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Vanguard Mega Cap Index Fund Investment Objectives and Goals - ETF Prospectus [Member] - Vanguard Mega Cap Index Fund
Aug. 31, 2025
Prospectus [Line Items]  
Risk/Return [Heading] <span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;">Vanguard Mega Cap ETF</span>
Objective [Heading] <span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block] Vanguard Mega Cap ETF, an exchange-traded share class of Vanguard Mega Cap Index Fund (the “Fund”), seeks to track the performance of a benchmark index that measures the investment return of large-capitalization stocks in the United States.