American Beacon Aberdeen Municipal High Income ETF American Beacon Aberdeen Municipal High Income ETF Dababerdeenmunicipalhighincomeetffyepro_2797 American Beacon Aberdeen Municipal High Income ETF Dababerdeenmunicipalhighincomeetffyesai_2798 AB Aberdeen Municipal High Income ETF_FYE_01_31_SAI Class American Beacon Aberdeen Municipal High Income ETF - C000276651 American Beacon Aberdeen Municipal High Income ETF Callable Securities Risk Callable Securities Risk [Member] Counterparty Risk Counterparty Risk [Member] Credit Risk Credit Risk [Member] Cybersecurity and Operational Risk Cybersecurity and Operational Risk [Member] Debentures Risk Debentures Risk [Member] Exchange-Traded Funds (ETFs) Risk Exchange-Traded Funds (ETFs) Risk [Member] High-Yield Securities Risk High-Yield Securities Risk [Member] Interest Rate Risk Interest Rate Risk [Member] Investment Risk Investment Risk [Member] Issuer Risk Issuer Risk [Member] Liquidity Risk Liquidity Risk [Member] Market Risk Market Risk [Member] Municipal Securities Risk Municipal Securities Risk [Member] New Fund Risk New Fund Risk [Member] Restricted Securities Risk Restricted Securities Risk [Member] Sector Risk Sector Risk [Member] Secured, Partially Secured and Unsecured Obligation Risk Secured, Partially Secured and Unsecured Obligation Risk [Member] Securities Selection Risk Securities Selection Risk [Member] Tax and Political Risk Tax and Political Risk [Member] Unrated Securities Risk Unrated Securities Risk [Member] Valuation Risk Valuation Risk [Member] Variable and Floating Rate Securities Risk Variable and Floating Rate Securities Risk [Member] Zero Coupon Securities Risk Zero Coupon Securities Risk [Member]