Vanguard Mid-Cap Index Fund Expense Example - Investor Prospectus [Member] - Vanguard Mid-Cap Index Fund - Investor Shares	Dec. 31, 2025 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 17
Expense Example, with Redemption, 3 Years	55
Expense Example, with Redemption, 5 Years	96
Expense Example, with Redemption, 10 Years	$ 217

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