Related Party Transactions (Details) - USD ($) $ in Millions			3 Months Ended		6 Months Ended
	Jan. 28, 2019	Nov. 15, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Related Party Transaction [Line Items]
Selling, general and administrative expense			$ 141.3	$ 104.2	$ 245.9	$ 203.4
Cost of products sold			362.2	205.9	658.6	500.9
Other items, net			(3.8)	(0.9)	13.1	(2.2)
Accrued related party amount			34.7		34.7		$ 0.0
Receivable from agreement			11.5		11.5
Net (loss)/earnings			(73.3)	$ 7.8	(2.5)	$ 68.2
Transition Services Agreement
Related Party Transaction [Line Items]
Selling, general and administrative expense			5.0
Cost of products sold					0.4
Other items, net					(0.1)
Expense resulting from supply agreement					4.4
Transition Services Agreement | Accounts Payable
Related Party Transaction [Line Items]
Expense resulting from supply agreement					1.1
Transition Services Agreement | Discontinued Operations
Related Party Transaction [Line Items]
Other items, net					(0.7)
Net (loss)/earnings					(4.1)
Payable recorded in liabilities held for sale			9.9		9.9
Receivable recorded in assets held for sale			$ 8.7		$ 8.7
Spectrum Auto Care Acquisition
Related Party Transaction [Line Items]
Newly-issued common stock in acquisition	$ 5.3	$ 312.5
Percentage of common stock owned			7.60%		7.60%