Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Millions	Mar. 31, 2024	Sep. 30, 2023
Segment Reporting, Asset Reconciling Item [Line Items]
Goodwill and other intangible assets	$ 2,231.4	$ 2,253.9
Total assets	4,286.9	4,509.6
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Tangible assets	1,654.7	1,785.5
Operating Segments | Batteries & Lights
Segment Reporting, Asset Reconciling Item [Line Items]
Tangible assets	1,240.1	1,362.0
Operating Segments | Auto Care
Segment Reporting, Asset Reconciling Item [Line Items]
Tangible assets	414.6	423.5
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Tangible assets	$ 400.8	$ 470.2