Vanguard Mega Cap Index Fund Investment Objectives and Goals - Institutional 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 Index Fund</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 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. |