Retirement Benefits (Tables)

6 Months Ended

Mar. 31, 2026

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 2026 and 2025 were as follows:

	Pension Benefits
	2026			2025
Three Months Ended 31 March	U.S.	International	Total	U.S.	International	Total
Service cost	$1.9	$2.6	$4.5	$2.3	$2.7	$5.0
Non-service cost:
Interest cost	29.1	15.0	44.1	29.9	13.8	43.7
Expected return on plan assets	(35.3)	(17.2)	(52.5)	(33.2)	(14.5)	(47.7)
Prior service cost amortization	0.3	0.2	0.5	0.3	0.2	0.5
Actuarial loss amortization	8.5	2.7	11.2	11.7	2.4	14.1
Settlements	1.2	0.1	1.3	—	0.1	0.1
Other	—	0.3	0.3	—	—	—
Net Periodic Cost	$5.7	$3.7	$9.4	$11.0	$4.7	$15.7

	Pension Benefits
	2026			2025
Six Months Ended 31 March	U.S.	International	Total	U.S.	International	Total
Service cost	$3.8	$5.6	$9.4	$4.6	$5.6	$10.2
Non-service cost:
Interest cost	58.1	29.6	87.7	59.8	27.7	87.5
Expected return on plan assets	(70.5)	(34.2)	(104.7)	(66.4)	(29.2)	(95.6)
Prior service cost amortization	0.6	0.5	1.1	0.6	0.4	1.0
Actuarial loss amortization	17.4	5.2	22.6	23.4	4.8	28.2
Settlements	1.2	0.1	1.3	—	0.1	0.1
Other	—	0.6	0.6	—	0.1	0.1
Net Periodic Cost	$10.6	$7.4	$18.0	$22.0	$9.5	$31.5