Retirement Plans

9 Months Ended

Sep. 30, 2023

Retirement Benefits [Abstract]

Retirement Plans

(10) Retirement Plans

The components of the net periodic benefit cost (credit) for our plans were as follows:

	Defined Benefit Pension Plan
	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2023			2022			2023			2022
Service cost	$	3.9		$	4.7		$	11.6		$	14.7
Interest cost		5.3			2.1			15.8			6.6
Expected return on assets		(4.8	)		(3.6	)		(14.2	)		(11.1	)
Net (gain) loss		(0.8	)		0.5			(2.5	)		1.4
Prior service cost		0.2			0.2			0.5			0.5
Total benefit cost	$	3.8		$	3.9		$	11.2		$	12.1
	Retiree Health Care Plan
	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2023			2022			2023			2022
Interest cost	$	0.1		$	0.1		$	0.4		$	0.2
Prior service credit		(0.2	)		(0.2	)		(0.6	)		(0.6	)
Net loss		—			—			—			0.1
Total benefit credit	$	(0.1	)	$	(0.1	)	$	(0.2	)	$	(0.3	)

During the three and nine months ended September 30, 2023, contributions made to our pension plans were $4.0 and $14.6, respectively, and contributions made to our retiree health care plan were $0.3 and $0.9, respectively. During 2023, we expect to make total contributions of approximately $20.0 to our pension plans and to fund our retiree health care payments as incurred.