Goodwill and intangible assets (Tables)

6 Months Ended

Mar. 31, 2024

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The following table sets forth goodwill by segment as of October 1, 2023 and March 31, 2024:

	Batteries & Lights		Auto Care		Total
Balance at October 1, 2023	$	882.0	$	134.2	$	1,016.2
Belgium Acquisition	0.7		—		0.7
Cumulative translation adjustment	5.4		—		5.4
Balance at March 31, 2024	$	888.1	$	134.2	$	1,022.3

Schedule of Finite-Lived Intangible Assets

Total intangible assets at March 31, 2024 are as follows:

	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trademarks and trade names	$	142.6	$	(33.4)	$	109.2
Customer relationships	394.5		(153.2)		241.3
Patents	34.1		(19.4)		14.7
Proprietary technology	172.5		(108.8)		63.7
Proprietary formulas	29.2		(12.0)		17.2
Total Amortizable intangible assets	772.9		(326.8)		446.1
Trademarks and trade names - indefinite lived	763.0		—		763.0
Total Other intangible assets, net	$	1,535.9	$	(326.8)	$	1,209.1

Total intangible assets at September 30, 2023 were as follows:

	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Trademarks and trade names	$	142.4	$	(29.4)	$	113.0
Customer relationships	394.2		(139.7)		254.5
Patents	33.9		(18.2)		15.7
Proprietary technology	172.5		(100.0)		72.5
Proprietary formulas	29.2		(10.0)		19.2
Total Amortizable intangible assets	772.2		(297.3)		474.9
Trademarks and trade names - indefinite lived	762.8		—		762.8
Total Other intangible assets, net	$	1,535.0	$	(297.3)	$	1,237.7