Fair Value (Fair Value Liabilities Measured on Recurring Basis Unobservable Input Reconciliation) (Details) - Fair Value, Measurements, Recurring [Member] $ in Millions	6 Months Ended
	Mar. 30, 2018 USD ($)
Fair Value, Liabilities [Roll Forward]
Balance as of September 29, 2017	$ 11.9
Balance as of March 30, 2018	9.1
Fair Value, Inputs, Level 3 [Member]
Fair Value, Liabilities [Roll Forward]
Balance as of September 29, 2017	11.9
Balance as of March 30, 2018	9.1
Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Liabilities [Roll Forward]
Balance as of September 29, 2017	11.9
Decreases to contingent consideration liability recorded for business combinations	(2.8)
Balance as of March 30, 2018	$ 9.1