Employees (Tables)

12 Months Ended

Dec. 31, 2023

Retirement Benefits [Abstract]

Schedule of Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan

Financial information related to our pension plans is presented below (in millions):

	Year Ended December 31,
	2023		2022
Change in projected benefit obligation:
Benefit obligation at beginning of year	$	105.3	$	140.8
Interest cost	5.3		3.7
Actuarial loss (gain)	2.0		(33.5)
Benefits paid	(5.9)		(5.7)
Projected benefit obligations at end of year	$	106.7	$	105.3
Change in plan assets:
Fair value of plan assets at beginning of year	$	102.2	$	137.9
Actual gain (loss) on plan assets	7.9		(30.0)
Benefits paid	(5.9)		(5.7)
Fair value of plan assets at end of year	$	104.2	$	102.2
Reconciliation of funded status:
Fair value of plan assets at end of year	$	104.2	$	102.2
Less projected benefit obligations at end of year	106.7		105.3
Under-funded status at end of year	$	(2.5)	$	(3.1)

Schedule of Net Periodic Benefit Cost Not yet Recognized

The pre-tax amounts in accumulated other comprehensive loss that have not yet been recognized as components of net periodic benefit cost were as follows (in millions):

	Year Ended December 31,
	2023		2022
Net actuarial loss	$	6.0	$	6.5
Projected benefit obligations at end of year	$	6.0	$	6.5

Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets

The accumulated benefit obligation for each of our pension plans was in excess of the fair value of plan assets. The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for the pension plans were as follows (in millions):

	Year Ended December 31,
	2023		2022
Projected benefit obligation	$	106.7	$	105.3
Accumulated benefit obligation	$	106.7	$	105.3
Fair value of plan assets	$	104.2	$	102.2

Schedule of Assumptions Used

The weighted-average assumptions used to determine benefit obligations were as follows:

	Year Ended December 31,
	2023		2022
Discount rate	4.90	%	5.10	%

The weighted-average assumptions used to determine net periodic benefit costs were as follows:

	Year Ended December 31,
	2023		2022		2021
Discount rate	5.10	%	2.75	%	2.45	%
Expected long-term rate of return on plan assets	5.55	%	4.05	%	4.65	%

Schedule of Net Benefit Costs

The components of net periodic benefit cost related to our benefit plans consisted of the following (in millions):

	Year Ended December 31,
Components of net periodic benefit:	2023		2022		2021
Interest cost	5.3		3.7		3.5
Expected return on plan assets	(5.4)		(5.2)		(6.0)
Amortization of net gain	(0.1)		—		—
Net periodic benefit	$	(0.2)	$	(1.5)	$	(2.5)

Schedule of Allocation of Plan Assets

The weighted-average asset allocation of our pension benefits plan assets were as follows:

	Year Ended December 31,
	2023		2022
Investments in common collective trust consisting of:
U.S. and International companies	10.0	%	20.2	%
Fixed-income	90.0	%	79.8	%
Total	100.0	%	100.0	%

The fair value of our pension assets by category were as follows (in millions):

	Quoted Prices in Active Markets For Identical Assets or Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Consolidated Total
Year Ended December 31, 2023
U.S. companies	$	—	$	7.3	$	—	$	7.3
International companies	—		3.1		—		3.1
Fixed-income	—		93.8		—		93.8
Total	$	—	$	104.2	$	—	$	104.2
Year Ended December 31, 2022
U.S. companies	$	—	$	14.3	$	—	$	14.3
International companies	—		6.3		—		6.3
Fixed-income	—		81.6		—		81.6
Total	$	—	$	102.2	$	—	$	102.2