Vanguard Extended Market Index Fund Expense Example - Investor Prospectus [Member] - Vanguard Extended Market Index Fund - Investor Shares	Dec. 31, 2025 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 19
Expense Example, with Redemption, 3 Years	61
Expense Example, with Redemption, 5 Years	107
Expense Example, with Redemption, 10 Years	$ 243

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