Vanguard 500 Index Fund Investment Strategy - Investor Prospectus [Member] - Vanguard 500 Index Fund	Dec. 31, 2025
Prospectus [Line Items]
Strategy [Heading]	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	The Fund employs an indexing investment approach designed to track the performance of the S&P 500 Index (the “Target Index”), a widely recognized benchmark of U.S. stock market performance that is dominated by the stocks of large U.S. companies. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the stocks that make up the Target Index. The Fund attempts to replicate the Target Index by investing all, or substantially all, of its assets in the stocks that make up the Target Index, holding each stock in approximately the same proportion as its weighting in the Target Index. The Fund may become nondiversified, as defined under the Investment Company Act of 1940, solely as a result of tracking an index. This could occur due to events such as an index rebalance or market movement. A nondiversified fund may invest a greater percentage of its assets in the securities of particular issuers as compared with diversified funds. In addition, the Fund could become concentrated in an industry or group of industries if the Target Index becomes concentrated due to market conditions or the performance of a single or related group of issuers.

Vanguard 500 Index Fund Investment Strategy - Investor Prospectus [Member] - Vanguard 500 Index Fund

Dec. 31, 2025

<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategies</span>

The Fund employs an indexing investment approach designed to track the performance of the S&P 500 Index (the “Target Index”), a widely recognized benchmark of U.S. stock market performance that is dominated by the stocks of large U.S. companies. Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in the stocks that make up the Target Index. The Fund attempts to replicate the Target Index by investing all, or substantially all, of its assets in the stocks that make up the Target Index, holding each stock in approximately the same proportion as its weighting in the Target Index. The Fund may become nondiversified, as defined under the Investment Company Act of 1940, solely as a result of tracking an index. This could occur due to events such as an index rebalance or market movement. A nondiversified fund may invest a greater percentage of its assets in the securities of particular issuers as compared with diversified funds. In addition, the Fund could become concentrated in an industry or group of industries if the Target Index becomes concentrated due to market conditions or the performance of a single or related group of issuers.