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Retirement Plans (Tables)

12 Months Ended

Sep. 30, 2024

Retirement Benefits [Abstract]

Schedule of Net Periodic Benefit Cost

The components of net periodic cost (benefit) for our Pension Plan are presented below.

			2024						2023						2022
			(in millions)
Service cost			$	0.6					$	0.8					$	1.3
Components of net periodic cost (benefit) excluded from operating income:
Interest cost			13.9						13.9						9.8
Expected return on plan assets			(13.0)						(13.9)						(15.4)
Amortization of actuarial net loss			3.1						3.7						1.7
Pension expense (benefit) other than service			4.0						3.7						(3.9)
Net periodic cost (benefit)			$	4.6					$	4.5					$	(2.6)

Schedule Of Defined Benefit Plans Disclosures

Amounts recognized for the Pension Plan are presented below.

			September 30,
			2024						2023
			(in millions)
Projected benefit obligations:
Beginning of year			$	233.2					$	251.2
Service cost			0.6						0.8
Interest cost			13.9						13.9
Actuarial loss/(gain)			22.2						(10.4)
Benefits paid			(22.0)						(22.3)
Accumulated benefit obligations at end of year			$	247.9					$	233.2
Plan assets:
Beginning of year			$	239.8					$	251.8
Actual return on plan assets			43.6						10.3
Benefits paid			(22.0)						(22.3)
Fair value of plan assets at end of year			$	261.4					$	239.8
Prepaid benefit cost at end of year:
Funded status			$	13.5					$	6.6
Recognized on balance sheet:
Other noncurrent assets			$	13.5					$	6.6
Recognized in accumulated other comprehensive income (loss), before tax:
Net actuarial loss			$	56.6					$	68.2

Schedule of Pension and Other Postretirement Benefits Activity in Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Pension Plan activity in accumulated other comprehensive loss, before tax, in 2024 is presented below, in millions.

Balance at beginning of year			$	68.2
Actuarial loss			(8.4)
Prior year actuarial loss amortization to net periodic cost			(3.2)
Balance at end of year			$	56.6

Schedule of Assumptions Used

A summary of key assumptions for the valuations of our Pension Plan is as follows:

			September 30,
			2024						2023						2022
Weighted average used to determine benefit obligations:
Discount rate			5.07		%				6.29		%				5.79		%
Weighted average used to determine net periodic cost:
Discount rate			6.29		%				5.79		%				3.01		%
Expected return on plan assets			5.75		%				5.75		%				4.50		%

Schedule of Strategic Allocation of Plan Assets [Table Text Block]

Strategic asset allocations, tactical range at September 30, 2024 and actual asset allocations are as follows:

			Strategic asset allocation																		Actual asset allocations at
																					September 30,
									Tactical range												2024						2023						2022
Fixed income investments			70		%				67		%	-			73		%				69		%				70		%				70		%
Equity investments			30						27		%	-			33		%				30						29						29
Cash			—						0		%	-			5		%				1						1						1
			100		%																100		%				100		%				100		%

Schedule of Allocation of Plan Assets

The assets of the Pension Plan by level within the fair value hierarchy are as follows:

			September 30, 2024
			Level 1						Level 2												Total
			(in millions)
Fixed income			$	131.8					$	49.8											$	181.6
Equity:
Large cap index funds			39.1						—												39.1
International stocks:
International funds			38.9						—												38.9
Total equity			78.0						—												78.0
Cash and cash equivalents			1.8						—												1.8
Total Plan assets			$	211.6					$	49.8											$	261.4

			September 30, 2023
			Level 1						Level 2												Total
			(in millions)
Fixed income			$	121.1					$	45.6											$	166.7
Equity:
Large cap index funds			35.6						—												35.6
International stocks:
International funds			35.6						—												35.6
Total equity			71.2						—												71.2
Cash and cash equivalents			1.9						—												1.9
Total Plan assets			$	194.2					$	45.6											$	239.8

Schedule of Expected Benefit Payments

Our estimated future pension benefit payments are presented below (in millions):

2025			$	22.6
2026			22.3
2027			21.9
2028			21.4
2029			20.8
2030-2034			94.1
Total			$	203.1

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Tabular disclosure of assumption used to determine benefit obligation and net periodic benefit cost of defined benefit plan. Includes, but is not limited to, discount rate, rate of compensation increase, expected long-term rate of return on plan assets and interest crediting rate.

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