Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	NORTHERN FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 31, 2013
NORTHERN INCOME EQUITY FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	INCOME EQUITY FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide a high level of current income and long-term 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	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 11.27% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	11.27%
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	In seeking to achieve its investment objective, the Fund will, under normal circumstances, invest at least 80% of its net assets in income-producing equity securities, including dividend-paying common and preferred stocks and convertible securities. The Fund also may invest up to 20% of its net assets in a broad range of non-convertible fixed-income securities without limitation as to maturity. The Fund seeks to provide a high level of current income relative to other mutual funds that invest in equity securities. Using fundamental research and quantitative analysis, the Fund's investment adviser buys and sells securities based on factors such as a company's: Current income; Prospects for growth; and Capital appreciation potential. In determining capital appreciation potential, the Fund's investment adviser will analyze such fundamental factors as sales and earnings growth, financial condition, product development and the valuation of the stock relative to market and historical norms. For convertible securities, the team also analyzes the conversion feature and the potential value of the underlying equity securities. Subject to the requirement that the Fund invest at least 80% of its assets in income-producing equity securities, there is no limit on the Fund’s ability to invest in convertible securities or non-convertible fixed-income securities that are below-investment grade. Non-investment grade bonds may constitute a significant portion of the Fund’s portfolio. These bonds tend to offer higher yields than higher rated securities with similar maturities. However, such bonds are considered speculative and generally involve greater price volatility and greater risk of loss than higher rated securities. There is no minimum rating for a security purchased or held by the Fund, and the Fund may purchase securities that are in default, although investments in such securities are expected to be minimal.
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. It includes the risk that a particular style of investing, such as growth or value, may underperform the market generally. MANAGEMENT RISK is the risk that a strategy used by the Fund's investment adviser may fail to produce the intended results. HIGH-YIELD RISK is the risk that the Fund's non-investment grade fixed-income securities, sometimes known as "junk bonds," will be subject to greater credit risk, price volatility and risk of loss than investment grade securities, which can adversely impact the Fund's return and net asset value. High yield securities are considered primarily speculative with respect to the issuer's continuing ability to make principal and interest payment. 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. CREDIT (OR DEFAULT) RISK is the risk that the inability or unwillingness of an issuer or guarantor of a fixed-income security, or a counterparty to a repurchase or other transaction, to meet its payment or other financial obligations will adversely affect the value of the Fund's investments and its returns. Changes in the credit rating of a debt security held by the Fund could have a similar effect. 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 11.67%. For the periods shown in the bar chart above, the highest quarterly return was 15.19% in the third quarter of 2009, and the lowest quarterly return was (18.35)% 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 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.
NORTHERN INCOME EQUITY FUND | NORTHERN INCOME EQUITY FUND
Risk/Return:	rr_RiskReturnAbstract
Shareholder Fees (fees paid directly from your investment)	rr_ShareholderFeeOther	none
Management Fees	rr_ManagementFeesOverAssets	0.85%
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	1.23%
Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.23%)	[1]
Total Annual Fund Operating Expenses After Expense Reimbursement	rr_NetExpensesOverAssets	1.00%
1 Year	rr_ExpenseExampleYear01	102
3 Years	rr_ExpenseExampleYear03	368
5 Years	rr_ExpenseExampleYear05	654
10 Years	rr_ExpenseExampleYear10	$ 1,468
2003	rr_AnnualReturn2003	20.13%
2004	rr_AnnualReturn2004	10.37%
2005	rr_AnnualReturn2005	5.85%
2006	rr_AnnualReturn2006	18.26%
2007	rr_AnnualReturn2007	5.43%
2008	rr_AnnualReturn2008	(30.82%)
2009	rr_AnnualReturn2009	32.22%
2010	rr_AnnualReturn2010	15.99%
2011	rr_AnnualReturn2011	2.18%
2012	rr_AnnualReturn2012	10.61%
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	11.67%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest quarterly return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	15.19%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest quarterly return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(18.35%)
1-Year	rr_AverageAnnualReturnYear01	10.61%
5-Year	rr_AverageAnnualReturnYear05	3.70%
10-Year	rr_AverageAnnualReturnYear10	7.69%
Since Inception	rr_AverageAnnualReturnSinceInception	7.99%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 01, 1994
NORTHERN INCOME EQUITY FUND | Return after taxes on distributions | NORTHERN INCOME EQUITY FUND
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	10.22%
5-Year	rr_AverageAnnualReturnYear05	3.12%
10-Year	rr_AverageAnnualReturnYear10	6.66%
Since Inception	rr_AverageAnnualReturnSinceInception	6.20%
NORTHERN INCOME EQUITY FUND | Return after taxes on distributions and sale of Fund shares | NORTHERN INCOME EQUITY FUND
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	7.39%
5-Year	rr_AverageAnnualReturnYear05	2.94%
10-Year	rr_AverageAnnualReturnYear10	6.36%
Since Inception	rr_AverageAnnualReturnSinceInception	6.07%
NORTHERN INCOME EQUITY FUND | S&P 500® Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	16.00%
5-Year	rr_AverageAnnualReturnYear05	1.66%
10-Year	rr_AverageAnnualReturnYear10	7.10%
Since Inception	rr_AverageAnnualReturnSinceInception	8.45%

[1] 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 1.00%. 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.