Vanguard Market Neutral Fund Average Annual Total Returns - Institutional Prospectus [Member]	12 Months Ended	60 Months Ended	120 Months Ended
	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
Spliced Market Neutral Index USD (reflects no deduction for fees, expenses, or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent	4.40%	3.31%	2.23%
FTSE 3-Month Treasury Bill Index (Daily) (reflects no deduction for fees, expenses, or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent	4.40%	3.31%	2.23%
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%
Institutional Shares
Prospectus [Line Items]
Average Annual Return, Percent	9.27%	12.73%	3.67%
Institutional Shares \| After Taxes on Distributions
Prospectus [Line Items]
Average Annual Return, Percent	7.95%	11.58%	2.95%
Institutional Shares \| After Taxes on Distributions and Sales
Prospectus [Line Items]
Average Annual Return, Percent	5.71%	9.76%	2.63%