Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	PIONEER HIGH YIELD FUND
Prospectus Date	rr_ProspectusDate	Mar. 01, 2016
Pioneer High Yield Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	PIONEER HIGH YIELD FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Maximize total return through a combination of income and capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	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 53 and the "Sales charges" section of the statement of additional information beginning on page 63.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	SHAREOWNER FEES (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual 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 32% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	32.00%
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	Class A purchases of $500,000 or more that are not subject to an initial sales charge may be subject to a contingent deferred sales charge of 1%. See "Sales charges."
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	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]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 100,000
Expense Example [Heading]	rr_ExpenseExampleHeading	EXAMPLE
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 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]	rr_ExpenseExampleByYearCaption	IF YOU REDEEM YOUR SHARES NUMBER OF YEARS YOU OWN YOUR SHARES
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	IF YOU DO NOT REDEEM YOUR SHARES NUMBER OF YEARS YOU OWN YOUR SHARES
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Normally, the fund invests at least 80% of its total assets in below investment grade (high yield) debt securities and preferred stocks. Derivative instruments that provide exposure to such high yield debt securities and preferred stock or have similar economic characteristics may be used to satisfy the fund's 80% policy. Debt securities rated below investment grade are commonly referred to as "junk bonds" and are considered speculative. The fund may invest in high yield securities of any rating, including securities where the issuer is in default or bankruptcy at the time of purchase. The fund invests 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 and dividend payment and reset terms, including fixed rate, adjustable rate, floating rate, zero coupon, contingent, deferred, payment in kind and auction rate features. The fund's investments may include instruments that allow for balloon payments or negative amortization payments. The fund may invest in investment grade and below investment grade convertible bonds and preferred stocks that are convertible into the equity securities of the issuer. The fund may invest up to 20% of its net assets in inverse floating rate obligations (a type of derivative instrument). The fund may invest up to 20% of its net assets in common stock and other equity investments, such as exchange-traded funds (ETFs) that invest primarily in equity securities, depositary receipts, warrants, rights and equity interests in real estate investment trusts (REITs). The fund may invest up to 15% of its total assets in securities of non-U.S. issuers. The fund may invest a portion of its assets in mortgage-related securities, including "sub-prime" mortgages, and asset-backed securities. The fund also may invest a portion of its assets in subordinated debt securities, event-linked bonds and other insurance-linked securities. The fund may, but is not required to, use derivatives. The fund may use derivatives, such as credit default swaps and bond and interest rate futures, for a variety of purposes, including: in an attempt to hedge against adverse changes in the market price of securities, interest rates or currency exchange rates; as a substitute for purchasing or selling securities; to attempt to increase the fund's return as a non-hedging strategy that may be considered speculative; to manage portfolio characteristics; and as a cash flow management technique. 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 hold cash or other short-term investments. The fund's investment adviser uses a value approach to select investments to buy and sell. The adviser seeks to identify securities that are selling at reasonable prices or substantial discounts to their underlying values and then holds these securities for their incremental yields or until the market values reflect their intrinsic values. The adviser evaluates a security's potential value, including the attractiveness of its market valuation, based on the company's assets and prospects for earnings growth. In making that assessment, the adviser employs fundamental research and an evaluation of the issuer based on its financial statements and operations. The adviser also considers a security's potential to provide income.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS OF INVESTING IN THE FUND
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	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, lack of liquidity in the bond markets or adverse investor sentiment. In the past several years, financial markets, such as those in the United States, Europe, Asia and elsewhere, have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. Governmental and non-governmental issuers have defaulted on, or been forced to restructure, their debts. These conditions may continue, recur, worsen or spread. The U.S. government and the Federal Reserve, as well as certain foreign governments and their central banks, have taken steps to support financial markets, including by keeping interest rates at historically low levels. This and other government intervention may not work as intended, particularly if the efforts are perceived by investors as being unlikely to achieve the desired results. The Federal Reserve recently has reduced its market support activities. Further reduction or withdrawal of Federal Reserve or other U.S. or non-U.S. governmental or central bank support, including interest rate increases, could negatively affect financial markets generally, increase market volatility and reduce the value and liquidity of securities in which the fund invests. Policy and legislative changes in the U.S. and in other countries are affecting many aspects of financial regulation, and may in some instances contribute to decreased liquidity and increased volatility in the financial markets. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time. Economies and financial markets throughout the world are becoming increasingly interconnected. As a result, 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. The fund may experience a substantial or complete loss on any individual security or derivative position. 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. These risks are more pronounced for securities that are already in default. 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 or durations). For example, if interest rates increase by 1%, the value of a fund's portfolio with a portfolio duration of ten years would be expected to decrease by 10%, all other things being equal. Interest rates in the U.S. recently have been historically low, so the fund faces a heightened risk that interest rates may rise. A general rise in interest rates may cause investors to move out of fixed income securities on a large scale, which could adversely affect the price and liquidity of fixed income securities and could also result in increased redemptions from the fund. Rising interest rates can lead to increased default rates, as issuers of floating rate securities find themselves faced with higher payments. Unlike fixed rate securities, floating rate securities generally will not increase in value if interest rates decline. Changes in interest rates also will affect the amount of interest income the fund earns on its floating rate investments. 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 typically decline. 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 not benefit from the rise in market price that normally accompanies a decline in interest rates, and 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 and reduce the value of the security. LIQUIDITY RISK. Some securities and derivatives held by the fund may be impossible or difficult to purchase, sell or unwind, particularly during times of market turmoil. An instrument's liquidity may be affected by reduced trading volume, a relative lack of market makers or legal restrictions, and illiquid securities and derivatives also may be difficult to value. Liquidity risk may be magnified in a rising interest rate environment. If the fund is forced to sell an illiquid asset or unwind a derivatives position to meet redemption requests or other cash needs, the fund may be forced to sell at a loss. PORTFOLIO SELECTION RISK. The adviser's judgment about the quality, relative yield, relative value or market trends affecting a particular sector or region, market segment, security or about interest rates generally may prove to be incorrect. 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. Mortgage-backed securities tend to be more sensitive to changes in interest rate than other types of debt securities. These securities are also subject to prepayment and extension risks. 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 INSTRUMENTS THAT ALLOW FOR BALLOON PAYMENTS OR NEGATIVE AMORTIZATION PAYMENTS. Certain debt instruments allow for balloon payments or negative amortization payments. Such instruments permit the borrower to avoid paying currently a portion of the interest accruing on the instrument. While these features make the debt instrument more affordable to the borrower in the near term, they increase the risk that the borrower will be unable to make the resulting higher payment or payments that become due at the maturity of the loan. RISKS OF INVESTING IN FLOATING RATE LOANS. Floating rate loans and similar investments may be illiquid or less liquid than other investments and difficult to value. 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. Market quotations for these securities may be volatile and/or subject to large spreads between bid and ask prices. No active trading market may exist for many floating rate loans, and many loans are subject to restrictions on resale. Any secondary market may be subject to irregular trading activity and extended trade settlement periods. In particular, loans may take longer than seven days to settle, potentially leading to the sale proceeds of loans not being available to meet redemptions for a substantial period of time after the sale of the loans. To the extent that sale proceeds of loans are not available, the fund may sell securities that have shorter settlement periods or may access other sources of liquidity to meet redemption requests. Loans may not be considered "securities", and purchasers, such as the fund, therefore may not be entitled to rely on the anti-fraud protections afforded by federal securities laws. RISKS OF INVESTING IN INSURANCE-LINKED SECURITIES. The return of principal and the payment of interest on "event-linked" bonds and other insurance-linked securities are contingent on the non-occurrence of a pre-defined "trigger" event, such as a hurricane or an earthquake of a specific magnitude or other event that leads to physical or economic loss. 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, the fund may lose a portion or all of its accrued interest and/or principal invested in the 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. Certain insurance-linked securities may have limited liquidity, or may be illiquid. The fund has limited transparency into the individual contracts underlying certain insurance-linked securities, which may make the risk assessment of such securities more difficult. Certain insurance-linked securities may be difficult to value. 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. RISKS OF ZERO COUPON BONDS, PAYMENT IN KIND, DEFERRED AND CONTINGENT PAYMENT SECURITIES. These 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 shareholders. 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. Depositary receipts may involve higher expenses and may trade at a discount (or premium) to the underlying security. A number of countries in the European Union (EU) have experienced, and may continue to experience, severe economic and financial difficulties. If one or more stockholders of a supranational entity such as the World Bank fail to make necessary additional capital contributions, the entity may be unable to pay interest or repay principal on its debt securities. 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. 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 stocks of larger companies. RISKS 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. DERIVATIVES RISK. Using swaps, futures and other 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. The U.S. government is in the process of adopting and implementing regulations governing derivatives markets, including mandatory clearing of certain derivatives, margin and reporting requirements. The ultimate impact of the regulations remains unclear. Additional regulation of derivatives may make them more costly, may limit their availability, may disrupt markets or may otherwise adversely affect their value or performance. 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 the issuer of the referenced obligation and either the counterparty to the credit default swap or, if it is a cleared transaction, the brokerage firm through which the trade was cleared and the clearing organization that is the counterparty to that trade. 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. FORWARD FOREIGN CURRENCY TRANSACTIONS RISK. The fund may not fully benefit from or may lose money on forward foreign currency transactions if changes in currency rates do not occur as anticipated or do not correspond accurately to changes in the value of the fund's holdings, or if the counterparty defaults. Such transactions may also prevent the fund from realizing profits on favorable movements in exchange rates. Risk of counterparty default is greater for counterparties located in emerging markets. 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 and creates a risk of loss of value on 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. REPURCHASE AGREEMENT RISK. In the event that the other party to a repurchase agreement defaults on its obligations, the fund may encounter delay and incur costs before being able to sell the security. Such a delay may involve loss of interest or a decline in price of the security. In addition, if the fund is characterized by a court as an unsecured creditor, it would be at risk of losing some or all of the principal and interest involved in the transaction. 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. VALUATION RISK. The sales price the fund could receive for any particular portfolio investment may differ from the fund's last valuation of the investment, particularly for illiquid securities and 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. 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]	rr_RiskLoseMoney	You could lose money on your investment in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	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]	rr_BarChartAndPerformanceTableHeading	THE FUND'S PAST PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	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 following indices: Bank of America (BofA) Merrill Lynch U.S. High Yield Index, the fund's primary benchmark, and BofA Merrill Lynch All Convertibles Speculative Quality Index, an unmanaged index of high yield U.S. convertible securities. Each benchmark is 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 acquired the assets of Third Avenue High Yield Fund (the predecessor fund) on February 25, 2000. The performance of Class A and Class C shares of the fund includes the net asset value performance of the predecessor fund's single class of shares prior to the reorganization, which has been restated to reflect any applicable sales charges and Rule 12b-1 fees (but not other differences in expenses). This adjustment had the effect of reducing the previously reported performance of the predecessor fund. 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]	rr_PerformanceInformationIllustratesVariabilityOfReturns	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 following indices: Bank of America (BofA) Merrill Lynch U.S. High Yield Index, the fund's primary benchmark, and BofA Merrill Lynch All Convertibles Speculative Quality Index, an unmanaged index of high yield U.S. convertible securities. Each benchmark is a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies.
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	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 following indices: Bank of America (BofA) Merrill Lynch U.S. High Yield Index, the fund's primary benchmark, and BofA Merrill Lynch All Convertibles Speculative Quality Index, an unmanaged index of high yield U.S. convertible securities. Each benchmark is a broad-based measure of market performance that has characteristics relevant to the fund's investment strategies.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-225-6292
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	https://us.pioneerinvestments.com/performance
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	ANNUAL RETURN CLASS A SHARES (%) (Year ended December 31)
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	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 25.55% (04/01/2009 TO 06/30/2009). THE LOWEST CALENDAR QUARTERLY RETURN WAS -27.58% (10/01/2008 TO 12/31/2008).
Performance Table Heading	rr_PerformanceTableHeading	AVERAGE ANNUAL TOTAL RETURN (%) (for periods ended December 31, 2015)
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 and Class Y shares 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 and Class Y shares shares will vary.
Pioneer High Yield Fund | CLASS A
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) when you buy shares (as a percentage of offering price)	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_MaximumDeferredSalesChargeOverOther	none	[1]
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.27%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.17%
1	rr_ExpenseExampleYear01	$ 564
3	rr_ExpenseExampleYear03	805
5	rr_ExpenseExampleYear05	1,065
10	rr_ExpenseExampleYear10	1,806
1	rr_ExpenseExampleNoRedemptionYear01	564
3	rr_ExpenseExampleNoRedemptionYear03	805
5	rr_ExpenseExampleNoRedemptionYear05	1,065
10	rr_ExpenseExampleNoRedemptionYear10	$ 1,806
2006	rr_AnnualReturn2006	10.60%
2007	rr_AnnualReturn2007	6.95%
2008	rr_AnnualReturn2008	(36.99%)
2009	rr_AnnualReturn2009	62.02%
2010	rr_AnnualReturn2010	17.58%
2011	rr_AnnualReturn2011	(1.75%)
2012	rr_AnnualReturn2012	14.99%
2013	rr_AnnualReturn2013	12.31%
2014	rr_AnnualReturn2014	(0.16%)
2015	rr_AnnualReturn2015	(4.89%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	HIGHEST CALENDAR QUARTERLY RETURN
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	25.55%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	LOWEST CALENDAR QUARTERLY RETURN
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(27.58%)
1 YEAR	rr_AverageAnnualReturnYear01	(9.17%)
5 YEARS	rr_AverageAnnualReturnYear05	2.84%
10 YEARS	rr_AverageAnnualReturnYear10	5.03%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	7.40%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 12, 1998	[2]
Pioneer High Yield Fund | CLASS C
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) when you buy shares (as a percentage of offering price)	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_MaximumDeferredSalesChargeOverOther	1.00%
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.24%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.89%
1	rr_ExpenseExampleYear01	$ 292
3	rr_ExpenseExampleYear03	594
5	rr_ExpenseExampleYear05	1,021
10	rr_ExpenseExampleYear10	2,212
1	rr_ExpenseExampleNoRedemptionYear01	192
3	rr_ExpenseExampleNoRedemptionYear03	594
5	rr_ExpenseExampleNoRedemptionYear05	1,021
10	rr_ExpenseExampleNoRedemptionYear10	$ 2,212
1 YEAR	rr_AverageAnnualReturnYear01	(5.49%)	[3]
5 YEARS	rr_AverageAnnualReturnYear05	3.11%	[3]
10 YEARS	rr_AverageAnnualReturnYear10	4.81%	[3]
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	7.00%	[3]
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 12, 1998	[2],[3]
Pioneer High Yield Fund | CLASS R
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) when you buy shares (as a percentage of offering price)	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_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other Expenses	rr_OtherExpensesOverAssets	0.36%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.51%
1	rr_ExpenseExampleYear01	$ 154
3	rr_ExpenseExampleYear03	477
5	rr_ExpenseExampleYear05	824
10	rr_ExpenseExampleYear10	1,802
1	rr_ExpenseExampleNoRedemptionYear01	154
3	rr_ExpenseExampleNoRedemptionYear03	477
5	rr_ExpenseExampleNoRedemptionYear05	824
10	rr_ExpenseExampleNoRedemptionYear10	$ 1,802
1 YEAR	rr_AverageAnnualReturnYear01	(5.15%)
5 YEARS	rr_AverageAnnualReturnYear05	3.46%
10 YEARS	rr_AverageAnnualReturnYear10	5.23%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	6.44%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Apr. 01, 2003
Pioneer High Yield Fund | CLASS Y
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) when you buy shares (as a percentage of offering price)	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_MaximumDeferredSalesChargeOverOther	none
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.23%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.88%
1	rr_ExpenseExampleYear01	$ 90
3	rr_ExpenseExampleYear03	281
5	rr_ExpenseExampleYear05	488
10	rr_ExpenseExampleYear10	1,084
1	rr_ExpenseExampleNoRedemptionYear01	90
3	rr_ExpenseExampleNoRedemptionYear03	281
5	rr_ExpenseExampleNoRedemptionYear05	488
10	rr_ExpenseExampleNoRedemptionYear10	$ 1,084
1 YEAR	rr_AverageAnnualReturnYear01	(4.60%)
5 YEARS	rr_AverageAnnualReturnYear05	4.14%
10 YEARS	rr_AverageAnnualReturnYear10	5.94%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	7.23%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 25, 2000
Pioneer High Yield Fund | Return after taxes on distributions | CLASS A
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	(11.23%)
5 YEARS	rr_AverageAnnualReturnYear05	0.41%
10 YEARS	rr_AverageAnnualReturnYear10	2.55%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	4.49%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 12, 1998	[2]
Pioneer High Yield Fund | Return after taxes on distributions and sale of shares | CLASS A
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	(5.00%)
5 YEARS	rr_AverageAnnualReturnYear05	1.38%
10 YEARS	rr_AverageAnnualReturnYear10	3.07%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	4.73%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 12, 1998	[2]
Pioneer High Yield Fund | BofA Merrill Lynch U.S. High Yield Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	(4.64%)
5 YEARS	rr_AverageAnnualReturnYear05	4.84%
10 YEARS	rr_AverageAnnualReturnYear10	6.81%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	6.01%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 12, 1998
Pioneer High Yield Fund | BofA Merrill Lynch All-Convertibles Speculative Quality Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 YEAR	rr_AverageAnnualReturnYear01	(10.29%)
5 YEARS	rr_AverageAnnualReturnYear05	5.01%
10 YEARS	rr_AverageAnnualReturnYear10	6.41%
SINCE INCEPTION	rr_AverageAnnualReturnSinceInception	6.48%
INCEPTION DATE	rr_AverageAnnualReturnInceptionDate	Feb. 28, 1998

[1] Class A purchases of $500,000 or more that are not subject to an initial sales charge may be subject to a contingent deferred sales charge of 1%. See "Sales charges."

[2] Inception date of the predecessor fund's single class of shares. Class A and Class C shares commenced operations on February 25, 2000.

[3] The performance of Class C shares does not reflect the 1% front-end sales charge in effect prior to February 1, 2004. If you paid a 1% sales charge, your returns would be lower than those shown above.