Accumulated Other Comprehensive Income (Tables)

3 Months Ended

Mar. 31, 2025

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income

The following table presents the changes in the accumulated balances for each component of AOCI (in millions of dollars):

	Quarter Ended March 31,
	2025			2024
Defined Benefit Plans:
Beginning balance	$	19.1		$	11.0
Actuarial loss arising during the period		(0.1	)		—
Amortization of net actuarial gain1		(0.6	)		(0.3	)
Amortization of prior service cost (credit)1		0.9			(0.3	)
Less: income tax (expense) benefit2		(0.1	)		0.1
Other comprehensive income (loss), net of tax		0.1			(0.5	)
Ending balance	$	19.2		$	10.5
Cash Flow Hedges:
Beginning balance	$	1.4		$	2.1
Unrealized gain (loss) on cash flow hedges		8.7			(4.2	)
Less: income tax (expense) benefit		(2.0	)		1.0
Net unrealized gain (loss) on cash flow hedges		6.7			(3.2	)
Reclassification of unrealized (gain) loss upon settlement of cash flow hedges		(5.5	)		2.1
Less: income tax benefit (expense)2		1.3			(0.5	)
Net (gain) loss reclassified from AOCI to Net income		(4.2	)		1.6
Other comprehensive income (loss), net of tax		2.5			(1.6	)
Ending balance3	$	3.9		$	0.5
Total AOCI ending balance	$	23.1		$	11.0

1.Amounts amortized out of AOCI related to pension and other postretirement and postemployment benefits were included within Net periodic postretirement and postemployment benefit cost (see Note 3).

2.Income tax amounts reclassified out of AOCI were included as a component of Income tax provision.

3.As of March 31, 2025, we estimate a net mark-to-market gain before tax of $4.4 million in AOCI will be reclassified into Net income upon settlement within the next 12 months.