Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	Other
Document Period End Date	dei_DocumentPeriodEndDate	Aug. 31, 2011
Registrant Name	dei_EntityRegistrantName	Vanguard Admiral Funds
Central Index Key	dei_EntityCentralIndexKey	0000891190
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Sep. 11, 2012
Document Effective Date	dei_DocumentEffectiveDate	Aug. 31, 2012
Vanguard Admiral Treasury Money Market Fund | Participant
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Dec. 27, 2011
Operating Expenses Caption	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)
Vanguard Admiral Treasury Money Market Fund | Retail
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Dec. 27, 2011
Operating Expenses Caption	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment)
Vanguard Admiral Treasury Money Market Fund | Vanguard Admiral Treasury Money Market Fund - Investor Shares
Risk/Return:	rr_RiskReturnAbstract
Management Expenses	rr_ManagementFeesOverAssets	0.10%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.02%
Total Annual Fund Operating Expenses	rr_NetExpensesOverAssets	0.12%	[1],[2]
1 YEAR	rr_ExpenseExampleNoRedemptionYear01	12
3 YEAR	rr_ExpenseExampleNoRedemptionYear03	39
5 YEAR	rr_ExpenseExampleNoRedemptionYear05	68
10 YEAR	rr_ExpenseExampleNoRedemptionYear10	154

[1] Vanguard and the Fund's Board have voluntarily agreed to temporarily limit certain net operating expenses in excess of the Fund's daily yield so as to maintain a zero or positive yield for the Fund. Vanguard and the Fund's Board may terminate the temporary expense limitation at any time.

[2] Vanguard and the Fund's Board have voluntarily agreed to temporarily limit certain net operating expenses in excess of the Fund|s daily yield so as to maintain a zero or positive yield for the Fund. Vanguard and the Fund|s Board may terminate the temporary expense limitation at any time.