Summary of Significant Accounting Policies (Details) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 28, 2020 USD ($) store $ / shares	Jun. 30, 2019 USD ($) $ / shares	Jun. 28, 2020 USD ($) $ / shares	Jun. 30, 2019 USD ($) $ / shares	Sep. 30, 2019 USD ($)	Sep. 29, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 8,214.0		$ 8,214.0			$ 0.0
Deferred Tax Assets, Net, Noncurrent	1,740.0		1,740.0			1,765.8
Income Tax Expense (Benefit)	$ (133.9)	$ 303.7	$ 190.0	$ 670.1
Earnings/(loss) per share - diluted | $ / shares	$ (0.58)	$ 1.12	$ 0.45	$ 2.25
Earnings Per Share, Basic | $ / shares	$ (0.58)	$ 1.13	$ 0.46	$ 2.27
Deferred Revenue, Noncurrent	$ 6,642.6		$ 6,642.6			6,744.4
Deferred Tax and Other Liabilities, Noncurrent	821.1		821.1			1,370.5
Retained Earnings (Accumulated Deficit)	(8,208.3)		(8,208.3)			(5,771.2)
store occupancy cost	555.5	$ 611.6	1,768.1	$ 1,800.0
PAYROLL TAX INCENTIVES	$ 266.0		301.0
Number of Store Closures | store	78
Other Receivables	$ 214.0		214.0			$ 0.0
Restructuring Costs and Asset Impairment Charges	56.0
Deferred Tax Assets, Valuation Allowance	55.0		55.0
Facility Closing [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restructuring Costs and Asset Impairment Charges	41.5
lease termination [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restructuring Costs and Asset Impairment Charges	14.5
Store Operating Expense [Domain]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Asset Impairment Charges	$ 20.0
UNITED STATES
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of Store Closures | store	400
International Segment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rent Concession	$ 21.7		21.7
CANADA
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of Store Closures | store	200
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset					$ 8,400.0
Retained Earnings (Accumulated Deficit)					$ 17.3
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restructuring and Related Cost, Expected Cost	$ 300.0		300.0
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restructuring and Related Cost, Expected Cost	$ 400.0		$ 400.0