Commitments and Contingencies - Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Oct. 02, 2020	Oct. 02, 2020	Sep. 27, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 31.8
Finance lease cost:
Amortization of right-of-use assets	0.7
Interest on lease liabilities	0.5
Variable lease cost	16.5
Total lease cost	49.5
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for leases		$ 33.0
Operating leases:
Operating right-of-use assets	121.0	121.0	$ 0.0
Accrued liabilities	27.2	27.2
Long-term lease liabilities	101.1	101.1	$ 0.0
Total lease liabilities	128.3	128.3
Finance leases:
Property, plant, and equipment, net	11.5	11.5
Accrued liabilities	3.4	3.4
Other long-term liabilities	8.7	8.7
Total lease liabilities	$ 12.1	$ 12.1
Weighted Average Lease Term and Discount Rates [Abstract]
Operating leases	7 years 2 months 12 days	7 years 2 months 12 days
Finance leases	4 years 2 months 12 days	4 years 2 months 12 days
Operating leases	5.00%	5.00%
Finance leases	3.90%	3.90%
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseLiabilityNoncurrent	us-gaap:OperatingLeaseLiabilityNoncurrent
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent