Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Summary of Activities Relating to Company's CARO Liabilities

The following table summarizes activity relating to CARO liabilities (in millions of dollars):

	Year Ended December 31,
	2022			2021			2020
Beginning balance	$	7.2		$	6.7		$	6.5
Liabilities added during the period		2.3			—			—
Liabilities settled during the period		(0.1	)		(0.1	)		(0.1	)
Accretion expense		0.7			0.6			0.5
Adjustment to accretion expense due to revisions to    estimated cash flow and timing of expenditure1		—			—			(0.2	)
Ending balance	$	10.1		$	7.2		$	6.7

1.The adjustments to accretion expense had a $0.01 impact on the basic and diluted net income per share for 2020.

Schedule of Changes in Environmental Contingencies

The following table presents the changes in our environmental accrual, which was primarily included in Long-term liabilities (in millions of dollars):

	Year Ended December 31,
	2022			2021			2020
Beginning balance	$	16.8		$	18.7		$	17.0
Additional accruals		3.2			0.1			5.2
Less: expenditures		(2.3	)		(2.0	)		(3.5	)
Ending balance	$	17.7		$	16.8		$	18.7