Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	NORTHERN FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 31, 2013
NORTHERN HIGH YIELD FIXED INCOME FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	HIGH YIELD FIXED INCOME FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks a high level of current income. In doing so, the Fund also may consider the potential for 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 115.51% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	115.51%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	The Total Annual Fund Operating Expenses and Total Annual Fund Operating Expenses After Expense Reimbursement will not correlate to the Fund’s ratios of average net assets to (1) expenses before reimbursements and credits and (2) expenses net of reimbursements and credits, respectively, included in the Fund’s Financial Highlights in the Fund’s complete Prospectus, which do not reflect indirect expenses, such as Acquired Fund Fees and Expenses.
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 invest, under normal circumstances, at least 80% of its net assets in lower quality bonds and other fixed-income securities (commonly referred to as "junk bonds"). These may include: Obligations of U.S. and foreign corporations and banks; Obligations of state, local and foreign governments; Obligations of the U.S. government or its agencies, instrumentalities or sponsored enterprises, including obligations that are issued by private issuers that are guaranteed as to principal and interest by the U.S. or foreign governments, their agencies or instrumentalities; Senior and subordinated bonds and debentures; Zero coupon, pay-in-kind and capital appreciation bonds; Convertible securities, preferred stock, structured securities and loan participations; Warrants, rights and other equity securities that are acquired in connection with the Fund's investments in debt or convertible securities; and Repurchase agreements relating to the above instruments. Lower quality securities are rated BB, Ba or lower by a Nationally Recognized Statistical Rating Organization ("NRSRO"). Unrated securities will be of comparable quality as determined by the Fund's investment adviser. Lower rated securities tend to offer higher yields than higher rated securities with similar maturities. However, lower rated securities 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 the Fund invests primarily in lower quality fixed-income securities, it may invest a portion of its assets in securities of higher quality. During temporary defensive periods, the Fund may invest all of its assets in securities of higher quality. The Fund may not achieve its investment objective when this temporary strategy is used. Although the Fund primarily invests in the debt obligations of domestic issuers, it may make limited investments in the securities of foreign issuers. In buying and selling securities for the Fund, the Fund's investment adviser uses a relative value approach. This approach involves an analysis of general economic and market conditions. It also involves the use of models that analyze and compare expected returns and assumed risks. Under the relative value approach, the Fund's investment adviser will emphasize particular securities and types of securities (such as asset-backed, mortgage-backed and corporate securities) that the team believes will provide a favorable return in light of the risks. The Fund's investment adviser also may consider obligations with a more favorable or improving credit or industry outlook that provide the potential for capital appreciation. The Fund does not have any portfolio maturity limitation, and may invest its assets from time to time in instruments with short, medium or long maturities. The instruments held by the Fund are considered speculative, and an investment in the Fund presents substantial risks in relation to a fund that invests in investment grade instruments.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	MARKET RISK is the risk that the market values of fixed-income securities owned by the Fund may decline, at times sharply and unpredictably. MANAGEMENT RISK is the risk that a strategy used by the Fund's investment adviser may fail to produce the intended results. LIQUIDITY RISK is the risk that certain portfolio securities may be less liquid than others, which may make them difficult or impossible to sell at the time and the price that the Fund would like, adversely affecting the value of the Fund's investments and its returns. INTEREST RATE/MATURITY RISK is the risk that the value of the Fund's assets will decline because of rising interest rates. This risk is generally lower for funds that have shorter-weighted maturities, such as money market funds and short-term bond funds. The magnitude of this decline will often be greater for longer-term fixed-income securities than shorter-term fixed-income securities. PREPAYMENT (OR CALL) RISK is the risk that prepayment of some fixed-income securities may result in a decreased rate of return and a decline in value of those securities. DEBT EXTENSION RISK is the risk that an issuer will exercise its right to pay principal on an obligation held by the Fund later than expected. Under these circumstances, the value of the obligation will decrease and the Fund will suffer from the inability to invest in higher yielding 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. 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 payments. 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. 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. PORTFOLIO TURNOVER RISK is the risk that high portfolio turnover may lead to increased Fund expenses resulting in lower investment returns. High portfolio turnover may also result in higher short-term capital gains taxable to shareholders. For the last fiscal year, the annual portfolio turnover rate of the Fund exceeded 100%. 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 1.82%. For the periods shown in the bar chart above, the highest quarterly return was 10.22% in the second quarter of 2009, and the lowest quarterly return was (11.14)% 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 HIGH YIELD FIXED INCOME FUND | NORTHERN HIGH YIELD FIXED INCOME 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	0.65%
Other Expenses	rr_OtherExpensesOverAssets	0.30%
Administration Fees	rr_Component1OtherExpensesOverAssets	0.15%
Transfer Agency Fees	rr_Component2OtherExpensesOverAssets	0.10%
Other Operating Expenses	rr_Component3OtherExpensesOverAssets	0.05%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.96%	[2]
Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.15%)	[3]
Total Annual Fund Operating Expenses After Expense Reimbursement	rr_NetExpensesOverAssets	0.81%	[2]
1 Year	rr_ExpenseExampleYear01	$ 83
3 Years	rr_ExpenseExampleYear03	291
5 Years	rr_ExpenseExampleYear05	516
10 Years	rr_ExpenseExampleYear10	$ 1,164
2003	rr_AnnualReturn2003	23.58%
2004	rr_AnnualReturn2004	8.44%
2005	rr_AnnualReturn2005	1.77%
2006	rr_AnnualReturn2006	10.08%
2007	rr_AnnualReturn2007	1.35%
2008	rr_AnnualReturn2008	(19.29%)
2009	rr_AnnualReturn2009	33.48%
2010	rr_AnnualReturn2010	13.60%
2011	rr_AnnualReturn2011	3.75%
2012	rr_AnnualReturn2012	15.08%
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	1.82%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest quarterly return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	10.22%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest quarterly return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(11.14%)
1-Year	rr_AverageAnnualReturnYear01	15.08%
5-Year	rr_AverageAnnualReturnYear05	7.87%
10-Year	rr_AverageAnnualReturnYear10	8.31%
Since Inception	rr_AverageAnnualReturnSinceInception	6.34%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 31, 1998
NORTHERN HIGH YIELD FIXED INCOME FUND | Return after taxes on distributions | NORTHERN HIGH YIELD FIXED INCOME FUND
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	12.28%
5-Year	rr_AverageAnnualReturnYear05	4.89%
10-Year	rr_AverageAnnualReturnYear10	5.42%
Since Inception	rr_AverageAnnualReturnSinceInception	3.24%
NORTHERN HIGH YIELD FIXED INCOME FUND | Return after taxes on distributions and sale of Fund shares | NORTHERN HIGH YIELD FIXED INCOME FUND
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	9.69%
5-Year	rr_AverageAnnualReturnYear05	4.89%
10-Year	rr_AverageAnnualReturnYear10	5.39%
Since Inception	rr_AverageAnnualReturnSinceInception	3.42%
NORTHERN HIGH YIELD FIXED INCOME FUND | Barclays U.S. Corporate High Yield 2% Issuer Capped Index (reflects no deduction for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
1-Year	rr_AverageAnnualReturnYear01	15.78%
5-Year	rr_AverageAnnualReturnYear05	10.45%
10-Year	rr_AverageAnnualReturnYear10	10.60%
Since Inception	rr_AverageAnnualReturnSinceInception	7.57%

[1] (within 30 days of purchase)

[2] The Total Annual Fund Operating Expenses and Total Annual Fund Operating Expenses After Expense Reimbursement will not correlate to the Fund’s ratios of average net assets to (1) expenses before reimbursements and credits and (2) expenses net of reimbursements and credits, respectively, included in the Fund’s Financial Highlights in the Fund’s complete Prospectus, which do not reflect indirect expenses, such as Acquired Fund Fees and Expenses.

[3] 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 0.80%. 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.