Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BMO FUNDS, INC.
Prospectus Date	rr_ProspectusDate	Dec. 29, 2014
BMO Global Low Volatility Equity Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	BMO Global Low Volatility Equity Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective:
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	To provide 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 and your family invest, or agree to invest in the future, at least $50,000 in Class A shares of certain BMO Funds. More information about these and other discounts is available from your financial professional and under “How to Buy Shares – Sales Charge” on page 110 of this Prospectus and under “How to Buy Shares – Waivers and Reductions of Sales Charges – Class A Shares” beginning on page 111 of this Prospectus and “How to Buy Shares” beginning on page B-43 of the Fund’s Statement of Additional Information.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	December 31, 2015
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund incurs 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 period ended August 31, 2014, the Fund’s portfolio turnover rate (not annualized) was 29% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	29.00%
Expense Footnotes [Text Block]	rr_ExpenseFootnotesTextBlock	BMO Asset Management Corp. (Adviser) has agreed to waive or reduce its investment advisory fee and reimburse expenses to the extent necessary to prevent class total annual operating expenses (excluding interest, taxes, brokerage commissions, other investment-related costs, and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business, and Acquired Fund Fees and Expenses) from exceeding 0.85% for Class I and 1.10% for Class A through December 31, 2015. This expense limitation agreement may not be terminated prior to December 31, 2015 without the consent of the Fund’s Board of Directors, unless terminated due to the termination of the investment advisory agreement.
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	The Maximum Deferred Sales Charge on Class A shares is applied only to purchases of $1,000,000 or more that are redeemed within 18 months of purchase.
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Class A shares of certain BMO Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	50,000
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	“Other Expenses” for the Class A shares are based on estimated amounts for the current fiscal year.
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	Other Expenses have been restated to reflect current fees, effective June 1, 2015.
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 funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses are as shown in the table and remain the same. The costs in the one-year example and for the first year of the three-, five-, and ten-year examples reflect the Adviser’s agreement to waive fees and reimburse expenses through December 31, 2015. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests at least 80% of its assets in equity securities of companies located in the countries included, at the time of purchase, in the MSCI All Country World Index, which includes 24 developed and 21 emerging market countries. The Fund normally invests at least 40% of its net assets in securities located outside the United States and will be diversified among at least three countries. The Fund may invest in companies across all market capitalizations. The Fund invests in a portfolio that exhibits less price volatility than the MSCI All Country World Index. The Adviser defines “volatility” as the standard deviation of the Fund’s returns compared to the standard deviation of the returns in the Index. Under normal market conditions, the Adviser targets a range for the Fund that is 10–40% less volatile than the Index. Using a unique, quantitative approach based on the Adviser’s multi-factor risk/return models, the Adviser selects stocks that either exhibit less price volatility than the Index and/or reduce the overall portfolio volatility due to their negative correlation to other stocks in the portfolio. This approach seeks to provide the Fund with lower downside risk and meaningful upside participation relative to the Index. In determining where a company is located, the Adviser relies on the country where the company is incorporated, but also may consider the country where the company’s revenues are derived and the primary market listing for the class of shares to be purchased. Although the Fund invests primarily in companies located in countries included in the MSCI All Country World Index, the Fund may invest up to 20% of its net assets in companies located in countries not represented in this Index. From time to time, the Fund maintains a portion of its assets in cash. The Fund may increase its cash holdings in response to market conditions or in the event attractive investment opportunities are not available.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Fund cannot assure that it will achieve its investment objective. An investment in the Fund is not a deposit of BMO Harris Bank N.A., or any of its affiliates, and is not insured or guaranteed by the FDIC or any other government agency. The net asset value of the Fund will vary and you could lose money by investing in the Fund. In addition, the Fund is subject to the following risks. Stock Market Risks. The Fund is subject to fluctuations in the stock market, which has periods of increasing and decreasing values. Stocks are more volatile than debt securities. The value of equity securities purchased by the Fund may decline if the financial condition of the companies in which the Fund invests declines or if overall market and economic conditions deteriorate. If the value of the Fund’s investments goes down, you may lose money. Sector Risks. Companies with similar characteristics, such as those within the same industry, may be grouped together in broad categories called sectors. To the extent the Fund invests its assets in a particular sector, the Fund’s performance may be more susceptible to any economic, business, or other developments that generally affect that sector. Management Risks. The Adviser’s judgments about the attractiveness, value, level of expected volatility, and potential appreciation of the Fund’s investments may prove to be incorrect. Accordingly, no guarantee exists that the investment techniques used by the Fund’s managers will produce the desired results. In addition, the Adviser’s strategy may limit the Fund’s gains in rising markets. Foreign Securities Risks. Investing in foreign securities may involve additional risks, including currency-rate fluctuations, political and economic instability, differences in financial reporting standards, less-strict regulation of the securities markets, and possible imposition of foreign withholding taxes. Furthermore, the Fund may incur higher costs and expenses when making foreign investments, which will affect the Fund’s total return. Emerging Markets Risks. Investments in emerging markets can involve risks in addition to and greater than those generally associated with investing in more developed foreign markets, which may make emerging market securities more volatile and potentially less liquid than securities issued in more developed markets. Company Size Risks. Generally, the smaller the market capitalization of a company, the fewer the number of shares traded daily, the less liquid its stock, and the more volatile its price. Companies with smaller market capitalizations also tend to have unproven track records, a limited product or service base, and limited access to capital. These factors also increase risks and make these companies more likely to fail than companies with larger market capitalizations. Currency Risks. To the extent that the Fund invests directly in foreign (non-U.S.) currencies or in securities denominated in, or that trade in, foreign (non-U.S.) currencies, it is subject to the risk that those currencies will decline in value relative to the U.S. dollar or, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency being hedged. Information Risks. When the quantitative models (“Models”) and information and data (“Data”) used in managing the Fund prove to be incorrect or incomplete, any investment decisions made in reliance on the Models and Data may not produce the desired results and the Fund may realize losses. The success of Models that are predictive in nature is dependent largely upon the accuracy and reliability of the supplied historical data. All Models are susceptible to input errors that may cause the resulting information to be incorrect. Quantitative Model Investment Risks. The success of a quantitative investment model depends on the analyses and assessments that were used in developing such model. Incorrect analyses and assessments or inaccurate or incomplete data would adversely affect performance. There can be no assurance that the Model will enable the Fund to achieve its investment objective.
Risk Lose Money [Text]	rr_RiskLoseMoney	The net asset value of the Fund will vary and you could lose money by investing in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit of BMO Harris Bank N.A., or any of its affiliates, and is not insured or guaranteed by the FDIC or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Fund Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	Performance information is not included because the Fund does not have one full calendar year of performance as of the date of this Prospectus.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	Performance information is not included because the Fund does not have one full calendar year of performance as of the date of this Prospectus.
BMO Global Low Volatility Equity Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of shares redeemed within 18 months of purchase)	rr_MaximumDeferredSalesChargeOverOther	none	[1]
Redemption Fee (as a percentage of amount redeemed, for shares held less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	12.68%	[2],[3]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	13.33%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(12.48%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	0.85%	[2]
1 Year	rr_ExpenseExampleYear01	87
3 Years	rr_ExpenseExampleYear03	2,637
5 Years	rr_ExpenseExampleYear05	4,780
10 Years	rr_ExpenseExampleYear10	8,758
BMO Global Low Volatility Equity Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.00%
Maximum Deferred Sales Charge (Load) (as a percentage of shares redeemed within 18 months of purchase)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[1]
Redemption Fee (as a percentage of amount redeemed, for shares held less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	12.68%	[2],[3]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	13.58%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(12.48%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	1.10%	[2]
1 Year	rr_ExpenseExampleYear01	607
3 Years	rr_ExpenseExampleYear03	3,062
5 Years	rr_ExpenseExampleYear05	5,115
10 Years	rr_ExpenseExampleYear10	8,890

[1] The Maximum Deferred Sales Charge on Class A shares is applied only to purchases of $1,000,000 or more that are redeemed within 18 months of purchase.

[2] “Other Expenses” for the Class A shares are based on estimated amounts for the current fiscal year.

[3] Other Expenses have been restated to reflect current fees, effective June 1, 2015.