Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BMO FUNDS, INC.
Prospectus Date	rr_ProspectusDate	Dec. 27, 2013
BMO Target Retirement 2035 Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	BMO Target Retirement 2035 Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective:
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	To achieve growth, income, and conservation of capital to varying degrees depending on its proximity to its target date. As the Fund approaches and passes its target date, the Fund will reduce its emphasis on growth and increase its emphasis on income and preservation of capital.
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.
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Because the Fund is new, these expenses are based on estimated amounts for the Fund’s current fiscal year.
Acquired Fund Fees and Expenses, Based on Estimates [Text]	rr_AcquiredFundFeesAndExpensesBasedOnEstimates	Because the Fund is new, these expenses are based on estimated amounts for the Fund’s current fiscal year.
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-year example 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 will attempt to achieve its investment objectives by investing in a mix of BMO Funds and unaffiliated funds (the underlying funds) in different combinations and weightings. The Adviser may periodically rebalance or modify the asset mix of the funds and change the underlying funds. The specific retirement year (2035) included in the Fund’s name refers to the approximate year an investor would plan to retire and assumes a retirement age of 65. The target date is the year that an investor likely would stop making new investments in the Fund. The Fund is designed for an investor who expects to retire in or around the year 2035 at age 65 and who plans to withdraw the value of the investor’s account in the Fund gradually after retirement. The Fund may invest no more than 90% of its total assets in funds that invest principally in equity securities (Stock Funds). Equity securities in which the underlying funds may invest may be of any market capitalization and include common stock, preferred stock, rights and warrants, and securities convertible into common stock. The Fund also may invest in underlying funds that invest in fixed income securities of any quality or maturity (Bond Funds) and cash, cash equivalents, and other short-term fixed income instruments, including money market funds. While the Fund will invest primarily in underlying funds that invest in U.S. securities, some underlying funds may invest in foreign securities, including emerging markets. The allocation to asset classes and funds is expected to change over time, becoming more conservative as time elapses. This change is referred to as the “glide path” to the retirement date. The decline in the equity allocation is necessary to reduce market risk and portfolio volatility approaching and into retirement. The Fund does not guarantee a level of income during retirement. It is intended to serve as a post-retirement investment portfolio to provide an income stream made up of regular withdrawals throughout retirement, as well as some growth to offset the effects of inflation. The following chart illustrates the Adviser’s approach to making these changes over time. At the target date (2035), the Fund’s allocation to funds that invest principally in equity securities is anticipated to be approximately 47% of its total assets. The Fund’s exposure to funds that invest principally in equity securities will continue to decline for as long as 10 years after its target date, when its allocation to funds that invest principally in equity securities will remain fixed at approximately 30% of its total assets with the remaining allocation devoted to funds that invest principally in fixed income securities and money market instruments. The allocations shown in the glide path represent target allocations, but they do not reflect any tactical decisions made by the Adviser to overweight or underweight a particular asset class or sector based on its market expectations. The target allocations assigned to the broad asset classes (equities and fixed income) are based upon the current market outlook. The Adviser will continuously monitor the Fund and may make modifications to either the investment approach or the underlying fund allocations that the Adviser believes could benefit shareholders. Any change to existing target allocations or from tactical adjustments around the target allocations are not expected to vary from the existing target allocations set forth in the glide path by more than plus or minus ten percentage points. Although the Fund intends to invest primarily in a combination of underlying funds, the Fund may invest directly in equity and fixed income securities and money market securities.
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. There are risks associated with investments in target date funds, and there is no guarantee that the Fund will provide adequate income at and through a shareholder’s retirement. This section describes the principal risks associated with the Fund’s principal investment strategies. The net asset value of the Fund will vary, and you could lose money by investing in the Fund. The likelihood of loss may be greater if you invest for a shorter period of time. Investors in the Fund should have a long-term perspective and be able to tolerate potentially sharp declines in value. Affiliated Fund Risk. The Adviser’s authority to select and substitute underlying funds from a variety of affiliated and unaffiliated mutual funds may create a conflict of interest because the Adviser and its affiliated companies typically receive fees from the affiliated funds. Asset Allocation Risk. Investments in the Fund are subject to risks related to the Adviser’s allocation choices. The selection of the underlying funds and the allocation of the Fund’s assets among the various asset classes and market segments could cause the Fund to lose value or cause the Fund to underperform relevant benchmarks or other funds with similar investment objectives. Market Risk. Stock and bond markets rise and fall daily. As with any investment whose performance is tied to these markets, the value of your investment in the Fund will fluctuate, which means that you could lose money. Underlying Fund Investment Risk. The Fund invests in underlying funds and incurs expenses related to the underlying funds. In addition, investors in the Fund will incur fees to pay for certain expenses related to the operations of the Fund. An investor holding the underlying funds directly and in the same proportions as the Fund would incur lower overall expenses, but would not receive the benefit of the portfolio management and other services provided by the Fund. The Fund’s risks are directly related to the risks of the underlying funds. It is important to understand the risks associated with investing in the underlying funds. Equity Risk. The prices of equity securities rise and fall daily. These price movements may result from factors affecting individual companies, industries, or the securities market as a whole. In addition, equity markets tend to move in cycles, which may cause stock prices to fall over short or extended periods of time. Large-, Mid-, and Small-Cap Risk. Stocks of different market capitalizations tend to go in and out of favor based on market and economic conditions. Historically, small- and mid-cap stocks tend to be more volatile than large-cap stocks, and small-cap stocks have been riskier than large- and mid-cap stocks. During a period when stocks of a particular market capitalization fall behind other types of investments, an underlying fund’s large-, mid-, or small-cap holdings could reduce performance. Style Risk. Different investment styles, such as growth or equity, tend to shift in and out of favor depending on market and investor sentiment. The Fund may underperform other funds that invest in underlying funds with similar asset classes but employ different investment styles. Foreign Securities Risk. 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, a fund may incur higher costs and expenses when making foreign investments, which will affect the fund’s total return. Emerging Markets Risk. 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. Liquidity Risk. Liquidity risk refers to the possibility that a fund may not be able to sell or buy a security or close out an investment contract at a favorable price or time. Consequently, an underlying fund may have to accept a lower price to sell a security, sell other securities to raise cash, or give up an investment opportunity, any of which could have a negative effect on the fund’s performance. Fixed Income Risk. Interest rates rise and fall over time, which will affect an underlying fund’s yield and share price. The credit quality of a portfolio investment could also cause an underlying fund’s share price to fall. An underlying fund could lose money if the issuer or counterparty defaults by failing to pay interest or principal when due. Fixed income securities may be paid off earlier or later than expected. Either situation could cause an underlying fund to hold securities paying lower-than-market rates of interest, which could hurt the fund’s yield or share price. High Yield Securities Risk. High yield securities, also referred to as “junk bonds” or non-investment grade securities, tend to be more sensitive to economic conditions than are higher-rated securities, generally involve more credit risk than securities in the higher-rated categories and are predominantly considered to be speculative. The issuers of high yield securities are typically more leveraged, and the risk of loss due to default by an issuer of high yield securities is significantly greater than issuers of higher-rated securities because such securities are generally unsecured and are often subordinated to other creditors. Sector Risk. Companies with similar characteristics, such as those within the same industry, may be grouped together in broad categories called sectors. To the extent an underlying 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.
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 Target Retirement 2035 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	none
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.64%	[1]
Acquired (underlying) Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.28%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.27%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	1.01%	[2]
1 Year	rr_ExpenseExampleYear01	$ 103
3 Years	rr_ExpenseExampleYear03	379
BMO Target Retirement 2035 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	none
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.39%	[1]
Acquired (underlying) Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.03%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.27%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	0.76%	[2]
1 Year	rr_ExpenseExampleYear01	78
3 Years	rr_ExpenseExampleYear03	301
BMO Target Retirement 2035 Fund | Class R-3
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	none
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.50%
Other Expenses	rr_OtherExpensesOverAssets	0.39%	[1]
Acquired (underlying) Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.53%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.27%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	1.26%	[2]
1 Year	rr_ExpenseExampleYear01	128
3 Years	rr_ExpenseExampleYear03	457
BMO Target Retirement 2035 Fund | Class R-6
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Management Fees	rr_ManagementFeesOverAssets	none
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.24%	[1]
Acquired (underlying) Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.64%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.88%
Fee Waiver and Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.27%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and Expense Reimbursement	rr_NetExpensesOverAssets	0.61%	[2]
1 Year	rr_ExpenseExampleYear01	62
3 Years	rr_ExpenseExampleYear03	$ 254

[1] Because the Fund is new, these expenses are based on estimated amounts for the Fund's current fiscal year.

[2] BMO Asset Management Corp. (Adviser) has agreed to waive or reduce fees and reimburse expenses to the extent necessary to prevent class total annual operating expenses (excluding acquired fund fees and expenses, 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) from exceeding the amounts shown above 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.