Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	NORTHERN FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 31, 2013
NORTHERN GLOBAL REAL ESTATE INDEX FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	GLOBAL REAL ESTATE INDEX FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide investment results approximating the overall performance of the securities included in the FTSE® EPRA®/NAREIT® Global Index (“FTSE EPRA/NAREIT Index”).
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	July 31, 2014
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 portfolio operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 7.75% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	7.75%
Expense Example [Heading]	rr_ExpenseExampleHeading	EXAMPLE
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following 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 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 remain the same. Although your actual costs 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	Under normal circumstances, the Fund will invest substantially all (and at least 80%) of its net assets in equity securities included in the FTSE EPRA/NAREIT Global Index ("FTSE EPRA/NAREIT Index"), in weightings that approximate the relative composition of the securities contained in the FTSE EPRA/NAREIT Index. Companies included in the FTSE EPRA/NAREIT Index are engaged principally in real estate activities, including ownership, trading and development of income-producing real estate, and include REITs. The FTSE EPRA/NAREIT Index is a free float, market capitalization-weighted real estate index designed to represent publicly traded equity REITs and listed property companies in 36 countries worldwide, covering both the developed and emerging markets. As of May 31, 2013, the FTSE EPRA/NAREIT Index consisted of issuers from the following 36 countries: Australia, Austria, Belgium, Brazil, Canada, China, Czech Republic, Egypt, Finland, France, Germany, Greece, Hong Kong, India, Indonesia, Israel, Italy, Japan, Malaysia, Mexico, the Netherlands, New Zealand, Norway, the Philippines, Poland, Russia, Singapore, South Africa, Sweden, Switzerland, Taiwan, Thailand, Turkey, the United Arab Emirates, the United Kingdom and the United States. The Fund is passively managed, which means it tries to duplicate the investment composition and performance of the FTSE EPRA/NAREIT Index by using computer programs and statistical procedures. The Fund's investment adviser will buy and sell securities in response to changes in the FTSE EPRA/NAREIT Index. Because the Fund will have fees and transaction expenses (while the FTSE EPRA/NAREIT Index has none), returns are likely to be below those of the FTSE EPRA/NAREIT Index. The proportions of the Fund's assets allocated to each country will approximate and vary with the relative country weights in the FTSE EPRA/NAREIT Index. As of May 31, 2013, the FTSE EPRA/NAREIT Index consisted primarily of issuers located in developed countries, concentrated in the following geographic areas: Americas, Asia Pacific and Europe. As of the same date, approximately 42.3% of the issuers in the FTSE EPRA/NAREIT Index were located in the United States. The Fund's investment adviser expects that, under normal circumstances, the quarterly performance of the Fund, before expenses, will track the performance of the FTSE EPRA/NAREIT Index within a 0.95 correlation coefficient. FTSE International Limited ("FTSE"), The European Public Real Estate Association ("EPRA") and the National Association of Real Estate Investment Trusts ("NAREIT") do not endorse any of the securities in the FTSE EPRA/NAREIT Index. These entities are not sponsors of the Global Real Estate Index Fund and are not affiliated with the Fund in any way.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	Under normal circumstances, the Fund will invest substantially all (and at least 80%) of its net assets in equity securities included in the FTSE EPRA/NAREIT Global Index ("FTSE EPRA/NAREIT Index"), in weightings that approximate the relative composition of the securities contained in the FTSE EPRA/NAREIT Index. Companies included in the FTSE EPRA/NAREIT Index are engaged principally in real estate activities, including ownership, trading and development of income-producing real estate, and include REITs.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	MARKET RISK is the risk that the value of equity securities owned by the Fund may decline, at times sharply and unpredictably, because of economic changes or other events that affect individual issuers or large portions of the market. MANAGEMENT RISK is the risk that a strategy used by the Fund's investment adviser may fail to produce the intended results. TRACKING RISK is the risk that the Fund's performance may vary substantially from the performance of the benchmark index it tracks as a result of share purchases and redemptions, transaction costs, expenses and other factors. FOREIGN SECURITIES RISK is the risk that investing in foreign (non-U.S.) securities may result in the Fund experiencing more rapid and extreme changes in value than a fund that invests exclusively in securities of U.S. companies, due to less liquid markets and adverse economic, political, diplomatic, financial, and regulatory factors. Foreign governments also may impose limits on investment and repatriation and impose taxes. Any of these events could cause the value of the Fund's investments to decline. To the extent that the Fund's assets are concentrated in a single country or geographic region, the Fund will be subject to the risks associated with that particular country or region. CURRENCY RISK is the risk that foreign currencies will fluctuate in value relative to the U.S. dollar, adversely affecting the value of the Fund's investments and its returns. Because the Fund's net asset value is determined on the basis of U.S. dollars, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the market value of the Fund's holdings appreciates. MID CAP STOCK RISK is the risk that stocks of mid-sized companies may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Mid-sized companies may have limited product lines or financial resources, and may be dependent upon a particular niche of the market. SMALL CAP STOCK RISK is the risk that stocks of smaller companies may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Small companies may have limited product lines or financial resources, or may be dependent upon a small or inexperienced management group, and their securities may trade less frequently and in lower volume than the securities of larger companies, which could lead to higher transaction costs. Generally the smaller the company size, the greater the risk. IPO RISK is the risk that the market value of shares in an initial public offering (IPO) will fluctuate considerably or decline shortly after the initial public offering, due to factors such as the absence of a prior public market, unseasoned trading, the small number of shares available for trading and limited information about the issuer. REAL ESTATE SECURITIES CONCENTRATION RISK is the risk that investments in securities of real estate companies will make the Fund more susceptible to risks associated with the ownership of real estate and with the real estate industry in general. Real estate companies may have lower trading volumes and may be subject to more abrupt or erratic price movements than the overall securities markets. The value of real estate securities may underperform other sectors of the economy or broader equity markets. To the extent that the Fund concentrates its investments in the real estate sector, it may be subject to greater risk of loss than if it were diversified across different industry sectors. REIT RISK is the risk that the Fund's investments will be affected by factors affecting real estate investment trusts (REITs) and the real estate sector generally. Investing in REITs involves certain unique risks in addition to those risks associated with investing in the real estate industry in general. REITs whose underlying properties are concentrated in a particular industry or geographic region are also subject to risks affecting such industries and regions. REITs (especially mortgage REITs) are also subject to interest rate risks. By investing in REITs through the Fund, a shareholder will bear expenses of the REITs in addition to expenses of the Fund. INTEREST RATE/MATURITY RISK is the risk that the value of the Fund's assets will decline because of rising interest rates. The magnitude of this decline will often be greater for longer-term fixed-income securities than shorter-term fixed-income securities. As with any mutual fund, it is possible to lose money on an investment in the Fund. An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation, any other government agency, or The Northern Trust Company, its affiliates, subsidiaries or any other bank.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any mutual fund, it is possible to lose money on an investment in the Fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation, any other government agency, or The Northern Trust Company, its affiliates, subsidiaries or any other bank.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	FUND PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow provide an indication of the risks of investing in the Fund by showing (A) changes in the performance of the Fund from year to year, and (B) how the average annual total returns of the Fund compare to those of a broad-based securities market index. 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 information for the Fund is available and may be obtained on the Fund’s Web site at www.northernfunds.com or by calling 800-595-9111.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow provide an indication of the risks of investing in the Fund by showing (A) changes in the performance of the Fund from year to year, and (B) how the average annual total returns of the Fund compare to those of a broad-based securities market index.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-595-9111
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.northernfunds.com
Performance Past Does Not Indicate Future [Text]	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	CALENDAR YEAR TOTAL RETURN*
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	* Year to date total return for the six months ended June 30, 2013 is 0.51%. For the periods shown in the bar chart above, the highest quarterly return was 36.26% in the second quarter of 2009, and the lowest quarterly return was (33.21)% in the fourth quarter of 2008.
Performance Table Heading	rr_PerformanceTableHeading	AVERAGE ANNUAL TOTAL RETURN (For the periods ended December 31, 2012)
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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	In calculating the federal income taxes due on redemptions, capital gains taxes resulting from redemptions are subtracted from the redemption proceeds and the tax benefits from capital losses resulting from the redemptions are added to the redemption proceeds. Under certain circumstances, the addition of the tax benefits from capital losses resulting from redemptions may cause the Returns After Taxes on Distributions and Sale of Fund Shares to be greater than the Returns After Taxes on Distributions or even the Returns Before Taxes.
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 an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. In calculating the federal income taxes due on redemptions, capital gains taxes resulting from redemptions are subtracted from the redemption proceeds and the tax benefits from capital losses resulting from the redemptions are added to the redemption proceeds. Under certain circumstances, the addition of the tax benefits from capital losses resulting from redemptions may cause the Returns After Taxes on Distributions and Sale of Fund Shares to be greater than the Returns After Taxes on Distributions or even the Returns Before Taxes.
NORTHERN GLOBAL REAL ESTATE INDEX FUND | NORTHERN GLOBAL REAL ESTATE INDEX FUND
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Redemption Fee (as a percentage of amount redeemed, if applicable)	rr_RedemptionFeeOverRedemption	2.00%	[1]
Management Fees	rr_ManagementFeesOverAssets	0.35%
Other Expenses	rr_OtherExpensesOverAssets	0.38%
Administration Fees	rr_Component1OtherExpensesOverAssets	0.15%
Transfer Agency Fees	rr_Component2OtherExpensesOverAssets	0.10%
Other Operating Expenses	rr_Component3OtherExpensesOverAssets	0.13%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.73%
Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.23%)	[2]
Total Annual Fund Operating Expenses After Expense Reimbursement	rr_NetExpensesOverAssets	0.50%
1 Year	rr_ExpenseExampleYear01	$ 51
3 Years	rr_ExpenseExampleYear03	210
5 Years	rr_ExpenseExampleYear05	383
10 Years	rr_ExpenseExampleYear10	$ 885
2007	rr_AnnualReturn2007	(8.49%)
2008	rr_AnnualReturn2008	(48.04%)
2009	rr_AnnualReturn2009	36.96%
2010	rr_AnnualReturn2010	19.40%
2011	rr_AnnualReturn2011	(8.93%)
2012	rr_AnnualReturn2012	29.44%
Year to Date Return, Label	rr_YearToDateReturnLabel	Year to date total return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2013
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.51%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest quarterly return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	36.26%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest quarterly return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(33.21%)
1-Year	rr_AverageAnnualReturnYear01	29.44%
5-Years	rr_AverageAnnualReturnYear05	0.03%
Since Inception	rr_AverageAnnualReturnSinceInception	1.80%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 26, 2006
NORTHERN GLOBAL REAL ESTATE INDEX FUND | Return after taxes on distributions | NORTHERN GLOBAL REAL ESTATE INDEX FUND
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	28.04%
5-Years	rr_AverageAnnualReturnYear05	(0.91%)
Since Inception	rr_AverageAnnualReturnSinceInception	0.86%
NORTHERN GLOBAL REAL ESTATE INDEX FUND | Return after taxes on distributions and sale of Fund shares | NORTHERN GLOBAL REAL ESTATE INDEX FUND
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	19.38%
5-Years	rr_AverageAnnualReturnYear05	(0.53%)
Since Inception	rr_AverageAnnualReturnSinceInception	1.00%
NORTHERN GLOBAL REAL ESTATE INDEX FUND | FTSE®EPRA®/NAREIT® Global Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	28.98%
5-Years	rr_AverageAnnualReturnYear05	0.07%
Since Inception	rr_AverageAnnualReturnSinceInception	2.38%

[1] (within 30 days of purchase)

[2] Northern Trust Investments, Inc. has contractually agreed to reimburse a portion of the operating expenses of the Fund (other than acquired fund fees and expenses; a portion of the compensation paid to each Trustee who is not an officer, director or employee of Northern Trust Corporation or its subsidiaries; expenses related to third-party consultants engaged by the Board of Trustees of the Trust; membership dues paid to the Investment Company Institute and Mutual Fund Directors Forum; and extraordinary expenses and interest, if any) to the extent the "Total Annual Fund Operating Expenses" exceed 0.50%. This contractual limitation may not be terminated before July 31, 2014 without the approval of the Board of Trustees. Northern Trust Investments, Inc. serves as the investment adviser and administrator to the Fund. The Northern Trust Company, an affiliate of Northern Trust Investments, Inc., serves as transfer agent, custodian and sub-administrator to the Fund.