invests in obligations issued by agencies and instrumentalities of the U.S. government. Government-sponsored entities such as Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal Home Loan Banks (FHLBs), although chartered or sponsored by Congress, are not funded by congressional appropriations and the debt and mortgage-backed securities issued by them are neither guaranteed nor issued by the U.S. government. Such debt and mortgage-backed securities are subject to the risk of default on the payment of interest and/or principal, similar to debt of private issuers. Although the U.S. government has provided financial support to Fannie Mae and Freddie Mac in the past, there can be no assurance that it will support these or other government-sponsored entities in the future.

MORTGAGE-RELATED AND ASSET-BACKED SECURITIES RISK. The value of mortgage-related and asset-backed securities will be influenced by factors affecting the housing market and the assets underlying such securities. As a result, during periods of declining asset value, difficult or frozen credit markets, swings in interest rates, or deteriorating economic conditions, mortgage-related and asset-backed securities may decline in value, face valuation difficulties, become more volatile and/or become illiquid. Additionally, during such periods and also under normal conditions, these securities are also subject to prepayment and call risk. Some of these securities may receive little or no collateral protection from the underlying assets and are thus subject to the risk of default. The risk of such defaults is generally higher in the case of mortgage-backed investments that include so-called "sub-prime" mortgages. The structure of some of these securities may be complex and there may be less available information than for other types of debt securities. Upon the occurrence of certain triggering events or defaults, the fund may become the holder of underlying assets at a time when those assets may be difficult to sell or may be sold only at a loss.

RISKS OF SUBORDINATED SECURITIES. A holder of securities that are subordinated or "junior" to more senior securities of an issuer is entitled to payment after holders of more senior securities of the issuer. Subordinated securities are more likely to suffer a credit loss than non-subordinated securities of the same issuer, any loss incurred by the subordinated securities is likely to be proportionately greater, and any recovery of interest or principal may take more time. As a result, even a perceived decline in creditworthiness of the issuer is likely to have a greater impact on them.

HIGH YIELD OR "JUNK" BOND RISK. Debt securities that are below investment grade, called "junk bonds," are speculative, have a higher risk of default or are already in default, tend to be less liquid and are more difficult to value than higher grade securities. Junk bonds tend to be volatile and more susceptible to adverse events and negative sentiments.

RISKS OF INVESTING IN FLOATING RATE LOANS. Floating rate loans and similar investments may be illiquid or less liquid than other investments. The value of collateral, if any, securing a floating rate loan can decline or may be insufficient to meet the issuer's obligations or may be difficult to liquidate. No active trading market may exist for many floating rate loans, and many loans are subject to restrictions on resale. Market quotations for these securities may be volatile and/or subject to large spreads between bid and ask prices. Any secondary market may be subject to irregular trading activity and extended trade settlement periods.

RISKS OF INVESTING IN INVERSE FLOATING RATE OBLIGATIONS. The interest rate on inverse floating rate obligations will generally decrease as short-term interest rates increase, and increase as short-term rates decrease. Due to their leveraged structure, the sensitivity of the market value of an inverse floating rate obligation to changes in interest rates is generally greater than a comparable long-term bond issued by the same issuer and with similar credit quality, redemption and maturity provisions. Inverse floating rate obligations may be volatile and involve leverage risk.

RISKS OF INVESTING IN EVENT-LINKED BONDS. The return of principal and the payment of interest on "event-linked" bonds are contingent on the non-occurrence of a pre-defined "trigger" event, such as a hurricane or an earthquake of a specific magnitude. If a trigger event, as defined within the terms of an event-linked bond, involves losses or other metrics exceeding a specific magnitude in the geographic region and time period specified therein, the fund may lose a portion or all of its accrued interest and/or principal invested in such event-linked bond. In addition to the specified trigger events, event-linked bonds may expose the fund to other risks, including but not limited to issuer (credit) default, adverse regulatory or jurisdictional interpretations and adverse tax consequences.

EQUITY SECURITIES RISK. Equity securities represent an ownership interest in an issuer, rank junior in a company's capital structure to debt securities and consequently may entail greater risk of loss than debt securities. Equity securities are subject to the risk that stock prices may rise and fall in periodic cycles and may perform poorly relative to other investments. This risk may be greater in the short term.

SMALL AND MID-SIZE COMPANIES RISK. Compared to large companies, small- and mid-size companies, and the market for their equity securities, may be more sensitive to changes in earnings results and investor expectations, have more limited product lines and capital resources, experience sharper swings in market values, have limited liquidity, be harder to value or to sell at the times and prices the adviser thinks appropriate, and offer greater potential for gain and loss.

RISK OF INVESTMENT IN OTHER FUNDS. Investing in other investment companies, including exchange-traded funds (ETFs), subjects the fund to the risks of investing in the underlying securities or assets held by those funds. When investing in another fund, the fund will bear a pro rata portion of the underlying fund's expenses, in addition to its own expenses. Although the amount of investment in other funds is limited by legal or tax considerations in certain circumstances, the fund may invest extensively in other funds under certain rules and other forms of relief. ETFs are bought and sold based on market prices and can trade at a premium or a discount to the ETF's net asset value. ETFs that invest in commodities may be subject to regulatory trading limits that could affect the value of their securities.

EXCHANGE-TRADED NOTE RISK. Exchange-traded notes (ETNs) are debt securities that are linked to the performance of an underlying index. An ETN's value generally depends on the performance of the underlying index and the credit rating of the issuer. The market price of an ETN may be more volatile than the price of the underlying securities. The cost of owning an ETN may exceed the cost of investing directly in the underlying securities.

RISKS OF INVESTMENTS IN REITS. Investing in REITs involves unique risks. They are significantly affected by the market for real estate and are dependent upon management skills and cash flow. REITs may have lower trading volumes and may be subject to more abrupt or erratic price movements than the overall securities markets. In addition to its own expenses, the fund will indirectly bear its proportionate share of any management and other expenses paid by REITs in which it invests. Many real estate companies, including REITs, utilize leverage.

RISKS OF NON-U.S. INVESTMENTS. Investing in non-U.S. issuers, or in U.S. issuers that have significant exposure to foreign markets, may involve unique risks compared to investing in securities of U.S. issuers. These risks are more pronounced for issuers in emerging markets or to the extent that the fund invests significantly in one region or country. These risks may include different financial reporting practices and regulatory standards, less liquid trading markets, extreme price volatility, currency risks, changes in economic, political, regulatory and social conditions, sustained economic downturns, financial instability, tax burdens, and investment and repatriation restrictions. Lack of information and less market regulation also may affect the value of these securities. Withholding and other non-U.S. taxes may decrease the fund's return. Non-U.S. issuers may be located in parts of the world that have historically been prone to natural disasters. Investing in depositary receipts is subject to many of the same risks as investing directly in non-U.S. issuers.

CURRENCY RISK. Because the fund may invest in non-U.S. currencies, securities denominated in non-U.S. currencies, and other currency-related investments, the fund is subject to currency risk, meaning that the fund could experience losses based on changes in the exchange rate between non-U.S. currencies and the U.S. dollar. Currency exchange rates can be volatile, and are affected by factors such as general economic conditions, the actions of the U.S. and foreign governments or central banks, the imposition of currency controls and speculation.

COMMODITY INVESTMENTS RISK. Exposure to the commodities markets may subject the fund to greater volatility than investments in other securities. The value of commodity-linked derivatives may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity, such as drought, floods, weather, livestock disease, embargoes, tariffs and international economic, political and regulatory developments. The prices of energy, industrial metals, precious metals, agriculture and livestock sector commodities may fluctuate widely due to factors such as changes in value, supply and demand and governmental regulatory policies. Commodity-related investments may be more volatile and less liquid than the underlying commodities, instruments or measures, are subject to the credit risks associated with the issuer, and their values may decline substantially if the issuer's creditworthiness deteriorates. As a result, returns of commodity-linked investments may deviate significantly from the return of the underlying commodity, instruments or measures. The fund intends to gain exposure to commodities by investing in the Subsidiary, a foreign entity that will be treated as a corporation for U.S. federal income tax purposes. The fund's ability to invest in commodity-related investments, and the means through which any such investments may be made, will be limited by tax considerations.

RISKS OF INVESTING IN THE SUBSIDIARY. The Subsidiary is not registered under the 1940 Act and is not subject to all of the investor protections of the 1940 Act. Thus, the fund, as an investor in the Subsidiary, will not have all of the regulatory protections offered to investors in registered investment companies. In addition, changes in the laws of the United States and/or the Cayman Islands, under which the fund and the Subsidiary, respectively, are organized, could affect the ability of the fund and/or the Subsidiary to operate as described in this prospectus and could negatively affect the fund and its shareholders.

DERIVATIVES RISK. Using derivatives can increase fund losses and reduce opportunities for gains when market prices, interest rates or the derivative instruments themselves behave in a way not anticipated by the fund. Using derivatives may increase the volatility of the fund's net asset value and may not provide the result intended. Derivatives may have a leveraging effect on the fund. Some derivatives have the potential for unlimited loss, regardless of the size of the fund's initial investment. Changes in a derivative's value may not correlate well with the referenced asset or metric. The fund also may have to sell assets at inopportune times to satisfy its obligations. Derivatives may be difficult to sell, unwind or value, and the counterparty may default on its obligations to the fund. New regulations are changing the derivatives markets. The regulations may make using derivatives more costly, may limit their availability, or may otherwise adversely affect their value or performance. For derivatives that are required to be traded through a clearinghouse or exchange, the fund also will be exposed to the credit risk of the clearinghouse and the broker that submits trades for the fund. The extent and impact of the new regulations are not yet fully known and may not be for some time.

CREDIT DEFAULT SWAP RISK. Credit default swap contracts, a type of derivative instrument, involve special risks and may result in losses to the fund. Credit default swaps may in some cases be illiquid, and they increase credit risk since the fund has exposure to both the issuer of the referenced obligation and the counterparty to the credit default swap. Swaps may be difficult to unwind or terminate. The swap market could be disrupted or limited as a result of the new regulations, and these changes could adversely affect the fund.

SHORT POSITION RISK. Taking short positions involves leverage of the fund's assets and presents various risks. If the price of the instrument or market on which the fund has taken a short position increases, then the fund will incur a loss. Because of leverage, taking short positions involves the risk that losses may be exaggerated, potentially more than the actual cost of the investment. Unlike purchasing a financial instrument like a stock, where potential losses are limited to the purchase price and there is no upside limit on potential gain, short sales involve no cap on maximum losses, while gains are limited to the price of the stock at the time of the short sale. Also, there is the risk that a counterparty may fail to perform the terms of the arrangement, causing a loss to the fund.

LIQUIDITY RISK. Some securities held by the fund may be difficult to sell, or illiquid, particularly during times of market turmoil. Illiquid securities also may be difficult to value. If the fund is forced to sell an illiquid asset to meet redemption requests or other cash needs, the fund may be forced to sell at a loss.

LEVERAGING RISK. The value of your investment may be more volatile and other risks tend to be compounded if the fund borrows or uses derivatives or other investments, such as ETFs, that have embedded leverage. Leverage generally magnifies the effect of any increase or decrease in the value of the fund's underlying assets or creates investment risk with respect to a larger pool of assets than the fund would otherwise have, potentially resulting in the loss of all assets. Engaging in such transactions may cause the fund to liquidate positions when it may not be advantageous to do so to satisfy its obligations or meet segregation requirements.

PORTFOLIO TURNOVER RISK. If the fund does a lot of trading, it may incur additional operating expenses, which would reduce performance. A higher level of portfolio turnover may also cause taxable shareholders to incur a higher level of taxable income or capital gains.

PORTFOLIO SELECTION RISK. The adviser's judgment about a particular security or issuer, or about the economy or a particular sector, region or market segment, or about an investment strategy, may prove to be incorrect.

RISKS OF CONVERTIBLE SECURITIES. The market values of convertible securities tend to decline as interest rates increase and, conversely, to increase as interest rates decline. A downturn in equity markets may cause the price of convertible securities to decrease relative to other fixed income securities.

PREFERRED STOCKS RISK. Preferred stocks may pay fixed or adjustable rates of return. Preferred stocks are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company's preferred stocks generally pay dividends only after the company makes required payments to holders of its bonds and other debt. Thus, the value of preferred stocks will usually react more strongly than bonds and other debt to actual or perceived changes in the company's financial condition or prospects. The market value of preferred stocks generally decreases when interest rates rise. Preferred stocks of smaller companies may be more vulnerable to adverse developments than preferred stock of larger companies.

WARRANTS RISK. A warrant gives the fund the right to buy stock. If the price of the underlying stock does not rise above the exercise price before the warrant expires, the warrant generally expires without any value and the fund loses any amount it paid for the warrant. Thus, investments in warrants may involve substantially more risk than investments in common stock. Warrants may trade in the same markets as their underlying stock; however, the price of the warrant does not necessarily move with the price of the underlying stock.

RISKS OF ZERO COUPON BONDS AND PAYMENT IN KIND SECURITIES. Zero coupon bonds and payment in kind securities may be more speculative and may fluctuate more in value than securities which pay income periodically and in cash. In addition, although the fund receives no periodic cash payments on such securities, the fund is deemed for tax purposes to receive income from such securities, which applicable tax rules require the fund to distribute to shareholders. Such distributions may be taxable when distributed to taxable shareholders.

VALUATION RISK. The sales price the fund could receive for any particular portfolio investment may differ from the fund's valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair value methodology. Investors who purchase or redeem fund shares on days when the fund is holding fair-valued securities 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 security or had used a different valuation methodology.

RISKS OF INVESTING IN "WHEN-ISSUED" SECURITIES. The market value of when-issued or delayed delivery transactions may increase or decrease as a result of changes in interest rates. These transactions involve risk of loss if the value of the underlying security changes unfavorably before the settlement date. There is also a risk that the other party to the transaction will default on its obligation to purchase or sell the security, which may result in the fund missing the opportunity to obtain a favorable price or yield elsewhere.

MARKET SEGMENT RISK. To the extent the fund emphasizes, from time to time, investments in a market segment, the fund will be subject to a greater degree to the risks particular to that segment, and may experience greater market fluctuation than a fund without the same focus.

EXPENSE RISK. Your actual costs of investing in the fund may be higher than the expenses shown in "Annual fund operating expenses" for a variety of reasons. For example, expense ratios may be higher than those shown if overall net assets decrease. Net assets are more likely to decrease and fund expense ratios are more likely to increase when markets are volatile.

Please note that there are many other factors that could adversely affect your investment and that could prevent the fund from achieving its goals.

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

Risk Lose Money [Text]

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You could lose money on your investment in the fund.

Risk Nondiversified Status [Text]

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NON-DIVERSIFICATION RISK. The fund is not diversified, which means that it can invest a higher percentage of its assets in the securities of any one or more issuers than a diversified fund. Being non-diversified may magnify the fund's losses from adverse events affecting a particular issuer.

Risk Not Insured Depository Institution [Text]

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

Bar Chart and Performance Table [Heading]

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THE FUND'S PAST PERFORMANCE

Performance Narrative [Text Block]

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The bar chart and table indicate the risks and volatility of an investment in the fund by showing how the fund has performed in the past. The bar chart shows changes in the performance of the fund's Class A shares from calendar year to calendar year. The table shows the average annual total returns for each class of the fund over time and compares these returns to the returns of the Barclays Capital U.S. Treasury TIPS 1 - 10 Year Index, a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies. You can obtain updated performance information by visiting https://us.pioneerinvestments.com/performance or by calling 1-800-225-6292.

The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.

The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.

Performance Information Illustrates Variability of Returns [Text]

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Performance One Year or Less [Text]

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No performance information is presented for Class R and Class Z shares in the table because Class R and Class Z shares do not have annual returns for at least one calendar year.

Performance Availability Phone [Text]

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1-800-225-6292

Performance Availability Website Address [Text]

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https://us.pioneerinvestments.com/performance

Performance Past Does Not Indicate Future [Text]

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The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.

Bar Chart [Heading]

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ANNUAL RETURN CLASS A SHARES (%)
(Year ended December 31)

Bar Chart Does Not Reflect Sales Loads [Text]

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The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

For the period covered by the bar chart:
THE HIGHEST CALENDAR QUARTERLY RETURN WAS 7.89% (01/01/2012 TO 03/31/2012).
THE LOWEST CALENDAR QUARTERLY RETURN WAS -3.33% (04/01/2012 TO 06/30/2012).

At June 30, 2013, the year-to-date return was 4.12%.

Performance Table Heading

rr_PerformanceTableHeading

AVERAGE ANNUAL TOTAL RETURN (%)
(for periods ended December 31, 2012)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest 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

Actual after-tax returns depend on the investor's tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax returns are shown only for Class A shares. After-tax returns for Class C, Class R, Class Y and Class Z shares will vary.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

After-tax returns are shown only for Class A shares. After-tax returns for Class C, Class R, Class Y and Class Z shares will vary.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

No performance information is presented for Class R and Class Z shares in the table because Class R and Class Z shares do not have annual returns for at least one calendar year. The returns for Class R and Class Z shares would differ from those of Class A, Class C and Class Y shares because they have different expenses.

Pioneer Multi-Asset Real Return Fund | CLASS A

Maximum sales charge (load) when you buy shares (as a percentage of offering price)

rr_RiskReturnAbstract

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

Maximum deferred sales charge (load) (as a percentage of offering price or the amount you receive when you sell shares, whichever is less)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

rr_ManagementFeesOverAssets

0.70%

rr_DistributionAndService12b1FeesOverAssets

0.25%

rr_Component1OtherExpensesOverAssets

0.26%

^[1]

rr_Component2OtherExpensesOverAssets

0.01%

^[1]

rr_OtherExpensesOverAssets

0.27%

Total Annual Fund Operating Expenses Plus Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

^[2]

rr_ExpensesOverAssets

1.24%

rr_FeeWaiverOrReimbursementOverAssets

(0.02%)

^[3]

Year to Date Return, Label

rr_NetExpensesOverAssets

1.22%

^[3]

rr_ExpenseExampleYear01

569

rr_ExpenseExampleYear03

824

rr_ExpenseExampleYear05

1,099

rr_ExpenseExampleYear10

1,881

rr_ExpenseExampleNoRedemptionYear01

569

rr_ExpenseExampleNoRedemptionYear03

824

rr_ExpenseExampleNoRedemptionYear05

1,099

rr_ExpenseExampleNoRedemptionYear10

1,881

2011

rr_AnnualReturn2011

3.06%

2012

rr_AnnualReturn2012

13.90%

rr_YearToDateReturnLabel

year-to-date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2013

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.12%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

HIGHEST CALENDAR QUARTERLY RETURN

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

7.89%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

LOWEST CALENDAR QUARTERLY RETURN

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(3.33%)

rr_AverageAnnualReturnYear01

8.74%

rr_AverageAnnualReturnSinceInception

7.29%

rr_AverageAnnualReturnInceptionDate

May 03, 2010

Pioneer Multi-Asset Real Return Fund | CLASS C

Maximum sales charge (load) when you buy shares (as a percentage of offering price)

rr_RiskReturnAbstract

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a percentage of offering price or the amount you receive when you sell shares, whichever is less)

rr_MaximumDeferredSalesChargeOverOfferingPrice

1.00%

rr_ManagementFeesOverAssets

0.70%

rr_DistributionAndService12b1FeesOverAssets

1.00%

rr_Component1OtherExpensesOverAssets

0.24%

^[1]

rr_Component2OtherExpensesOverAssets

0.01%

^[1]

rr_OtherExpensesOverAssets

0.25%

Total Annual Fund Operating Expenses Plus Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

^[2]

rr_ExpensesOverAssets

1.97%

rr_FeeWaiverOrReimbursementOverAssets

none

^[3]

rr_NetExpensesOverAssets

1.97%

^[3]

rr_ExpenseExampleYear01

300

rr_ExpenseExampleYear03

618

rr_ExpenseExampleYear05

1,062

rr_ExpenseExampleYear10

2,296

rr_ExpenseExampleNoRedemptionYear01

200

rr_ExpenseExampleNoRedemptionYear03

618

rr_ExpenseExampleNoRedemptionYear05

1,062

rr_ExpenseExampleNoRedemptionYear10

2,296

rr_AverageAnnualReturnYear01

13.05%

rr_AverageAnnualReturnSinceInception

8.34%

rr_AverageAnnualReturnInceptionDate

May 03, 2010

Pioneer Multi-Asset Real Return Fund | CLASS R

Maximum sales charge (load) when you buy shares (as a percentage of offering price)

rr_RiskReturnAbstract

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a percentage of offering price or the amount you receive when you sell shares, whichever is less)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

rr_ManagementFeesOverAssets

0.70%

rr_DistributionAndService12b1FeesOverAssets

0.50%

rr_Component1OtherExpensesOverAssets

0.29%

^[1]

rr_Component2OtherExpensesOverAssets

0.01%

^[1]

rr_OtherExpensesOverAssets

0.30%

Total Annual Fund Operating Expenses Plus Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

^[2]

rr_ExpensesOverAssets

1.52%

rr_FeeWaiverOrReimbursementOverAssets

none

^[3]

rr_NetExpensesOverAssets

1.52%

^[3]

rr_ExpenseExampleYear01

155

rr_ExpenseExampleYear03

480

rr_ExpenseExampleYear05

829

rr_ExpenseExampleYear10

1,813

rr_ExpenseExampleNoRedemptionYear01

155

rr_ExpenseExampleNoRedemptionYear03

480

rr_ExpenseExampleNoRedemptionYear05

829

rr_ExpenseExampleNoRedemptionYear10

1,813

Pioneer Multi-Asset Real Return Fund | CLASS Y

Maximum sales charge (load) when you buy shares (as a percentage of offering price)

rr_RiskReturnAbstract

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a percentage of offering price or the amount you receive when you sell shares, whichever is less)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

rr_ManagementFeesOverAssets

0.70%

rr_DistributionAndService12b1FeesOverAssets

none

rr_Component1OtherExpensesOverAssets

0.20%

^[1]

rr_Component2OtherExpensesOverAssets

0.01%

^[1]

rr_OtherExpensesOverAssets

0.21%

Total Annual Fund Operating Expenses Plus Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

^[2]

rr_ExpensesOverAssets

0.93%

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

rr_NetExpensesOverAssets

0.92%

^[3]

rr_ExpenseExampleYear01

rr_ExpenseExampleYear03

295

rr_ExpenseExampleYear05

514

rr_ExpenseExampleYear10

1,142

rr_ExpenseExampleNoRedemptionYear01

rr_ExpenseExampleNoRedemptionYear03

295

rr_ExpenseExampleNoRedemptionYear05

514

rr_ExpenseExampleNoRedemptionYear10

1,142

rr_AverageAnnualReturnYear01

14.28%

rr_AverageAnnualReturnSinceInception

9.47%

rr_AverageAnnualReturnInceptionDate

May 03, 2010

Pioneer Multi-Asset Real Return Fund | CLASS Z

Maximum sales charge (load) when you buy shares (as a percentage of offering price)

rr_RiskReturnAbstract

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) (as a percentage of offering price or the amount you receive when you sell shares, whichever is less)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

rr_ManagementFeesOverAssets

0.70%

rr_DistributionAndService12b1FeesOverAssets

none

rr_Component1OtherExpensesOverAssets

0.24%

^[1]

rr_Component2OtherExpensesOverAssets

0.01%

^[1]

rr_OtherExpensesOverAssets

0.25%

Total Annual Fund Operating Expenses Plus Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.02%

^[2]

rr_ExpensesOverAssets

0.97%

rr_FeeWaiverOrReimbursementOverAssets

none

^[3]

rr_NetExpensesOverAssets

0.97%

^[3]

rr_ExpenseExampleYear01

rr_ExpenseExampleYear03

309

rr_ExpenseExampleYear05

536

rr_ExpenseExampleYear10

1,190

rr_ExpenseExampleNoRedemptionYear01

rr_ExpenseExampleNoRedemptionYear03

309

rr_ExpenseExampleNoRedemptionYear05

536

rr_ExpenseExampleNoRedemptionYear10

$ 1,190

Pioneer Multi-Asset Real Return Fund | Return after taxes on distributions | CLASS A

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

8.29%

rr_AverageAnnualReturnSinceInception

6.70%

rr_AverageAnnualReturnInceptionDate

May 03, 2010

Pioneer Multi-Asset Real Return Fund | Return after taxes on distributions and sale of shares | CLASS A

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

5.66%

rr_AverageAnnualReturnSinceInception

5.88%

rr_AverageAnnualReturnInceptionDate

May 03, 2010

Pioneer Multi-Asset Real Return Fund | Barclays Capital U.S. Treasury TIPS 1-10 Year Index (reflects no deduction for fees, expenses or taxes)

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

5.04%

rr_AverageAnnualReturnSinceInception

6.40%