Retirement Benefits

6 Months Ended

Mar. 31, 2023

Retirement Benefits [Abstract]

Retirement Benefits

Retirement Benefits

The components of net periodic pension and postretirement benefit cost were (in millions):

	Pension Benefits
	Three Months Ended March 31,				Six Months Ended March 31,
	2023		2022		2023		2022
Service cost	$	10.6	$	20.3	$	21.2	$	40.7
Interest cost	39.5		32.4		78.7		64.8
Expected return on plan assets	(51.7)		(59.3)		(103.0)		(118.7)
Amortization of prior service cost	—		0.8		—		0.8
Amortization of net actuarial (gain) loss	(1.0)		22.3		(2.0)		44.6
Settlement charge	117.9		24.9		117.9		24.9
Net periodic pension benefit cost	$	115.3	$	41.4	$	112.8	$	57.1

	Other Postretirement Benefits
	Three Months Ended March 31,				Six Months Ended March 31,
	2023		2022		2023		2022
Service cost	$	0.1	$	0.2	$	0.2	$	0.4
Interest cost	0.5		0.3		1.1		0.6
Amortization of prior service credit	—		(0.2)		—		(0.4)
Amortization of net actuarial loss	0.2		0.1		0.3		0.3
Net periodic postretirement benefit cost	$	0.8	$	0.4	$	1.6	$	0.9

The service cost component is included in Cost of sales and Selling, general and administrative expenses in the Consolidated Statement of Operations. All other components are included in Other expense in the Consolidated Statement of Operations.

In March 2023, we remeasured our U.S. pension plan assets and liabilities in accordance with U.S. GAAP settlement accounting rules and recognized settlement expense of $117.9 million. Settlement accounting was required due to the amount of lump-sum payments made by the U.S. pension plan to retirees, current employees electing an in-service distribution, and other separated employees. Remeasurement of our U.S. pension plan assets and liabilities increased our net benefit obligation by $76.2 million. The discount rate used for the remeasurement as of March 31, 2023, was 5.25 percent compared to 5.65 percent at our September 30, 2022, annual measurement date.