Restructuring and Severance Charges - Restructuring Activities and Accrued Liabilities (Details) $ in Millions	6 Months Ended
	Apr. 01, 2018 USD ($)
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 18.6
Provisions	9.1
Reversal/adjustment of prior provision	(0.5)
Cash expenditures	(12.8)
Other non-cash settlement	(2.0)
Ending Balance	12.4
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	8.5
Provisions	7.4
Reversal/adjustment of prior provision	0.0
Cash expenditures	(10.3)
Other non-cash settlement	0.0
Ending Balance	5.6
Contract Termination Costs
Restructuring Reserve [Roll Forward]
Beginning Balance	8.4
Provisions	0.8
Reversal/adjustment of prior provision	(0.2)
Cash expenditures	(2.4)
Other non-cash settlement	(0.8)
Ending Balance	5.8
Other Associated Costs
Restructuring Reserve [Roll Forward]
Beginning Balance	1.7
Provisions	0.9
Reversal/adjustment of prior provision	(0.3)
Cash expenditures	(0.1)
Other non-cash settlement	(1.2)
Ending Balance	$ 1.0