Expense Example, No Redemption (Vanguard Mega Cap Index Fund Institutional)	Vanguard Mega Cap Index Fund Vanguard Mega Cap Index Fund - Institutional Shares 9/1/2013 - 8/31/2014 USD ($)
Expense Example, No Redemption:
1 YEAR	8
3 YEAR	26
5 YEAR	45
10 YEAR	103

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You would pay the following expenses if you did not redeem your shares. Include the second 1-, 3-, 5-, and 10-year periods and related narrative explanation only if a sales charge (load) or other fee is charged upon redemption.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

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-Number N-1A

-Chapter A

-Section 3

-Subsection instructions

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