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Vanguard Value Index Fund Average Annual Total Returns - Admiral Prospectus [Member]
12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
CRSP US Large Cap Value Index (reflects no deduction for fees, expenses, or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 15.31% 12.60% 11.68%
Dow Jones U.S. Total Stock Market Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)[Member]      
Prospectus [Line Items]      
Average Annual Return, Percent 17.05% 13.07% 14.21%
Admiral Shares      
Prospectus [Line Items]      
Average Annual Return, Percent 15.26% 12.59% 11.66%
Admiral Shares | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 14.68% 11.95% 10.99%
Admiral Shares | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 9.41% 9.94% 9.50%