BENEFIT PLANS (Details)	12 Months Ended
	Aug. 01, 2020 USD ($) agreement	Aug. 03, 2019 USD ($) employee agreement	Jul. 28, 2018 USD ($)	Jul. 29, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of union employees participating in multiemployer retirement plans under collective bargaining agreements		50.00%
Increase in accumulated postretirement benefit obligation		$ 700,000
Increase in service and interest cost		100,000
Decrease in accumulated postretirement benefit obligation		700,000
Decrease in service and interest cost		100,000
Total employer contribution expenses		21,000,000	$ 11,600,000	$ 10,100,000
Multiemployer plan, contributions by employer		$ 41,000,000
Number of employees | employee		19,000
Employees covered by collective bargaining agreements | employee		4,800
Number of collective bargaining agreements | agreement		46
Number of initial collective bargaining agreements in progress | agreement		2
Employees covered by initial collective bargaining agreements | employee		33
Number of collective bargaining agreements renegotiated | agreement		14
Employees covered by renegotiated collective bargaining agreements | employee		1,300
Number of collective bargaining agreements expired | agreement		6
Employees covered by expired collective bargaining agreements | employee		550
Employees covered by collective bargaining agreements scheduled to expire | employee		470
Minimum
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plans and postretirement benefit plans		$ 0
Maximum
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plans and postretirement benefit plans		$ 6,000,000
Retirement Plan, Before Age 65 | Postemployment Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Assumed healthcare cost trend rate (as a percent)		7.30%
Ultimate healthcare cost trend rate (as a percent)		4.50%
Retirement Plan, After Age 65 | Postemployment Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Assumed healthcare cost trend rate (as a percent)		8.10%
Ultimate healthcare cost trend rate (as a percent)		4.50%
Multiemployer Plans, Postretirement Benefit
Defined Benefit Plan Disclosure [Line Items]
Multiemployer pension plan withdrawal liability		$ 3,400,000
Multiemployer plan, contributions by employer		41,300,000	$ 500,000	$ 0
Multiemployer Plans, Health and Welfare Benefit | Multiemployer Plans, Postretirement Benefit
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, contributions by employer		58,500,000
Unified Grocers, Inc. Cash Balance Plan
Defined Benefit Plan Disclosure [Line Items]
Minimum pension contributions		8,250,000
Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Estimated actuarial loss	$ 0
Estimated amortization from accumulated other comprehensive gain into net periodic benefit cost	$ 3,100,000
Subsequent Event | Scenario, Forecast
Defined Benefit Plan Disclosure [Line Items]
Number of collective bargaining agreements scheduled to expire | agreement	6
SUPERVALU
Defined Benefit Plan Disclosure [Line Items]
Multiemployer pension plan withdrawal liability		$ 35,700,000
Multiemployer pension plan, payment period		20 years