Leases (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Sep. 26, 2020
Operating Leases [Abstract]
Operating lease right-of-use assets	$ 572		$ 562
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseRightOfUseAsset		us-gaap:OperatingLeaseRightOfUseAsset
Current operating lease liabilities	$ 118		$ 115
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent		us-gaap:OtherLiabilitiesCurrent
Noncurrent operating lease liabilities	$ 471		$ 464
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseLiabilityNoncurrent		us-gaap:OperatingLeaseLiabilityNoncurrent
Finance Leases [Abstract]
Finance lease right-of-use assets	$ 67		$ 78
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet		us-gaap:PropertyPlantAndEquipmentNet
Current finance lease liabilities	$ 14		$ 17
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent		us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Noncurrent finance lease liabilities	$ 51		$ 59
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations		us-gaap:LongTermDebtAndCapitalLeaseObligations
Cash Paid for Amounts Included in Lease Liabilities [Abstract]
Operating cash flows from operating leases	$ 31	$ 29
Operating cash flows from finance leases	1	1
Financing cash flows from finance leases	11	$ 13
Right-of-use assets obtained in exchange for operating lease liabilities	$ 11