FAIR VALUE MEASUREMENTS OF FINANCIAL INSTRUMENTS - Narrative (Details) $ in Millions	12 Months Ended
Jul. 29, 2023 USD ($)
Fair Value Disclosures [Abstract]
Effect of one percent increase on fair value of interest rate fair value hedging instruments	$ 8
Effect of one percent decrease on fair value of interest rate fair value hedging instruments	$ 8

Effect of One Percent Increase on Fair Value of Interest Rate Fair Value Hedging Instruments

No definition available.

Name:	unfi_EffectofOnePercentIncreaseonFairValueofInterestRateFairValueHedgingInstruments
Namespace Prefix:	unfi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration