Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	NORTHERN FUNDS
Prospectus Date	rr_ProspectusDate	Jul. 31, 2013
NORTHERN U.S. GOVERNMENT SELECT MONEY MARKET FUND
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	U.S. GOVERNMENT SELECT MONEY MARKET FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund is a money market fund that seeks to maintain a stable net asset value (“NAV”) of $1.00 per share. The Fund seeks to maximize current income to the extent consistent with the preservation of capital and maintenance of liquidity by investing exclusively in high quality money market instruments.
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
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	The Fund seeks to achieve its objective by investing, under normal circumstances, substantially all (and at least 80%) of its net assets in securities issued or guaranteed as to principal and interest by the U.S. government or by its agencies, instrumentalities or sponsored enterprises. Under normal circumstances, the Fund will seek to acquire only those U.S. government securities paying interest that generally is exempt from state income taxation. These securities include obligations issued by the U.S. Treasury and certain U.S. government agencies, instrumentalities or sponsored enterprises, such as the Federal Home Loan Bank and the Federal Farm Credit Banks Funding Corp. The Securities and Exchange Commission imposes strict requirements on the investment quality, maturity, and diversification of the Fund's investments. Accordingly, the Fund's investments must have a remaining maturity of no more than 397 days and must be high quality. The Fund's investment adviser may consider, among other things, credit, interest rate and prepayment risks as well as general market conditions when deciding whether to buy or sell investments for the Fund. Under unusual circumstances, as when appropriate securities that are exempt from state taxes are unavailable, the Fund also may invest in non-exempt U.S. government securities and cash equivalents, including money market funds and repurchase agreements, and hold uninvested cash. Cash assets will not generate income. The Fund may not achieve its investment objective during this time. The Fund makes significant investments in securities issued by U.S. government-sponsored entities. Such securities are neither issued nor guaranteed by the U.S. Treasury.
Risk [Heading]	rr_RiskHeading	PRINCIPAL RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	STABLE NAV RISK is the risk that the Fund will not be able to maintain an NAV per share of $1.00 at all times. A significant enough market disruption or drop in market prices of securities held by the Fund, especially at a time when the Fund needs to sell securities to meet shareholder redemption requests, could cause the value of the Fund's shares to decrease to a price less than $1.00 per share. INTEREST RATE RISK is the risk that during periods of rising interest rates, the Fund's yield (and the market value of its securities) will tend to be lower than prevailing market rates; in periods of falling interest rates, the Fund's yield (and the market value of its securities) will tend to be higher. GUARANTOR (OR CREDIT ENHANCEMENT) RISK is the risk that changes in credit quality of a U.S. or foreign bank, insurance company or other financial institution or such entity's failure to fulfill its obligations could cause the Fund's investments to decline in value. Adverse developments in the banking or bond insurance industries also may negatively affect the Fund. PREPAYMENT (OR CALL) RISK is the risk that prepayment of the underlying mortgages or other collateral 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 (such as an asset-backed security) later than expected. This may happen during a period of rising interest rates. Under these circumstances, the value of the obligation will decrease and the Fund will suffer from the inability to invest in higher yielding securities. INCOME RISK is the risk that falling interest rates will cause the Fund's income to decline. Income risk is generally higher for short-term debt securities. MANAGEMENT RISK is the risk that a strategy used by the Fund's investment adviser may fail to produce the intended results. U.S. GOVERNMENT SECURITIES RISK is the risk that the U.S. government will not provide financial support to its agencies, instrumentalities or sponsored enterprises if it is not obligated to do so by law. Many U.S. government securities purchased by the Fund are not backed by the full faith and credit of the United States. It is possible that the issuers of such securities will not have the funds to meet their payment obligations in the future. 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. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the Fund.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	Although the Fund seeks to preserve the value of your investment at $1.00 per share, it is possible to 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 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 changes in the performance of the Fund from year to year. The Fund’s past performance 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 changes in the performance of the Fund from year to year.
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 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 0.01%. For the periods shown in the bar chart above, the highest quarterly return was 1.18% in the fourth quarter of 2006, and the lowest quarterly return was 0.00% in the fourth quarter of 2012.
Performance Table Heading	rr_PerformanceTableHeading	AVERAGE ANNUAL TOTAL RETURN (For the periods ended December 31, 2012)
Performance Table Closing [Text Block]	rr_PerformanceTableClosingTextBlock	The 7-day yield for the Fund as of December 31, 2012: 0.01%. For the current 7-day yield call 800-595-9111 or visit www.northernfunds.com.
Money Market Seven Day Yield, Caption [Text]	rr_MoneyMarketSevenDayYieldCaption	The 7-day yield for the Fund as of December 31, 2012
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	800-595-9111
Money Market Seven Day Yield	rr_MoneyMarketSevenDayYield	0.01%
NORTHERN U.S. GOVERNMENT SELECT MONEY MARKET FUND | NORTHERN U.S. GOVERNMENT SELECT MONEY MARKET FUND
Risk/Return:	rr_RiskReturnAbstract
Shareholder Fees (fees paid directly from your investment)	rr_ShareholderFeeOther	none
Management Fees	rr_ManagementFeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.23%
Administration Fees	rr_Component1OtherExpensesOverAssets	0.10%
Transfer Agency Fees	rr_Component2OtherExpensesOverAssets	0.10%
Other Operating Expenses	rr_Component3OtherExpensesOverAssets	0.03%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.48%
Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.13%)	[1]
Total Annual Fund Operating Expenses After Expense Reimbursement	rr_NetExpensesOverAssets	0.35%
1 Year	rr_ExpenseExampleYear01	36
3 Years	rr_ExpenseExampleYear03	141
5 Years	rr_ExpenseExampleYear05	256
10 Years	rr_ExpenseExampleYear10	$ 591
2003	rr_AnnualReturn2003	0.68%
2004	rr_AnnualReturn2004	0.82%
2005	rr_AnnualReturn2005	2.68%
2006	rr_AnnualReturn2006	4.45%
2007	rr_AnnualReturn2007	4.62%
2008	rr_AnnualReturn2008	1.70%
2009	rr_AnnualReturn2009	0.02%
2010	rr_AnnualReturn2010	0.01%
2011	rr_AnnualReturn2011	0.01%
2012	rr_AnnualReturn2012	0.01%
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	0.01%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest quarterly return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2006
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	1.18%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest quarterly return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2012
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.00%
1-Year	rr_AverageAnnualReturnYear01	0.01%
5-Year	rr_AverageAnnualReturnYear05	0.35%
10-Year	rr_AverageAnnualReturnYear10	1.49%
Since Inception	rr_AverageAnnualReturnSinceInception	2.85%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 12, 1994

[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 0.35%. 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.