Borrowings - Long-term Debt (Narrative) (Details)		12 Months Ended
	Mar. 27, 2019 USD ($) tranche	Oct. 02, 2020 USD ($)	Mar. 25, 2020 USD ($)	Mar. 25, 2020 GBP (£)	Sep. 27, 2019 USD ($)	Sep. 28, 2018 USD ($)	Mar. 12, 2018 USD ($)	Sep. 28, 2017 USD ($)	Feb. 07, 2014 USD ($)
Line of Credit Facility [Line Items]
Total long-term debt, net		$ 1,676,941,000			$ 1,201,245,000
Senior Notes [Member]
Line of Credit Facility [Line Items]
Contingent interest rate (in basis points)							0.75%
Minimum
Line of Credit Facility [Line Items]
Facility fee percentage		0.08%
Maximum
Line of Credit Facility [Line Items]
Facility fee percentage		0.20%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Number of tranches in revolving credit facility | tranche	2
Total long-term debt, net		$ 152,794,000			303,780,000
Long-term debt fair value		543,700,000
Letter of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		400,000,000.0
Sub Facility Of Swing Line Loans
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		50,000,000.0
Senior Notes As Amended Note Purchase Agreement
Line of Credit Facility [Line Items]
Total long-term debt, net							$ 500,000,000.0
$1.6 Billion Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity									$ 1,600,000,000
Available borrowing capacity		2,090,000,000.00
$1.6 Billion Revolving Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	$ 2,250,000,000
Accordion feature of loan	$ 3,250,000,000
$1.6 Billion Revolving Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Direct borrowings on credit facility		2,300,000
Committed And Uncommitted Letter Of Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Direct borrowings on credit facility		260,700,000
Term Loan Facility 2017
Line of Credit Facility [Line Items]
Total long-term debt, net		0			$ 400,000,000
Term Loan Facility 2020
Line of Credit Facility [Line Items]
Aggregate principal amount			$ 730,000,000.0
Total long-term debt, net		1,025,826,000				$ 0
Term Loan Facility 2020 | Subsidiaries
Line of Credit Facility [Line Items]
Aggregate principal amount | £				£ 250,000,000.0
2017 Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Total long-term debt, net								$ 1,500,000,000
Line of Credit
Line of Credit Facility [Line Items]
Letters of credit outstanding		$ 263,000,000.0