Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Mar. 29, 2020	Mar. 31, 2019	Sep. 30, 2019	Sep. 29, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 8,260.8		$ 8,260.8			$ 0.0
Deferred Tax Assets, Net, Noncurrent	1,709.7		1,709.7			1,765.8
Income Tax Expense (Benefit)	$ 65.4	$ 161.2	$ 324.0	$ 366.4
Earnings per share - diluted	$ 0.28	$ 0.53	$ 1.02	$ 1.14
Earnings Per Share, Basic	$ 0.28	$ 0.54	$ 1.03	$ 1.15
Deferred Revenue, Noncurrent	$ 6,685.5		$ 6,685.5			6,744.4
Deferred Tax and Other Liabilities, Noncurrent	751.4		751.4			1,370.5
Retained Earnings (Accumulated Deficit)	(7,050.6)		(7,050.6)			$ (5,771.2)
store occupancy cost		$ 591.8		$ 1,200.0
Deferred Tax Assets, Net	1,700.0		1,700.0
PAYROLL TAX INCENTIVES	35.0
Foreign jurisdiction [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Tax Assets, Net	$ 100.0		$ 100.0
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