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First Trust NASDAQ Clean Edge Green Energy Index Fund Investment Objectives and Goals - First Trust NASDAQ Clean Edge Green Energy Index Fund
Dec. 31, 2025
Prospectus [Line Items]  
Risk/Return [Heading] <span style="color:#000000;font-family:Arial;font-size:12.60pt;font-weight:bold;">First Trust NASDAQ</span><span style="color:#000000;font-family:Arial;font-size:7.38pt;font-weight:bold;position:relative;top:-4.25pt;">®</span><span style="color:#000000;font-family:Arial;font-size:12.60pt;font-weight:bold;"> Clean Edge</span><span style="color:#000000;font-family:Arial;font-size:7.38pt;font-weight:bold;position:relative;top:-4.25pt;">®</span><span style="color:#000000;font-family:Arial;font-size:12.60pt;font-weight:bold;"> Green Energy Index Fund (QCLN)</span>
Objective [Heading] <span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block] The First Trust NASDAQ® Clean Edge® Green Energy Index Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq® Clean Edge® Green EnergyTM Index (the “Index”).