Expense Example, No Redemption (Vanguard Prime Money Market Fund Institutional)	Vanguard Prime Money Market Fund Vanguard Prime Money Market Fund - Institutional Shares 9/1/2013 - 8/31/2014 USD ($)
Expense Example, No Redemption:
1 YEAR	10
3 YEAR	32
5 YEAR	56
10 YEAR	128

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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

-Publisher SEC

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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

-Name Form

-Number N-1A

-Chapter A

-Section 3

-Subsection instructions

-Paragraph 4

-Subparagraph f

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