Retirement Benefits (Tables)

6 Months Ended

Mar. 31, 2025

Retirement Benefits [Abstract]

Schedule of Net Periodic (Benefit) Cost

The components of net periodic cost for our defined benefit pension plans for the three and six months ended 31 March 2025 and 2024 were as follows:

	Pension Benefits
	2025			2024
Three Months Ended 31 March	U.S.	International	Total	U.S.	International	Total
Service cost	$2.3	$2.7	$5.0	$2.4	$2.8	$5.2
Non-service cost:
Interest cost	29.9	13.8	43.7	33.7	15.0	48.7
Expected return on plan assets	(33.2)	(14.5)	(47.7)	(30.0)	(11.9)	(41.9)
Prior service cost amortization	0.3	0.2	0.5	0.3	0.3	0.6
Actuarial loss amortization	11.7	2.4	14.1	14.3	3.2	17.5
Settlements	—	0.1	0.1	—	0.2	0.2
Other	—	—	—	—	0.1	0.1
Net Periodic Cost	$11.0	$4.7	$15.7	$20.7	$9.7	$30.4

	Pension Benefits
	2025			2024
Six Months Ended 31 March	U.S.	International	Total	U.S.	International	Total
Service cost	$4.6	$5.6	$10.2	$4.8	$5.6	$10.4
Non-service cost:
Interest cost	59.8	27.7	87.5	67.4	29.8	97.2
Expected return on plan assets	(66.4)	(29.2)	(95.6)	(60.0)	(23.5)	(83.5)
Prior service cost amortization	0.6	0.4	1.0	0.6	0.5	1.1
Actuarial loss amortization	23.4	4.8	28.2	28.6	6.4	35.0
Settlements	—	0.1	0.1	—	0.2	0.2
Other	—	0.1	0.1	—	0.2	0.2
Net Periodic Cost	$22.0	$9.5	$31.5	$41.4	$19.2	$60.6