Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Oct. 28, 2011
UBS HIGH YIELD FUND (Prospectus Summary) | UBS HIGH YIELD FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	UBS High Yield Fund Summary
Investment Objective, Heading	rr_ObjectiveHeading	Investment objective
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide high current income, as well as capital growth when consistent with high current income.
Expense, Heading	rr_ExpenseHeading	Fees and expenses
Expense, Narrative	rr_ExpenseNarrativeTextBlock	These tables describe the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for a sales charge waiver or discount if you and your family invest, or agree to invest in the future, at least $100,000 in the Fund. More information about these and other discounts and waivers, as well as eligibility requirements for each share class, is available from your financial advisor and in "Managing your fund account" on page 33 of the Fund's prospectus and in "Reduced sales charges, additional purchase, exchange and redemption information and other services" on page 103 of the Fund's statement of additional information ("SAI").
Shareholder Fees, Caption	rr_ShareholderFeesCaption	Shareholder fees (fees paid directly from your investment)
Operating Expenses, Caption	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	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 Breakpoint, Discounts	rr_ExpenseBreakpointDiscounts	You may qualify for a sales charge waiver or discount if you and your family invest, or agree to invest in the future, at least $100,000 in the Fund.
Expense Breakpoint, Minimum Investment Required Amount	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 100,000
Expense Example, Heading	rr_ExpenseExampleHeading	Example
Expense Example, Narrative	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 shares at the end of those periods unless otherwise stated. The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The costs described in the example reflect the expenses of the Fund that would result from the contractual fee waiver and expense reimbursement agreement with the Advisor for the first year only. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Investment Strategy, Heading	rr_StrategyHeading	Principal strategies
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	Principal investments The Fund invests in a portfolio of higher yielding, lower-rated debt securities issued by foreign and domestic companies. Under normal conditions, at least 80% of the Fund's net assets (plus borrowings for investment purposes, if any) are invested in fixed income securities that provide higher yields and are lower-rated. The Fund may invest in fixed income securities of any maturity, but generally invests in securities having an initial maturity of more than one year. Investments in fixed income securities may include, but are not limited to, mortgage-backed and asset-backed securities. Up to 25% of the Fund's total assets may be invested in foreign securities, which may include securities of issuers in emerging markets. The Fund may, but is not required to, use exchange-traded or over-the-counter derivative instruments for risk management purposes or as part of the Fund's investment strategies. The derivatives in which the Fund may invest include options, futures, forward agreements, swap agreements (specifically, interest rate, total return, currency and credit default swaps), credit-linked securities and structured investments. All of these derivatives may be used for risk management purposes, such as hedging against a specific security or currency, or to manage or adjust the risk profile of the Fund. In addition, all of the derivative instruments listed above may be used for investment (non-hedging) purposes to earn income; to enhance returns; to replace more traditional direct investments; to obtain exposure to certain markets; to establish net short positions for individual sectors, markets, currencies or securities; or to adjust the Fund's portfolio duration. Lower-rated bonds are bonds rated in the lower rating categories of Moody's Investors Service, Inc. ("Moody's") and Standard & Poor's Ratings Group ("S&P"), including securities rated Ba or lower by Moody's or BB or lower by S&P. Securities rated in these categories are considered to be of poorer quality and predominantly speculative. Bonds in these categories may also be called "high yield bonds" or "junk bonds." Management process The Fund invests in securities that the Advisor expects will appreciate in value as a result of declines in long-term interest rates or favorable developments affecting the business or prospects of the issuer which may improve the issuer's financial condition and credit rating. In selecting securities, the Advisor uses a quantitative and qualitative credit review process that assesses the ways in which macroeconomic forces (such as inflation, risk premiums and interest rates), as well as certain quantitative factors, such as historical operating results, calculation of credit ratios and expected future outlook, may affect industry trends. Against the output of this model, the Advisor considers the viability of specific debt securities, assessing management strength, market position, competitive environment and financial flexibility. The Advisor determines optimal sector, security and credit rating weightings based on its assessment of macro and microeconomic factors. Depending on market conditions, undervalued securities may be found in different sectors. Therefore, all investment decisions are interrelated and made using ongoing sector, security and rating evaluation.
Risk, Heading	rr_RiskHeading	Main risks
Risk, Narrative	rr_RiskNarrativeTextBlock	All investments carry a certain amount of risk and the Fund cannot guarantee that it will achieve its investment objective. You may lose money by investing in the Fund. An investment in the Fund is not a deposit of the bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Below are some of the specific risks of investing in the Fund. Interest rate risk: An increase in prevailing interest rates typically causes the value of fixed income securities to fall. Changes in interest rates will likely affect the value of longer-duration fixed income securities more than shorter-duration securities and higher quality securities more than lower quality securities. When interest rates are falling, some fixed income securities provide that the issuer may repay them earlier than the maturity date, and if this occurs the Fund may have to reinvest these repayments at lower interest rates. Credit risk: The risk that the Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to or guarantor of a derivative contract, is unable or unwilling to meet its financial obligations. This risk is likely greater for lower quality investments than for investments that are higher quality. High yield bond risk: The risk that the issuer of bonds with ratings of BB (S&P) or Ba (Moody's) or below, or deemed of equivalent quality, will default or otherwise be unable to honor a financial obligation. These securities are considered to be predominately speculative with respect to an issuer's capacity to pay interest and repay principal in accordance with the terms of the obligations. Lower-quality bonds are more likely to be subject to an issuer's default or downgrade than investment grade (higher-quality) bonds. Market risk: The risk that the market value of the Fund's investments may fluctuate, sometimes rapidly or unpredictably, as the stock and bond markets fluctuate. Market risk may affect a single issuer, industry, or sector of the economy, or it may affect the market as a whole. Foreign investing risk: The value of the Fund's investments in foreign securities may fall due to adverse political, social and economic developments abroad and due to decreases in foreign currency values relative to the US dollar. Investments in foreign government bonds involve special risks because the Fund may have limited legal recourse in the event of default. Also, foreign securities are sometimes less liquid and more difficult to sell and to value than securities of US issuers. These risks are greater for investments in emerging market issuers. In addition, investments in emerging market issuers may decline in value because of unfavorable foreign government actions, greater risks of political instability or the absence of accurate information about emerging market issuers. Derivatives risk: The value of "derivatives"-so called because their value "derives" from the value of an underlying asset, reference rate or index-may rise or fall more rapidly than other investments. When using derivatives for non-hedging purposes, it is possible for the Fund to lose more than the amount it invested in the derivative. The risks of investing in derivative instruments also include market and management risks. Derivatives relating to fixed income markets are especially susceptible to interest rate risk and credit risk. In addition, many types of swaps and other non-exchange traded derivatives may be subject to liquidity risk, credit risk and mispricing or valuation complexity. These derivatives risks are different from, and may be greater than, the risks associated with investing directly in securities and other instruments. Leverage risk associated with financial instruments: The use of financial instruments to increase potential returns, including derivatives used for investment (non-hedging) purposes, may cause the Fund to be more volatile than if it had not been leveraged. The use of leverage may also accelerate the velocity of losses and can result in losses to the Fund that exceed the amount originally invested. Management risk: The risk that the investment strategies, techniques and risk analyses employed by the Advisor may not produce the desired results.
Risk, Lose Money	rr_RiskLoseMoney	You may lose money by investing in the Fund.
Risk, Not Insured Depository Institution	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit of the bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	Performance
Performance, Narrative	rr_PerformanceNarrativeTextBlock	The performance information that follows shows the Fund's performance information in a bar chart and an average annual total returns table. The information provides some 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 total returns compare with those of a broad measure of market performance. Index reflects no deduction for fees, expenses or taxes. 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 for the Fund is available at http://globalam-us.ubs.com/corpweb/performance.do. 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 an investor's tax situation and may differ from those shown. In addition, 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 for other classes will vary from the Class Y shares' after-tax returns shown.
Performance, Information Illustrates Variability of Returns	rr_PerformanceInformationIllustratesVariabilityOfReturns	The performance information that follows shows the Fund's performance information in a bar chart and an average annual total returns table. The information provides some 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 total returns compare with those of a broad measure of market performance.
Performance, Availability Website Address	rr_PerformanceAvailabilityWebSiteAddress	http://globalam-us.ubs.com/corpweb/performance.do.
Performance, Past Does Not Indicate Future	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	UBS High Yield Fund Annual Total Returns of Class Y Shares
Bar Chart, Closing	rr_BarChartClosingTextBlock	Total return January 1 - September 30, 2011: (3.35)% Best quarter during calendar years shown-2Q 2009: 19.58% Worst quarter during calendar years shown-4Q 2008: (16.49)%
Index No Deduction for Fees, Expenses, Taxes	rr_IndexNoDeductionForFeesExpensesTaxes	Index reflects no deduction for fees, expenses or taxes.
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	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	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns for other classes will vary from the Class Y shares' after-tax returns shown.
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	Average annual total returns (for the periods ended December 31, 2010)
UBS HIGH YIELD FUND (Prospectus Summary) | UBS HIGH YIELD FUND | CLASS A
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2012-10-27
UBS HIGH YIELD FUND (Prospectus Summary) | UBS HIGH YIELD FUND | CLASS B
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2012-10-27
UBS HIGH YIELD FUND (Prospectus Summary) | UBS HIGH YIELD FUND | CLASS C
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2012-10-27
UBS HIGH YIELD FUND (Prospectus Summary) | UBS HIGH YIELD FUND | CLASS Y
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2012-10-27
Year to Date Return, Label	rr_YearToDateReturnLabel	Total return January 1 - September 30, 2011:
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2011
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(3.35%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best quarter during calendar years shown-2Q 2009:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	19.58%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst quarter during calendar years shown-4Q 2008:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(16.49%)
UBS HIGH YIELD FUND | Bofa Merrill Lynch US High Yield Cash Pay Constrained Index
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	BofA Merrill Lynch US High Yield Cash Pay Constrained Index
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	15.10%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	8.66%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	8.84%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception		[1]
UBS HIGH YIELD FUND | CLASS A
Risk/Return:	rr_RiskReturnAbstract
Maximum front-end sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.50%
Maximum contingent deferred sales charge (load) (CDSC) (as a % of purchase or sales price, whichever is less)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Redemption fee (as a % of amount redeemed within 90 days of purchase, if applicable)	rr_RedemptionFeeOverRedemption	(1.00%)
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.52%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.37%
Less management fee waiver/expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.17%)
Total annual fund operating expenses after management fee waiver/expense reimbursements	rr_NetExpensesOverAssets	1.20%	[3]
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	567
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	848
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,151
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,008
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class A Return before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	8.73%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.81%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	6.64%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	5.40%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 31, 1998
UBS HIGH YIELD FUND | CLASS B
Risk/Return:	rr_RiskReturnAbstract
Maximum front-end sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (CDSC) (as a % of purchase or sales price, whichever is less)	rr_MaximumDeferredSalesChargeOverOfferingPrice	5.00%
Redemption fee (as a % of amount redeemed within 90 days of purchase, if applicable)	rr_RedemptionFeeOverRedemption	(1.00%)
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other expenses	rr_OtherExpensesOverAssets	0.57%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	2.17%
Less management fee waiver/expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.22%)
Total annual fund operating expenses after management fee waiver/expense reimbursements	rr_NetExpensesOverAssets	1.95%	[3]
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	698
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	958
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,344
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,096
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	198
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	658
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	1,144
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,096
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class B Return before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	8.19%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.74%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	7.23%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 07, 2001
UBS HIGH YIELD FUND | CLASS C
Risk/Return:	rr_RiskReturnAbstract
Maximum front-end sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (CDSC) (as a % of purchase or sales price, whichever is less)	rr_MaximumDeferredSalesChargeOverOfferingPrice	0.75%
Redemption fee (as a % of amount redeemed within 90 days of purchase, if applicable)	rr_RedemptionFeeOverRedemption	(1.00%)
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.75%
Other expenses	rr_OtherExpensesOverAssets	0.51%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.86%
Less management fee waiver/expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.16%)
Total annual fund operating expenses after management fee waiver/expense reimbursements	rr_NetExpensesOverAssets	1.70%	[3]
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	248
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	569
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	991
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,167
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	173
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	569
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	991
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,167
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class C Return before taxes	[4]
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	12.72%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	6.30%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	7.25%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Nov. 07, 2001
UBS HIGH YIELD FUND | CLASS Y
Risk/Return:	rr_RiskReturnAbstract
Maximum front-end sales charge (load) imposed on purchases (as a % of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum contingent deferred sales charge (load) (CDSC) (as a % of purchase or sales price, whichever is less)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Redemption fee (as a % of amount redeemed within 90 days of purchase, if applicable)	rr_RedemptionFeeOverRedemption	(1.00%)
Management fees	rr_ManagementFeesOverAssets	0.60%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.43%	[2]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.03%
Less management fee waiver/expense reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.08%)
Total annual fund operating expenses after management fee waiver/expense reimbursements	rr_NetExpensesOverAssets	0.95%	[3]
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	97
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	320
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	561
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	$ 1,252
Annual Return 2001	rr_AnnualReturn2001	4.15%
Annual Return 2002	rr_AnnualReturn2002	(0.78%)
Annual Return 2003	rr_AnnualReturn2003	23.16%
Annual Return 2004	rr_AnnualReturn2004	13.35%
Annual Return 2005	rr_AnnualReturn2005	0.68%
Annual Return 2006	rr_AnnualReturn2006	10.25%
Annual Return 2007	rr_AnnualReturn2007	0.83%
Annual Return 2008	rr_AnnualReturn2008	(23.23%)
Annual Return 2009	rr_AnnualReturn2009	44.50%
Annual Return 2010	rr_AnnualReturn2010	14.41%
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class Y Return before taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	14.41%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	7.12%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	7.43%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	6.30%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 30, 1997
UBS HIGH YIELD FUND | CLASS Y | After Taxes on Distributions
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class Y Return after taxes on distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	10.98%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.83%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	3.75%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.62%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 30, 1997
UBS HIGH YIELD FUND | CLASS Y | After Taxes on Distributions and Sales
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Class Y Return after taxes on distributions and sale of fund shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	9.22%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.05%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	4.02%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	2.99%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 30, 1997

[1] Average annual total returns for the BofA Merrill Lynch US High Yield Cash Pay Constrained Index for the life of each class were as follows: Class A--7.10%; Class B--9.21%; Class C--9.21%; Class Y--6.89%.

[2] "Other expenses" include "Acquired fund fees and expenses," which were less than 0.01% of the average net assets of the Fund.

[3] The Trust, with respect to the Fund, and UBS Global Asset Management (Americas) Inc., the Fund's investment advisor ("UBS Global AM (Americas)" or the "Advisor"), have entered into a written agreement pursuant to which the Advisor has agreed to waive a portion of its management fees and/or to reimburse expenses (excluding expenses incurred through investment in other investment companies, interest, taxes, brokerage commissions, extraordinary expenses, dividend expense and security loan fees for securities sold short) to the extent necessary so that the Fund's ordinary operating expenses (excluding expenses incurred through investment in other investment companies, interest, taxes, brokerage commissions, extraordinary expenses, dividend expense and security loan fees for securities sold short), through the period ending October 27, 2012, do not exceed 1.20% for Class A shares, 1.95% for Class B shares, 1.70% for Class C shares and 0.95% for Class Y shares. Pursuant to the written agreement, the Advisor is entitled to be reimbursed for any fees it waives and expenses it reimburses for a period of three years following such fee waivers and expense reimbursements to the extent that such reimbursement of the Advisor by the Fund will not cause the Fund to exceed any applicable expense limit that is in place for the Fund.

[4] Prior to September 30, 2003, Class C shares were subject to a maximum front-end sales charge of 1.00%; this front-end sales charge is not reflected in the average annual total returns presented for the Class C shares shown above.