BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 25, 2019 USD ($)	Sep. 07, 2019 USD ($) store_format shares	Sep. 08, 2018 USD ($)	Sep. 07, 2019 USD ($) division store_format segment shares	Sep. 08, 2018 USD ($)	Feb. 23, 2019 USD ($) shares	Feb. 24, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash		$ 29.4		$ 29.4		$ 41.6
LIFO expense (benefit)		5.8	$ 3.4	16.3	$ 12.9
Equity-based compensation expense		0.9		2.1
Compensation cost not yet recognized		8.7		$ 8.7
Period for recognition of unrecognized compensation cost				4 years
Fair value of equity interests deemed granted	$ 10.8
Payments for repurchased of common stock						25.8
Income tax expense (benefit)		$ 81.9	$ (11.9)	$ 97.6	$ (14.9)
Effective tax rate		21.70%	26.80%	22.10%	22.90%
Number of divisions | division				13
Number of reportable segments | segment				1
Number of store format | store_format		1		1
Receivables, net		$ 518.6		$ 518.6		586.2
Contract liability related to gift cards		45.3		45.3		55.9
Right-of-use assets		5,831.8		5,831.8
Lease liabilities		5,974.4		5,974.4
Adoption of new accounting standards, net of tax							$ 574.6
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets							5,300.0
Lease liabilities							5,400.0
Cumulative effect adjustment							776.0
Adoption of new accounting standards, net of tax							574.6
ASU 2016-02, Deferred Gains On Sale-Leaseback
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment							865.8
ASU 2016-02, Impairment Loss
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment							(87.3)
ASU 2016-02, Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment							(17.2)
ASU 2016-02, Liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment							(14.7)
ASU 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adoption of new accounting standards, net of tax							$ 16.6
Pharmacy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Receivables, net		259.3		259.3		$ 252.2
Common Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of shares repurchased (in shares) | shares						1,772,018
Phantom units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equity-based compensation expense		5.6	$ 12.2	15.5	$ 25.6
Income tax benefit		1.5	$ 3.3	4.1	$ 6.9
Compensation cost not yet recognized		$ 35.8		$ 35.8
Number of unvested phantom units (in shares) | shares		1,500,000		1,500,000
Period for recognition of unrecognized compensation cost				1 year 10 months 24 days
Phantom units | Investor Incentive Units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Units received upon vesting (in shares) | shares				1