Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) $ in Millions				3 Months Ended			9 Months Ended
	Dec. 17, 2018 USD ($) property	Nov. 09, 2018 USD ($) shares	Aug. 16, 2018 USD ($) property	Dec. 01, 2018 USD ($) store_format shares	Feb. 24, 2018 USD ($)	Dec. 02, 2017 USD ($)	Dec. 01, 2018 USD ($) division store_format segment shares	Dec. 02, 2017 USD ($)	Nov. 16, 2018 USD ($)	Feb. 25, 2018 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restricted cash				$ 23.5	$ 10.5	$ 11.3	$ 23.5	$ 11.3
LIFO expense (benefit)				2.8		0.4	15.7	24.0
Equity-based compensation expense				9.9		6.5	35.5	24.6
Income tax benefit from compensation expense				2.7		1.3	9.6	5.0
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payments for repurchased of common stock				25.8			25.8	0.0
Receivables, net				566.9	615.3		566.9
Number of properties sold and leaseback | property			2
Proceeds from financing leases			$ 290.0				0.0	99.9
Lease term of sale-leaseback			20 years
Annual rental payment			$ 17.0
Annual rent increase percentage			1.50%
Other expense (income)				(28.3)		15.4	(88.3)	20.1
Selling and administrative expenses				3,678.0		3,725.7	12,337.0	12,509.0
Decrease in net cash used in investing activities							(360.6)	(614.4)
Increase in cash, cash equivalents, and restricted cash from adoption of new accounting principle							(194.7)	(744.5)
Provisional tax benefit as a result of the Tax Act					430.4		60.3
Income tax benefit				$ 65.4		$ 523.5	$ 80.3	590.8
Number of divisions | division							13
Number of reportable segments | segment							1
Number of store format | store_format				1			1
Contract liability related to gift cards				$ 58.2	55.6		$ 58.2
ASU 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other expense (income)				6.1			20.3
Selling and administrative expenses				6.1			20.3
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in net cash used in investing activities								1.4
Increase in cash, cash equivalents, and restricted cash from adoption of new accounting principle								$ 1.4
Retained earnings | ASU 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adopting new accounting principle										$ 5.8
Pharmacy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Receivables, net				$ 246.1	$ 205.5		246.1
Common stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of shares repurchased | shares				1,772,018
Phantom units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of share-based units issued during period | shares		1,281,416
Compensation cost not yet recognized				$ 71.5			$ 71.5
Number of unvested Phantom units | shares				2,700,000			2,700,000
Period for recognition of unrecognized compensation cost							2 years 2 months 12 days
Line of credit | Asset-Based Loan Facility
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing costs capitalized									$ 13.5
Subsequent event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties sold and leaseback | property	5
Proceeds from financing leases	$ 660.0
Annual rental payment	$ 38.0
Subsequent event | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease term of sale-leaseback	15 years
Annual rent increase percentage	1.50%
Subsequent event | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease term of sale-leaseback	20 years
Annual rent increase percentage	1.75%
Time-based vesting | Phantom units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of share-based units granted during period | shares		948,254
Aggregate grant date value of shares granted		$ 30.3
Performance-based vesting | Phantom units
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of share-based units issued during period | shares		333,162