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American Century ETF Trust | American Century Diversified Corporate Bond ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Diversified Corporate Bond ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 181% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 181.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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
Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in corporate debt securities and corporate debt investments. Corporate debt investments are derivatives whose reference securities are corporate debt securities.
The fund invests primarily in U.S. dollar denominated corporate debt securities issued by U.S. and foreign entities, but may also invest in securities issued by supranational entities. Although the fund invests primarily in investment-grade debt securities, up to 35% of the fund’s net assets may be invested in high-yield securities (also referred to as “junk bonds”).
The fund also may invest in derivative instruments such as futures contracts, and swap agreements (including, but not limited to, interest rate swaps and credit default swap indexes). The fund may use derivative instruments to earn income, enhance returns, increase liquidity, manage target duration, gain exposure to certain instruments or markets, and/or hedge its exposure to particular investments.
Under normal market conditions, the weighted average duration of the fund’s portfolio is expected to be between three and seven years. The fund may engage in active and frequent trading of portfolio securities to achieve its principal investment strategies. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. To determine whether to buy or sell a security, the portfolio managers consider, among other things, various fund requirements and standards, along with economic conditions, alternative investments, interest rates and various credit metrics.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in corporate debt securities and corporate debt investments.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•High-Yield Risk — Issuers of high-yield securities are more vulnerable to real or perceived economic changes (such as an economic down turn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations. Investment in high-yield securities is inherently speculative.
•Foreign Securities Risk — Foreign securities have certain unique risks, such as currency risk, social, political and economic risk, and foreign market and trading risk. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•High Portfolio Turnover Risk — The fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the issuers whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 7.56% Lowest Performance Quarter (1Q 2020): -4.27%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -12.35%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Diversified Corporate Bond ETF | Bloomberg U.S. Intermediate Corporate Bond Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Bloomberg U.S. Intermediate Corporate Bond Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 (1.00%)
Since Inception rr_AverageAnnualReturnSinceInception 4.07%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century Diversified Corporate Bond ETF | American Century Diversified Corporate Bond ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol KORP
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.29%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 30
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 93
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 163
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 369
Annual Return 2019 rr_AnnualReturn2019 10.06%
Annual Return 2020 rr_AnnualReturn2020 7.17%
Annual Return 2021 rr_AnnualReturn2021 (0.34%)
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (12.35%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 7.56%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (4.27%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (0.34%)
Since Inception rr_AverageAnnualReturnSinceInception 3.82%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century Diversified Corporate Bond ETF | American Century Diversified Corporate Bond ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (1.09%)
Since Inception rr_AverageAnnualReturnSinceInception 2.64%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century Diversified Corporate Bond ETF | American Century Diversified Corporate Bond ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (0.20%)
Since Inception rr_AverageAnnualReturnSinceInception 2.43%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century Diversified Municipal Bond ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Diversified Municipal Bond ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks current income that is exempt from federal income tax.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 46% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 46.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests in municipal and other debt securities. Under normal market conditions, the portfolio managers invest at least 80% of the fund’s net assets, plus borrowings for investment purposes, in municipal securities with interest payments exempt from federal income tax. Some of these investments in municipal securities are not necessarily exempt from the federal alternative minimum tax.
The fund principally invests in investment-grade debt securities but may invest in high-yield securities (junk bonds). A high-yield security is one that has been rated below investment-grade or determined by the investment advisor to be of similar quality, including bonds that are in technical or monetary default. Issuers of these securities often have short financial histories or have questionable credit or have had and may continue to have problems making interest and principal payments. The portfolio managers also may buy unrated securities if they determine such securities meet the investment objective of the fund.
The fund may purchase debt securities of any duration, and the average duration of the fund will vary based on the portfolio managers’ forecast of interest rates.
Although the fund seeks current income, it also employs techniques designed to realize capital appreciation. For example, the portfolio managers may select bonds with maturities and coupon rates that position the fund for potential capital appreciation for a variety of reasons, including their view on the direction of future interest-rate movements and the potential for a credit upgrade.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. When determining whether to buy or sell a security, portfolio managers consider, among other things, current and anticipated changes in interest rates, the credit quality of a particular issuer, comparable alternatives, general market conditions and any other factor deemed relevant by the portfolio managers.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers invest at least 80% of the fund’s net assets, plus borrowings for investment purposes, in municipal securities with interest payments exempt from federal income tax.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Credit Risk — Debt securities, even investment-grade debt securities, are subject to credit risk. The risk that the inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect. The fund’s investments may have high credit risk, which helps the fund pursue a higher yield than more conservatively managed bond funds.
•Below Investment-Grade Securities Risk — Issuers of lower rated, high-yield securities are more vulnerable to real or perceived economic changes (such as an economic downturn or a prolonged period of rising interest rates), political changes, or
adverse developments specific to the issuer. Adverse economic, political and other developments may be more likely to cause an issuer of low-quality bonds to default on its obligation to pay interest and principal due under its securities. The fund may invest in securities rated below investment-grade or that are unrated, including bonds that are in technical or monetary default. By definition, the issuers of many of these securities have had and may continue to have problems making interest and principal payments.
•Interest Rate Risk — When interest rates change, the fund’s share value will be affected. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. Because the fund may invest in intermediate-term and long-term bonds, the fund’s interest rate risk is generally higher than for funds with shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Municipal Securities Risk — Because the fund invests principally in municipal securities, it will be sensitive to events that affect municipal markets, including legislative or political changes and the financial condition of the issuers of municipal securities. The fund may have a higher level of risk than funds that invest in a larger universe of securities. Additionally, the novel coronavirus (COVID -19) pandemic has stressed the financial resources of many municipal issuers, which may impair a municipal issuer’s ability to meet its financial obligations when due and could adversely impact the value of its bonds, which could negatively impact the performance of the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Tax Risk — Some or all of the fund’s income may be subject to the federal alternative minimum tax. There is no guarantee that all of the fund’s income will remain exempt from federal or state income taxes. Income from municipal bonds held by a fund could be declared taxable because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state tax authorities, or noncompliant conduct of a bond issuer. The fund may sell securities that lose their tax-exempt statuses at inopportune times, which may cause tax consequences or a decrease in the fund’s value.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, to meet redemptions, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund’s share price. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The risk that the value of securities owned by the fund may go up and down, sometimes rapidly or unpredictably. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a
significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 3.62% Lowest Performance Quarter (1Q 2020): -2.74%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -12.29%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Diversified Municipal Bond ETF | S&P National AMT-Free Municipal Bond Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel S&P National AMT-Free Municipal Bond Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 1.59%
Since Inception rr_AverageAnnualReturnSinceInception 4.56%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Diversified Municipal Bond ETF | American Century Diversified Municipal Bond ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol TAXF
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.29%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 30
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 93
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 163
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 369
Annual Return 2019 rr_AnnualReturn2019 8.79%
Annual Return 2020 rr_AnnualReturn2020 5.47%
Annual Return 2021 rr_AnnualReturn2021 2.88%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (12.29%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 3.62%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (2.74%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 2.88%
Since Inception rr_AverageAnnualReturnSinceInception 5.30%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Diversified Municipal Bond ETF | American Century Diversified Municipal Bond ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 2.88%
Since Inception rr_AverageAnnualReturnSinceInception 5.30%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Diversified Municipal Bond ETF | American Century Diversified Municipal Bond ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 2.36%
Since Inception rr_AverageAnnualReturnSinceInception 4.60%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Emerging Markets Bond ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Emerging Markets Bond ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide current income and capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 64% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 64.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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
Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in debt securities related to emerging market countries. Debt securities in which the fund invests include sovereign and quasi-sovereign debt, emerging markets corporate debt securities, and emerging markets debt investments. Emerging markets debt investments include emerging markets derivatives whose reference securities are corporate and sovereign debt securities. Investments are predominantly made in instruments denominated in U.S. dollars but the fund may also invest in securities denominated in local emerging markets currency. The portfolio managers select investments for the fund using proprietary fundamental research, quantitative model inputs and qualitative assessments that consider multiple inputs such as macroeconomic factors, country and fundamental issuer analysis, and market and relative value.
The fund considers an emerging market country to be any country other than a developed country. However, the fund typically invests in the subset of emerging markets countries that comprise the JP Morgan EMBI Global Diversified Index. In determining where a company is located, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located and the country in which the company was legally organized. The weight given to each of these factors will vary depending on the circumstances in a given case.
The fund invests in both investment-grade and high-yield debt securities. Investment grade securities are those that have been rated in one of the top four credit quality categories by an independent rating agency or determined by the advisor to be of comparable credit quality. High-yield securities, which are also known as “junk bonds,” are those that have been rated by an independent rating agency below the highest four categories or determined by the advisor to be of similar quality. The fund has no average maturity or duration limitations.
The fund also may invest in derivative instruments such as interest rate futures contracts. The fund may use derivative instruments to earn income, enhance returns, increase liquidity, manage target duration, gain exposure to certain instruments or markets, and/or hedge its exposure to particular investments.
The portfolio managers may engage in hedging of portfolio positions, which usually involves entering into a derivative transaction that has the opposite characteristic of the position being hedged. The net effect of these two positions is intended to reduce or eliminate the exposure created by the first position.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. To determine whether to buy or sell a security, the portfolio managers consider the fund requirements and standards described above, along with economic conditions, alternative investments, interest rates and various credit metrics.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in debt securities related to emerging market countries.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Foreign Securities Risk — Foreign securities have certain unique risks, such as currency risk, social, political and economic risk, and foreign market and trading risk. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Emerging Market Risk — Investing in securities of issuers located in emerging market countries generally is riskier than investing in securities of issuers located in foreign developed countries due to lower liquidity, market manipulation concerns, limited reliable access to capital, and differing company organizational structures. Emerging market countries may have unstable governments and/or economies that are subject to sudden change. These changes may be magnified by the countries’ emergent financial markets, resulting in significant volatility to investments in these countries. These countries also may lack the legal, business, and social framework to support securities markets. Additionally, certain jurisdictions do not provide the PCAOB with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks.
•Currency Risk — Because the fund may invest in securities denominated in foreign currencies, the fund may be subject to currency risk, meaning that the fund could experience gains or losses based solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Sovereign Debt Risk — Sovereign debt instruments, which are instruments issued by foreign governmental entities, are subject to the risk that the governmental entity may be unable or unwilling to repay the principal or interest on its sovereign debt due to, among other reasons, cash flow problems, insufficient foreign currency reserves, political considerations, the relative size of the governmental entity’s debt or its failure to implement economic reforms. There is no bankruptcy process for collecting sovereign debt and legal remedies may be limited and onerous to pursue.
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•High-Yield Risk — Issuers of high-yield securities are more vulnerable to real or perceived economic changes (such as an economic down turn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations. Investment in high-yield securities is inherently speculative.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience dramatic price changes and imperfect correlations between the price of the contract and the underlying security, index or currency.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less
(or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the issuers whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Emerging Markets Bond ETF | American Century Emerging Markets Bond ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AEMB
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.39%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.39%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 40
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 126
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 219
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 493
American Century ETF Trust | American Century Low Volatility ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Low Volatility ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 167% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 167.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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 (unless otherwise indicated), that you earn 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
Portfolio managers utilize quantitative models to select securities with attractive fundamentals that they expect will provide enhanced risk-adjusted returns over the long term, while realizing less volatility.
The fund generally invests in common stocks of U.S. companies that have a market capitalization greater than $2 billion. To select securities for the fund, portfolio managers utilize proprietary models to screen and rank companies based on fundamental metrics. The information used to generate these measures is typically contained in financial statement data and market information, but may include other sources. The fund seeks to deliver a lower realized portfolio volatility than its benchmark, the S&P 500® Index, by utilizing a stock selection process that expands on traditional measures of price volatility by including measures of asymmetric (i.e., downside) volatility and seeking securities of businesses that demonstrate consistent cash-flows, stable operations, and strong balance sheets. Portfolio managers employ a multi-dimensional approach to stock selection and risk management—which includes evaluating empirical measures of stock price risks and fundamental measures of business safety and continuity—to construct a portfolio that balances the return and risk objectives of the fund. This approach seeks to identify risks of individual securities and across key dimensions such as economic segment. Finally, portfolio managers review the output of the quantitative model, considering factors such as risk management, transaction costs, and liquidity management.
The portfolio managers generally sell securities from the fund’s portfolio when they believe a security becomes less attractive relative to other opportunities, a security’s risk characteristics outweigh its return opportunity, or specific events alter a security’s prospects.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Low Volatility Strategy Risk — There is no assurance that the fund will be less volatile than the market over the long term or for any specified period. The fund’s strategy of constructing a portfolio that realizes lower volatility than the market may not produce the intended result. A security’s volatility can change very quickly, and specific securities in the fund’s portfolio may become more volatile than expected. Additionally, low volatility investments may underperform the equity markets during periods of strong, rising or speculative equity markets.
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes could be higher than if the fund sold and redeemed shares in-kind.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Low Volatility ETF | American Century Low Volatility ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol LVOL
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.29%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 30
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 93
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 163
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 369
American Century ETF Trust | American Century Multisector Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Multisector Income ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide a high level of current income and total return.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 147% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 147.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests in various sectors of the fixed income market holding instruments such as corporate bonds and notes, government securities, securitized credit instruments, and emerging markets debt securities. The portfolio managers select securities using a sector rotation approach that integrates proprietary fundamental research and quantitative model inputs, such as economic activity, inflation and monetary policy, and technical analysis of relative value among various sectors. The fund invests in both investment-grade and high-yield debt securities. Investment grade securities are those that have been rated in one of the top four credit quality categories by an independent rating agency or determined by the advisor to be of comparable credit quality. High-yield securities, which are also known as “junk bonds,” are those that have been rated by an independent rating agency below the highest four categories or determined by the advisor to be of similar quality.
The debt securities in which the fund invests may be payable in U.S. or foreign currencies, including emerging markets currencies. The fund may also invest in certain equity securities such as preferred stock, convertible securities, or equity equivalents provided that such investments are consistent with the fund’s investment objectives. The fund has no average maturity or duration limitations.
In addition to the securities listed above, the fund may also invest in bank loans.
The fund may also utilize derivative instruments provided that such investments are in keeping with the fund’s investment objectives. Such derivative instruments include options, futures contracts, options on futures contracts, and swaps (such as credit default swaps either on a single issuer or a securities index), or in mortgage- or asset-backed securities. The fund may invest in collateralized debt obligations, including collateralized loan obligations, collateralized mortgage obligations, and other similarly structured investments. The fund may use foreign currency exchange contracts to shift investment exposure from one currency into another for hedging purposes or to enhance returns.
The portfolio managers may engage in hedging of portfolio positions, which usually involves entering into a derivative transaction that has the opposite characteristic of the position being hedged. The net effect of these two positions is intended to reduce or eliminate the exposure created by the first position.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. To determine whether to buy or sell a security, the portfolio managers consider, among other things, various fund requirements and standards, along with economic conditions, alternative investments, interest rates and various credit metrics.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•High-Yield Risk — Issuers of high-yield securities are more vulnerable to real or perceived economic changes (such as an economic down turn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations. Investment in high-yield securities is inherently speculative.
•Foreign Securities Risk — Foreign securities have certain unique risks, such as currency risk, social, political and economic risk, and foreign market and trading risk. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Emerging Market Risk — Investing in securities of companies located in emerging market countries generally is also riskier than investing in securities of companies located in foreign developed countries. Emerging market countries may have unstable governments and/or economies that are subject to sudden change. These changes may be magnified by the countries’ emergent financial markets, resulting in significant volatility to investments in these countries. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the PCAOB with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment.
Futures contracts may experience dramatic price changes and imperfect correlations between the price of the contract and the underlying security, index or currency.
Swap agreements subject a fund to the risk that the counterparty to the transaction may not meet its obligations. The fund also bears the risk of loss of the amount expected to be received under a swap agreement in the event of the default or bankruptcy of a counterparty. Swap agreements may also be considered illiquid.
Foreign currency forward contracts and other derivatives contracts on foreign currencies involve a risk of loss if currency exchange rates move against the fund’s position.
•Bank Loan Risk — The market for bank loans may not be highly liquid and the fund may have difficulty selling them. In connection with purchasing loan participations, the fund generally will have no right to enforce compliance by borrowers with loan terms nor any set off rights, and the fund may not benefit directly from any posted collateral. As a result, the fund may be subject to the credit risk of both the borrower and the lender selling the participation. Bank loan transactions may take more than seven days to settle, meaning that proceeds would be unavailable to make additional investments or meet redemptions. To the extent the extended loan settlement process gives rise to short-term liquidity needs, such as the need to satisfy redemption requests, the fund may hold cash or sell investments.
•Collateralized Debt Obligations Risk — Collateralized debt obligations and collateralized loan obligations (CLOs) are subject to credit, interest rate, valuation, and prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. The market value of CLOs may be affected by, among other things, changes in the market value of the underlying assets held by the CLO, changes in the distributions on the underlying assets, defaults and recoveries on the underlying assets, capital gains and losses on the underlying assets, prepayments on underlying assets and the availability, prices and interest rate of underlying assets. Lower rated tranches of such debt are subject to a higher risk of total loss and deferral or nonpayment of interest than the more senior tranches to which they are subordinated.
•Convertible Securities Risk — The value of convertible securities may rise and fall with the market value of the underlying stock or, like a debt security, vary with changes in interest rates and the credit quality of the issuer. A convertible security tends to perform more like a stock when the underlying stock price is high relative to the conversion price and more like a debt security when the underlying stock price is low relative to the conversion price.
•Preferred Securities Risk — Preferred securities combine some of the characteristics of both common stocks and bonds. Preferred securities are typically subordinated to a company’s other debt which subjects them to greater credit risk . Generally,
holders of preferred securities have no voting rights. In certain circumstances, an issuer of preferred securities may defer payment on the securities and, in some cases, redeem the securities prior to a specified date. Preferred securities may also be substantially less liquid than other securities and may have less upside potential than common stock.
•Counterparty Risk — If the fund enters into financial contracts, the fund will be subject to the credit risk presented by the counterparties.
•LIBOR Transition Risk — The fund may invest in instruments that have variable or floating coupon rates based on the London Interbank Offered Rate (LIBOR). LIBOR is a benchmark interest rate intended to be representative of the rate at which certain major international banks lend to one another over short-terms. Financial institutions have started the process of phasing out LIBOR and the transition process to a replacement rate may lead to increased volatility or illiquidity in markets for instruments that rely on LIBOR. This could result in a change to the value of such instruments or a change in the cost of temporary borrowing for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•High Portfolio Turnover Risk — The fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the issuers whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or other assets. If these underlying assets are prepaid, the fund may benefit less from declining interest rates than funds of similar duration that invest less heavily in mortgage and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation) especially in periods of rising interest rates. These events may lengthen the duration (i.e., interest rate sensitivity) and potentially reduce the value of these securities.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels
or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Multisector Income ETF | American Century Multisector Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol MUSI
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.35%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.01%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.36%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 37
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 116
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 202
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 456
American Century ETF Trust | American Century Quality Convertible Securities ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Quality Convertible Securities ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks total return.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 64% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 64.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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
Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in convertible securities. Convertible securities have characteristics similar to both bonds and common stocks and typically consist of debt securities and preferred stocks that may be converted into or exchanged for a prescribed amount of common stock or other equity security, of the same or a different issuer, within a particular time period, at a specified price.
The portfolio managers select securities using a quantitative and fundamental investment process. They first screen the investment universe for liquidity and then select individual securities utilizing a quantitative and fundamental investment process informed by fundamental and technical measures such as sales or earnings growth, profitability, leverage, balance sheet strength, price momentum relative to peers, and valuation and yield relative to other convertible securities. Portfolio holdings are weighted to achieve the optimal balance between risk and return by considering each portfolio security’s fundamental scores, benchmark weight, and equity sensitivity.
The fund is nondiversified. The fund may invest in high-yield securities (also referred to as “junk bonds”). The fund may engage in active and frequent trading of portfolio securities to achieve its principal investment strategies. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. To determine whether to buy or sell a security, the portfolio managers consider, among other things, various fund requirements and standards, along with economic conditions, alternative investments, interest rates and various credit metrics.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in convertible securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Convertible Securities Risk — The value of convertible securities may rise and fall with the market value of the underlying stock or, like a debt security, vary with changes in interest rates and the credit quality of the issuer. A convertible security tends to perform more like a stock when the underlying stock price is high relative to the conversion price and more like a debt security when the underlying stock price is low relative to the conversion price.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•High-Yield Risk — Issuers of high-yield securities are more vulnerable to real or perceived economic changes (such as an economic down turn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations. Investment in high-yield securities is inherently speculative.
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
•Sector Risk — The fund may invest a significant portion of its assets in the technology sector and, therefore, the performance of the fund could be negatively impacted by events affecting this sector. New market entrants, short product cycles, aggressive pricing, and problems with bringing products to market can affect security prices in the technology sector.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes could be higher than if the fund sold and redeemed shares in-kind.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•High Portfolio Turnover Risk — High portfolio turnover (higher than 100% annually), may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of securities.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an
authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the Cboe BZX Exchange, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
Risk Nondiversified Status [Text] rr_RiskNondiversifiedStatus Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Quality Convertible Securities ETF | American Century Quality Convertible Securities ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol QCON
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.32%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.32%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 33
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 103
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 180
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 406
American Century ETF Trust | American Century Quality Diversified International ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Quality Diversified International ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide investment results that closely correspond, before fees and expenses, to the performance of the Index.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 108% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 108.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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 (unless otherwise indicated), that you earn 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
Under normal market conditions, the fund invests at least 80% of its assets, exclusive of collateral held from securities lending, in the component securities of the underlying index. The American Century Quality Diversified International Equity Index (Index) is a rules-based index maintained by American Century Investment Management, Inc. (the index provider).
The Index is designed to select securities with attractive quality, growth and valuation fundamentals. The universe of the Index is comprised of large- and mid-capitalization equity securities of global issuers outside of the United States. The Index focuses on securities of issuers from developed economies but also includes issuers from rising economies. To construct the Index, the index provider first screens the underlying universe, selecting securities with higher profitability, return on assets, return on equity, and gross margins while considering earnings, leverage and momentum. The index provider next determines a growth score and a value score for each selected security. The growth scores are based on sales, earnings, profitability, cash flows and momentum. The value scores are based on value, earnings yield, dividend yield, and cash flow metrics. The index provider categorizes securities into sub-portfolios based on country and attribute, and then weights securities in each sub-portfolio based on combined growth and value scores. Though component securities of the Index may change from time to time, the index typically consists of 300–500 securities and, as of September 30, 2022, the market capitalization range of the Index was approximately $3.4 billion and larger.
For purposes of investing at least 80% of its assets in securities included in the Index, the fund may invest in depositary receipts representing securities included in the Index or securities representing depositary receipts included in the Index.
The Index and the fund are rebalanced monthly and reconstituted quarterly.
The fund may use a “representative sampling” strategy with respect to its Index instead of a replication strategy. For example, the fund may use such strategy when there are practical difficulties or substantial costs involved in compiling a portfolio of securities to follow the Index or, in certain instances, when a component security becomes temporarily illiquid, unavailable or less liquid. To the extent the fund uses representative sampling, the advisor invests in what it believes to be a representative sample of the component securities in the Index using quantitative analytical procedures to give the fund’s portfolio an investment profile similar to that of its Index. The fund also may realize savings in transaction costs or other efficiencies by investing up to 20% of its assets in securities or instruments not included in the Index but which the advisor believes will help the fund track the Index.
In addition, the fund may use futures contracts to invest cash balances, simulate investments in the Index, facilitate trading or minimize transaction costs. The portfolio managers may also use futures contracts to seek to reduce the fund’s tracking error relative to the Index.
The fund may concentrate its investments (i.e., hold 25% or more of its net assets) in a particular industry or group of industries to the extent that the Index is concentrated.
If the Index has high portfolio turnover, the fund may also have high portfolio turnover. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund invests at least 80% of its assets, exclusive of collateral held from securities lending, in the component securities of the underlying index.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Foreign Securities Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), and natural disasters occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Index-Related Risk — Unlike many investment companies, the fund is not actively managed, and the portfolio managers do not attempt to take defensive positions under any market conditions, including declining markets. Therefore, the portfolio managers generally will not buy or sell securities unless they are added or removed from the Index, even if a security is underperforming. There is no assurance that the Index will be determined, composed or calculated accurately. While the index provider provides descriptions of what the Index is designed to achieve, the index provider does not guarantee the quality, accuracy or completeness of data in respect of its indices and does not guarantee that the Index will be in line with the described index methodology. Gains, losses or costs to the fund caused by errors in the Index may therefore be borne by the fund and its shareholders.
•Geographic Risk — The fund will be subject to the risks of volatile economic cycles and/or conditions and developments that may be particular to a country or region in which it invests, such as: adverse securities markets; adverse exchange rates; adverse social, political, regulatory, economic, business, environmental or other developments; or natural disasters.
•Single Country Risk — If a particular country or region comprises a large percentage of the fund’s Index, the fund will likely invest a significant portion of assets in that country or region. Investing a significant portion of assets in one country or region makes the fund more dependent upon the political and economic circumstances of that particular country or region than a fund that is more widely diversified.
•Emerging Market Risk — Investing in emerging market countries generally is riskier than investing in foreign developed countries. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the PCAOB with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Rebalance Risk — The fund rebalances its portfolio in accordance with the Index’s rebalance schedule. Accordingly, any change to this schedule will result in corresponding changes to the fund’s rebalance schedule.
•Calculation Methodology Risk — The Index relies on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the fund nor American Century Investment Management, Inc. (the advisor) can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers.
•Style Risk — There can be no assurance that the investment factor stock selection process and screens of the Index will enhance performance. Exposure to certain investment factors and use of screens may detract from performance in some market environments, perhaps for extended periods.
•Currency Risk — The fund could experience gains or losses based solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Valuation Risk — The sale price the fund receives for a security may differ from the fund’s valuation of the security and may differ from the value used by the Index, particularly for securities that trade in low volume or volatile markets or that are valued using a fair value methodology. Non-U.S. exchanges may be open on days when the fund does not price its shares, thus the value of securities in the fund’s portfolio may change on days when investors are unable to purchase or sell the fund.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Mid-Capitalization Company Risk — Investments in medium-size companies may involve greater risk and price volatility than investments in larger, more mature companies.
•Tracking Error Risk — Tracking error is the divergence of the fund’s performance from that of the Index. Tracking error may occur because of differences between the securities held in the fund’s portfolio and those included in the Index, pricing differences, transaction costs, the fund’s holding of cash, differences in timing of the accrual of dividends or interest, changes to the Index or the need to meet various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the fund incurs fees and expenses, while the Index does not. In addition, any issues the fund encounters with regard to currency convertibility and repatriation may also increase Index tracking risk.
•High Portfolio Turnover Risk — High portfolio turnover (higher than 100% annually), may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of securities.
•Sampling Risk — To the extent the fund uses a representative sampling strategy, it may hold a smaller number of securities than are in the Index or it may hold securities that are not included in the Index. As a result, an adverse development respecting an issuer of securities held by the fund could result in a greater decline in the fund’s NAV than would be the case if all of the securities in the Index were held. The fund’s use of a representative sampling strategy may also include the risk that it may not track the return of the Index with the same degree of accuracy as would an investment vehicle that invested in every component security of the Index with the same weightings as the Index.
•Management Risk — To the extent the fund uses representative sampling, the strategy may fail to produce the intended results.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Non-Correlation Risk — There is no guarantee that the fund will achieve a high degree of correlation to the Index and therefore achieve its investment objective. Market disruptions and regulatory restrictions could have an adverse effect on the fund’s ability to adjust its exposure to the required levels in order to track the Index. In addition, the fund’s NAV may deviate from the Index if the fund fair values a portfolio security at a price other than the price used by the Index for that security.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in exchange-traded funds (ETFs) generally.
•Concentration Risk — To the extent the fund concentrates in a specific industry or a group of industries, it may be subject to greater risks and market fluctuations than a portfolio investing in a broader range of industries.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the
trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Derivatives Risk — The use of derivative instruments such as futures contracts involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 21.25% Lowest Performance Quarter (1Q 2020): -21.54%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -31.18%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
Performance Table Market Index Changed rr_PerformanceTableMarketIndexChanged Effective September 9, 2022, the fund’s Index changed from the Alpha Vee American Century Diversified International Equity Index to the American Century Quality Diversified International Equity Index. The inception date of the American Century Quality Diversified International Equity Index was March 23, 2022.
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Quality Diversified International ETF | American Century Quality Diversified International Equity Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes) [1]
Label rr_AverageAnnualReturnLabel American Century Quality Diversified International Equity Index1  (reflects no deduction for fees, expenses or taxes) [1]
American Century ETF Trust | American Century Quality Diversified International ETF | Alpha Vee American Century Diversified International Equity Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes) [1]
Label rr_AverageAnnualReturnLabel Alpha Vee American Century Diversified International Equity Index1  (reflects no deduction for fees, expenses or taxes) [1]
1 Year rr_AverageAnnualReturnYear01 9.72% [1]
Since Inception rr_AverageAnnualReturnSinceInception 10.93% [1]
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018 [1]
American Century ETF Trust | American Century Quality Diversified International ETF | MSCI World ex USA Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI World ex USA Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 12.62%
Since Inception rr_AverageAnnualReturnSinceInception 9.19%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Quality Diversified International ETF | American Century Quality Diversified International ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol QINT
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.39%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.39%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 40
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 126
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 219
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 493
Annual Return 2019 rr_AnnualReturn2019 24.15%
Annual Return 2020 rr_AnnualReturn2020 17.57%
Annual Return 2021 rr_AnnualReturn2021 8.85%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (31.18%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 21.25%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (21.54%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 8.85%
Since Inception rr_AverageAnnualReturnSinceInception 10.12%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Quality Diversified International ETF | American Century Quality Diversified International ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 8.43%
Since Inception rr_AverageAnnualReturnSinceInception 9.71%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Quality Diversified International ETF | American Century Quality Diversified International ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 5.83%
Since Inception rr_AverageAnnualReturnSinceInception 7.94%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century Quality Preferred ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Quality Preferred ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks current income and capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 51% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 51.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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 (unless otherwise indicated), that you earn 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
Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in preferred securities issued by U.S. and non-U.S. companies. Preferred securities in which the fund may invest include preferred stock, hybrid preferred securities that have characteristics similar to both preferred stock and debt securities, floating rate preferred securities, junior subordinated debt, senior unsecured debt obligations denominated in $25 par amounts (senior notes or baby bonds), re-packaged preferreds, and convertible securities.
The portfolio managers screen securities utilizing a quantitative and fundamental investment process informed by fundamental and technical measures such as liquidity, credit risk, size, quality, and momentum. The strategy screens for profitability and leverage and selects issuers and issues based on favorable quality, yield and valuation metrics.
The fund is nondiversified. The fund concentrates its investments in the group of industries that comprise the financials sector. The fund may engage in active and frequent trading of portfolio securities to achieve its principal investment strategies. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains. The fund may invest in securities of any duration or maturity.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. To determine whether to buy or sell a security, the portfolio managers consider, among other things, various fund requirements and standards, along with economic conditions, alternative investments, interest rates and various credit metrics.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in preferred securities issued by U.S. and non-U.S. companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Preferred Securities Risk -Preferred securities combine some of the characteristics of both common stocks and bonds. Preferred securities are typically subordinated to a company’s other debt which subjects them to greater credit risk . Generally, holders of preferred securities have no voting rights. In certain circumstances, an issuer of preferred securities may defer payment on the securities and, in some cases, redeem the securities prior to a specified date. Preferred securities may also be substantially less liquid than other securities and may have less upside potential than common stock.
•Floating Rate Securities Risk — Floating rate securities are structured so that the security’s coupon rate fluctuates based upon the level of a reference rate. In a falling interest rate environment, the coupon on floating rate securities will generally decline, causing a reduction in the fund’s income. A floating rate security’s coupon rate resets periodically according to the terms of the security. In a rising interest rate environment, floating rate securities with coupon rates that reset infrequently may lag behind the
changes in market interest rates. Floating rate securities may also contain terms that impose a maximum coupon rate the issuer will pay decreasing the value of the security.
•Fixed-To-Floating Rate Securities Risk — Securities with a floating or variable interest rate component can be less sensitive to interest rate changes than securities with fixed interest rates but may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. They generally carry lower yields than similar fixed-rate securities.
•Call Risk — Some debt securities may be redeemed, or “called,” at the option of the issuer before their stated maturity date. In general, an issuer will call its debt securities if they can be refinanced by issuing new debt securities which bear a lower interest rate. During periods of falling interest rates an issuer may call its high yielding debt securities, the fund would then have to invest the proceeds at lower interest rates, likely resulting in an income decline.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Extension Risk — When interest rates rise certain obligations the issuer (or other obligated party) may pay off obligations more slowly than anticipated, causing the value of these debt securities to fall. Rising interest rates tend to extend the duration of debt securities, making their market value more sensitive to changes in interest rates.
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Concentration Risk — Concentrating investments in a particular industry or group of industries gives the fund greater exposure than other funds to market, economic and other factors affecting that industry or group of industries. The financials sector can be significantly affected by changes in interest rates, government regulation, the rate of defaults on corporate, consumer and government debt, and the availability and cost of capital.
•LIBOR Transition Risk — The fund may invest in instruments that have variable or floating coupon rates based on the London Interbank Offered Rate (LIBOR). LIBOR is a benchmark interest rate intended to be representative of the rate at which certain major international banks lend to one another over short-terms. Financial institutions have started the process of phasing out LIBOR and the transition process to a replacement rate may lead to increased volatility or illiquidity in markets for instruments that rely on LIBOR. This could result in a change to the value of such instruments or a change in the cost of temporary borrowing for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes could be higher than if the fund sold and redeemed shares in-kind.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in exchange-traded funds (ETFs) generally.
•High Portfolio Turnover Risk — High portfolio turnover (higher than 100% annually), may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of securities.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the Cboe BZX Exchange, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
Risk Nondiversified Status [Text] rr_RiskNondiversifiedStatus Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Quality Preferred ETF | American Century Quality Preferred ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol QPFF
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.32%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.32%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 33
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 103
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 180
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 406
American Century ETF Trust | American Century Select High Yield ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Select High Yield ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide high current income.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from November 16, 2021, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 12% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 12.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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
Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in high-yield debt securities. A high-yield security is one that has been rated below the four highest categories used by a nationally recognized statistical rating organization (for example, below BBB by Standard & Poor’s Corporation or below Baa by Moody’s Investors Service, Inc.), or, if unrated, determined by the investment advisor to be of similar quality. High-yield securities are also referred to as junk bonds.
The portfolio managers generally operate a long-only strategy using a bottom-up investment philosophy by investing in companies that they believe can carry debt loads through different economic cycles. The portfolio managers look for companies that demonstrate the ability to generate strong, sustainable cash flow, which may enable them to decrease leverage and improve their ratings. The portfolio managers also use a top-down investment overlay to identify areas of the high yield market that they believe are undervalued relative to the rest of the market. The portfolio managers decide which debt securities to buy and sell by, among other things:
•    identifying debt securities that satisfy the fund’s credit quality standards;
•    considering the price of the security and the issuer’s financial history, condition, management and prospects;
•    assessing current and anticipated interest rates;
•    evaluating current economic conditions and the risk of inflation; or
•    evaluating special features of the debt securities that may make them more or less attractive to alternatives.
The portfolio managers will actively allocate the fund’s assets in a range of high-yield corporate bonds. The fund also may invest in preferred securities, convertible securities and cash and cash equivalents. The fund will invest primarily in securities rated BB or B, but may invest a portion of its portfolio in securities rated BBB and above, or CCC and below.
The fund has no average maturity limitations. The fund typically invests in debt securities with maturities of 3-10 years, but may also hold securities maturing in less than 3 years and more than 10 years.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. American Century Investment Management, Inc. (the advisor) has hired Nomura Corporate Research and Asset Management Inc. (the
subadvisor) to make investment recommendations for the fund by delivering a model portfolio together with portfolio parameters to the advisor. The advisor has investment discretion to implement the model portfolio delivered by the subadvisor.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s net assets, plus any borrowings for investment purposes, in high-yield debt securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•High-Yield Risk — Issuers of high-yield securities are more vulnerable to real or perceived economic changes (such as an economic down turn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations. Investment in high-yield securities is inherently speculative.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Convertible Securities Risk — The value of convertible securities may rise and fall with the market value of the underlying stock or, like a debt security, vary with changes in interest rates and the credit quality of the issuer. A convertible security tends to perform more like a stock when the underlying stock price is high relative to the conversion price and more like a debt security when the underlying stock price is low relative to the conversion price.
•Preferred Securities Risk — Preferred securities combine some of the characteristics of both common stocks and bonds. Preferred securities are typically subordinated to a company’s other debt which subjects them to greater credit risk . Generally, holders of preferred securities have no voting rights. In certain circumstances, an issuer of preferred securities may defer payment on the securities and, in some cases, redeem the securities prior to a specified date. Preferred securities may also be substantially less liquid than other securities and may have less upside potential than common stock.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to net asset value (NAV). Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Absence of Active Market Risk — Although shares of the fund are listed for trading on one or more stock exchanges, there can be no assurance that an active trading market for such shares will develop or be maintained by market makers or authorized participants. Authorized participants are not obligated to execute purchase or redemption orders for creation units. In periods of market volatility, market makers and/or authorized participants may be less willing to transact in fund shares. The absence of an active market for the fund’s shares may contribute to the fund’s shares trading at a premium or discount to NAV and also greater than normal bid/ask spreads.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the issuers whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Select High Yield ETF | American Century Select High Yield ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AHYB
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.45%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.45%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 46
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 145
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 252
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 567
American Century ETF Trust | American Century Short Duration Strategic Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Short Duration Strategic Income ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks income.
Objective, Secondary [Text Block] rr_ObjectiveSecondaryTextBlock As a secondary objective, the fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. Because the fund is new, the fund’s portfolio turnover rate is not available.
Other Expenses, New Fund, Based on Estimates [Text] rr_OtherExpensesNewFundBasedOnEstimates Other expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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
Portfolio managers assess current and anticipated interest rates and economic conditions, and then select short duration debt securities for the fund that satisfy the fund’s credit quality standards and meet the fund’s maturity requirements. The weighted average duration of the fund’s portfolio must be three years or shorter. Duration is an indication of the relative sensitivity of a security’s market value to changes in interest rates. The longer the weighted average duration of the fund’s portfolio, the more sensitive its market value is to interest rate fluctuations. Duration is different from maturity in that it attempts to measure the interest rate sensitivity of a security, as opposed to its expected final maturity. For example, if the weighted average duration of the fund’s portfolio is two years, a 2% change in the value of the fund’s portfolio would be expected for every 1% change in interest rates.
The fund invests in both investment-grade and high-yield, short duration debt securities. These securities may include corporate bonds and notes, government securities and securities backed by mortgages or other assets. Investment grade securities are those that have been rated in one of the top four credit quality categories by an independent rating agency or determined by the advisor to be of comparable credit quality. High-yield securities, which are also known as “junk bonds”, are those that have been rated by an independent rating agency below the highest four categories or determined by the advisor to be of similar quality. 
The debt securities in which the fund invests may be payable in U.S. or foreign currencies. 
The fund may also invest in certain equity securities such as preferred stock, convertible securities or equity equivalents provided that such investments are consistent with the fund’s investment objectives.
The fund may invest in securities issued or guaranteed by the U.S. Treasury and certain U.S. government agencies or instrumentalities such as the Government National Mortgage Association (Ginnie Mae). Ginnie Mae is supported by the full faith and credit of the U.S. government. Securities issued or guaranteed by other U.S. government agencies or instrumentalities, such as the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac), and the Federal Home Loan Bank (FHLB) are not guaranteed by the U.S. Treasury or supported by the full faith and credit of the U.S. government. However, they are authorized to borrow from the U.S. Treasury to meet their obligations.
In addition to the securities listed above, the fund may also invest in bank loans.
The fund may also utilize derivative instruments provided that such investments are in keeping with the fund’s investment objectives. Such derivative instruments may include currency forwards and swaps (such as credit default swaps either on a single issuer or a securities index). The fund may invest in collateralized debt obligations, including collateralized loan obligations, collateralized mortgage obligations, mortgage- or asset- backed securities, and other similarly structured investments. The fund may use foreign currency exchange contracts to shift investment exposure from one currency into another for hedging purposes or to enhance returns.
To determine whether to buy or sell a security, the portfolio managers consider, among other things, various fund requirements and standards, along with economic conditions, alternative investments and interest rates.
The portfolio managers may engage in hedging of portfolio positions, which usually involves entering into a derivative transaction that has the opposite characteristic of the position being hedged. The net effect of the two positions is intended to reduce or eliminate the exposure created by the first position.
The fund may engage in active and frequent trading of portfolio securities to achieve its principal investment strategies. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. To determine whether to buy or sell a security, the portfolio managers consider, among other things, various fund requirements and standards, along with economic conditions, alternative investments, interest rates and various credit metrics.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•High-Yield Risk — Issuers of high-yield securities are more vulnerable to real or perceived economic changes (such as an economic down turn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations. Investment in high-yield securities is inherently speculative.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivatives can be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Bank Loan Risk — The market for bank loans may not be highly liquid and the fund may have difficulty selling them. In connection with purchasing loan participations, the fund generally will have no right to enforce compliance by borrowers with loan terms nor any set off rights, and the fund may not benefit directly from any posted collateral. As a result, the fund may be subject to the credit risk of both the borrower and the lender selling the participation. Bank loan transactions may take more than seven days to settle, meaning that proceeds would be unavailable to make additional investments or meet redemptions. To the extent the extended loan settlement process gives rise to short-term liquidity needs, such as the need to satisfy redemption requests, the fund may hold cash or sell investments.
•Collateralized Debt Obligations Risk — Collateralized debt obligations and collateralized loan obligations (CLOs) are subject to credit, interest rate, valuation, and prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. The market value of CLOs may be affected by, among other things, changes in the market value of the underlying assets held by the CLO, changes in the distributions on the underlying assets, defaults and recoveries on the underlying assets, capital gains and losses on the underlying assets, prepayments on underlying assets and the availability, prices and interest rate of underlying assets.
•Counterparty Risk — If the fund enters into financial contracts, the fund will be subject to the credit risk presented by counterparties.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, to meet redemptions it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund’s share price. In addition, when the market for certain investments is illiquid, the fund may be unable to achieve its desired level of exposure to a certain sector. Illiquid securities may be difficult to value. Changing regulatory and market conditions, including increases in interest rates and credit spreads, may adversely affect the liquidity of the fund’s investments.
•Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or other assets. If these underlying assets are prepaid, the fund may benefit less from declining interest rates than funds of similar duration that invest less
heavily in mortgage- and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation) especially in periods of rising interest rates. These events may lengthen the duration (i.e. interest rate sensitivity) and potentially reduce the value of these securities.
•Foreign Securities Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Currency Risk — Because the fund may invest in securities denominated in foreign currencies, the fund could experience gains or losses based solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Convertible Securities Risk — The fund may invest in convertible securities, which may be affected by changes in interest rates, the credit of the issuer, and the value of the underlying common stock. In addition, because these securities are convertible into common stock, they are subject to general stock market risk, though to a lesser degree.
•Preferred Securities Risk -Preferred securities combine some of the characteristics of both common stocks and bonds. Preferred securities are typically subordinated to a company’s other debt which subjects them to greater credit risk . Generally, holders of preferred securities have no voting rights. In certain circumstances, an issuer of preferred securities may defer payment on the securities and, in some cases, redeem the securities prior to a specified date. Preferred securities may also be substantially less liquid than other securities and may have less upside potential than common stock.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•High Portfolio Turnover Risk — The fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the issuers whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the
trading volume on the listing exchange and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Short Duration Strategic Income ETF | American Century Short Duration Strategic Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol SDSI
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.32%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none [2]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.32%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 33
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 $ 103
American Century ETF Trust | American Century STOXX U.S. Quality Growth ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® STOXX® U.S. Quality Growth ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide investment results that closely correspond, before fees and expenses, to the performance of the iSTOXX American Century USA Quality Growth Index (the “Index”).
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 153% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 153.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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 (unless otherwise indicated), that you earn 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
Under normal market conditions, the fund invests at least 80% of its assets, exclusive of collateral held from securities lending, in the component securities of the underlying index. The Index is a rules-based index maintained and calculated by STOXX® Ltd. (the index provider). The Index is designed to select securities of large- and mid-capitalization U.S. companies with attractive growth and quality fundamentals.
The Index universe is defined by the STOXX® USA 900 Index, which consists of the 900 largest publicly traded U.S. equity securities. The Index is designed to measure the performance of securities in the universe and identify those that exhibit higher growth and quality characteristics relative to their peers. To construct the Index, the index provider first screens the underlying universe and selects securities with higher profitability, return on assets, return on equity, and gross margins. The index provider next calculates a growth score for each security, which is based on sales, earnings, operating income, profitability and cash flows. The index provider then weights securities based on the calculated growth score. Though component securities of the Index may change from time to time, the index typically consists of 150–250 securities and, as of September 30, 2022, the market capitalization range of the Index was approximately $1.91 billion and larger.
The Index and fund are rebalanced monthly and reconstituted quarterly.
The fund may use a “representative sampling” strategy with respect to its Index instead of a replication strategy. For example, the fund may use such strategy when there are practical difficulties or substantial costs involved in compiling a portfolio of securities to follow the Index or, in certain instances, when a component security becomes temporarily illiquid, unavailable or less liquid. To the extent the fund uses representative sampling, the advisor invests in what it believes to be a representative sample of the component securities in the Index using quantitative analytical procedures to give the fund’s portfolio an investment profile similar to that of its Index. The fund also may realize savings in transaction costs or other efficiencies by investing up to 20% of its assets in securities or instruments not included in the Index but which the advisor believes will help the fund track the Index.
In addition, the fund may use futures contracts to invest cash balances, simulate investments in the Index, facilitate trading or minimize transaction costs. The portfolio managers may also use futures contracts to seek to reduce the fund’s tracking error relative to the Index.
The fund may concentrate its investments (i.e., hold 25% or more of its net assets) in a particular industry or group of industries to the extent that the Index is concentrated.
If the Index has high portfolio turnover, the fund may also have high portfolio turnover. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund invests at least 80% of its assets, exclusive of collateral held from securities lending, in the component securities of the underlying index.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Index-Related Risk — Unlike many investment companies, the fund is not actively managed, and the portfolio managers do not attempt to take defensive positions under any market conditions, including declining markets. Therefore, the portfolio managers generally will not buy or sell securities unless they are added or removed from the Index, even if a security is underperforming. There is no assurance that the Index will be determined, composed or calculated accurately. While the index provider provides descriptions of what the Index is designed to achieve, the index provider does not guarantee the quality, accuracy or completeness of data in respect of its indices and does not guarantee that the Index will be in line with the described index methodology. Gains, losses or costs to the fund caused by errors in the Index may therefore be borne by the fund and its shareholders.
•Calculation Methodology Risk — The Index relies on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the fund nor American Century Investment Management, Inc. (the advisor) can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers.
•Growth Stocks Risk — Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Rebalance Risk — The fund rebalances its portfolio in accordance with the underlying index’s rebalance schedule. Accordingly, any change to this schedule will result in corresponding changes to the fund’s rebalance schedule.
•Style Risk — There can be no assurance that the investment factor stock selection process and screens of the Index will enhance performance. Exposure to certain investment factors and use of screens may detract from performance in some market environments, perhaps for extended periods.
•Mid-Capitalization Company Risk — Investments in medium-size companies may involve greater risk and price volatility than investments in larger, more mature companies.
•Tracking Error Risk — Tracking error is the divergence of the fund’s performance from that of the Index. Tracking error may occur because of differences between the securities held in the fund’s portfolio and those included in the Index, pricing differences, transaction costs, the fund’s holding of cash, differences in timing of the accrual of dividends or interest, changes to the Index or the need to meet various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the fund incurs fees and expenses, while the Index does not.
•High Portfolio Turnover Risk — High portfolio turnover (higher than 100% annually), may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of securities.
•Sampling Risk — To the extent the fund uses a representative sampling strategy, it may hold a smaller number of securities than are in the Index or it may hold securities that are not included in the Index. As a result, an adverse development respecting an issuer of securities held by the fund could result in a greater decline in the fund’s NAV than would be the case if all of the securities in the Index were held. The fund’s use of a representative sampling strategy may also include the risk that it may not
track the return of the Index with the same degree of accuracy as would an investment vehicle that invested in every component security of the Index with the same weightings as the Index.
•Management Risk — To the extent the fund uses representative sampling, the strategy may fail to produce the intended results.
•Non-Correlation Risk — There is no guarantee that the fund will achieve a high degree of correlation to the Index and therefore achieve its investment objective. Market disruptions and regulatory restrictions could have an adverse effect on the fund’s ability to adjust its exposure to the required levels in order to track the Index. In addition, the fund’s NAV may deviate from the Index if the fund fair values a portfolio security at a price other than the price used by the Index for that security.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in exchange-traded funds (ETFs) generally.
•Concentration Risk — To the extent the fund concentrates in a specific industry or a group of industries, it may be subject to greater risks and market fluctuations than a portfolio investing in a broader range of industries.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Derivatives Risk — The use of derivative instruments such as futures contracts involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 31.62% Lowest Performance Quarter (1Q 2020): -16.87%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -28.25%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century STOXX U.S. Quality Growth ETF | iSTOXX® American Century USA Quality Growth Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel iSTOXX® American Century USA Quality Growth Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 25.21%
Since Inception rr_AverageAnnualReturnSinceInception 22.57%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Growth ETF | American Century STOXX U.S. Quality Growth ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol QGRO
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.29%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 30
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 93
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 163
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 369
Annual Return 2019 rr_AnnualReturn2019 34.54%
Annual Return 2020 rr_AnnualReturn2020 38.05%
Annual Return 2021 rr_AnnualReturn2021 24.54%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (28.25%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 31.62%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (16.87%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 24.54%
Since Inception rr_AverageAnnualReturnSinceInception 22.11%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Growth ETF | American Century STOXX U.S. Quality Growth ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 24.44%
Since Inception rr_AverageAnnualReturnSinceInception 22.01%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Growth ETF | American Century STOXX U.S. Quality Growth ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 14.59%
Since Inception rr_AverageAnnualReturnSinceInception 17.65%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 10, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® STOXX® U.S. Quality Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to provide investment results that closely correspond, before fees and expenses, to the performance of the iSTOXX® American Century USA Quality Value Index (the underlying index).
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 118% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 118.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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 (unless otherwise indicated), that you earn 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
Under normal market conditions, the fund invests at least 80% of its assets in the component securities of the underlying index. The underlying index is a rules-based index maintained and calculated by STOXX® Ltd. (the index provider). The underlying index is designed to select securities of large- and mid-capitalization companies that are undervalued or have sustainable income.
The underlying index universe is defined by the STOXX® USA 900 Index, which consists of the 900 largest publicly traded U.S. equity securities. The underlying index is constructed using a rules-based methodology that screens and weights stocks based on fundamental measures of quality, value and income. A quality screen seeks to eliminate the bottom of the universe of stocks based on measures of profitability, earnings quality, management quality and earnings estimate revisions. A valuation score is computed for the remaining stocks, determined by the attractiveness of each stock relative to its peers in the same industry group based on value, earnings yield and cash flow yield metrics. An income sustainability screen based on dividend growth and dividend coverage metrics is applied to eliminate the bottom of the universe of dividend-paying stocks, and an income score based on dividend-yield is computed for the remaining stocks. The underlying index is constructed by combining the value stocks and income stocks using the valuation and income scores and portfolio optimization. Portfolio optimization uses quantitative models to build a portfolio of stocks from the scores described above that are expected to provide the optimal balance between risk and expected return. Though component securities of the underlying index may change from time to time, the index typically consists of 200-300 securities and, as of September 30, 2022, its market capitalization range was approximately $1.91 billion to $2.22 trillion.
The fund may use a “representative sampling” strategy with respect to its underlying index when a replication strategy might be detrimental to shareholders. For example, the fund may use such strategy when there are practical difficulties or substantial costs involved in compiling a portfolio of securities to follow the underlying index or, in certain instances, when a component security becomes temporarily illiquid, unavailable or less liquid. To the extent the fund uses representative sampling, the advisor invests in what it believes to be a representative sample of the component securities in the underlying index using quantitative analytical procedures to give the fund’s portfolio an investment profile similar to that of its underlying index. The fund also may realize savings in transaction costs or other efficiencies by investing up to 20% of its assets in securities or instruments not included in the underlying index but which the advisor believes will help the fund track the underlying index.
In addition, the fund may use futures contracts to invest cash balances, simulate investments in the underlying index, facilitate trading or minimize transaction costs. The portfolio managers may also use futures contracts to seek to reduce the fund’s tracking error relative to the underlying index.
The underlying index and fund are rebalanced monthly and reconstituted quarterly.
The fund will concentrate its investments (i.e., hold 25% or more of its net assets) in a particular industry or group of industries to approximately the same extent that the underlying index is concentrated.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund invests at least 80% of its assets in the component securities of the underlying index.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Index-Related Risk — Unlike many investment companies, the fund is not actively managed and the portfolio managers do not attempt to take defensive positions under any market conditions, including declining markets. Therefore, the portfolio managers generally will not buy or sell a security unless that security is added or removed, respectively, from the underlying index, even if that security generally is underperforming. There is no assurance that the underlying index will be determined, composed or calculated accurately. While the index provider provides descriptions of what the underlying index is designed to achieve, the index provider does not guarantee the quality, accuracy or completeness of data in respect of its indices, and does not guarantee that the underlying index will be in line with the described index methodology. Gains, losses or costs to the fund caused by errors in the underlying index may therefore be borne by the fund and its shareholders.
•Rebalance Risk — The fund rebalances its portfolio in accordance with the underlying index’s rebalance schedule. Accordingly, any change to this schedule will result in corresponding changes to the fund’s rebalance schedule.
•Calculation Methodology Risk — The underlying index relies on various sources of information to assess the criteria of issuers included in the underlying index, including information that may be based on assumptions and estimates. Neither the fund nor American Century Investment Management, Inc. (the advisor) can offer assurances that the underlying index’s calculation methodology or sources of information will provide an accurate assessment of included issuers.
•Style Risk — There can be no assurance that the investment factor stock selection process and screens of the underlying index will enhance performance. Exposure to certain investment factors and use of screens may detract from performance in some market environments, perhaps for extended periods.
•Market Risk — The value of the fund’s shares will go up and down, sometimes rapidly or unpredictably, based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Mid-Capitalization Company Risk — Investments in medium-size companies may involve greater risk and price volatility than investments in larger, more mature companies.
•Tracking Error Risk — Tracking error is the divergence of the fund’s performance from that of the underlying index. Tracking error may occur because of differences between the securities held in the fund’s portfolio and those included in the underlying index, pricing differences, transaction costs, the fund’s holding of cash, differences in timing of the accrual of dividends or interest, changes to the underlying index or the need to meet various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the fund incurs fees and expenses, while the underlying index does not.
•Sampling Risk — To the extent the fund uses a representative sampling strategy, it may hold a smaller number of securities than are in the underlying index or it may hold securities that are not included in the underlying index. As a result, an adverse development respecting an issuer of securities held by the fund could result in a greater decline in the fund’s NAV than would be
the case if all of the securities in the underlying index were held. The fund’s use of a representative sampling strategy may also include the risk that it may not track the return of the underlying index with the same degree of accuracy as would an investment vehicle that invested in every component security of the underlying index with the same weightings as the underlying index.
•Management Risk — To the extent the fund uses representative sampling, the strategy may fail to produce the intended results.
•Non-Correlation Risk — There is no guarantee that the fund will achieve a high degree of correlation to the underlying index and therefore achieve its investment objective. Market disruptions and regulatory restrictions could have an adverse effect on the fund’s ability to adjust its exposure to the required levels in order to track the underlying index. In addition, the fund’s NAV may deviate from the underlying index if the fund fair values a portfolio security at a price other than the price used by the underlying index for that security.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in exchange-traded funds (ETFs) generally.
•Concentration Risk — To the extent the fund concentrates in a specific industry or a group of industries, it may be subject to greater risks and market fluctuations than a portfolio investing in a broader range of industries.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Derivatives Risk — The use of derivative instruments such as futures contracts involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 15.82% Lowest Performance Quarter (1Q 2020): -26.89%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -19.02%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century STOXX U.S. Quality Value ETF | iSTOXX® American Century USA Quality Value Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel iSTOXX® American Century USA Quality Value Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 27.64%
Since Inception rr_AverageAnnualReturnSinceInception 9.75%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Value ETF | American Century STOXX U.S. Quality Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol VALQ
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.29%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 30
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 93
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 163
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 369
Annual Return 2019 rr_AnnualReturn2019 24.03%
Annual Return 2020 rr_AnnualReturn2020 0.50%
Annual Return 2021 rr_AnnualReturn2021 27.11%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (19.02%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 15.82%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (26.89%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 27.11%
Since Inception rr_AverageAnnualReturnSinceInception 9.43%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Value ETF | American Century STOXX U.S. Quality Value ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 26.60%
Since Inception rr_AverageAnnualReturnSinceInception 8.83%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | American Century STOXX U.S. Quality Value ETF | American Century STOXX U.S. Quality Value ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 16.36%
Since Inception rr_AverageAnnualReturnSinceInception 7.25%
Inception Date rr_AverageAnnualReturnInceptionDate Jan. 11, 2018
American Century ETF Trust | Avantis All Equity Markets ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® All Equity Markets ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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 December 31, 2023
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. Because the fund is new, the fund’s portfolio turnover rate is not available.
Other Expenses, New Fund, Based on Estimates [Text] rr_OtherExpensesNewFundBasedOnEstimates Other Expenses and Acquired Fund Fees and Expenses are based on estimated amounts for the current fiscal year.
Acquired Fund Fees and Expenses, Based on Estimates [Text] rr_AcquiredFundFeesAndExpensesBasedOnEstimates Other Expenses and Acquired Fund Fees and Expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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
Avantis All Equity Markets ETF is a “fund of funds,” meaning that it seeks to achieve its objective by investing in other Avantis exchange-traded funds (ETFs) (collectively, the underlying funds). The underlying funds represent a broadly diversified basket of equity securities that seek to overweight securities that are expected to have higher returns or better risk characteristics than a passive, market-cap weighted index.
The following table indicates the fund’s target weight and range for allocation among the fund’s major asset classes and shows the underlying funds that comprise each asset class. This information is as of the date of this prospectus.
Target WeightTarget Range
U.S. Equity
70%
63% to 77%
Avantis U.S. Equity ETF
Avantis U.S. Small Cap Equity ETF
Avantis U.S. Large Cap Value ETF
Avantis U.S. Small Cap Value ETF
Target WeightTarget Range
Non-U.S. Developed Markets
17%
10% to 24%
Avantis International Equity ETF
Avantis International Large Cap Value ETF
Avantis International Small Cap Value ETF
Emerging Markets10%3% to 17%
Avantis Emerging Markets Equity ETF
Avantis Emerging Markets Value ETF
Sector Equity
3%
1% to 6%
Avantis Real Estate ETF
Under normal market conditions, the fund will invest at least 80% of its assets in equity ETFs. The managers will strategically allocate to the underlying funds across geographies and investment styles to achieve the desired allocation. The U.S. vs. non-U.S. allocations across geographies will be predicated on each region’s relative market capitalization with a home bias toward the U.S. The portfolio managers regularly review the fund’s allocations to determine whether rebalancing is appropriate. To better balance risks in changing market environments and control costs and tax realizations, the portfolio managers may allocate within the target range in light of prevailing market conditions and relative performance. We reserve the right to modify the target ranges and underlying funds from time to time should circumstances warrant a change.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity ETFs.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Allocation Risk — The fund’s performance and risks depend in part on the managers’ skill in selecting and weighting the underlying funds, and implementing any deviations from the target range. The managers’ evaluations and assumptions regarding asset classes or underlying funds may differ from actual market conditions.
•Fund of Funds Risks — The fund’s performance and risks reflect the performance and risks of the underlying funds in which it invests. The fund’s investment in other funds advised by American Century Investments may create a conflict of interest for the fund’s advisor.
•Equity Securities Risk — The underlying funds invest in equity securities. The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Foreign Securities Risk — Some of the underlying funds invest in foreign securities. Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), and natural disasters occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Emerging Market Risk — Some of the underlying funds invest in emerging markets securities. Investing in emerging market countries generally is riskier than investing in foreign developed countries. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the Public Company Accounting Oversight Board (PCAOB) with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks.
•ETF Risk — ETF shares are based on market price rather than net asset value (NAV), as a result, shares may trade at a price greater than NAV (a premium) or less than NAV (a discount). The fund may also incur brokerage commissions, as well as the cost of the bid/ask spread, when purchase or selling ETF shares.
•Small- and Mid-Cap Stock Risks — Stocks of smaller companies may be more volatile than larger-company stocks. Smaller companies may have limited financial resources, product lines and markets, and their securities may trade less frequently and in more limited volumes than the securities of larger companies, which could lead to higher transaction costs. To the extent an underlying fund invests in these companies, it may take on more risk.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the underlying funds in which it invests. The value of the underlying funds’ shares will, in turn, fluctuate based on the performance of the companies whose securities they own and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Real Estate Investing Risk — If an underlying fund invests in real estate, it may be subject to many of the same risks as a direct investment in real estate. These risks include changes in economic conditions, interest rates, property values, property tax increases, overbuilding and increased competition, environmental contamination, zoning and natural disasters. This is due to the fact that the value of the fund’s investments may be affected by the value of the real estate owned by the companies in which it invests. To the extent the fund invests in companies that make loans to real estate companies, the fund also may be subject to interest rate risk and credit risk.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis All Equity Markets ETF | Avantis All Equity Markets ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVGE
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.05%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none [3]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.20% [3]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.02% [4]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.23%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 24
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 $ 79
American Century ETF Trust | Avantis Core Fixed Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Core Fixed Income ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to maximize total return.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 382% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 382.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in investment grade quality debt obligations from a diverse group of U.S. and non-U.S. issuers.
The fund’s investment process uses an analytical framework, which includes an assessment of securities’ expected income and capital appreciation, to seek securities with high expected returns. The portfolio managers categorize securities within the fund’s investment universe into component groups based on factors such as industry sector, credit rating, duration, country, and currency. The portfolio managers then calculate the expected return implied by the yield curve of each component group, while considering valuation metrics such as yield, duration, and option adjusted spreads. Finally, the portfolio managers adjust the portfolio to arrive at position weightings for each component group with the goal of building a portfolio with enhanced expected return.
Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities. Fixed income securities in which the fund may invest include corporate bonds and notes issued by U.S. and foreign corporations, securities issued by governments and their agencies, instrumentalities, or sponsored corporations—including supranational organizations. The fund may also invest in derivative instruments such as futures contracts or swap agreements, including credit default swaps, credit default swap indexes, and total return swaps.
The fund will invest primarily in investment grade securities as rated by an independent rating agency or determined by the advisor to be of comparable credit quality if a rating is unavailable. The fund expects to maintain a weighted average duration within 2 years of the weighted average duration of its benchmark, the Bloomberg U.S. Aggregate Bond index, as calculated by the manager. Duration is used to assess the sensitivity of a security’s price to changes in interest rates.
The fund may engage in foreign currency transactions on a spot basis and may also use currency forward contracts to hedge exposure to foreign currencies. The fund may purchase or sell when-issued, forward-settling, delayed delivery or forward commitment obligations. The fund may invest more than 25% of its total assets in U.S. Treasury, federal agencies and instrumentalities obligations.
The fund may also engage in securities lending. Collateral received by the fund in connection with loaning its securities may consist of cash and U.S. government securities. Cash collateral may be invested in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or assets such as auto loan, home equity loan or student loan receivables. These underlying obligations may be prepaid, as when a homeowner refinances a mortgage to take advantage of declining interest rates. If so, the fund must reinvest prepayments at current rates, which may be less than the rate of the prepaid mortgage. Because of this prepayment risk, the fund may benefit less from declining interest rates than funds of similar duration that invest less heavily in mortgage- and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation), especially in periods of rising interest rates. These events may lengthen the duration (i.e., interest rate sensitivity) and potentially reduce the value of these securities.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience potentially dramatic price changes (losses) and imperfect correlations between the price of the contract and the underlying security, index or currency. Swap agreements subject a fund to counterparty risk. Interest rate swaps could result in losses if the fund does not correctly anticipate interest rate changes. Credit default swaps could result in losses if the fund does not correctly evaluate the creditworthiness of the issuer on which the credit default swap is based.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2021): 2.36% Lowest Performance Quarter (1Q 2021): -3.92%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -15.77%.
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis Core Fixed Income ETF | Bloomberg U.S. Aggregate Bond Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Bloomberg U.S. Aggregate Bond Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 (1.54%)
Since Inception rr_AverageAnnualReturnSinceInception (0.77%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Core Fixed Income ETF | Avantis Core Fixed Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVIG
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
Annual Return 2021 rr_AnnualReturn2021 (2.06%)
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (15.77%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 2.36%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (3.92%)
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (2.06%)
Since Inception rr_AverageAnnualReturnSinceInception (1.00%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Core Fixed Income ETF | Avantis Core Fixed Income ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (2.51%)
Since Inception rr_AverageAnnualReturnSinceInception (1.44%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Core Fixed Income ETF | Avantis Core Fixed Income ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (1.22%)
Since Inception rr_AverageAnnualReturnSinceInception (0.94%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Core Municipal Fixed Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Core Municipal Fixed Income ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks current income that is exempt from federal income tax.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 2% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 2.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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’s investment process uses an analytical framework, which includes an assessment of securities’ expected income and capital appreciation, to seek securities with high expected returns. The portfolio managers categorize securities within the fund’s investment universe into component groups based on factors such as industry sector, credit rating, duration, country, and currency. The portfolio managers then calculate the expected return implied by the yield curve of each component group, while considering valuation metrics such as yield, duration, and option adjusted spreads. Finally, the portfolio managers adjust the portfolio to arrive at position weightings for each component group with the goal of building a portfolio with enhanced expected return.
Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in municipal fixed income securities with interest payments exempt from federal income tax. A municipal fixed income security is a debt obligation issued by or on behalf of a state, its political subdivisions, agencies or instrumentalities, the District of Columbia or a U.S. territory or possession. Municipal securities include revenue bonds, general obligation bonds, municipal lease obligations, and industrial development bonds. The fund may use derivatives, such as futures contracts or swap agreements, to gain or limit exposures. The fund may purchase or sell when-issued, forward-settling, delayed delivery or forward commitment basis.
The fund will invest primarily in investment grade securities as rated by an independent rating agency or determined by the advisor to be of comparable credit quality if a rating is unavailable.
The fund may also engage in securities lending. Collateral received by the fund in connection with loaning its securities may consist of cash and U.S. government securities. Cash collateral may be invested in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in municipal fixed income securities with interest payments exempt from federal income tax.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock •Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Municipal Securities Risk — Because the fund invests principally in municipal securities, it will be sensitive to events that affect municipal markets, including legislative or political changes and the financial condition of the issuers of municipal securities. The fund may have a higher level of risk than funds that invest in a larger universe of securities. Additionally, the novel coronavirus (COVID -19) pandemic has stressed the financial resources of many municipal issuers, which may impair a municipal issuer’s ability to meet its financial obligations when due and could adversely impact the value of its bonds, which could negatively impact the performance of the fund.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Tax Risk — Some or all of the fund’s income may be subject to the federal alternative minimum tax. There is no guarantee that all of the fund’s income will remain exempt from federal or state income taxes. Income from municipal bonds held by a fund could be declared taxable because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state tax authorities, or noncompliant conduct of a bond issuer. The fund may sell securities that lose their tax-exempt statuses at inopportune times, which may cause tax consequences or a decrease in the fund’s value.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, to meet redemptions, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund’s share price. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience potentially dramatic price changes (losses) and imperfect correlations between the price of the contract and the underlying security, index or currency. Swap agreements subject a fund to counterparty risk. Interest rate swaps could result in losses if the fund does not correctly anticipate interest rate changes. Credit default swaps could result in losses if the fund does not correctly evaluate the creditworthiness of the issuer on which the credit default swap is based.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2021): 1.34% Lowest Performance Quarter (1Q 2021): -1.08%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -11.18%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis Core Municipal Fixed Income ETF | S&P National AMT-Free Municipal Bond Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel S&P National AMT-Free Municipal Bond Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 1.59%
Since Inception rr_AverageAnnualReturnSinceInception 1.85%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 08, 2020
American Century ETF Trust | Avantis Core Municipal Fixed Income ETF | Avantis Core Municipal Fixed Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVMU
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
Annual Return 2021 rr_AnnualReturn2021 0.52%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (11.18%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 1.34%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (1.08%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 0.52%
Since Inception rr_AverageAnnualReturnSinceInception 0.74%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 08, 2020
American Century ETF Trust | Avantis Core Municipal Fixed Income ETF | Avantis Core Municipal Fixed Income ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 0.52%
Since Inception rr_AverageAnnualReturnSinceInception 0.74%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 08, 2020
American Century ETF Trust | Avantis Core Municipal Fixed Income ETF | Avantis Core Municipal Fixed Income ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 0.62%
Since Inception rr_AverageAnnualReturnSinceInception 0.73%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 08, 2020
American Century ETF Trust | Avantis Emerging Markets Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Emerging Markets Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 3% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 3.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of companies related to emerging markets across market sectors, industry groups and countries. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of emerging markets companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries. The fund considers an emerging market country to be any country other than a developed country. However, the fund generally intends to focus its investments in a subset of the emerging markets countries that comprise the MSCI Emerging Markets IMI Index. The countries comprising the index will change from time to time, but as of September 30, 2022 include: Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hungary, India, Indonesia, Korea, Kuwait, Malaysia, Mexico, Peru, Philippines, Poland, Qatar, Saudi Arabia, South Africa, Taiwan, Thailand, Turkey and United Arab Emirates. To determine whether a company is related to an emerging market country, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived,
where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the MSCI Emerging Markets IMI. The weight given to each of these factors will vary depending on the circumstances in a given case. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Emerging Markets Risk — Investing in emerging market countries generally is riskier than investing in foreign developed countries. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the PCAOB with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks. As a result of the foregoing risks, the fund is intended for aggressive investors seeking significant gains through investments in foreign securities. Those investors must be willing and able to accept the significantly greater risks associated with the investment strategy that the fund will pursue. An investment in the fund is not appropriate for individuals with limited investment resources or who are unable to tolerate fluctuations in the value of their investment.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Greater China Risk — Investing in Chinese securities is riskier than investing in U.S. securities. Investing in China involves risk of loss due to nationalization, expropriation, and confiscation of assets and property. Losses may also occur due to new or expanded restrictions on foreign investments or repatriation of capital. Due to Chinese governmental restrictions on foreign ownership of companies in certain industries, Chinese operating companies often use variable interest entity (VIE) structures to raise capital from international investors. Shares of VIEs are not equity ownership interests in Chinese operating companies. The Chinese government never explicitly approved these structures and thus could determine that the underlying contractual arrangements on which control of the VIE is based violate Chinese law. Such determination from the Chinese government could result in a loss in the value of an investment in a U.S.-listed company that utilizes the VIE structure The Chinese market is subject to less regulation and oversight than the U.S. market. U.S. regulators have limited ability to inspect international auditing standards of U.S. companies operating in China, thus there is substantially greater risk that disclosures will be incomplete or misleading and, in the event of investor harm, substantially less access to recourse.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 21.67% Lowest Performance Quarter (1Q 2020): -27.72%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -26.62%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis Emerging Markets Equity ETF | MSCI Emerging Markets IMI Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI Emerging Markets IMI Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.28%)
Since Inception rr_AverageAnnualReturnSinceInception 12.03%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 17, 2019
American Century ETF Trust | Avantis Emerging Markets Equity ETF | Avantis Emerging Markets Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVEM
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.33%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.33%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 34
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 106
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 186
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 419
Annual Return 2020 rr_AnnualReturn2020 15.24%
Annual Return 2021 rr_AnnualReturn2021 4.89%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (26.62%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 21.67%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (27.72%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 4.89%
Since Inception rr_AverageAnnualReturnSinceInception 13.05%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 17, 2019
American Century ETF Trust | Avantis Emerging Markets Equity ETF | Avantis Emerging Markets Equity ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 4.21%
Since Inception rr_AverageAnnualReturnSinceInception 12.48%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 17, 2019
American Century ETF Trust | Avantis Emerging Markets Equity ETF | Avantis Emerging Markets Equity ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 3.31%
Since Inception rr_AverageAnnualReturnSinceInception 10.07%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 17, 2019
American Century ETF Trust | Avantis Emerging Markets Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Emerging Markets Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from September 28, 2021, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 8% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 8.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of companies related to emerging markets across market sectors, industry groups and countries. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of emerging markets companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries. The fund considers an emerging market country to be any country other than a developed country. However, the fund generally intends to focus its investments in a subset of the emerging markets countries that comprise the MSCI Emerging Markets Value IMI Index. The countries comprising the index will change from time to time, but as of September 30, 2022 include: Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hungary, India, Indonesia, Korea, Kuwait, Malaysia, Mexico, Peru, Philippines, Poland, Qatar, Saudi Arabia, South Africa, Taiwan, Thailand, Turkey and United Arab Emirates. In determining which of these countries to invest in, the portfolio managers consider the costs and benefits of investing in a particular country, including the
size of the market and liquidity. To determine whether a company is related to an emerging market country, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the MSCI Emerging Markets Value IMI Index. The weight given to each of these factors will vary depending on the circumstances in a given case. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Emerging Markets Risk — Investing in emerging market countries generally is riskier than investing in foreign developed countries due to lower liquidity, market manipulation concerns, limited reliable access to capital, and differing company organizational structures. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the PCAOB with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks. As a result of the foregoing risks, the fund is intended for aggressive investors seeking significant gains through investments in foreign securities. Those investors must be willing and able to accept the significantly greater risks associated with the investment strategy that the fund will pursue. An investment in the fund is not appropriate for individuals with limited investment resources or who are unable to tolerate fluctuations in the value of their investment.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Greater China Risk — Investing in Chinese securities is riskier than investing in U.S. securities. Investing in China involves risk of loss due to nationalization, expropriation, and confiscation of assets and property. Losses may also occur due to new or expanded restrictions on foreign investments or repatriation of capital. Due to Chinese governmental restrictions on foreign ownership of companies in certain industries, Chinese operating companies often use variable interest entity (VIE) structures to raise capital from international investors. Shares of VIEs are not equity ownership interests in Chinese operating companies. The Chinese government never explicitly approved these structures and thus could determine that the underlying contractual arrangements on which control of the VIE is based violate Chinese law. Such determination from the Chinese government could result in a loss in the value of an investment in a U.S.-listed company that utilizes the VIE structure. The Chinese market is subject to less regulation and oversight than the U.S. market. U.S. regulators have limited ability to inspect international auditing standards of U.S. companies operating in China, thus there is substantially greater risk that disclosures will be incomplete or misleading and, in the event of investor harm, substantially less access to recourse.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Emerging Markets Value ETF | Avantis Emerging Markets Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVES
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.36%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.36%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 37
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 116
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 202
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 456
American Century ETF Trust | Avantis Inflation Focused Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Inflation Focused Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. Because the fund is new, the fund’s portfolio turnover rate is not available.
Other Expenses, New Fund, Based on Estimates [Text] rr_OtherExpensesNewFundBasedOnEstimates Other expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of U.S. companies in market sectors and industry groups the portfolio managers expect to appreciate in value if the U.S. inflation rate rises or is believed to be rising. The fund seeks to focus its investments in those industries that historically have had, or are expected to have, better performance in periods of inflation, which as of the date of this prospectus include Financial Services, Petroleum and Natural Gas, Metal and non-Metallic Mining, Healthcare and Consumer Staples.
Within the industries correlated with inflation as described above, the fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired set of industries correlated with inflation.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities. The fund may invest in companies of all market capitalizations.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Inflation Correlation Risk — The fund intends its investments to correlate with inflation; however, there is no guarantee the value of the fund’s securities will increase over time or that the future investment performance will correlate with inflation. Purchasing power decreases as inflation increases, and the future value of the fund’s assets could decline. Further, to the extent the fund’s investments do correlate with inflation, the value of the fund’s investments could decline if inflation or inflation expectations recede.
•Sector Risk — If the fund is overweighted in a sector, any negative development related to that stock or sector will have a greater impact on the fund than other funds that are not overweighted in that sector.
•Health Care Sector Risk — The fund invests in securities that are issued by companies involved in the health care sector. Companies in the health care sector are subject to extensive government regulation, and their profitability can be significantly affected by restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure (including price discounting), limited product lines, litigation, obsolescence of technology and an increased emphasis on the delivery of health care through outpatient services. The business operations and profitability of companies in the pharmaceuticals and biotechnology industry can be significantly affected by, among other things, government approval of products and services, government regulation and reimbursement rates, product liability claims, patent expirations and protection, and intense competition.
•Oil and Gas Industry Risk — The fund invests in securities that are issued by companies involved in the oil and gas industry. Investments in the oil and gas industry can be significantly affected by worldwide energy prices, exploration costs and production spending. Oil and gas companies may be adversely affected by natural disasters or other catastrophes; changes in exchange rates, interest rates or economic conditions; technological developments, prices for competitive energy services and increased competition. Other risks may include changes in the actual or perceived availability of oil deposits; imposition of import controls, changes in tax treatment, or government regulation or government intervention; negative public perception; or unfavorable events in the regions where companies operate. Companies in the oil and gas industry may have significant capital investments in, or engage in transactions involving, emerging market countries, which may heighten these risks. Companies that own or operate gas pipelines are subject to certain risks, including pipeline and equipment leaks and ruptures, explosions, fires, unscheduled downtime, transportation interruptions, discharges or releases of toxic or hazardous gases and other environmental risks. Companies in the oil and gas industry may be at risk for environmental damage claims and other types of litigation.
•Small- and Mid-Cap Stock Risks — Stocks of smaller companies may be more volatile than larger-company stocks. Smaller companies may have limited financial resources, product lines and markets, and their securities may trade less frequently and in more limited volumes than the securities of larger companies, which could lead to higher transaction costs.
•Commodity Risk — Investing in securities of companies that are sensitive to commodity prices, such as mining and oil and gas companies, may subject the fund to greater volatility than investing in other types of securities. Commodity prices may be influenced by unpredictable geological and environmental factors as well as changes in government regulation such as tariffs, embargoes, or production restrictions.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the listing exchange and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Inflation Focused Equity ETF | Avantis Inflation Focused Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVIE
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none [5]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 26
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 $ 81
American Century ETF Trust | Avantis International Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® International Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 7% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 7.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of non-U.S. companies across countries, market sectors and industry groups. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of non-U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to
enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 17.49% Lowest Performance Quarter (1Q 2020): -26.33%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -26.74%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis International Equity ETF | MSCI World ex USA IMI Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI World ex USA IMI Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 12.40%
Since Inception rr_AverageAnnualReturnSinceInception 12.64%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Equity ETF | Avantis International Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVDE
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.23%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.23%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 24
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 74
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 130
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 293
Annual Return 2020 rr_AnnualReturn2020 7.84%
Annual Return 2021 rr_AnnualReturn2021 13.68%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (26.74%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 17.49%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (26.33%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 13.68%
Since Inception rr_AverageAnnualReturnSinceInception 13.21%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Equity ETF | Avantis International Equity ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 13.02%
Since Inception rr_AverageAnnualReturnSinceInception 12.69%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Equity ETF | Avantis International Equity ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 8.56%
Since Inception rr_AverageAnnualReturnSinceInception 10.22%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Large Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® International Large Cap Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from September 28, 2021, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 47% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 47.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of non-U.S. companies across countries, market sectors and industry groups.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of companies with lower levels of profitability and less attractive value characteristics. To identify companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of non-U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of large capitalization companies. For purposes of this 80% test, the fund defines large capitalization companies as those with market capitalizations at least as large as the smallest company in the MSCI World ex-USA Value Index. Though market capitalization may change from time to time, as of September 30, 2022, the market capitalization of the smallest company in the MSCI World ex-USA Value Index was approximately $1.4 billion. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
Additionally, under normal market conditions, the fund will invest at least 40% (unless the portfolio managers deem market conditions unfavorable, in which case the fund would invest at least 30%) of its assets in securities of issuers located outside the United States. The fund will allocate its assets among at least three different countries outside the United States.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of large capitalization companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis International Large Cap Value ETF | Avantis International Large Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVIV
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 26
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 81
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 141
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 319
American Century ETF Trust | Avantis International Small Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® International Small Cap Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 21% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 21.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of non-U.S. small cap value companies across market sectors, industry groups, and countries.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of non-U.S. companies.
When selecting investments for the fund, the portfolio managers consider the distribution of market capitalization of all companies in each country in which the fund invests, meaning that a company of a given size may be considered small in one country, but not in another. Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies. For purposes of the fund’s 80% test, small cap companies include companies with market capitalizations not greater than that of the largest company on the MSCI World ex USA Small Cap Index at the time of investment. Though capitalizations will change from time to time, as of September 30, 2022, the total market capitalization of the largest company in the index was $8.75 billion.
The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 22.47% Lowest Performance Quarter (1Q 2020): -34.03%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -25.08%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis International Small Cap Value ETF | MSCI World ex-U.S. Small Cap Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI World ex-U.S. Small Cap Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 11.14%
Since Inception rr_AverageAnnualReturnSinceInception 15.32%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Small Cap Value ETF | Avantis International Small Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVDV
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.36%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.36%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 37
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 116
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 202
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 456
Annual Return 2020 rr_AnnualReturn2020 4.71%
Annual Return 2021 rr_AnnualReturn2021 15.65%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (25.08%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 22.47%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (34.03%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 15.65%
Since Inception rr_AverageAnnualReturnSinceInception 14.10%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Small Cap Value ETF | Avantis International Small Cap Value ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 14.94%
Since Inception rr_AverageAnnualReturnSinceInception 13.49%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis International Small Cap Value ETF | Avantis International Small Cap Value ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 9.67%
Since Inception rr_AverageAnnualReturnSinceInception 10.84%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis Real Estate ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Real Estate ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from September 28, 2021, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 7% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 7.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of real estate securities globally, in particular real estate investment trusts (REITs) and REIT-like entities, across a variety of property sectors. The fund seeks securities of companies that it expects to have higher returns or better risk characteristics. For example, REITs and REIT-like entities tend to distribute a large fraction of their earnings to qualify as tax passthrough entities, so it is common for REITs to have high levels of leverage to finance their growth or many of their business operations. The fund may exclude or underweight securities with high levels of leverage with the goal of achieving a better risk/return profile, in particular in times when borrowing, refinancing, or raising capital may become more expensive for entities with high leverage, which may dilute current holders of those entities. The portfolio managers may also consider other factors when selecting, or increasing their emphasis in, a security, including the past performance of the security relative to other securities, its profitability, its market capitalization, its liquidity, its float, and tax, governance or cost considerations, among others. The fund generally invests in companies located in countries included in the fund’s benchmark, the S&P Global REIT Index.
Under normal market conditions, the fund will invest at least 80% of its assets in securities issued by REITs and other companies engaged in the real estate industry (collectively, real estate securities). A REIT invests primarily in income-producing real estate or makes loans to persons involved in the real estate industry. The portfolio managers consider a company to be engaged in the real estate industry if at least 50% of its revenues or 50% of the market value of its assets at the time the securities are purchased by the fund are attributed to the ownership, construction, management or sale of real estate. Because the fund’s investment strategy is concentrated in real estate securities, the fund may be subject to greater risks and market fluctuations compared to other funds that hold securities in a broader range of industries.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in securities issued by REITs and other companies engaged in the real estate industry (collectively, real estate securities).
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Real Estate Investing Risk — An investment in the fund may be subject to many of the same risks as a direct investment in real estate. These risks include changes in economic conditions, interest rates, property values, property tax increases, overbuilding and increased competition, environmental contamination, zoning and natural disasters. This is due to the fact that the value of the fund’s investments may be affected by the value of the real estate owned by the companies in which it invests. To the extent the fund invests in companies that make loans to real estate companies, the fund also may be subject to interest rate risk and credit risk.
•REITs Risk — Investments in REITs are subject to credit risk and interest rate risk with respect to the loans made by the REITs in which the fund invests, even though the fund does not invest in the loans themselves. Credit risk is the risk that the borrower will not be able to make interest and principal payments on the loan to the REIT when they are due. Interest rate risk is the risk that a change in the prevailing interest rate will cause the value of the loan portfolio held by the REIT to rise or fall.
•Concentration Risk — Because the fund concentrates its investments in real estate securities, it may be subject to greater risks and market fluctuations than a portfolio investing in a broader range of industries.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Emerging Market Risk — Investing in emerging market countries generally is riskier than investing in foreign developed countries. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Real Estate ETF | Avantis Real Estate ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVRE
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.17%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.17%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 17
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 55
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 96
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 218
American Century ETF Trust | Avantis Responsible Emerging Markets Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Responsible Emerging Markets Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from March 28, 2022, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 2% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 2.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of companies related to emerging markets across market sectors, industry groups and countries. The fund may invest in companies of all market capitalizations.
The portfolio management team limits its investable universe of companies by screening out those that raise concerns based on the team’s evaluation of multiple ESG metrics. The portfolio managers utilize third party commercial data sources and scoring systems (currently, MSCI and Sustainalytics), as well as proprietary evaluations, to decide what securities should be excluded due to ESG concerns. Though the factors considered in the proprietary screening model may change from time to time, currently the fund excludes the following issuers from its investable universe:
•companies with significant revenue (e.g., 5% thresholds and up depending on the category) from any of the following: oil and gas production or distribution; manufacture or sale of civilian firearms and ammunition; manufacture of chemical, biological, or nuclear weapons and related systems or components; factory farming; palm oil production; production or sale of tobacco or cannabis; gambling; or adult entertainment;
•companies with more than de minimis revenue from thermal coal;
•companies ranking in the bottom 5% in terms of carbon emissions intensity;
•companies with low corporate governance scores; and
•companies involved in environmental, social, or governance controversies that, in the portfolio management team’s judgment, merit exclusion.
When information used in the fund’s ESG screening model is not provided by the fund’s third party commercial data sources with respect to an issuer, the issuer will be eligible for purchase by the fund if the portfolio managers are not aware of any other ESG concerns related to the issuer that in their judgment would warrant exclusion. The eligibility of a security for inclusion in the fund’s portfolio will be determined at the time of purchase. In the event of a subsequent change in the ESG characteristics of (or the availability of ESG information about) an issuer, the fund will not be obligated to dispose of that security and may continue to hold the security if otherwise deemed appropriate by the portfolio managers.
Within the fund’s investable universe of issuers that have been screened for ESG characteristics, the fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security including, industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of emerging markets companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries. The fund considers an emerging market country to be any country other than a developed country. However, the fund generally intends to focus its investments in a subset of the emerging markets countries that comprise the MSCI Emerging Markets IMI Index. The countries comprising the index will change from time to time, but as of September 30, 2022 include: Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hungary, India, Indonesia, Korea, Kuwait, Malaysia, Mexico, Peru, Philippines, Poland, Qatar, Saudi Arabia, South Africa, Taiwan, Thailand, Turkey and United Arab Emirates. To determine whether a company is related to an emerging market country, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the MSCI Emerging Markets IMI. The weight given to each of these factors will vary depending on the circumstances in a given case. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•ESG Risk — Because the portfolio managers screen securities based on ESG characteristics, the fund may exclude the securities of certain issuers or industry sectors for other than financial reasons and, as a result, the fund may perform differently or maintain a different risk profile than the market generally or compared to funds that do not use similar ESG-based screens. Investing based on ESG considerations may also prioritize long term rather than short term returns. Furthermore, when analyzing ESG criteria for issuers, the portfolio management team relies on proprietary evaluations and information, ratings and scoring models published by third party sources (collectively, “ESG Data”). Due to the lack of regulation and uniform reporting standards with respect to ESG characteristics of issuers, ESG Data may be inconsistent across sources and, in certain cases, incorrect. In addition, ESG Data is not currently available for many issuers and, when available, frequently only includes some but not all of the ESG characteristics considered by the team when applying their ESG screens.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Emerging Markets Risk — Investing in emerging market countries generally is riskier than investing in foreign developed countries due to lower liquidity, market manipulation concerns, limited reliable access to capital, and differing company organizational structures. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the Public Company Accounting Oversight Board (PCAOB) with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks. As a result of the foregoing risks, the fund is intended for aggressive investors seeking significant gains through investments in foreign securities. Those investors must be willing and able to accept the significantly greater risks associated with the investment strategy that the fund will pursue. An investment in the fund is not appropriate for individuals with limited investment resources or who are unable to tolerate fluctuations in the value of their investment.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Greater China Risk — Investing in Chinese securities is riskier than investing in U.S. securities. Investing in China involves risk of loss due to nationalization, expropriation, and confiscation of assets and property. Losses may also occur due to new or expanded restrictions on foreign investments or repatriation of capital. Due to Chinese governmental restrictions on foreign ownership of companies in certain industries, Chinese operating companies often use variable interest entity (VIE) structures to raise capital from international investors. Shares of VIEs are not equity ownership interests in Chinese operating companies. The Chinese government never explicitly approved these structures and thus could determine that the underlying contractual arrangements on which control of the VIE is based violate Chinese law. Such determination from the Chinese government could result in a loss in the value of an investment in a U.S.-listed company that utilizes the VIE structure The Chinese market is subject to less regulation and oversight than the U.S. market. U.S. regulators have limited ability to inspect international auditing standards of U.S. companies operating in China, thus there is substantially greater risk that disclosures will be incomplete or misleading and, in the event of investor harm, substantially less access to recourse.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Responsible Emerging Markets Equity ETF | Avantis Responsible Emerging Markets Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVSE
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.33%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.33%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 34
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 106
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 186
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 419
American Century ETF Trust | Avantis Responsible International Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Responsible International Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from March 15, 2022, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 3% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 3.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of non-U.S. companies across countries, market sectors and industry groups. The fund may invest in companies of all market capitalizations.
The portfolio management team limits its investable universe of companies by screening out those that raise concerns based on the team’s evaluation of multiple ESG metrics. The portfolio managers utilize third party commercial data sources and scoring systems (currently, MSCI and Sustainalytics), as well as proprietary evaluations, to decide what securities should be excluded due to ESG concerns. Though the factors considered in the proprietary screening model may change from time to time, currently the fund excludes the following issuers from its investable universe:
•companies with significant revenue (e.g., 5% thresholds and up depending on the category) from any of the following: oil and gas production or distribution; manufacture or sale of civilian firearms and ammunition; manufacture of chemical, biological, or nuclear weapons and related systems or components; factory farming; palm oil production; production or sale of tobacco or cannabis; gambling; or adult entertainment;
•companies with more than de minimis revenue from thermal coal;
•companies ranking in the bottom 5% in terms of carbon emissions intensity;
•companies with low corporate governance scores; and
•companies involved in environmental, social, or governance controversies that, in the portfolio management team’s judgment, merit exclusion.
When information used in the fund’s ESG screening model is not provided by the fund’s third party commercial data sources with respect to an issuer, the issuer will be eligible for purchase by the fund if the portfolio managers are not aware of any other ESG concerns related to the issuer that in their judgment would warrant exclusion. The eligibility of a security for inclusion in the fund’s portfolio will be determined at the time of purchase. In the event of a subsequent change in the ESG characteristics of (or the availability of ESG information about) an issuer, the fund will not be obligated to dispose of that security and may continue to hold the security if otherwise deemed appropriate by the portfolio managers.
Within the fund’s investable universe of issuers that have been screened for ESG characteristics, the fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security including, industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of non-U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•ESG Risk — Because the portfolio managers screen securities based on ESG characteristics, the fund may exclude the securities of certain issuers or industry sectors for other than financial reasons and, as a result, the fund may perform differently or maintain a different risk profile than the market generally or compared to funds that do not use similar ESG-based screens. Investing based on ESG considerations may also prioritize long term rather than short term returns. Furthermore, when analyzing ESG criteria for issuers, the portfolio management team relies on proprietary evaluations and information, ratings and scoring models published by third party sources (collectively, “ESG Data”). Due to the lack of regulation and uniform reporting standards with respect to ESG characteristics of issuers, ESG Data may be inconsistent across sources and, in certain cases, incorrect. In addition, ESG Data is not currently available for many issuers and, when available, frequently only includes some but not all of the ESG characteristics considered by the team when applying their ESG screens.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Responsible International Equity ETF | Avantis Responsible International Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVSD
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.23%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.23%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 24
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 74
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 130
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 293
American Century ETF Trust | Avantis Responsible U.S. Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Responsible U.S. Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from March 15, 2022, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 3% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 3.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of U.S. companies across market sectors and industry groups. The fund may invest in companies of all market capitalizations.
The portfolio management team limits its investable universe of companies by screening out those that raise concerns based on the team’s evaluation of multiple ESG metrics. The portfolio managers utilize third party commercial data sources and scoring systems (currently, MSCI and Sustainalytics), as well as proprietary evaluations, to decide what securities should be excluded due to ESG concerns. Though the factors considered in the proprietary screening model may change from time to time, currently the fund excludes the following issuers from its investable universe:
•companies with significant revenue (e.g., 5% thresholds and up depending on the category) from any of the following: oil and gas production or distribution; manufacture or sale of civilian firearms and ammunition; manufacture of chemical, biological, or nuclear weapons and related systems or components; factory farming; palm oil production; production or sale of tobacco or cannabis; gambling; or adult entertainment;
•companies with more than de minimis revenue from thermal coal;
•companies ranking in the bottom 5% in terms of carbon emissions intensity;
•companies with no members on their boards of directors who are women;
•companies with low corporate governance scores; and
•companies involved in environmental, social, or governance controversies that, in the portfolio management team’s judgment, merit exclusion.
When information used in the fund’s ESG screening model is not provided by the fund’s third party commercial data sources with respect to an issuer, the issuer will be eligible for purchase by the fund if the portfolio managers are not aware of any other ESG concerns related to the issuer that in their judgment would warrant exclusion. The eligibility of a security for inclusion in the fund’s portfolio will be determined at the time of purchase. In the event of a subsequent change in the ESG characteristics of (or the availability of ESG information about) an issuer, the fund will not be obligated to dispose of that security and may continue to hold the security if otherwise deemed appropriate by the portfolio managers.
Within the fund’s investable universe of issuers that have been screened for ESG characteristics, the fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security including, industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of U.S. companies. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 3000® Index.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of U.S. companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•ESG Risk — Because the portfolio managers screen securities based on ESG characteristics, the fund may exclude the securities of certain issuers or industry sectors for other than financial reasons and, as a result, the fund may perform differently or maintain a different risk profile than the market generally or compared to funds that do not use similar ESG-based screens. Investing based on ESG considerations may also prioritize long term rather than short term returns. Furthermore, when analyzing ESG criteria for issuers, the portfolio management team relies on proprietary evaluations and information, ratings and scoring models published by third party sources (collectively, “ESG Data”). Due to the lack of regulation and uniform reporting standards with respect to ESG characteristics of issuers, ESG Data may be inconsistent across sources and, in certain cases, incorrect. In addition, ESG Data is not currently available for many issuers and, when available, frequently only includes some but not all of the ESG characteristics considered by the team when applying their ESG screens.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Responsible U.S. Equity ETF | Avantis Responsible U.S. Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVSU
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
American Century ETF Trust | Avantis Short-Term Fixed Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Short-Term Fixed Income ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to maximize total return.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 38% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 38.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in investment grade quality debt obligations from a diverse group of U.S. and non-U.S. issuers.
The fund’s investment process uses an analytical framework, which includes an assessment of securities’ expected income and capital appreciation, to seek securities with high expected returns. The portfolio managers categorize securities within the fund’s investment universe into component groups based on factors such as industry sector, credit rating, duration, country, and currency. The portfolio managers then calculate the expected return implied by the yield curve of each component group, while considering valuation metrics such as yield, duration, and option adjusted spreads. Finally, the portfolio managers adjust the portfolio to arrive at position weightings for each component group with the goal of building a portfolio with enhanced expected return.
Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities. Fixed income securities in which the fund may invest include corporate bonds and notes issued by U.S. and foreign corporations, securities issued by governments and their agencies, instrumentalities, or sponsored corporations—including supranational organizations. The fund may also invest in derivative instruments such as futures contracts or swap agreements, including credit default swaps, credit default swap indexes, and total return swaps.
The fund expects to maintain a weighted average maturity of three years or less. The fund will invest primarily in investment grade securities as rated by an independent rating agency or determined by the advisor to be of comparable credit quality if a rating is unavailable.
The fund may engage in foreign currency transactions on a spot basis and may also use currency forward contracts to hedge exposure to foreign currencies. The fund may purchase or sell when-issued, forward-settling, delayed delivery or forward commitment obligations. The fund may invest more than 25% of its total assets in U.S. Treasury, federal agencies and instrumentalities obligations.
The fund may also engage in securities lending. Collateral received by the fund in connection with loaning its securities may consist of cash and U.S. government securities. Cash collateral may be invested in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or assets such as auto loan, home equity loan or student loan receivables. These underlying obligations may be prepaid, as when a homeowner refinances a mortgage to take advantage of declining interest rates. If so, the fund must reinvest prepayments at current rates, which may be less than the rate of the prepaid mortgage. Because of this prepayment risk, the fund may benefit less from declining interest rates than funds of similar duration that invest less heavily in mortgage- and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation), especially in periods of rising interest rates. These events may lengthen the duration (i.e., interest rate sensitivity) and potentially reduce the value of these securities.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience potentially dramatic price changes (losses) and imperfect correlations between the price of the contract and the underlying security, index or currency. Swap agreements subject a fund to counterparty risk. Interest rate swaps could result in losses if the fund does not correctly anticipate interest rate changes. Credit default swaps could result in losses if the fund does not correctly evaluate the creditworthiness of the issuer on which the credit default swap is based.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2021): 0.37% Lowest Performance Quarter (1Q 2021): -0.77%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -6.71%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis Short-Term Fixed Income ETF | Bloomberg U.S. Aggregate Government & Credit 1-5 Year Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Bloomberg U.S. Aggregate Government & Credit 1-5 Year Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.97%)
Since Inception rr_AverageAnnualReturnSinceInception (0.56%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Short-Term Fixed Income ETF | Avantis Short-Term Fixed Income ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVSF
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
Annual Return 2021 rr_AnnualReturn2021 (1.14%)
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (6.71%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 0.37%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (0.77%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 (1.14%)
Since Inception rr_AverageAnnualReturnSinceInception (0.57%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Short-Term Fixed Income ETF | Avantis Short-Term Fixed Income ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 (1.33%)
Since Inception rr_AverageAnnualReturnSinceInception (0.76%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis Short-Term Fixed Income ETF | Avantis Short-Term Fixed Income ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 (0.68%)
Since Inception rr_AverageAnnualReturnSinceInception (0.51%)
Inception Date rr_AverageAnnualReturnInceptionDate Oct. 13, 2020
American Century ETF Trust | Avantis U.S. Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 4% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 4.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of U.S. companies across market sectors and industry groups. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of U.S. companies. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 3000® Index.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of U.S. companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk —  The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 22.61% Lowest Performance Quarter (1Q 2020): -24.70%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -21.39%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis U.S. Equity ETF | Russell 3000 Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell 3000 Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 25.66%
Since Inception rr_AverageAnnualReturnSinceInception 25.06%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Equity ETF | Avantis U.S. Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVUS
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
Annual Return 2020 rr_AnnualReturn2020 17.45%
Annual Return 2021 rr_AnnualReturn2021 28.62%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (21.39%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 22.61%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (24.70%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 28.62%
Since Inception rr_AverageAnnualReturnSinceInception 24.71%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Equity ETF | Avantis U.S. Equity ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 28.26%
Since Inception rr_AverageAnnualReturnSinceInception 24.32%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Equity ETF | Avantis U.S. Equity ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 17.16%
Since Inception rr_AverageAnnualReturnSinceInception 19.32%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Large Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Large Cap Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from September 21, 2021, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 23% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 23.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of U.S. companies across market sectors and industry groups.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of companies with lower levels of profitability and less attractive value characteristics. To identify companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of large capitalization U.S. companies. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 1000® Value Index. The fund defines large capitalization companies as those with market capitalizations at least as large as the smallest company in the Russell 1000® Value Index. Though market capitalizations will change from time to time, as of September 30, 2022, the market capitalization of the smallest company in the Russell 1000® Value Index was approximately $271.14 million.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of large capitalization U.S. companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis U.S. Large Cap Value ETF | Avantis U.S. Large Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVLV
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
American Century ETF Trust | Avantis U.S. Small Cap Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Small Cap Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from January 11, 2022, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 14% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 14.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of U.S. small cap companies across market sectors and industry groups.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of small capitalization companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of small capitalization companies located in the United States. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 2000® Index. The portfolio managers consider the following to be small capitalization companies: (i) companies smaller than the largest 1000 U.S. companies; (ii) companies
representing the bottom 10% of the market capitalization of all U.S. listed companies; and (iii) companies in the fund’s benchmark. Though market capitalizations will change from time to time, as of September 30, 2022, the largest company that could be considered a small capitalization company for purposes of this 80% test had a total market capitalization of approximately $10.83 billion.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of small capitalization companies located in the United States.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis U.S. Small Cap Equity ETF | Avantis U.S. Small Cap Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVSC
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 26
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 81
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 141
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 319
American Century ETF Trust | Avantis U.S. Small Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Small Cap Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 24% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 24.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 invests primarily in a diverse group of U.S. small cap companies across market sectors and industry groups.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of small capitalization companies.
Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies located in the United States. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 2000® Value Index. The portfolio managers consider the following to be small capitalization companies: (i) companies smaller than the largest 1000 U.S. companies; (ii) companies representing the bottom 10% of the market capitalization of all U.S. listed companies; and (iii) companies in the fund’s benchmark. Though market capitalizations will change from time to time, as of September 30, 2022, the largest company that could be considered a small capitalization company for purposes of this 80% test had a total market capitalization of approximately $10.83 billion.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies located in the United States.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Cash Transactions Risk — The fund may effect its creations and redemptions for cash, rather than for in-kind securities. Therefore, it may be required to sell portfolio securities and subsequently recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As such, investments in fund shares may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. Cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. Brokerage fees and taxes will be higher than if the fund sold and redeemed shares in-kind.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 33.34% Lowest Performance Quarter (1Q 2020): -42.29%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -16.05%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | Avantis U.S. Small Cap Value ETF | Russell 2000 Value Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell 2000 Value Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 28.27%
Since Inception rr_AverageAnnualReturnSinceInception 17.95%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value ETF | Avantis U.S. Small Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVUV
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 26
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 81
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 141
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 319
Annual Return 2020 rr_AnnualReturn2020 6.60%
Annual Return 2021 rr_AnnualReturn2021 42.29%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (16.05%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 33.34%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (42.29%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 42.29%
Since Inception rr_AverageAnnualReturnSinceInception 24.59%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value ETF | Avantis U.S. Small Cap Value ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 41.83%
Since Inception rr_AverageAnnualReturnSinceInception 24.16%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value ETF | Avantis U.S. Small Cap Value ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 25.32%
Since Inception rr_AverageAnnualReturnSinceInception 19.21%
Inception Date rr_AverageAnnualReturnInceptionDate Sep. 24, 2019
American Century ETF Trust | Avantis Core Fixed Income Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Core Fixed Income Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to maximize total return.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 481% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 481.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in investment grade quality debt obligations from a diverse group of U.S. and non-U.S. issuers.
The fund’s investment process uses an analytical framework, which includes an assessment of securities’ expected income and capital appreciation, to seek securities with high expected returns. The portfolio managers categorize securities within the fund’s investment universe into component groups based on factors such as industry sector, credit rating, duration, country, and currency. The portfolio managers then calculate the expected return implied by the yield curve of each component group, while considering valuation metrics such as yield, duration, and option adjusted spreads. Finally, the portfolio managers adjust the portfolio to arrive at position weightings for each component group with the goal of building a portfolio with enhanced expected return.
Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities. Fixed income securities in which the fund may invest include corporate bonds and notes issued by U.S. and foreign corporations, securities issued by governments and their agencies, instrumentalities, or sponsored corporations—including supranational organizations. The fund may also invest in derivative instruments such as futures contracts or swap agreements, including credit default swaps, credit default swap indexes, and total return swaps.
The fund will invest primarily in investment grade securities as rated by an independent rating agency or determined by the advisor to be of comparable credit quality if a rating is unavailable. The fund expects to maintain a weighted average duration within 2 years of the weighted average duration of its benchmark, the Bloomberg U.S. Aggregate Bond index, as calculated by the manager. Duration is used to assess the sensitivity of a security’s price to changes in interest rates.
The fund may engage in foreign currency transactions on a spot basis and may also use currency forward contracts to hedge exposure to foreign currencies. The fund may purchase or sell when-issued, forward-settling, delayed delivery or forward commitment obligations. The fund may invest more than 25% of its total assets in U.S. Treasury, federal agencies and instrumentalities obligations.
The fund may also engage in securities lending. Collateral received by the fund in connection with loaning its securities may consist of cash and U.S. government securities. Cash collateral may be invested in eligible securities, such as a government money market fund.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or assets such as auto loan, home equity loan or student loan receivables. These underlying obligations may be prepaid, as when a homeowner refinances a mortgage to take advantage of declining interest rates. If so, the fund must reinvest prepayments at current rates, which may be less than the rate of the prepaid mortgage. Because of this prepayment risk, the fund may benefit less from declining interest rates than funds of similar duration that invest less heavily in mortgage- and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation), especially in periods of rising interest rates. These events may lengthen the duration (i.e., interest rate sensitivity) and potentially reduce the value of these securities.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience potentially dramatic price changes (losses) and imperfect correlations between the price of the contract and the underlying security, index or currency. Swap agreements subject a fund to counterparty risk. Interest rate swaps could result in losses if the fund does not correctly anticipate interest rate changes. Credit default swaps could result in losses if the fund does not correctly evaluate the creditworthiness of the issuer on which the credit default swap is based.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Core Fixed Income Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVIGX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
American Century ETF Trust | Avantis Core Fixed Income Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVBNX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.15% [6]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
American Century ETF Trust | Avantis Core Municipal Fixed Income Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Core Municipal Fixed Income Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks current income that is exempt from federal income tax.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 2% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 2.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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’s investment process uses an analytical framework, which includes an assessment of securities’ expected income and capital appreciation, to seek securities with high expected returns. The portfolio managers categorize securities within the fund’s investment universe into component groups based on factors such as industry sector, credit rating, duration, country, and currency. The portfolio managers then calculate the expected return implied by the yield curve of each component group, while considering valuation metrics such as yield, duration, and option adjusted spreads. Finally, the portfolio managers adjust the portfolio to arrive at position weightings for each component group with the goal of building a portfolio with enhanced expected return.
Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in municipal fixed income securities with interest payments exempt from federal income tax. A municipal fixed income security is a debt obligation issued by or on behalf of a state, its political subdivisions, agencies or instrumentalities, the District of Columbia or a U.S. territory or possession. Municipal securities include revenue bonds, general obligation bonds, municipal lease obligations, and industrial development bonds. The fund may use derivatives, such as futures contracts or swap agreements, to gain or limit exposures. The fund may purchase or sell when-issued, forward-settling, delayed delivery or forward commitment basis.
The fund will invest primarily in investment grade securities as rated by an independent rating agency or determined by the advisor to be of comparable credit quality if a rating is unavailable.
The fund may also engage in securities lending. Collateral received by the fund in connection with loaning its securities may consist of cash and U.S. government securities. Cash collateral may be invested in eligible securities, such as a government money market fund.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in municipal fixed income securities with interest payments exempt from federal income tax.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Municipal Securities Risk — Because the fund invests principally in municipal securities, it will be sensitive to events that affect municipal markets, including legislative or political changes and the financial condition of the issuers of municipal securities. The fund may have a higher level of risk than funds that invest in a larger universe of securities. Additionally, the novel coronavirus (COVID -19) pandemic has stressed the financial resources of many municipal issuers, which may impair a municipal issuer’s ability to meet its financial obligations when due and could adversely impact the value of its bonds, which could negatively impact the performance of the fund.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Tax Risk — Some or all of the fund’s income may be subject to the federal alternative minimum tax. There is no guarantee that all of the fund’s income will remain exempt from federal or state income taxes. Income from municipal bonds held by a fund could be declared taxable because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state tax authorities, or noncompliant conduct of a bond issuer. The fund may sell securities that lose their tax-exempt statuses at inopportune times, which may cause tax consequences or a decrease in the fund’s value.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, to meet redemptions, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund’s share price. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience potentially dramatic price changes (losses) and imperfect correlations between the price of the contract and the underlying security, index or currency. Swap agreements subject a fund to counterparty risk. Interest rate swaps could result in losses if the fund does not correctly anticipate interest rate changes. Credit default swaps could result in losses if the fund does not correctly evaluate the creditworthiness of the issuer on which the credit default swap is based.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Core Municipal Fixed Income Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVMUX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
American Century ETF Trust | Avantis Core Municipal Fixed Income Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVFNX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.15% [7]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
American Century ETF Trust | Avantis Emerging Markets Equity Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Emerging Markets Equity Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 4% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 4.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in a diverse group of companies related to emerging markets across market sectors, industry groups and countries. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of emerging markets companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries. The fund considers an emerging market country to be any country other than a developed country. However, the fund generally intends to focus its investments in a subset of the emerging markets countries that comprise the MSCI Emerging Markets IMI Index. The countries comprising the index will change from time to time, but as of September 30, 2022 include: Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hungary, India, Indonesia, Korea, Kuwait, Malaysia, Mexico, Peru, Philippines, Poland, Qatar, Saudi Arabia, South Africa, Taiwan, Thailand, Turkey and United Arab Emirates. To determine whether a company is related to an emerging market country, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the MSCI Emerging Markets IMI. The weight given to each of these factors will vary depending on the circumstances in a given case. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of companies related to emerging market countries.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Emerging Markets Risk — Investing in emerging market countries generally is riskier than investing in foreign developed countries. Emerging market countries may have unstable governments, economies that are subject to sudden change, and significant volatility in their financial markets. These countries also may lack the legal, business and social framework to support securities markets. Additionally, certain jurisdictions do not provide the PCAOB with sufficient access to inspect audit work papers and practices, or otherwise do not cooperate with U.S. regulators, potentially exposing investors in U.S. capital markets to significant risks. As a result of the foregoing risks, the fund is intended for aggressive investors seeking significant gains through investments in foreign securities. Those investors must be willing and able to accept the significantly greater risks associated with the investment strategy that the fund will pursue. An investment in the fund is not appropriate for individuals with limited investment resources or who are unable to tolerate fluctuations in the value of their investment.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Greater China Risk — Investing in Chinese securities is riskier than investing in U.S. securities. Investing in China involves risk of loss due to nationalization, expropriation, and confiscation of assets and property. Losses may also occur due to new or expanded restrictions on foreign investments or repatriation of capital. Due to Chinese governmental restrictions on foreign ownership of companies in certain industries, Chinese operating companies often use variable interest entity (VIE) structures to raise capital from international investors. Shares of VIEs are not equity ownership interests in Chinese operating companies. The Chinese government never explicitly approved these structures and thus could determine that the underlying contractual arrangements on which control of the VIE is based violate Chinese law. Such determination from the Chinese government could result in a loss in the value of an investment in a U.S.-listed company that utilizes the VIE structure. The Chinese market is subject to less regulation and oversight than the U.S. market. U.S. regulators have limited ability to inspect international auditing standards of U.S. companies operating in China, thus there is substantially greater risk that disclosures will be incomplete or misleading and, in the event of investor harm, substantially less access to recourse.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. Because the G Class does not have investment performance for a full calendar year, it is not included. 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 21.51% Lowest Performance Quarter (1Q 2020): -26.98%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -26.93%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share classes will vary.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
American Century ETF Trust | Avantis Emerging Markets Equity Fund | MSCI Emerging Markets IMI Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI Emerging Markets IMI Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 (0.28%)
Since Inception rr_AverageAnnualReturnSinceInception 12.25%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis Emerging Markets Equity Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVEEX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.33%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.33%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.33%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 34
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 106
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 186
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 419
Annual Return 2020 rr_AnnualReturn2020 15.72%
Annual Return 2021 rr_AnnualReturn2021 5.18%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (26.93%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 21.51%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (26.98%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 5.18%
Since Inception rr_AverageAnnualReturnSinceInception 13.76%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis Emerging Markets Equity Fund | Institutional Class | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 4.68%
Since Inception rr_AverageAnnualReturnSinceInception 13.25%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis Emerging Markets Equity Fund | Institutional Class | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 3.37%
Since Inception rr_AverageAnnualReturnSinceInception 10.61%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis Emerging Markets Equity Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVENX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.33%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.33%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.33% [8]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess Because the G Class does not have investment performance for a full calendar year, it is not included.
American Century ETF Trust | Avantis International Equity Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® International Equity Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 6% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 6.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in a diverse group of non-U.S. companies across countries, market sectors and industry groups. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of non-U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities. The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs
or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. Because the G Class does not have investment performance for a full calendar year, it is not included. 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 17.03% Lowest Performance Quarter (1Q 2020): -25.60%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -26.72%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share classes will vary.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
American Century ETF Trust | Avantis International Equity Fund | MSCI World ex USA IMI Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI World ex USA IMI Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 12.40%
Since Inception rr_AverageAnnualReturnSinceInception 11.88%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Equity Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVDEX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.23%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.23%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.23%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 24
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 74
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 130
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 293
Annual Return 2020 rr_AnnualReturn2020 8.21%
Annual Return 2021 rr_AnnualReturn2021 13.28%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (26.72%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 17.03%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (25.60%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 13.28%
Since Inception rr_AverageAnnualReturnSinceInception 12.20%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Equity Fund | Institutional Class | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 12.32%
Since Inception rr_AverageAnnualReturnSinceInception 11.53%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Equity Fund | Institutional Class | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 8.45%
Since Inception rr_AverageAnnualReturnSinceInception 9.39%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Equity Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVDNX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.23%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.23%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.23% [9]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess Because the G Class does not have investment performance for a full calendar year, it is not included.
American Century ETF Trust | Avantis International Small Cap Value Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® International Small Cap Value Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 44% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 44.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in a diverse group of non-U.S. small cap value companies across market sectors, industry groups, and countries.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of non-U.S. companies.
When selecting investments for the fund, the portfolio managers consider the distribution of market capitalization of all companies in each country in which the fund invests, meaning that a company of a given size may be considered small in one country, but not in another. Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies. For purposes of the fund’s 80% test, small cap companies include companies with market capitalizations not greater than that of the largest company on the MSCI World ex USA Small Cap Index at the time of investment. Though capitalizations will change from time to time, as of September 30, 2022, the total market capitalization of the largest company in the index was $8.75 billion.
The fund may invest in securities that are denominated in foreign currencies and may also invest in foreign securities that are represented in the U.S. and other securities markets by American Depositary Receipts (ADRs), Global Depositary Receipts (GDRs), and other similar depositary arrangements.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. Because the G Class does not have investment performance for a full calendar year, it is not included. 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 21.74% Lowest Performance Quarter (1Q 2020): -33.75%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -24.59%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share classes will vary.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
American Century ETF Trust | Avantis International Small Cap Value Fund | MSCI World ex-U.S. Small Cap Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel MSCI World ex-U.S. Small Cap Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 11.14%
Since Inception rr_AverageAnnualReturnSinceInception 13.79%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Small Cap Value Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVDVX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.36%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.36%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.36%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 37
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 116
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 202
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 456
Annual Return 2020 rr_AnnualReturn2020 5.65%
Annual Return 2021 rr_AnnualReturn2021 15.34%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (24.59%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 21.74%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (33.75%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 15.34%
Since Inception rr_AverageAnnualReturnSinceInception 12.92%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Small Cap Value Fund | Institutional Class | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 13.86%
Since Inception rr_AverageAnnualReturnSinceInception 11.95%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Small Cap Value Fund | Institutional Class | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 9.52%
Since Inception rr_AverageAnnualReturnSinceInception 9.75%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis International Small Cap Value Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVANX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.36%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.36%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.36% [10]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess Because the G Class does not have investment performance for a full calendar year, it is not included.
American Century ETF Trust | Avantis Short-Term Fixed Income Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® Short-Term Fixed Income Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks to maximize total return.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 48% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 48.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in investment grade quality debt obligations from a diverse group of U.S. and non-U.S. issuers.
The fund’s investment process uses an analytical framework, which includes an assessment of securities’ expected income and capital appreciation, to seek securities with high expected returns. The portfolio managers categorize securities within the fund’s investment universe into component groups based on factors such as industry sector, credit rating, duration, country, and currency. The portfolio managers then calculate the expected return implied by the yield curve of each component group, while considering valuation metrics such as yield, duration, and option adjusted spreads. Finally, the portfolio managers adjust the portfolio to arrive at position weightings for each component group with the goal of building a portfolio with enhanced expected return.
Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities. Fixed income securities in which the fund may invest include corporate bonds and notes issued by U.S. and foreign corporations, securities issued by governments and their agencies, instrumentalities, or sponsored corporations—including supranational organizations. The fund may also invest in derivative instruments such as futures contracts or swap agreements, including credit default swaps, credit default swap indexes, and total return swaps.
The fund expects to maintain a weighted average maturity of three years or less. The fund will invest primarily in investment grade securities as rated by an independent rating agency or determined by the advisor to be of comparable credit quality if a rating is unavailable.
The fund may engage in foreign currency transactions on a spot basis and may also use currency forward contracts to hedge exposure to foreign currencies. The fund may purchase or sell when-issued, forward-settling, delayed delivery or forward commitment obligations. The fund may invest more than 25% of its total assets in U.S. Treasury, federal agencies and instrumentalities obligations.
The fund may also engage in securities lending. Collateral received by the fund in connection with loaning its securities may consist of cash and U.S. government securities. Cash collateral may be invested in eligible securities, such as a government money market fund.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in fixed income securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Interest Rate Risk — Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund is more susceptible to interest rate changes than funds that have shorter-weighted average maturities, such as money market and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance.
•Credit Risk — The inability or perceived inability of a security’s issuer to make interest and principal payments may cause the value of the security to decrease. As a result, the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.
•Liquidity Risk — During periods of market turbulence or unusually low trading activity, it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund. The market for lower-quality debt securities is generally less liquid than the market for higher-quality securities. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments.
•Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or assets such as auto loan, home equity loan or student loan receivables. These underlying obligations may be prepaid, as when a homeowner refinances a mortgage to take advantage of declining interest rates. If so, the fund must reinvest prepayments at current rates, which may be less than the rate of the prepaid mortgage. Because of this prepayment risk, the fund may benefit less from declining interest rates than funds of similar duration that invest less heavily in mortgage- and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation), especially in periods of rising interest rates. These events may lengthen the duration (i.e., interest rate sensitivity) and potentially reduce the value of these securities.
•Foreign Risk — Foreign securities are generally riskier than U.S. securities. Political events (such as civil unrest, national elections and imposition of exchange controls), social and economic events (such as labor strikes and rising inflation), natural disasters and public health emergencies occurring in a country where the fund invests could cause the fund’s investments in that country to experience gains or losses. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities.
•Derivatives Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. In addition, derivatives can create economic leverage in the fund’s portfolio, which may result in significant volatility and cause the fund to participate in losses (as well as gains) in an amount that exceeds the fund’s initial investment. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Futures contracts may experience potentially dramatic price changes (losses) and imperfect correlations between the price of the contract and the underlying security, index or currency. Swap agreements subject a fund to counterparty risk. Interest rate swaps could result in losses if the fund does not correctly anticipate interest rate changes. Credit default swaps could result in losses if the fund does not correctly evaluate the creditworthiness of the issuer on which the credit default swap is based.
•Currency Risk — The fund could experience gains or losses solely on changes in the exchange rate between foreign currencies and the U.S. dollar.
•Investment Process Risk — Securities selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis Short-Term Fixed Income Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVSFX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
American Century ETF Trust | Avantis Short-Term Fixed Income Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVGNX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.15% [11]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
American Century ETF Trust | Avantis U.S. Equity Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Equity Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 4% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 4.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in a diverse group of U.S. companies across market sectors and industry groups. The fund may invest in companies of all market capitalizations.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include and emphasize these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may deemphasize or dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to deemphasize or dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of U.S. companies. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 3000® Index.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of U.S. companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions, and investments in smaller foreign companies may experience more price volatility.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. Because the G Class does not have investment performance for a full calendar year, it is not included. 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2020): 22.63% Lowest Performance Quarter (1Q 2020): -23.87%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -21.92%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share classes will vary.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
American Century ETF Trust | Avantis U.S. Equity Fund | Russell 3000 Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell 3000 Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 25.66%
Since Inception rr_AverageAnnualReturnSinceInception 24.52%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Equity Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVUSX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
Annual Return 2020 rr_AnnualReturn2020 18.64%
Annual Return 2021 rr_AnnualReturn2021 27.46%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (21.92%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 22.63%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (23.87%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 27.46%
Since Inception rr_AverageAnnualReturnSinceInception 24.40%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Equity Fund | Institutional Class | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 27.18%
Since Inception rr_AverageAnnualReturnSinceInception 24.11%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Equity Fund | Institutional Class | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 16.45%
Since Inception rr_AverageAnnualReturnSinceInception 19.04%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Equity Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVUNX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.15% [12]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess Because the G Class does not have investment performance for a full calendar year, it is not included.
American Century ETF Trust | Avantis U.S. Large Cap Value Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Large Cap Value Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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. For the period from June 21, 2022, the fund’s inception, to the fiscal year ended August 31, 2022, the fund’s portfolio turnover rate was 0% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate none
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in a diverse group of U.S. large-cap companies across market sectors and industry groups.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of companies with lower levels of profitability and less attractive value characteristics. To identify companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider,
among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of U.S. companies.
Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of large capitalization U.S. companies. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 1000® Value Index. The fund defines large capitalization companies as those with market capitalizations at least as large as the smallest company in the Russell 1000® Value Index. Though market capitalizations will change from time to time, as of September 30, 2022, the market capitalization of the smallest company in the Russell 1000® Value Index was approximately $271.14 million.
The fund may also engage in securities lending and invest its collateral in eligible securities, such as a government money market fund.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in equity securities of large capitalization U.S. companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates as the cost of capital rises and borrowing costs increase.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit avantisinvestors.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | Avantis U.S. Large Cap Value Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVLVX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none [13]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 15
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 48
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 85
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 192
American Century ETF Trust | Avantis U.S. Large Cap Value Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol ALCEX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.15%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none [13]
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.15%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.15%
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
American Century ETF Trust | Avantis U.S. Small Cap Value Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading Avantis® U.S. Small Cap Value Fund
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 45% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 45.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn a 5% return each year, and that the fund’s operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. 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 invests primarily in a diverse group of U.S. small cap companies across market sectors and industry groups.
The fund seeks securities of companies that it expects to have higher returns by placing an enhanced emphasis on securities of companies with smaller market capitalizations and securities of companies with higher profitability and value characteristics. Conversely, the fund seeks to underweight or exclude securities it expects to have lower returns, such as securities of larger companies with lower levels of profitability and less attractive value characteristics. To identify small capitalization companies with higher profitability and value characteristics, the portfolio managers use reported and/or estimated company financials and market data including, but not limited to, shares outstanding, book value and its components, cash flows from operations, and accruals. The portfolio managers define “value characteristics” mainly as adjusted book/price ratio (though other price to fundamental ratios may be considered). The portfolio managers define “profitability” mainly as adjusted cash from operations to book value ratio (though other ratios may be considered). The portfolio managers may also consider other factors when selecting a security, including industry classification, the past performance of the security relative to other securities, its liquidity, its float, and tax, governance or cost considerations, among others. When portfolio managers identify securities with the desired capitalization, profitability, value, and past performance characteristics, they seek to include these securities in the broadly diversified portfolio. To determine the weight of a security within the portfolio, the portfolio managers use the market capitalization of the security relative to that of other eligible securities as a baseline, then overweight or underweight the security based on the characteristics described above. The portfolio managers may dispose of a security if it no longer has the desired market capitalization, profitability, or value characteristics. When determining whether to dispose of a security, the portfolio managers will also consider, among other things, relative past performance, costs, and taxes. The portfolio managers review the criteria for inclusion in the portfolio on a regular basis to maintain a focus on the desired broad set of small capitalization companies.
Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies located in the United States. To determine whether a company is a U.S. company, the portfolio managers will consider various factors, including where the company is headquartered, where the company’s principal operations are located, where a majority of the company’s revenues are derived, where the principal trading market is located, the country in which the company was legally organized, and whether the company is in the fund’s benchmark—the Russell 2000® Value Index. The portfolio managers consider the following to be small capitalization companies: (i) companies smaller than the largest 1000 U.S. companies; (ii) companies representing the bottom 10% of the market capitalization of all U.S. listed companies; and (iii) companies in the fund’s benchmark. Though market capitalizations will change from time to time, as of September 30, 2022, the largest company that could be considered a small capitalization company for purposes of this 80% test had a total market capitalization of approximately $10.83 billion.
The fund also may invest in derivative instruments such as futures contracts, currency forwards, and swap agreements. For example, the fund may use futures on securities and U.S. indices to gain exposure to equities to manage cash flows. The fund may also engage in securities lending and invest its collateral in eligible securities.
The portfolio managers continually analyze market and financial data to make buy, sell, and hold decisions. When buying or selling a security, the portfolio managers may consider the trade-off between expected returns of the security and implementation or tax costs of the trade in an attempt to gain trading efficiencies, avoid unnecessary risk, and enhance fund performance.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in securities of small capitalization companies located in the United States.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Equity Securities Risk — The value of equity securities, may fluctuate due to changes in investor perception of a specific issuer, changes in the general condition of the stock market, or occurrences of political or economic events that affect equity issuers and the market. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase.
•Small-Cap Stock Risk — Smaller companies may have limited financial resources, product lines, markets and have less publicly available information. These securities may trade less frequently and in more limited volumes than larger companies’ securities, leading to higher transaction costs. Smaller companies also may be more sensitive to changing economic conditions.
•Investment Process Risk — Stocks selected by the portfolio managers may perform differently than expected due to the portfolio managers’ judgments regarding the factors used, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the investment process (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Style Risk — If at any time the market is not favoring the fund’s investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments.
•Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit, and correlation risk. Derivative transactions may expose the fund to the effects of leverage, which could increase the fund’s exposure to the market and magnify potential losses, particularly when derivatives are used to enhance return rather than offset risk. Derivatives can also be highly illiquid and difficult to unwind or value, and changes in the value of a derivative held by the fund may not correlate with the value of the underlying instrument or the fund’s other investments.
•Securities Lending Risk — Securities lending involves the risk of loss of rights in, or delay in recovery of, the loaned securities if the borrower fails to return the security loaned or becomes insolvent.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Redemption Risk — The fund may need to sell securities at times it would not otherwise do so to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs or have tax consequences. To the extent that a large shareholder (including a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance. Because the G Class does not have investment performance for a full calendar year, it is not included. 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 avantisinvestors.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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 for Institutional Class shares. The table shows how the fund’s average annual returns for the periods shown compared with those of a broad measure of market performance.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress avantisinvestors.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2020): 34.51% Lowest Performance Quarter (1Q 2020): -41.60%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -16.21%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share classes will vary.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock The after-tax returns are shown only for Institutional Class shares. After-tax returns for other share 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 fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
American Century ETF Trust | Avantis U.S. Small Cap Value Fund | Russell 2000 Value Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell 2000 Value Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 28.27%
Since Inception rr_AverageAnnualReturnSinceInception 17.59%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value Fund | Institutional Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVUVX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets none
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.25%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 26
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 81
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 141
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 319
Annual Return 2020 rr_AnnualReturn2020 10.64%
Annual Return 2021 rr_AnnualReturn2021 40.17%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (16.21%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 34.51%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (41.60%)
Label rr_AverageAnnualReturnLabel Institutional Class Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 40.17%
Since Inception rr_AverageAnnualReturnSinceInception 26.43%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value Fund | Institutional Class | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 37.68%
Since Inception rr_AverageAnnualReturnSinceInception 25.22%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value Fund | Institutional Class | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 24.44%
Since Inception rr_AverageAnnualReturnSinceInception 20.37%
Inception Date rr_AverageAnnualReturnInceptionDate Dec. 04, 2019
American Century ETF Trust | Avantis U.S. Small Cap Value Fund | G Class  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol AVCNX
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.25%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets 0.25% [14]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets none
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 none
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 none
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 none
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 none
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess Because the G Class does not have investment performance for a full calendar year, it is not included.
American Century ETF Trust | American Century Focused Dynamic Growth ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Focused Dynamic Growth ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital growth.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 42% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 42.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 portfolio managers look for liquid stocks of early and rapid stage growth companies they believe will increase in value over time. The portfolio managers make their investment decisions based primarily on their fundamental analysis of individual companies, rather than on broad economic forecasts. Management of the fund is based on the belief that, over the long term, stock price movements follow growth in earnings, revenues and/or cash flow. The fund will invest primarily in securities of large cap companies, but may invest in companies of any market capitalization. The fund normally invests in a relatively limited number of companies, generally 30 to 45 securities, but may incorporate more securities to account for liquidity constraints.
The fund will invest principally in U.S. exchange-listed common stocks and American Depositary Receipts (ADRs). The fund uses ADRs to obtain exposure to foreign securities. ADRs are issued by a U.S. financial institution (depositary) and evidence ownership in a security or pool of securities issued by a foreign issuer that have been deposited with the depositary. The fund may only invest in exchange-traded ADRs that are registered with the Securities and Exchange Commission and trade on a U.S. exchange contemporaneously with the fund’s shares.
The portfolio managers use a variety of analytical research tools and techniques to help them make decisions about buying or holding stocks of companies that meet their investment criteria and selling the stocks of companies that do not. In addition to fundamental financial metrics, the portfolio managers may also consider environmental, social, and/or governance (ESG) data. However, the portfolio managers may not consider ESG data with respect to every investment decision and, even when such data is considered, they may conclude that other attributes of an investment outweigh ESG considerations when making decisions for the fund. Under normal market conditions, the portfolio managers seek securities of companies whose earnings or revenues are not only growing, but growing at an accelerated pace. This includes companies whose growth rates are expected to accelerate relative to factors including recent trends, market expectations, peers and historical data. Among other variables, the portfolio managers will consider the fund’s growth and momentum profile relative to the benchmark, the Russell 1000 Growth Index. These techniques help the portfolio managers buy or hold the stocks of companies they believe have favorable growth prospects and sell the stocks of companies whose characteristics no longer meet their criteria. The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index.
The fund may engage in active and frequent trading of portfolio securities to achieve its principal investment strategies. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Portfolio Transparency Risk — Unlike traditional ETFs, the fund does not tell the public what assets it holds each day. Instead, the fund provides a verified intraday indicative value (VIIV), calculated and disseminated every second throughout the trading day. The VIIV is intended to provide investors with enough information to allow for an effective arbitrage mechanism that will keep the market price of the fund’s shares trading at or close to the underlying net asset value (NAV) per share of the fund. There is, however, a risk, which may increase during periods of market disruption or volatility, that market prices will vary significantly from the underlying NAV of the fund. Similarly, because the fund’s shares trade on the basis of a published VIIV, they may trade at a wider bid/ask spread than shares of ETFs that publish their portfolios on a daily basis, especially during periods of market disruption or volatility, and therefore, may cost investors more to trade. Although the fund seeks to benefit from keeping its portfolio information secret, some market participants may attempt to use the VIIV to identify the fund’s trading strategy, which if successful, could result in such market participants engaging in certain predatory trading practices that may have the potential to harm the fund and its shareholders. The fund’s website will contain a historical comparison of each Business Day’s final VIIV to that Business Day’s NAV and the specific methodology for calculating the VIIV.
•Trading Issues Risk — Trading in fund shares on the Listing Exchange may be halted in certain circumstances. If at any time the securities representing 10% or more of the fund’s portfolio become subject to a trading halt or otherwise do not have a readily available market quotations, the fund’s advisor will request the Listing Exchange to halt trading of the fund. There may be other instances that require a trading halt specific to the VIIV. If there is a discrepancy of sufficient magnitude in the fund’s VIIV calculation, the fund’s advisor will request the Listing Exchange to halt trading. This “circuit breaker” is designed to prevent the VIIV from reflecting outlier prices. For more information see “The Verified Indicative Intraday Value” section below.
•Early Close/Trading Halt Risk — An exchange or market may close early or issue trading halts on portfolio securities. In times of market volatility, if trading is halted in some of the securities that the fund holds, there may be a disconnect between the market price of those securities and the market price of the fund. If at any time the securities representing 10% or more of the fund’s portfolio become subject to a trading halt or otherwise do not have readily available market quotations, the fund’s advisor will request the Cboe BZX Exchange, Inc. (Listing Exchange) to halt trading on the fund, meaning that investors would not be able to trade their shares. During any such trading halt, the VIIV would continue to be calculated and disseminated. Trading halts may have a greater impact on the fund than traditional ETFs because of its lack of transparency. Additionally, the fund’s advisor monitors the bid and ask quotations for the securities the fund holds, and, if it determines that such a security does not have readily available market quotations (such as during an extended trading halt), it will post that fact and the name and weighting of that security in the fund’s VIIV calculation on the fund’s web site. This information should permit market participants to calculate the effect of that security on the VIIV calculation, determine their own fair value of the disclosed portfolio security, and better judge the accuracy of that day’s VIIV for the fund. An extended trading halt in a portfolio security could exacerbate discrepancies between the VIIV and the fund’s NAV.
•Authorized Participant/Authorized Participant Representative Concentration Risk — The creation and redemption process for the fund occurs through a confidential brokerage account (Confidential Account) with an agent, called an AP Representative, on behalf of an Authorized Participant. Each day, the AP Representative will be given the names and quantities of the securities to be deposited, in the case of a creation, or redeemed, in the case of a redemption (Creation Basket), allowing the AP Representative to buy and sell positions in the portfolio securities to permit creations or redemptions on the Authorized Participant’s behalf, without disclosing the information to the Authorized Participant. The fund may have a limited number of institutions that act as Authorized Participants and AP Representatives, none of which are obligated to engage in creation or redemption transactions. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other Authorized Participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally. The fact that the fund is offering a novel and unique structure may affect the number of entities willing to act as Authorized Participants and AP Representatives. During times of market stress, Authorized Participants may be more likely to step away from this type of ETF than a traditional ETF.
•Growth Stocks Risk — Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized.
•Focused Portfolio Risk — Investing in a limited number of companies carries more risk because changes in the value of a single company may have a more significant effect, either negative or positive on the fund’s value.
•Style Risk — If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•ESG Integration Risk — When the portfolio managers consider ESG data in addition to fundamental financial metrics to help them make an investment decision for the fund, the fund may perform differently than funds for which ESG data is not considered. Additionally, despite their consideration of ESG data, the portfolio managers may nonetheless invest in companies with weak, or exclude companies with strong, ESG characteristics if they conclude that other attributes of an investment outweigh
ESG considerations. ESG data used by the portfolio managers often lacks standardization, consistency, and transparency, and for certain companies such data may not be available, complete, or accurate.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. Premiums and discounts may be larger for this fund than other ETFs because of its unique structure and lack of transparency. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
For at least the first three years after launch of the fund, the Board of Trustees (board) will promptly meet if, for 30 or more days in any quarter or 15 days in a row, the absolute difference between either the market closing price or the bid/ask price, on one hand, and NAV, on the other, exceeds 1.00% or the bid/ask spread exceeds 1.00%. In such a circumstance, the board will consider the continuing viability of the fund, whether shareholders are being harmed, and what, if any, action would be appropriate to among other things, narrow the premium/discount or spread, as applicable. The board will then decide whether to take any such action. Potential actions may include, but are not limited to, changing lead market makers, listing the fund on a different exchange, changing the size of Creation Units, changing the fund’s investment objective or strategy, and liquidating the fund.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term. The fund’s nontransparent structure may exacerbate this risk, particularly in volatile markets.
•Large-Cap Stock Risk — Larger companies are sometimes unable to attain the high growth rates of smaller companies, especially during extended periods of economic expansion.
•High Portfolio Turnover Risk — The fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover may result in increased transaction costs to the fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities. 
•Large Shareholder Risk — Certain shareholders, including other funds advised by the adviser, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the adviser or an affiliate of the adviser, an Authorized Participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment or that the size of the fund would be maintained at such levels. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the Listing Exchange and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2021): 9.80% Lowest Performance Quarter (1Q 2021): -1.38%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -34.98%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Focused Dynamic Growth ETF | Russell 1000® Growth Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell 1000® Growth Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 27.60%
Since Inception rr_AverageAnnualReturnSinceInception 50.89%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Dynamic Growth ETF | American Century Focused Dynamic Growth ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol FDG
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.45%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.45%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 46
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 145
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 252
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 567
Annual Return 2021 rr_AnnualReturn2021 8.68%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (34.98%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 9.80%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (1.38%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 8.68%
Since Inception rr_AverageAnnualReturnSinceInception 49.34%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Dynamic Growth ETF | American Century Focused Dynamic Growth ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 8.68%
Since Inception rr_AverageAnnualReturnSinceInception 49.33%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Dynamic Growth ETF | American Century Focused Dynamic Growth ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 5.14%
Since Inception rr_AverageAnnualReturnSinceInception 38.82%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Large Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Focused Large Cap Value ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital growth.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 22% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 22.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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
Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s assets in securities of large capitalization companies. For purposes of this 80% test, the fund defines large capitalization companies as those with capitalizations within the range of the Russell 1000® Index. Though market capitalization may change from time to time, as of September 30, 2022, the total market capitalization range of the Russell 1000® Index was approximately $271.14 million to $2.22 trillion.
In selecting stocks for the fund, the portfolio managers look for companies whose stock price may not reflect the company’s value, by looking for companies that are temporarily out of favor in, or whose value is not yet recognized by, the market. To identify these companies, the portfolio managers consider earnings, cash flows and/or assets that may not be reflected accurately in the companies’ stock prices. The managers attempt to purchase the stocks of these undervalued companies and hold each stock until the price has increased to, or is higher than, a level the managers believe more accurately reflects the fair value of the company. The portfolio managers use a variety of analytical research tools and techniques to help them buy or hold securities of companies that meet their investment criteria and sell the securities of companies that do not. In addition to fundamental financial metrics, the portfolio managers may also consider environmental, social, and/or governance (ESG) data. However, the portfolio managers may not consider ESG data with respect to every investment decision and, even when such data is considered, they may conclude that other attributes of an investment outweigh ESG considerations when making decisions for the fund. The fund normally invests in a relatively limited number of companies, generally 30-50.
The fund will invest principally in U.S. exchange-listed common stocks and American Depositary Receipts (ADRs). The fund uses ADRs to obtain exposure to foreign securities. ADRs are issued by a U.S. financial institution (depositary) and evidence ownership in a security or pool of securities issued by a foreign issuer that have been deposited with the depositary. The fund may only invest in exchange-traded ADRs that are registered with the Securities and Exchange Commission and trade on a U.S. exchange contemporaneously with the fund’s shares.
The fund is an actively managed exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. The portfolio managers may sell stocks from the fund’s portfolio if they believe a stock no longer meets their valuation criteria, a stock’s risk parameters outweigh its return opportunity, more attractive alternatives are identified or specific events alter a stock’s prospects.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s assets in securities of large capitalization companies.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Portfolio Transparency Risk — Unlike traditional ETFs, the fund does not tell the public what assets it holds each day. Instead, the fund provides a verified intraday indicative value (VIIV), calculated and disseminated every second throughout the trading day. The VIIV is intended to provide investors with enough information to allow for an effective arbitrage mechanism that will keep the market price of the fund’s shares trading at or close to the underlying net asset value (NAV) per share of the fund. There is, however, a risk, which may increase during periods of market disruption or volatility, that market prices will vary significantly from the underlying NAV of the fund. Similarly, because the fund’s shares trade on the basis of a published VIIV, they may trade at a wider bid/ask spread than shares of ETFs that publish their portfolios on a daily basis, especially during periods of market disruption or volatility, and therefore, may cost investors more to trade. Although the fund seeks to benefit from keeping its portfolio information secret, some market participants may attempt to use the VIIV to identify the fund’s trading strategy, which if successful, could result in such market participants engaging in certain predatory trading practices that may have the potential to harm the fund and its shareholders. The fund’s website will contain a historical comparison of each business day’s final VIIV to that business day’s NAV and the specific methodology for calculating the VIIV.
•Trading Issues Risk — Trading in fund shares on the Listing Exchange may be halted in certain circumstances. If at any time the securities representing 10% or more of the fund’s portfolio become subject to a trading halt or otherwise do not have a readily available market quotations, the fund’s advisor will request the Listing Exchange to halt trading of the fund. There may be other instances that require a trading halt specific to the VIIV. If there is a discrepancy of sufficient magnitude in the fund’s VIIV calculation, the fund’s advisor will request the Listing Exchange to halt trading. This “circuit breaker” is designed to prevent the VIIV from reflecting outlier prices. For more information see “The Verified Indicative Intraday Value” section below.
•Early Close/Trading Halt Risk — An exchange or market may close early or issue trading halts on portfolio securities. In times of market volatility, if trading is halted in some of the securities that the fund holds, there may be a disconnect between the market price of those securities and the market price of the fund. If at any time the securities representing 10% or more of the fund’s portfolio become subject to a trading halt or otherwise do not have readily available market quotations, the fund’s advisor will request the Cboe BZX Exchange, Inc. (Listing Exchange) to halt trading on the fund, meaning that investors would not be able to trade their shares. During any such trading halt, the VIIV would continue to be calculated and disseminated. Trading halts may have a greater impact on the fund than traditional ETFs because of its lack of transparency. Additionally, the fund’s advisor monitors the bid and ask quotations for the securities the fund holds, and, if it determines that such a security does not have readily available market quotations (such as during an extended trading halt), it will post that fact and the name and weighting of that security in the fund’s VIIV calculation on the fund’s web site. This information should permit market participants to calculate the effect of that security on the VIIV calculation, determine their own fair value of the disclosed portfolio security, and better judge the accuracy of that day’s VIIV for the fund. An extended trading halt in a portfolio security could exacerbate discrepancies between the VIIV and the fund’s NAV.
•Authorized Participant/Authorized Participant Representative Concentration Risk — The creation and redemption process for the fund occurs through a confidential brokerage account (Confidential Account) with an agent, called an AP Representative, on behalf of an Authorized Participant. Each day, the AP Representative will be given the names and quantities of the securities to be deposited, in the case of a creation, or redeemed, in the case of a redemption (Creation Basket), allowing the AP Representative to buy and sell positions in the portfolio securities to permit creations or redemptions on the Authorized Participant’s behalf, without disclosing the information to the Authorized Participant. The fund may have a limited number of institutions that act as Authorized Participants and AP Representatives, none of which are obligated to engage in creation or redemption transactions. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other Authorized Participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally. The fact that the fund is offering a novel and unique structure may affect the number of entities willing to act as Authorized Participants and AP Representatives. During times of market stress, Authorized Participants may be more likely to step away from this type of ETF than a traditional ETF.
•Style Risk — If the market does not consider the individual stocks purchased by the fund to be undervalued, the value of the fund’s shares may decline, even if stock prices generally are rising.
•Focused Portfolio Risk — Investing in a limited number of companies carries more risk because changes in the value of a single company may have a more significant effect, either negative or positive on the fund’s value.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•ESG Integration Risk — When the portfolio managers consider ESG data in addition to fundamental financial metrics to help them make an investment decision for the fund, the fund may perform differently than funds for which ESG data is not considered. Additionally, despite their consideration of ESG data, the portfolio managers may nonetheless invest in companies with weak, or exclude companies with strong, ESG characteristics if they conclude that other attributes of an investment outweigh ESG considerations. ESG data used by the portfolio managers often lacks standardization, consistency, and transparency, and for certain companies such data may not be available, complete, or accurate.
•Depositary Receipts Risk — Investment in depositary receipts does not eliminate all the risks inherent in investing in securities of non-U.S. issuers. The market value of depositary receipts is dependent upon the market value of the underlying securities and fluctuations in the relative value of the currencies in which the depositary receipts and the underlying securities are quoted.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. Premiums and discounts may be larger for this fund than other ETFs because of its unique structure and lack of transparency. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
For at least the first three years after launch of the fund, the Board of Trustees (board) will promptly meet if, for 30 or more days in any quarter or 15 days in a row, the absolute difference between either the market closing price or the bid/ask price, on one hand, and NAV, on the other, exceeds 1.00% or the bid/ask spread exceeds 1.00%. In such a circumstance, the board will consider the continuing viability of the fund, whether shareholders are being harmed, and what, if any, action would be appropriate to among other things, narrow the premium/discount or spread, as applicable. The board will then decide whether to take any such action. Potential actions may include, but are not limited to, changing lead market makers, listing the fund on a different exchange, changing the size of Creation Units, changing the fund’s investment objective or strategy, and liquidating the fund.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term. The fund’s nontransparent structure may exacerbate this risk, particularly in volatile markets.
•Large-Cap Stock Risk — Larger companies are sometimes unable to attain the high growth rates of smaller companies, especially during extended periods of economic expansion. 
•Large Shareholder Risk — Certain shareholders, including other funds advised by the adviser, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the adviser or an affiliate of the adviser, an Authorized Participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment or that the size of the fund would be maintained at such levels. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the Listing Exchange and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (1Q 2021): 6.93% Lowest Performance Quarter (3Q 2021): -0.99%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -11.97%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Focused Large Cap Value ETF | Russell 1000® Value Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell 1000® Value Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 25.16%
Since Inception rr_AverageAnnualReturnSinceInception 37.86%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Large Cap Value ETF | American Century Focused Large Cap Value ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol FLV
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.42%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.42%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 43
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 135
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 236
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 530
Annual Return 2021 rr_AnnualReturn2021 17.26%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (11.97%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Mar. 31, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 6.93%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (0.99%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 17.26%
Since Inception rr_AverageAnnualReturnSinceInception 31.09%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Large Cap Value ETF | American Century Focused Large Cap Value ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 15.81%
Since Inception rr_AverageAnnualReturnSinceInception 30.00%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Focused Large Cap Value ETF | American Century Focused Large Cap Value ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 10.67%
Since Inception rr_AverageAnnualReturnSinceInception 23.97%
Inception Date rr_AverageAnnualReturnInceptionDate Mar. 31, 2020
American Century ETF Trust | American Century Mid Cap Growth Impact ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Mid Cap Growth Impact ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital growth.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 44% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 44.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 portfolio managers look for stocks of medium capitalization companies they believe will increase in value over time, using proprietary fundamental research. The initial research process begins by analyzing the United Nations Sustainable Development Goals (SDG) to identify companies that generate, or could generate, social and environmental impact alongside a financial return. SDGs are a collection of global goals set by the United Nations General Assembly—examples include: affordable and clean energy; decent work and economic growth; industry, innovation, and infrastructure; and responsible consumption and production. The portfolio managers make their investment decisions based primarily on their analysis of individual companies, rather than on broad economic forecasts. They generate an impact thesis—an assessment of current or projected SDG alignment in combination with a fundamental growth profile—for each security.
The portfolio managers may use commercial third party mapping tools, frameworks provided by sustainable investing platforms, or internal research, which may include engaging with a company’s leadership, to create each security’s SDG impact thesis. To decide whether a security aligns with an SDG, the portfolio managers place the most emphasis on the impact created by the product or service its issuing company produces. This helps the portfolio managers to avoid impact washing—investing in a company that is not truly advancing any of the SDGs, but is attempting to present itself as though it is (i.e., a company with a poor environmental track record touting that it will convert all of its delivery vehicles to clean burning natural gas, or a company with documented human rights abuses publicizing the diversity of its board of directors). While some securities in the fund’s portfolio may align with more than one SDG, to be eligible for selection by the portfolio managers, it is only necessary that a security aligns with one SDG. The fund does not prioritize any SDG over another, and so long as each security maps to at least one SDG, there is no minimum number of SDGs that must be represented in the portfolio. 
When evaluating a security’s potential for financial return, portfolio managers seek companies with attractive returns on invested capital that are demonstrating or expected to demonstrate long-term business improvement. Analytical indicators helping to identify or forecast signs of business improvement could include accelerating earnings or revenue growth rates, increasing cash flows, or other indications of the relative strength of a company’s business. This analysis supports the portfolio managers’ decisions to buy or hold the stocks of companies that meet their selection criteria and sell the stocks of companies whose characteristics no longer meet their criteria.
The fund will invest principally in exchange-traded common stocks. Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s assets in securities of medium capitalization companies that the portfolio managers believe will create
impact by aligning with at least one of the SDGs, as described above. The portfolio managers consider medium capitalization companies to include those whose market capitalizations at the time of purchase are within the total capitalization range of the Russell Mid-Cap Growth Index. Though market capitalizations will change from time to time, as of September 30, 2022, the fund considers companies with market capitalizations between $271.14 million and $46.74 billion to be medium capitalization companies. The fund may purchase securities of small and large capitalization companies as well. The fund is nondiversified and normally invests in a relatively limited number of companies, generally 20–40 securities.
The fund may engage in active and frequent trading of portfolio securities to achieve its principal investment strategies. This may cause higher transaction costs and may affect performance. It may also result in the realization and distribution of capital gains.
The fund is an actively managed, nontransparent exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. In lieu of publishing its portfolio contents (Actual Portfolio) daily, the fund publishes a proxy portfolio (Proxy Portfolio) each day and on its website. There is no minimum overlap required between the Actual Portfolio and the Proxy Portfolio.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the portfolio managers will invest at least 80% of the fund’s assets in securities of medium capitalization companies that the portfolio managers believe will create impact by aligning with at least one of the SDGs, as described above.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Proxy Portfolio Risk — The goal of the Proxy Portfolio is, during all market conditions, to track closely the daily performance of the Actual Portfolio and minimize intra-day misalignment between the performance of the Proxy Portfolio and the performance of the Actual Portfolio. The Proxy Portfolio is designed to reflect the economic exposures and the risk characteristics of the Actual Portfolio on any given trading day.
◦The Proxy Portfolio methodology is novel and not yet proven as an effective arbitrage mechanism. The effectiveness of the Proxy Portfolio as an arbitrage mechanism is contingent upon, among other things, the fund’s factor model analysis creating a proxy portfolio that performs in a manner substantially identical to the performance of the fund’s actual portfolio. While the Proxy Portfolio may include some of the fund’s holdings, it is not the fund’s Actual Portfolio. ETFs trading on the basis of a published Proxy Portfolio may exhibit wider premiums and discounts, bid/ask spreads, and tracking error than other ETFs using the same investment strategies that publish their portfolios on a daily basis, especially during periods of market disruption or volatility. Therefore, shares of the fund may cost investors more to trade than shares of a traditional ETF.
◦Each day the fund calculates the overlap between the holdings of the prior Business Day’s Proxy Portfolio compared to the Actual Portfolio (Proxy Overlap) and the difference, in percentage terms, between the Proxy Portfolio per share NAV and that of the Actual Portfolio (Tracking Error). If the Tracking Error becomes large, there is a risk that the performance of the Proxy Portfolio may deviate from the performance of the Actual Portfolio.
◦The fund’s Board of Trustees monitors its Tracking Error and bid/spread. If deviations become too large, the Board will consider the continuing viability of the fund, whether shareholders are being harmed, and what, if any, corrective measures would be appropriate. See the Statement of Additional Information for further discussion of the Board’s monitoring responsibilities.
◦Although the fund seeks to benefit from keeping its portfolio information secret, market participants may attempt to use the Proxy Portfolio to identify a fund’s trading strategy, which if successful, could result in such market participants engaging in certain predatory trading practices that may have the potential to harm the fund and its shareholders.
•Premium/Discount Risk — Publication of the Proxy Portfolio is not the same level of transparency as the publication of the full portfolio by a fully transparent active ETF. Although the Proxy Portfolio is intended to provide investors with enough information to allow for an effective arbitrage mechanism that will keep the market price of the fund at or close to the underlying net asset value (NAV) per share of the fund, there is a risk (which may increase during periods of market disruption or volatility) that market prices will vary significantly from the underlying NAV of the fund. This means the price paid to buy shares on an exchange may not match the value of the fund’s portfolio. The same is true when shares are sold.
•Trading Issues Risk — If securities representing 10% or more of the fund’s Actual Portfolio do not have readily available market quotations, the fund will promptly request that the Exchange halt trading in the fund’s shares. Trading halts may have a greater impact on this fund compared to other ETFs due to the fund’s nontransparent structure. If the trading of a security held in the fund’s Actual Portfolio is halted, or otherwise does not have readily available market quotations, and the Advisor believes that the lack of any such readily available market quotations may affect the reliability of the Proxy Portfolio as an arbitrage vehicle, or otherwise determines it is in the best interest of the fund, the Advisor promptly will disclose on the fund’s website the identity and weighting of such security for so long as such security’s trading is halted or otherwise does not have readily available market quotations and remains in the Actual Portfolio. 
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally. The fact that the fund is offering a novel
and unique structure may affect the number of entities willing to act as Authorized Participants. During times of market stress, Authorized Participants may be more likely to step away from this type of ETF than a traditional ETF.
•United Nations SDG Criteria Risk — Because the portfolio managers consider the United Nations SDG in stock selection, the fund may exclude the securities of certain issuers for extra-financial reasons, and the fund may forgo some market opportunities available to funds that do not consider SDG. The fund’s investment process may also result in the portfolio investing in securities or industry sectors that perform differently or maintain a different risk profile than the market generally or compared to funds that do not use the SDG. SDG considerations may be linked to long term rather than short term returns. Furthermore, when analyzing securities for SDG impact, the portfolio managers rely on the veracity of management’s claims about its business operations and governance, as well as information published by commercial and industry sources. Stocks selected by the portfolio managers may perform differently or not have the impact expected due to the portfolio managers’ judgments given available information, the weight placed on each SDG, and changes from historical trends. There is no guarantee that the investment process will result in effective investment decisions for the fund.
•Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
•Sector Risk — If the fund is overweighted in a stock or sector, any negative development related to that stock or sector will have a greater impact on the fund. Companies in the same sector may be similarly affected by economic, regulatory, political or market events, or conditions, making the fund more vulnerable to unfavorable developments in that economic sector.
•Growth Stocks Risk — Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized.
•Mid Cap Stocks Risk — The fund invests in medium-capitialization and smaller companies, which may be more volatile and subject to greater risk than larger companies. Smaller companies may have limited financial resources, product lines and markets, and their securities may trade less frequently and in more limited volumes than the securities of larger companies, which could lead to higher transaction costs.
•Style Risk — If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
Risk Nondiversified Status [Text] rr_RiskNondiversifiedStatus Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (2Q 2021): 11.81% Lowest Performance Quarter (1Q 2021): -3.33%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -29.80%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Mid Cap Growth Impact ETF | Russell Midcap Growth Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel Russell Midcap Growth Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 12.73%
Since Inception rr_AverageAnnualReturnSinceInception 29.35%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Mid Cap Growth Impact ETF | American Century Mid Cap Growth Impact ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol MID
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.45%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.45%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 46
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 145
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 252
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 567
Annual Return 2021 rr_AnnualReturn2021 10.36%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (29.80%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 11.81%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (3.33%)
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 10.36%
Since Inception rr_AverageAnnualReturnSinceInception 30.79%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Mid Cap Growth Impact ETF | American Century Mid Cap Growth Impact ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 10.36%
Since Inception rr_AverageAnnualReturnSinceInception 30.79%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Mid Cap Growth Impact ETF | American Century Mid Cap Growth Impact ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 6.13%
Since Inception rr_AverageAnnualReturnSinceInception 23.79%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Sustainable Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Sustainable Equity ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks long-term capital growth.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 21% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 21.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 will generally invest in large capitalization companies it believes show sustainable business improvement using a proprietary multi-factor model that combines fundamental measures of a stock’s value and growth potential with environmental, social, and governance (ESG) metrics. The model assigns each security a financial metrics score and an ESG score that are combined on an equal basis to create an overall score.
To measure value, the portfolio managers may use ratios of stock price-to-earnings and stock price-to-cash flow. To measure growth, the managers may use the rate of growth of a company’s earnings and cash flow and changes in its earnings estimates. The model also considers price momentum. The team arrives at an ESG score by evaluating multiple metrics of each ESG characteristic—environmental, social, and governance. The portfolio managers utilize internal data and research, as well as third party commercial data sources and scoring systems, to evaluate each security’s ESG characteristics. To the extent such information is available, portfolio managers will consider, among others, a company’s carbon emission profile, energy and water usage, or waste generation (environmental), a company’s employee turnover rates, digital privacy, or worker safety (social), and a company’s corporate leadership, including board chair independence and the independence of audit and compensation committees or shareholder rights such as say on pay (governance). If an ESG score is unavailable or incomplete, a security may still be selected for the portfolio if the portfolio managers believe they can evaluate the security qualitatively, or if the financial metrics and/or remaining ESG data merit investment. Qualitative review of portfolio securities may include examination of registration statements and other information provided by the company as well as engagement with company management.
Final scores for each security are evaluated on a sector-specific basis, and the fund seeks to hold securities with the strongest scores in their respective sectors. Using this process, the portfolio managers attempt to build a portfolio of stocks that has sustainable competitive advantages, provides better returns without taking on significant additional risk, and maintains a stronger ESG profile than the S&P 500® Index.
Under normal market conditions, the fund will invest at least 80% of its assets in sustainable equity securities. For this purpose, the advisor defines sustainable securities as those to which the advisor’s proprietary model assigns an ESG score that is in the top three quartiles of the ESG scores the model assigns to all of the securities in the fund’s benchmark, the S&P 500® Index. Any assets held in cash or cash equivalents do not receive an ESG score and are not considered sustainable for purposes of the fund’s 80% test. The fund will invest principally in exchange-traded common stocks. The fund defines large capitalization companies as companies with capitalizations in the capitalization range of the S&P 500® Index.
When determining whether to sell a security, the portfolio managers consider among other things, a security’s price, whether a security’s risk parameters outweigh its return opportunities, general market conditions, and whether the security meets their ESG criteria.
The fund is an actively managed, nontransparent exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. In lieu of publishing its portfolio contents (Actual Portfolio) daily, the fund publishes a proxy portfolio (Proxy Portfolio) each day and on its website. There is no minimum overlap required between the Actual Portfolio and the Proxy Portfolio.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in sustainable equity securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Proxy Portfolio Risk — The goal of the Proxy Portfolio is, during all market conditions, to track closely the daily performance of the Actual Portfolio and minimize intra-day misalignment between the performance of the Proxy Portfolio and the performance of the Actual Portfolio. The Proxy Portfolio is designed to reflect the economic exposures and the risk characteristics of the Actual Portfolio on any given trading day.
◦The Proxy Portfolio methodology is novel and not yet proven as an effective arbitrage mechanism. The effectiveness of the Proxy Portfolio as an arbitrage mechanism is contingent upon, among other things, the fund’s factor model analysis creating a Proxy Portfolio that performs in a manner substantially identical to the performance of the fund’s Actual Portfolio. While the Proxy Portfolio may include some of the fund’s holdings, it is not the fund’s Actual Portfolio. ETFs trading on the basis of a published Proxy Portfolio may exhibit wider premiums and discounts, bid/ask spreads, and tracking error than other ETFs using the same investment strategies that publish their portfolios on a daily basis, especially during periods of market disruption or volatility. Therefore, shares of the fund may cost investors more to trade than shares of a traditional ETF.
◦Each day the fund calculates the overlap between the holdings of the prior Business Day’s Proxy Portfolio compared to the Actual Portfolio (Proxy Overlap) and the difference, in percentage terms, between the Proxy Portfolio per share NAV and that of the Actual Portfolio (Tracking Error). If the Tracking Error becomes large, there is a risk that the performance of the Proxy Portfolio may deviate from the performance of the Actual Portfolio.
◦The fund’s Board of Trustees monitors its Tracking Error and bid/spread. If deviations become too large, the Board will consider the continuing viability of the fund, whether shareholders are being harmed, and what, if any, corrective measures would be appropriate. See the Statement of Additional Information for further discussion of the Board’s monitoring responsibilities.
◦Although the fund seeks to benefit from keeping its portfolio information secret, market participants may attempt to use the Proxy Portfolio to identify a fund’s trading strategy, which if successful, could result in such market participants engaging in certain predatory trading practices that may have the potential to harm the fund and its shareholders.
•Premium/Discount Risk — Publication of the Proxy Portfolio is not the same level of transparency as the publication of the full portfolio by a fully transparent active ETF. Although the Proxy Portfolio is intended to provide investors with enough information to allow for an effective arbitrage mechanism that will keep the market price of the fund at or close to the underlying net asset value (NAV) per share of the fund, there is a risk (which may increase during periods of market disruption or volatility) that market prices will vary significantly from the underlying NAV of the fund. This means the price paid to buy shares on an exchange may not match the value of the fund’s portfolio. The same is true when shares are sold.
•Trading Issues Risk — If securities representing 10% or more of the fund’s Actual Portfolio do not have readily available market quotations, the fund will promptly request that the Exchange halt trading in the fund’s shares. Trading halts may have a greater impact on this fund compared to other ETFs due to the fund’s nontransparent structure. If the trading of a security held in the fund’s Actual Portfolio is halted, or otherwise does not have readily available market quotations, and the Advisor believes that the lack of any such readily available market quotations may affect the reliability of the Proxy Portfolio as an arbitrage vehicle, or otherwise determines it is in the best interest of the fund, the Advisor promptly will disclose on the fund’s website the identity and weighting of such security for so long as such security’s trading is halted or otherwise does not have readily available market quotations and remains in the Actual Portfolio. 
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally. The fact that the fund is offering a novel and unique structure may affect the number of entities willing to act as Authorized Participants. During times of market stress, Authorized Participants may be more likely to step away from this type of ETF than a traditional ETF.
•ESG Risk — Because the fund considers ESG metrics in addition to fundamental financial metrics when selecting securities, its portfolio may perform differently than funds that do not use ESG metrics. ESG considerations may prioritize long term rather than short term returns. Furthermore, when analyzing ESG criteria for securities, if the portfolio management team relies on the information and scoring models published by third party sources, there is a risk that this information might be incorrect or only
take into account one of many ESG related components of portfolio companies. Moreover, scores and ratings across third party providers may be inconsistent or incomparable.
•Style Risk — If at any time the market is not favoring the fund’s investment process, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, 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 bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
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 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 americancenturyetfs.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.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns 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.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.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 Returns
Bar Chart Does Not Reflect Sales Loads [Text] rr_BarChartDoesNotReflectSalesLoads 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 Closing [Text Block] rr_BarChartClosingTextBlock
Highest Performance Quarter (4Q 2021): 11.47% Lowest Performance Quarter (3Q 2021): 0.82%
As of September 30, 2022, the most recent calendar quarter end, the fund’s year-to-date return was -26.02%.
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns For the calendar year ended December 31, 2021
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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock 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.
American Century ETF Trust | American Century Sustainable Equity ETF | S&P 500 Index  
Prospectus [Line Items] rr_ProspectusLineItems  
Index No Deduction for Fees, Expenses, Taxes [Text] rr_IndexNoDeductionForFeesExpensesTaxes (reflects no deduction for fees, expenses or taxes)
Label rr_AverageAnnualReturnLabel S&P 500 Index  (reflects no deduction for fees, expenses or taxes)
1 Year rr_AverageAnnualReturnYear01 28.71%
Since Inception rr_AverageAnnualReturnSinceInception 34.42%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Sustainable Equity ETF | American Century Sustainable Equity ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol ESGA
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.39%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.39%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 40
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 126
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 219
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 493
Annual Return 2021 rr_AnnualReturn2021 28.92%
Year to Date Return, Label rr_YearToDateReturnLabel year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2022
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn (26.02%)
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel Highest Performance Quarter
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Dec. 31, 2021
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 11.47%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel Lowest Performance Quarter
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Sep. 30, 2021
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn 0.82%
Label rr_AverageAnnualReturnLabel Return Before Taxes
1 Year rr_AverageAnnualReturnYear01 28.92%
Since Inception rr_AverageAnnualReturnSinceInception 34.33%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Sustainable Equity ETF | American Century Sustainable Equity ETF | After Taxes on Distributions  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions
1 Year rr_AverageAnnualReturnYear01 28.68%
Since Inception rr_AverageAnnualReturnSinceInception 34.06%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Sustainable Equity ETF | American Century Sustainable Equity ETF | After Taxes on Distributions and Sales  
Prospectus [Line Items] rr_ProspectusLineItems  
Label rr_AverageAnnualReturnLabel Return After Taxes on Distributions and Sale of Fund Shares
1 Year rr_AverageAnnualReturnYear01 17.26%
Since Inception rr_AverageAnnualReturnSinceInception 26.52%
Inception Date rr_AverageAnnualReturnInceptionDate Jul. 13, 2020
American Century ETF Trust | American Century Sustainable Growth ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Risk/Return [Heading] rr_RiskReturnHeading American Century® Sustainable Growth ETF
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock The fund seeks capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock The following table describes the fees and expenses you may pay if you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
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)
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 29% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 29.00%
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other funds.
Expense Example by, Year, Caption [Text] rr_ExpenseExampleByYearCaption 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, that you earn 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 will generally invest in large capitalization companies it believes show sustainable business improvement using a proprietary multi-factor model that combines fundamental measures of a stock’s growth and value potential with environmental, social, and governance (ESG) metrics. The model assigns each security a financial metrics score and an ESG score that are combined on an equal basis to create an overall score.
To measure growth, the managers may use the rate of growth of a company’s earnings and cash flow and changes in its earnings estimates. To measure value, the portfolio managers may use ratios of stock price-to-earnings and stock price-to-cash flow. The model also considers price momentum. The team arrives at an ESG score by evaluating multiple metrics of each ESG characteristic—environmental, social, and governance. The portfolio managers utilize internal data and research, as well as third party commercial data sources and scoring systems, to evaluate each security’s ESG characteristics. To the extent such information is available, portfolio managers will consider, among others, a company’s carbon emission profile, energy and water usage, or waste generation (environmental), a company’s employee turnover rates, digital privacy, or worker safety (social), and a company’s corporate leadership, including board chair independence and the independence of audit and compensation committees or shareholder rights such as say on pay (governance). If an ESG score is unavailable or incomplete, a security may still be selected for the portfolio if the portfolio managers believe they can evaluate the security qualitatively, or if the financial metrics and/or remaining ESG data merit investment. Qualitative review of portfolio securities may include examination of registration statements and other information provided by the company as well as engagement with company management.
Final scores for each security are evaluated on a sector-specific basis, and the fund seeks to hold securities with the strongest scores in their respective sectors. Using this process, the portfolio managers attempt to build a portfolio of stocks that has sustainable competitive advantages, provides better returns without taking on significant additional risk, and maintains a stronger ESG profile than the Russell 1000 Growth Index.
Under normal market conditions, the fund will invest at least 80% of its assets in sustainable securities. For this purpose, the advisor defines sustainable securities as those to which the advisor’s proprietary model assigns an ESG score that is in the top three quartiles of the ESG scores the model assigns to all of the securities in the fund’s benchmark, the Russell 1000 Growth Index. Any assets held in cash or cash equivalents do not receive an ESG score and are not considered sustainable for purposes of the fund’s 80% test. The fund will invest principally in exchange-traded common stocks. The fund defines large capitalization companies as companies with capitalizations in the capitalization range of the Russell 1000 Growth Index.
When determining whether to sell a security, the portfolio managers consider among other things, a security’s price, whether a security’s risk parameters outweigh its return opportunities, general market conditions, and whether the security meets their ESG criteria.
The fund is nondiversified and will typically hold 70-90 stocks. The fund is an actively managed, nontransparent exchange-traded fund (ETF) that does not seek to replicate the performance of a specified index. In lieu of publishing its portfolio contents (Actual Portfolio) daily, the fund publishes a proxy portfolio (Proxy Portfolio) each day and on its website. There is no minimum overlap required between the Actual Portfolio and the Proxy Portfolio.
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Under normal market conditions, the fund will invest at least 80% of its assets in sustainable securities.
Risk [Heading] rr_RiskHeading Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
•Proxy Portfolio Risk — The goal of the Proxy Portfolio is, during all market conditions, to track closely the daily performance of the Actual Portfolio and minimize intra-day misalignment between the performance of the Proxy Portfolio and the performance of the Actual Portfolio. The Proxy Portfolio is designed to reflect the economic exposures and the risk characteristics of the Actual Portfolio on any given trading day.
◦The Proxy Portfolio methodology is novel and not yet proven as an effective arbitrage mechanism. The effectiveness of the Proxy Portfolio as an arbitrage mechanism is contingent upon, among other things, the fund’s factor model analysis creating a Proxy Portfolio that performs in a manner substantially identical to the performance of the fund’s Actual Portfolio. While the Proxy Portfolio may include some of the fund’s holdings, it is not the fund’s Actual Portfolio. ETFs trading on the basis of a published Proxy Portfolio may exhibit wider premiums and discounts, bid/ask spreads, and tracking error than other ETFs using the same investment strategies that publish their portfolios on a daily basis, especially during periods of market disruption or volatility. Therefore, shares of the fund may cost investors more to trade than shares of a traditional ETF.
◦Each day the fund calculates the overlap between the holdings of the prior Business Day’s Proxy Portfolio compared to the Actual Portfolio (Proxy Overlap) and the difference, in percentage terms, between the Proxy Portfolio per share NAV and that of the Actual Portfolio (Tracking Error). If the Tracking Error becomes large, there is a risk that the performance of the Proxy Portfolio may deviate from the performance of the Actual Portfolio.
◦The fund’s Board of Trustees monitors its Tracking Error and bid/spread. If deviations become too large, the Board will consider the continuing viability of the fund, whether shareholders are being harmed, and what, if any, corrective measures would be appropriate. See the Statement of Additional Information for further discussion of the Board’s monitoring responsibilities.
◦Although the fund seeks to benefit from keeping its portfolio information secret, market participants may attempt to use the Proxy Portfolio to identify a fund’s trading strategy, which if successful, could result in such market participants engaging in certain predatory trading practices that may have the potential to harm the fund and its shareholders.
•Premium/Discount Risk — Publication of the Proxy Portfolio is not the same level of transparency as the publication of the full portfolio by a fully transparent active ETF. Although the Proxy Portfolio is intended to provide investors with enough information to allow for an effective arbitrage mechanism that will keep the market price of the fund at or close to the underlying net asset value (NAV) per share of the fund, there is a risk (which may increase during periods of market disruption or volatility) that market prices will vary significantly from the underlying NAV of the fund. This means the price paid to buy shares on an exchange may not match the value of the fund’s portfolio. The same is true when shares are sold.
•Trading Issues Risk — If securities representing 10% or more of the fund’s Actual Portfolio do not have readily available market quotations, the fund will promptly request that the Exchange halt trading in the fund’s shares. Trading halts may have a greater impact on this fund compared to other ETFs due to the fund’s nontransparent structure. If the trading of a security held in the fund’s Actual Portfolio is halted, or otherwise does not have readily available market quotations, and the Advisor believes that the lack of any such readily available market quotations may affect the reliability of the Proxy Portfolio as an arbitrage vehicle, or otherwise determines it is in the best interest of the fund, the Advisor promptly will disclose on the fund’s website the identity and weighting of such security for so long as such security’s trading is halted or otherwise does not have readily available market quotations and remains in the Actual Portfolio. 
•Authorized Participant Concentration Risk — Only an authorized participant may engage in creation or redemption transactions directly with the fund. The fund may have a limited number of institutions that act as authorized participants. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the fund and no other authorized participant is able to step forward to process creation and/or redemption orders, fund shares may trade at a discount to net asset value (NAV) and possibly face trading halts and/or delisting. This risk may be more pronounced in volatile markets, potentially where there are significant redemptions in ETFs generally. The fact that the fund is offering a novel and unique structure may affect the number of entities willing to act as Authorized Participants. During times of market stress, Authorized Participants may be more likely to step away from this type of ETF than a traditional ETF.
•ESG Risk — Because the fund considers ESG metrics in addition to fundamental financial metrics when selecting securities, its portfolio may perform differently than funds that do not use ESG metrics. ESG considerations may prioritize long term rather than short term returns. Furthermore, when analyzing ESG criteria for securities, if the portfolio management team relies on the
information and scoring models published by third party sources, there is a risk that this information might be incorrect or only take into account one of many ESG related components of portfolio companies. Moreover, scores and ratings across third party providers may be inconsistent or incomparable.
•Style Risk — If at any time the market is not favoring the fund’s investment process, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles.
•Market Trading Risk — The fund faces numerous market trading risks, including the potential lack of an active market for fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation and/or redemption process of the fund. Any of these factors, among others, may lead to the fund’s shares trading at a premium or discount to NAV. Thus, you may pay more (or less) than NAV when you buy shares of the fund in the secondary market, and you may receive less (or more) than NAV when you sell those shares in the secondary market. The portfolio managers cannot predict whether shares will trade above (premium), below (discount) or at NAV.
•Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
•Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
•Public Health Emergency Risk — A pandemic, caused by the infectious respiratory illness COVID-19, has caused market disruption and other economic impacts. Markets have experienced volatility, reduced liquidity, and increased trading costs. The pandemic may continue to impact the fund and its underlying investments and could cause increased premiums or discounts to the fund’s NAV.
•Large Shareholder Risk — Certain shareholders, including other funds advised by the advisor, may from time to time own a substantial amount of the shares of the fund. In addition, a third party investor, the advisor or an affiliate of the advisor, an authorized participant, a market maker, or another entity may invest in the fund and hold its investment for a limited period of time solely to facilitate commencement of the fund or to facilitate the fund’s achieving a specified size or scale. There can be no assurance that any large shareholder would not redeem its investment, that the size of the fund would be maintained at such levels or that the fund would continue to meet applicable listing requirements. Redemptions by large shareholders could have a significant negative impact on the fund. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the NYSE Arca, Inc. and may, therefore, have a material upward or downward effect on the market price of the shares.
•Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Risk Lose Money [Text] rr_RiskLoseMoney Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.
Risk Nondiversified Status [Text] rr_RiskNondiversifiedStatus Nondiversification Risk — The fund is classified as nondiversified. A nondiversified fund may invest a greater percentage of its assets in a smaller number of securities than a diversified fund. This gives the portfolio managers the flexibility to hold large positions in a smaller number of securities. If so, a price change in any one of those securities may have a greater impact on the fund’s share price than would be the case in a diversified fund and the fund may be more volatile than if it was diversified.
Risk Not Insured Depository Institution [Text] rr_RiskNotInsuredDepositoryInstitution An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Fund Performance
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund. This information indicates the volatility of the fund’s historical returns from year to year. For current performance information, please visit americancenturyetfs.com.
Performance information is designed to help you see how fund returns can vary. Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns Performance information is designed to help you see how fund returns can vary.
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess The fund’s performance history is not available as of the date of this prospectus. When the fund has investment results for a full calendar year, this section will feature charts that show annual total returns, highest and lowest quarterly returns and average annual total returns for the fund.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress americancenturyetfs.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Keep in mind that past performance (before and after taxes) does not predict how the fund will perform in the future.
American Century ETF Trust | American Century Sustainable Growth ETF | American Century Sustainable Growth ETF  
Prospectus [Line Items] rr_ProspectusLineItems  
Trading Symbol dei_TradingSymbol ESGY
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.39%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets none
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.39%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 40
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 126
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 219
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 493
[1] Effective September 9, 2022, the fund’s Index changed from the Alpha Vee American Century Diversified International Equity Index to the American Century Quality Diversified International Equity Index. The inception date of the American Century Quality Diversified International Equity Index was March 23, 2022.
[2] Other expenses are based on estimated amounts for the current fiscal year.
[3] Other Expenses and Acquired Fund Fees and Expenses are based on estimated amounts for the current fiscal year.
[4] The advisor has agreed to waive 0.02 percentage points of the fund’s management fee. The advisor expects this waiver to continue until December 31, 2023 and cannot terminate it prior to such date without the approval of the Board of Trustees.
[5] Other expenses are based on estimated amounts for the current fiscal year.
[6] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[7] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[8] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[9] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[10] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[11] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[12] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[13] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.
[14] The advisor has agreed to waive the G Class’s management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Trustees.