Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BMO FUNDS, INC.
Prospectus Date	rr_ProspectusDate	Dec. 27, 2013
BMO Low Volatility Equity Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	FUND SUMMARY BMO 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.
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, 2014
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 period September 28, 2012 (inception date) to August 31, 2013, the Fund’s portfolio turnover rate (not annualized) was 101% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	101.00%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Total Annual Fund Operating Expenses shown will not correlate to the Fund’s ratios of expenses to average net assets appearing in the Financial Highlights tables, which do not include Acquired Fund Fees and Expenses.
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, 2014. 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 a broadly diversified portfolio of common stocks of large-sized U.S. companies similar in size, at the time of purchase, to those within the Russell 1000® Index. The largest company by market capitalization in the Russell 1000® Index was approximately $490.3 billion as of October 31, 2013 and the median market capitalization of companies in the Index as of the same date was approximately $7.2 billion. The Fund invests in stocks that exhibit less volatile stock price patterns when compared to stocks in the Russell 1000® Index. The Adviser selects low volatility, undervalued stocks using a unique, quantitative approach based on the Adviser’s multi-factor risk/return models. This strategy seeks to provide the Fund with lower downside risk and meaningful upside participation relative to the Russell 1000® 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. 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. Style Risks. Investments in value stocks are subject to the risk that their intrinsic values may never be realized by the market, that a stock judged to be undervalued may actually be appropriately priced, or that their prices may decline, even though in theory they are already undervalued. Value stocks can react differently to issuer, political, market, and economic developments than the market as a whole, and other types of stocks (e.g., growth stocks). 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. 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. 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 to the Fund to achieve its investment objective. Portfolio Turnover Risks. A high portfolio rate (100% or more) may result in the realization and distribution to shareholders of a greater amount of capital gains than if the Fund had a low portfolio turnover rate. Therefore, you may have higher tax liability. High portfolio turnover also may result in higher transaction costs, which may negatively affect Fund performance.
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 Low Volatility Equity Fund | Class Y
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	1.03%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.54%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.63%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	0.91%	[2]
1 Year	rr_ExpenseExampleYear01	$ 93
3 Years	rr_ExpenseExampleYear03	425
5 Years	rr_ExpenseExampleYear05	780
10 Years	rr_ExpenseExampleYear10	1,781
BMO Low Volatility Equity Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	0.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.78%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.29%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.63%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	0.66%	[2]
1 Year	rr_ExpenseExampleYear01	67
3 Years	rr_ExpenseExampleYear03	347
5 Years	rr_ExpenseExampleYear05	647
10 Years	rr_ExpenseExampleYear10	$ 1,501

[1] Acquired Fund Fees and Expenses represent the pro rata expense indirectly incurred by the Fund as a result of its investment in other investment companies. Total Annual Fund Operating Expenses shown will not correlate to the Fund's ratios of expenses to average net assets appearing in the Financial Highlights tables, which do not include Acquired Fund Fees and Expenses.

[2] 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 0.90% for Class Y and 0.65% for Class I through December 31, 2014. This expense limitation agreement may not be terminated prior to December 31, 2014 without the consent of the Fund's Board of Directors, unless terminated due to the termination of the investment advisory agreement.