EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Schedule of changes in benefit obligations, fair value of plan assets, and funded status of plan

The changes in the benefit obligation, the changes in fair value of plan assets, and the funded status of the Company’s Pension and Post-Retirement Medical Plans as of and for the years ended December 31, 2021 and 2020 were as follows:

	Pension Plans				Post-Retirement Medical Plan
(in millions)	2021		2020		2021		2020
Change in benefit obligation:
Benefit obligation at beginning of year	$	329.3	$	271.2	$	22.0	$	17.5
Service cost	57.5		59.0		1.1		1.0
Interest cost	5.3		6.9		0.3		0.4
Plan amendments	—		—		—		1.8
Benefit payments	(31.2)		(18.0)		(1.2)		(0.6)
Actuarial (gain) loss	(7.6)		10.2		(4.0)		1.9
Projected benefit obligation at end of year	$	353.3	$	329.3	$	18.2	$	22.0
Change in plan assets:
Fair value of plan assets at beginning of year	$	255.8	$	197.4	$	—	$	—
Actual return on plan assets	27.7		28.6		—		—
Benefits paid	(31.2)		(18.0)		(1.2)		(0.6)
Employer contributions	54.0		47.8		1.2		0.6
Fair value of plan assets at end of year	$	306.3	$	255.8	$	—	$	—
Reconciliation of funded status:
Fair value of plan assets at end of year	$	306.3	$	255.8	$	—	$	—
Less benefit obligations at end of year	353.3		329.3		18.2		22.0
Funded status at end of year	$	(47.0)	$	(73.5)	$	(18.2)	$	(22.0)

Schedule of expected benefit payments

Benefit payments, which reflect expected future services that the Company expects to pay are as follows for the years ended December 31:

(in millions)	Pension Benefits		Post-Retirement Medical Plan
2022	$	24.8	$	1.8
2023	18.1		1.7
2024	20.1		1.6
2025	23.7		1.5
2026	27.1		1.5
Years 2027-2031	168.6		6.8

Schedule of net periodic benefit cost

The components of net periodic benefit cost were as follows for the years ended December 31, 2021, 2020 and 2019: 

	Pension Benefits						Post-Retirement Medical Plan
(in millions)	2021		2020		2019		2021		2020		2019
Components of net periodic benefit cost:
Service cost	$	57.5	$	59.0	$	43.6	$	1.1	$	1.0	$	1.0
Interest cost	5.3		6.9		8.3		0.3		0.4		0.7
Expected return on plan assets	(14.2)		(12.5)		(9.6)		—		—		—
Amortization of prior service cost and actuarial loss	0.1		0.3		0.3		0.7		0.6		0.5
Net periodic benefit cost	$	48.7	$	53.7	$	42.6	$	2.1	$	2.0	$	2.2

Schedule of pre-tax amounts recognized in other comprehensive income (loss)

The pre-tax amounts recognized in other comprehensive (income) loss for the years ended December 31, 2021, 2020 and 2019 were as follows: 

	Pension Benefits						Post-Retirement Medical Plan
(in millions)	2021		2020		2019		2021		2020		2019
Prior service costs	$	—	$	—	$	—	$	—	$	1.8	$	—
Net actuarial (gain) loss	(21.1)		(5.9)		(10.7)		(4.0)		1.9		(2.3)
Amortization of losses and prior service cost	(0.1)		(0.3)		(0.3)		(0.7)		(0.6)		(0.5)
Total changes in other comprehensive (income) loss	$	(21.2)	$	(6.2)	$	(11.0)	$	(4.7)	$	3.1	$	(2.8)

Schedule of pre-tax amounts in accumulated other comprehensive loss not yet recognized as components of net periodic costs

The pre-tax amounts in accumulated other comprehensive income (loss) as of December 31, 2021, and 2020 that have not yet been recognized as components of net periodic costs were as follows: 

	Pension Benefits				Post-Retirement Medical Plan
(in millions)	2021		2020		2021		2020
Prior service costs	$	(0.5)	$	(0.6)	$	(4.3)	$	(5.0)
Net actuarial gain (loss)	12.7		(8.4)		7.8		3.9
Total	$	12.2	$	(9.0)	$	3.5	$	(1.1)

Schedule of assumptions used

The weighted average assumptions used to determine the benefit obligations as of December 31, 2021, and 2020 were as follows: 

	Qualified Plan				Supplemental Plan				Post-Retirement Medical Plan
	2021		2020		2021		2020		2021		2020
Discount rate - benefit obligations	2.78	%	2.36	%	2.73	%	2.21	%	2.46	%	1.90	%
Rate of compensation increase	4.26	%	4.28	%	4.50	%	4.50	%	—		—

The weighted average assumptions used to determine the net periodic benefit costs for the years ended December 31, 2021, 2020 and 2019 were as follows:

	Qualified Plan			Supplemental Plan			Post-Retirement Medical Plan
	2021	2020	2019	2021	2020	2019	2021	2020	2019
Discount rates:
Effective rate for service cost	2.40%	2.94%	4.24%	2.26%	2.79%	4.19%	2.35%	2.86%	4.21%
Effective rate for interest cost	1.74%	2.50%	3.92%	1.53%	2.33%	3.83%	1.28%	2.21%	3.69%
Effective rate for interest on service cost	1.92%	2.59%	4.00%	1.75%	2.42%	3.90%	2.11%	2.68%	4.09%
Cash balance interest credit rate	1.57%	2.19%	3.34%	1.57%	2.19%	3.34%	N/A	N/A	N/A
Expected long-term rate of return on plan assets	5.25%	5.75%	6.00%	N/A	N/A	N/A	N/A	N/A	N/A
Rate of compensation increase	4.28%	4.28%	4.55%	4.50%	4.50%	5.00%	N/A	N/A	N/A

Schedule of assumed health care cost trend rates

The assumed health care cost trend rates as of December 31, 2021 and 2020 were as follows: 

	Post-Retirement Medical Plan
	2021		2020
Health care cost trend rate assumed for next year	5.2	%	5.4	%
Rate to which the cost trend rate was assumed to decline (the ultimate trend rate)	4.0	%	4.5	%
Year that the rate reaches the ultimate trend rate	2046		2038

Schedule of fair value of assets of the Company's Qualified Plan

The table below presents the fair values of the assets of the Company’s Qualified Plan as of December 31, 2021 and 2020 by level of fair value hierarchy. Assets consist of collective trusts and are measured at fair value based on the closing net asset value (“NAV”) as determined by the fund manager and reported daily. As noted above, the Company’s post-retirement medical plan is funded on a pay-as-you-go basis and has no assets. 

	Fair Value Measurements Using NAV as Practical Expedient
	December 31,
(in millions)	2021		2020
Equities:
Domestic equities	$	73.9	$	64.4
Developed international equities	37.7		38.2
Global low volatility equities	24.1		22.5
Emerging market equities	24.8		20.7
Fixed-income	121.6		95.7
Real Estate	23.2		13.3
Cash and cash equivalents	1.0		1.0
Total	$	306.3	$	255.8