Performance Management - American Century ETF Trust - American Century Mid Cap Growth Insights ETF Series |
Jan. 01, 2026 |
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| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | Fund Performance |
| Performance Narrative [Text Block] | The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. The table also shows returns for the Russell Midcap® Growth Index, which the advisor considers to be more representative of the fund's investment strategy. The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. For current performance information, please visit americancentury.com. Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.
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| Performance Past Does Not Indicate Future [Text] | The fund’s past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. |
| Performance Information Illustrates Variability of Returns [Text] | The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund’s performance from year to year. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. |
| Bar Chart Does Not Reflect Sales Loads [Text] | Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown. |
| Bar Chart [Heading] | Calendar Year Total Returns |
| Performance Table Heading | Average Annual Total Returns For the calendar year ended December 31, 2024 |
| Performance Table Uses Highest Federal Rate | 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 | 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs. |
| Index No Deduction for Fees, Expenses, or Taxes [Text] | (reflects no deduction for fees, expenses or taxes) |
| Performance Table Closing [Text Block] | 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
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| American Century Mid Cap Growth Insights ETF Class | |
| Prospectus [Line Items] | |
| Year to Date Return, Label [Optional Text] | year-to-date return |
| Bar Chart, Year to Date Return | 10.23% |
| Bar Chart, Year to Date Return, Date | Sep. 30, 2025 |
| Highest Quarterly Return, Label [Optional Text] | Highest Performance Quarter |
| Highest Quarterly Return | 14.11% |
| Highest Quarterly Return, Date | Mar. 31, 2024 |
| Lowest Quarterly Return, Label [Optional Text] | Lowest Performance Quarter |
| Lowest Quarterly Return | (21.30%) |
| Lowest Quarterly Return, Date | Jun. 30, 2022 |