The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 100
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-100

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482130/360-10-45-15

+ Details

Name:	us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of loss from impairment of right-of-use asset from operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479365/842-20-25-6

+ Details

Name:	us-gaap_OperatingLeaseImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

Name:	us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 840
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481295/840-40-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479741/842-40-50-2

+ Details

Name:	us-gaap_SaleLeasebackTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=unfi_PennsylvaniaDistributionCenterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LEASES - Narrative (Details) - USD ($)	3 Months Ended			12 Months Ended
LEASES - Narrative (Details) - USD ($)	May 03, 2025	Nov. 02, 2024	Jan. 27, 2024	Aug. 02, 2025	Aug. 03, 2024	Jul. 29, 2023
Sale Leaseback Transaction [Line Items]
Asset impairment charges						$ 0
Leased assets obtained in exchange for new operating lease liabilities		$ 118,000,000	$ 205,000,000	$ 321,000,000	$ 361,000,000	$ 237,000,000
Disposal Group, Held-for-Sale, Not Discontinued Operations \| Pennsylvania Distribution Center
Sale Leaseback Transaction [Line Items]
Asset impairment charges	$ 24,000,000
Operating lease, impairment loss	$ 13,000,000