S000001588 [Member] Performance Management - International Developed Markets Fund |
Oct. 31, 2025 |
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| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | Performance |
| Performance Past Does Not Indicate Future [Text] | Past performance, both before-tax and after-tax, is no indication of future results. |
| Performance Information Illustrates Variability of Returns [Text] | The following bar chart illustrates the risks of investing in the Fund by showing how the performance of the Fund’sClass S Shares varies from year to year over a 10-year period. |
| Performance Additional Market Index [Text] | The International Developed Markets Linked Benchmark provides a means to compare the Fund’saverage annual returns to a secondary benchmark that takes into account historical changes in the Fund’s primarybenchmark. |
| Bar Chart Narrative [Text Block] | The following bar chart illustrates the risks of investing in the Fund by showing how the performance of the Fund’s Class S Shares varies from year to year over a 10-year period. The returns (both before and after tax) for other Classes of Shares offered by this Prospectus may be lower than the returns shown in the bar chart, depending upon the fees and expenses of those Classes. The highest and lowest returns for a full quarter during the periods shown in the bar chart are set forth next to the bar chart.
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| Bar Chart [Heading] | Class S Calendar Year Total Returns |
| Bar Chart Closing [Text Block] | Highest Quarterly Return: 19.34% (4Q/20) Lowest Quarterly Return: (26.45)% (1Q/20) |
| Performance Table Heading | Average annual total returns for the periods ended December 31, 2025 |
| Performance Table Narrative | The table accompanying the bar chart further illustrates the risks of investing in the Fund by showing how the Fund’s average annual total returns for the periods shown compare with the returns of one or more indexes that measure broad market performance. The first benchmark in the table is the Fund's primary benchmark. The second benchmark in the table is the Fund's secondary benchmark. Effective January 1, 2018, RIM changed the Fund’s primary benchmark from the Russell Developed ex-US Large Cap Index (net of tax on dividends from foreign holdings) to the MSCI World ex USA Index (net of tax on dividends from foreign holdings). The International Developed Markets Linked Benchmark represents the returns of the Russell Developed ex-US Large Cap Index (net of tax on dividends from foreign holdings) through December 31, 2017, and the returns of the MSCI World ex USA Index (net of tax on dividends from foreign holdings) thereafter. The International Developed Markets Linked Benchmark provides a means to compare the Fund’s average annual returns to a secondary benchmark that takes into account historical changes in the Fund’s primary benchmark. RIM assesses the Fund’s performance relative to its secondary benchmark. After-tax returns are shown only for one class. The after-tax returns for other classes will vary. 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 are not relevant to investors who hold their Shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns reflect foreign tax credits passed by the Fund to its shareholders thereby increasing total returns after taxes on distributions and total returns after taxes on distributions and sale of Fund Shares. If the Fund has realized capital losses, the total return after taxes on distributions and sale of Fund Shares may be higher than the total return before taxes and the total return after taxes on distributions. For more information, see the Performance Notes section in the Fund’s Prospectus. Past performance, both before-tax and after-tax, is no indication of future results. More current performance information is available at https://russellinvestments.com.
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| Performance Table Uses Highest Federal Rate | After-tax returns arecalculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of stateand local taxes. |
| Performance Table Not Relevant to Tax Deferred | After-taxreturns are not relevant to investors who hold their Shares through tax-deferred arrangements, such as 401(k) plans orindividual retirement accounts. |
| Performance Table Explanation after Tax Higher | Ifthe Fund has realized capital losses, the total return after taxes on distributions and sale of Fund Shares may be higherthan the total return before taxes and the total return after taxes on distributions. |
| Performance Table One Class of after Tax Shown [Text] | After-tax returns are shown only for one class. The after-tax returns for other classes will vary. |
| Performance Table Closing [Text Block] | Frank Russell Company is the source and owner of the trademarks, service marks and copyrights related to the Russell Indexes. Russell® is a trademark of Frank Russell Company.
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| Performance Availability Website Address [Text] | https://russellinvestments.com |
| Class S | |
| Prospectus [Line Items] | |
| Highest Quarterly Return, Label [Optional Text] | Highest Quarterly Return: |
| Highest Quarterly Return | 19.34% |
| Highest Quarterly Return, Date | Dec. 31, 2020 |
| Lowest Quarterly Return, Label [Optional Text] | Lowest Quarterly Return: |
| Lowest Quarterly Return | (26.45%) |
| Lowest Quarterly Return, Date | Mar. 31, 2020 |