Retirement Benefits (Tables)

6 Months Ended

Mar. 31, 2023

Retirement Benefits [Abstract]

Schedule of Net Periodic (Benefit) Cost

The components of net periodic cost (benefit) for our defined benefit pension plans for the three and six months ended 31 March 2023 and 2022 were as follows:

	Pension Benefits
	2023			2022
Three Months Ended 31 March	U.S.	Inter-national	Total	U.S.	Inter-national	Total
Service cost	$2.8	$3.0	$5.8	$4.6	$5.6	$10.2
Non-service cost (benefit):
Interest cost	32.5	14.9	47.4	18.4	7.6	26.0
Expected return on plan assets	(31.8)	(12.2)	(44.0)	(42.1)	(17.6)	(59.7)
Prior service cost amortization	0.3	0.1	0.4	0.3	—	0.3
Actuarial loss amortization	15.0	3.0	18.0	16.6	3.8	20.4
Settlements	0.9	0.2	1.1	0.9	0.2	1.1
Other	—	0.2	0.2	—	0.2	0.2
Net Periodic Cost (Benefit)	$19.7	$9.2	$28.9	($1.3)	($0.2)	($1.5)

	Pension Benefits
	2023			2022
Six Months Ended 31 March	U.S.	Inter-national	Total	U.S.	Inter-national	Total
Service cost	$5.5	$6.3	$11.8	$9.2	$11.2	$20.4
Non-service cost (benefit):
Interest cost	65.0	29.3	94.3	36.8	15.2	52.0
Expected return on plan assets	(63.6)	(24.0)	(87.6)	(84.2)	(35.3)	(119.5)
Prior service cost amortization	0.6	0.1	0.7	0.6	—	0.6
Actuarial loss amortization	29.8	6.0	35.8	33.3	7.7	41.0
Settlements	0.9	0.2	1.1	1.8	0.2	2.0
Curtailments	—	(1.9)	(1.9)	—	—	—
Other	—	0.5	0.5	—	1.0	1.0
Net Periodic Cost (Benefit)	$38.2	$16.5	$54.7	($2.5)	$—	($2.5)