Other Comprehensive Income (Tables)

6 Months Ended

Jun. 30, 2025

Statement of Comprehensive Income [Abstract]

Reclassification out of Accumulated Other Comprehensive Income

The following table details reclassifications out of AOCI and into Net income. The amounts in parentheses below indicate decreases to Net income in the Consolidated Statements of Income for the period, net of tax:


		Amount Reclassified from AOCI
		Three Months Ended June 30,						Six Months Ended June 30,
	Location on the Consolidated Statements of Income	2025			2024			2025			2024
		(in millions)
Gains and (losses) on cash flow hedges:
Interest rate swaps	Interest expense	$	(0.8	)	$	(0.7	)	$	(1.4	)	$	(1.4	)
Commodity contracts	Fuel, purchased power, and cost of natural gas sold		(0.1	)		(0.6	)		(0.6	)		(3.2	)
		$	(0.9	)	$	(1.3	)	$	(2.0	)	$	(4.6	)
Income tax	Income tax expense		0.2			0.3			0.5			1.0
Total reclassification adjustments related to cash flow hedges, net of tax		$	(0.7	)	$	(1.0	)	$	(1.5	)	$	(3.6	)

Amortization of components of defined benefit plans:
Actuarial (loss)	Operations and maintenance		—			—			(0.1	)		(0.1	)
Total reclassification adjustments related to defined benefit plans, net of tax		$	—		$	—		$	(0.1	)	$	(0.1	)
Total reclassifications		$	(0.7	)	$	(1.0	)	$	(1.6	)	$	(3.7	)

Schedule of Accumulated Other Comprehensive Income (Loss)

Balances by classification included within AOCI, net of tax on the accompanying Consolidated Balance Sheets were as follows:


	Derivatives Designated as Cash Flow Hedges
	Interest Rate Swaps			Commodity Derivatives			Employee Benefit Plans			Total
	(in millions)
As of December 31, 2024	$	(3.8	)	$	(0.3	)	$	(5.3	)	$	(9.4	)
Other comprehensive income (loss) before reclassifications		—			(0.2	)		—			(0.2	)
Amounts reclassified from AOCI		1.1			0.4			0.1			1.6
As of June 30, 2025	$	(2.7	)	$	(0.1	)	$	(5.2	)	$	(8.0	)


	Derivatives Designated as Cash Flow Hedges
	Interest Rate Swaps			Commodity Derivatives			Employee Benefit Plans			Total
	(in millions)
As of December 31, 2023	$	(6.1	)	$	(2.5	)	$	(6.2	)	$	(14.8	)
Other comprehensive income (loss) before reclassifications		—			(0.2	)		—			(0.2	)
Amounts reclassified from AOCI		1.1			2.5			0.1			3.7
As of June 30, 2024	$	(5.0	)	$	(0.2	)	$	(6.1	)	$	(11.3	)