Leases (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 28, 2020	Mar. 28, 2020	Sep. 28, 2019
Assets [Abstract]
Operating lease right-of-use assets	$ 574	$ 574	$ 0
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseRightOfUseAsset	us-gaap:OperatingLeaseRightOfUseAsset
Finance lease right-of-use assets	$ 99	$ 99
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Current Liabilities [Abstract]
Operating lease liabilities	$ 112	$ 112
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance lease liabilities	$ 19	$ 19
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Non-current Liabilities [Abstract]
Operating lease liabilities	$ 479	$ 479	$ 0
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseLiabilityNoncurrent	us-gaap:OperatingLeaseLiabilityNoncurrent
Finance lease liabilities	$ 81	$ 81
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations
Lease Cost [Abstract]
Operating lease cost	$ 28	$ 57
Finance Lease Cost [Abstract]
Amortization of right-of-use asset	4	8
Interest on lease liabilities	1	2
Total finance lease cost	5	10
Short-term lease cost	4	8
Total lease cost	$ 37	75
Cash Paid for Amounts Included in Lease Liabilities [Abstract]
Operating cash flows from operating leases		57
Operating cash flows from finance leases		1
Financing cash flows from finance leases		$ 17
Weighted-average remaining lease term - operating leases	8 years	8 years
Weighted-average remaining lease term - finance leases	4 years	4 years
Weighted-average discount rate - operating leases	4.50%	4.50%
Weighted-average discount rate - finance leases	3.70%	3.70%
Right-of-use assets obtained in exchange for operating lease liabilities	$ 5	$ 13
Annual Lease Commitments for Operating Leases [Abstract]
Remainder of 2020	59	59
2021	111	111
2022	97	97
2023	84	84
2024	70	70
Thereafter	303	303
Total lease payments	724	724
Less: Interest	(133)	(133)
Present value of lease liabilities	591	591
Annual Lease Commitments for Finance Leases [Abstract]
Remainder of 2020	19	19
2021	27	27
2022	26	26
2023	13	13
2024	7	7
Thereafter	15	15
Total lease payments	107	107
Less: Interest	(7)	(7)
Present value of lease liabilities	$ 100	$ 100