Revenue Recognition - Schedule of Product and Market Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Net Sales	$ 685.1	$ 587.0	$ 1,533.7	$ 1,323.8
Modern Markets
Disaggregation of Revenue [Line Items]
Net Sales	120.3	101.1	294.9	243.9
Developing Markets
Disaggregation of Revenue [Line Items]
Net Sales	49.8	46.2	106.7	97.4
Distributors Markets
Disaggregation of Revenue [Line Items]
Net Sales	33.0	29.8	63.5	58.1
North America
Disaggregation of Revenue [Line Items]
Net Sales	419.3	360.3	936.2	814.0
Latin America
Disaggregation of Revenue [Line Items]
Net Sales	62.7	49.6	132.4	110.4
Americas
Disaggregation of Revenue [Line Items]
Net Sales	482.0	409.9	1,068.6	924.4
International
Disaggregation of Revenue [Line Items]
Net Sales	203.1	177.1	465.1	399.4
Batteries
Disaggregation of Revenue [Line Items]
Net Sales	512.8	427.7	1,218.9	1,049.6
Auto Care
Disaggregation of Revenue [Line Items]
Net Sales	138.9	130.2	240.7	208.9
Lights, Licensing and Other
Disaggregation of Revenue [Line Items]
Net Sales	$ 33.4	$ 29.1	$ 74.1	$ 65.3