Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	RUSSELL INVESTMENT CO
Prospectus Date	rr_ProspectusDate	Mar. 01, 2013
Russell U.S. Mid Cap Equity Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	RUSSELL U.S. MID CAP EQUITY FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective (Non-Fundamental)
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide long term capital growth.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following tables describe the fees and expenses that you may pay if you buy and hold Shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Russell Funds. More information about these and other discounts is available from your financial professional and in the Front-End Sales Charges section and the More About Deferred Sales Charges section beginning on pages 216 and 219, respectively, of the Prospectus, and the Purchase, Exchange and Redemption of Fund Shares section, beginning on page 30 of the Fund's Statement of Additional Information. Please see the Expense Notes section of the Fund's Prospectus for further information regarding expenses 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	February 28, 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 fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 96% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	96.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Russell Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	50,000
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	"Other Expenses," "Total Annual Fund Operating Expenses" and "Net Annual Fund Operating Expenses" have been restated to reflect expenses expected to be incurred by the Fund during the 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 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 your investment has a 5% return each year and that operating expenses remain the same. The calculation of costs for the one year period takes into account the effect of any current contractual fee waivers and/or reimbursements. The calculation of costs for the remaining periods takes such fee waivers and/or reimbursements into account only for the first year of the periods.                Although your actual costs may be higher or lower, under these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	Investments, Risks and Performance Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund has a non-fundamental policy to invest, under normal circumstances, at least 80% of the value of its net assets plus borrowings for investment purposes in medium capitalization equity securities economically tied to the U.S. The Fund invests principally in common stocks of medium capitalization U.S. companies but may also invest in common stocks of small capitalization companies. The Fund defines medium capitalization stocks as stocks of those companies represented by the Russell MidCap® Index or within the capitalization range of the Russell MidCap® Index. The Fund employs a multi-style (growth, value, market-oriented, defensive and dynamic) and multi-manager approach whereby portions of the Fund are allocated to different money managers who employ distinct investment styles. Fund assets not allocated to money managers are managed by Russell Investment Management Company ("RIMCo"). Assets not allocated to money managers include the Fund's liquidity reserves and assets which may be managed directly by RIMCo to modify the Fund's overall portfolio characteristics by investing in securities or other instruments that RIMCo believes will achieve the desired risk/return profile for the Fund. The Fund usually, but not always, pursues a strategy to be fully invested by exposing all or a portion of its cash to the performance of appropriate markets by purchasing equity securities and/or derivatives, which typically include index futures contracts. The Fund may invest in securities of non-U.S. issuers by purchasing American Depositary Receipts ("ADRs") or Global Depositary Receipts ("GDRs"). The Fund may also invest a portion of its assets in securities of companies, known as real estate investment trusts ("REITs"), that own and/or manage properties. Please refer to the "Investment Objective and Investment Strategies" section in the Fund's Prospectus for further information.
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund, like any investment, has risks. The value of the Fund fluctuates and you could lose money. The principal risks of investing in the Fund are those associated with: Active Management. Despite strategies designed to achieve the Fund's investment objective, the value of investments will change with market conditions, and so will the value of any investment in the Fund and you could lose money. The securities selected for the portfolio may not perform as RIMCo or the Fund's money managers expect. Additionally, securities selected may cause a Fund to underperform relative to other funds with similar investment objectives and strategies. There is no guarantee that RIMCo will effectively assess a Fund's characteristics or exposures and it is possible that its judgments regarding a Fund's risk/return profile may prove incorrect. In addition, actions taken to modify overall portfolio characteristics, including risk, may be ineffective and/or cause the Fund to underperform. Multi-Manager Approach. While the investment styles employed by the money managers are intended to be complementary, they may not in fact be complementary. A multi-manager approach could result in more exposure to certain types of securities and higher portfolio turnover. Equity Securities. The value of equity securities will rise and fall in response to the activities of the company that issued them, general market conditions and/or economic conditions. Investments in small and medium capitalization companies may involve greater risks because these companies generally have narrower markets, more limited managerial and financial resources and a less diversified product offering than larger, more established companies. Small and some medium capitalization stocks may also be thinly traded, and thus, difficult to buy and sell in the market. American Depositary Receipts (ADRs) or Global Depositary Receipts (GDRs). ADRs and GDRs have the same currency and economic risks as the underlying non-U.S. shares they represent. They are affected by the risks associated with non-U.S. securities, such as changes in political or economic conditions of other countries and changes in the exchange rates of foreign currencies. REITs. REITs may be affected by changes in the value of the underlying properties owned by the REITs and by the quality of tenants' credit. Derivatives. Investments in a derivative instrument could lose more than the principal amount invested. Compared to conventional securities, derivatives can be more sensitive to changes in interest rates or to sudden fluctuations in market prices and thus the Fund's losses may be greater if it invests in derivatives than if it invests only in conventional securities. The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in equity or fixed income securities, currencies or other investments. Derivatives are subject to a number of risks such as liquidity risk, market risk, credit risk, default risk, counterparty risk (the risk that the other party in an agreement will fail to perform its obligations) and management risk. They also involve the risk of mispricing or improper valuation and the risk that changes in the value of the derivative may not correlate exactly with the change in the value of the underlying asset, rate or index. Large Redemptions. The Fund is used as an investment in asset allocation programs and may have a large percentage of its Shares held in such programs. Large redemption activity could result in the Fund incurring additional costs and being forced to sell portfolio securities at a loss to meet redemptions. Global Financial Markets Risk. Global economies and financial markets are becoming increasingly interconnected and conditions (including recent volatility and instability) and events (including natural disasters) in one country, region or financial market may adversely impact issuers in a different country, region or financial market. In addition, governmental and quasi-governmental organizations have taken a number of unprecedented actions designed to support the markets. Such events and conditions may adversely affect the value of the Fund's securities, result in greater market or liquidity risk or cause difficulty valuing the Fund's portfolio instruments or achieving the Fund's objective. Long-Term Viability Risk. There can be no assurance that the Fund will grow to an economically viable size, in which case the Fund may cease operations. In such an event, investors may be required to liquidate or transfer their investments at an inopportune time. You should consider your own investment goals and risk tolerance before investing in any Fund.                 Please refer to the "Risks" section in the Fund's Prospectus for further information.                An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Lose Money [Text]	rr_RiskLoseMoney	An investment in the Fund, like any investment, has risks. The value of the Fund fluctuates and you could lose money.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	Because the Fund is new, performance history and average annual returns for the Fund are not included in this Prospectus. Performance history and average annual returns for the Fund will be included in the Prospectus after the Fund has been in operation for one calendar year.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	Because the Fund is new, performance history and average annual returns for the Fund are not included in this Prospectus. Performance history and average annual returns for the Fund will be included in the Prospectus after the Fund has been in operation for one calendar year.
Russell U.S. Mid Cap Equity Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum Deferred Sales Charge (Load)	rr_MaximumDeferredSalesChargeOverOther	1.00%	[1]
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Advisory Fee	rr_ManagementFeesOverAssets	0.80%	[2]
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%	[2]
Other Expenses	rr_OtherExpensesOverAssets	0.46%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.51%	[2]
Less Fee Waivers and Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.29%)	[2]
Net Annual Fund Operating Expenses	rr_NetExpensesOverAssets	1.22%	[2]
1 Year	rr_ExpenseExampleYear01	693
3 Years	rr_ExpenseExampleYear03	998
5 Years	rr_ExpenseExampleYear05	1,326
10 Years	rr_ExpenseExampleYear10	2,249
Russell U.S. Mid Cap Equity Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load)	rr_MaximumDeferredSalesChargeOverOther	none	[1]
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Advisory Fee	rr_ManagementFeesOverAssets	0.80%	[2]
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.75%	[2]
Other Expenses	rr_OtherExpensesOverAssets	0.71%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.26%	[2]
Less Fee Waivers and Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.29%)	[2]
Net Annual Fund Operating Expenses	rr_NetExpensesOverAssets	1.97%	[2]
1 Year	rr_ExpenseExampleYear01	200
3 Years	rr_ExpenseExampleYear03	678
5 Years	rr_ExpenseExampleYear05	1,183
10 Years	rr_ExpenseExampleYear10	2,572
Russell U.S. Mid Cap Equity Fund | Class S
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load)	rr_MaximumDeferredSalesChargeOverOther	none	[1]
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Advisory Fee	rr_ManagementFeesOverAssets	0.80%	[2]
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none	[2]
Other Expenses	rr_OtherExpensesOverAssets	0.46%	[2]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.26%	[2]
Less Fee Waivers and Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.29%)	[2]
Net Annual Fund Operating Expenses	rr_NetExpensesOverAssets	0.97%	[2]
1 Year	rr_ExpenseExampleYear01	99
3 Years	rr_ExpenseExampleYear03	372
5 Years	rr_ExpenseExampleYear05	666
10 Years	rr_ExpenseExampleYear10	1,502

[1] The Maximum Deferred Sales Charge (Load) is charged on the lesser of the purchase price of the Shares being redeemed or the net asset value of those Shares at the time of redemption.

[2] Until February 28, 2014, Russell Investment Management Company ("RIMCo") has contractually agreed to waive up to the full amount of its 0.80% advisory fee and then to reimburse the Fund for other direct Fund-level expenses to the extent that such direct Fund-level expenses exceed 0.77% of the average daily net assets of the Fund on an annual basis. This waiver and reimbursement may not be terminated during the relevant period except with Board approval. Direct Fund-level expenses do not include 12b-1 fees, shareholder services fees, transfer agency fees, extraordinary expenses or the expenses of other investment companies in which the Fund invests which are borne indirectly by the Fund. "Other Expenses," "Total Annual Fund Operating Expenses" and "Net Annual Fund Operating Expenses" have been restated to reflect expenses expected to be incurred by the Fund during the current fiscal year.