Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Regulatory Assets and Liabilities

The following table presents a summary of OG&E's regulatory assets and liabilities.

	June 30,		December 31,
(In millions)	2025		2024
REGULATORY ASSETS
Current:
Oklahoma fuel clause under recoveries	$	97.9	$	112.7
SPP cost tracker under recoveries (A)		4.6		—
Oklahoma Energy Efficiency Rider under recoveries (A)		—		7.0
Other (A)		6.8		3.8
Total current regulatory assets	$	109.3	$	123.5
Non-current:
Oklahoma deferred storm expenses	$	248.3	$	244.3
Pension tracker		91.6		94.7
Benefit obligations regulatory asset		87.6		90.8
Arkansas Winter Storm Uri costs		59.0		63.0
Oklahoma SAP S/4 HANA deferred expenses		16.4		14.3
Sooner Dry Scrubbers		16.0		16.4
Arkansas deferred pension expenses		10.1		11.0
Oklahoma vegetation management program deferred costs		7.1		6.4
Unamortized loss on reacquired debt		5.9		6.3
COVID-19 impacts		4.8		5.4
Arkansas capacity power purchase agreements		4.3		3.5
Other		10.7		12.0
Total non-current regulatory assets	$	561.8	$	568.1
REGULATORY LIABILITIES
Current:
Arkansas fuel clause over recoveries	$	6.3	$	9.3
Oklahoma Energy Efficiency Rider over recoveries (B)		3.8		—
Oklahoma Investment Tax Credit over recoveries (B)		2.8		6.1
Other (B)		0.5		4.9
Total current regulatory liabilities	$	13.4	$	20.3
Non-current:
Income taxes refundable to customers, net	$	748.6	$	780.8
Accrued removal obligations, net		233.1		231.9
Other		3.5		3.7
Total non-current regulatory liabilities	$	985.2	$	1,016.4

(A)Included in Other Current Assets in the condensed balance sheets.

(B)Included in Other Current Liabilities in the condensed balance sheets.

Schedule of Accumulated Other Comprehensive Income (Loss)

The following tables present changes in the components of accumulated other comprehensive income (loss) attributable to OGE Energy during the six months ended June 30, 2025 and 2024. All amounts below are presented net of tax.

(In millions)	Pension Plan and Restoration of Retirement Income Plan			Postretirement Benefit Plans		Total
Balance at December 31, 2024	$	(8.8	)	$	6.1	$	(2.7	)
Amounts reclassified from accumulated other comprehensive income (loss)		0.2			—		0.2
Balance at June 30, 2025	$	(8.6	)	$	6.1	$	(2.5	)

(In millions)	Pension Plan and Restoration of Retirement Income Plan			Postretirement Benefit Plans			Total
Balance at December 31, 2023	$	(12.9	)	$	5.7		$	(7.2	)
Amounts reclassified from accumulated other comprehensive income (loss)		0.2			(0.1	)		0.1
Regulatory classification of certain pension costs		3.9			—			3.9
Balance at June 30, 2024	$	(8.8	)	$	5.6		$	(3.2	)

Reclassified Out of Accumulated Other Comprehensive Income (Loss)

The following table presents significant amounts reclassified out of accumulated other comprehensive income (loss) attributable to OGE Energy by the respective line items in net income during the three and six months ended June 30, 2025 and 2024.

Details about Accumulated Other Comprehensive Income (Loss) Components	Amount Reclassified from Accumulated Other Comprehensive Income (Loss)												Affected Line Item in OGE Energy's Statements of Income
	Three Months Ended						Six Months Ended
	June 30,						June 30,
(In millions)	2025			2024			2025			2024
Amortization of Pension Plan and Restoration of Retirement Income Plan items:
Actuarial losses	$	(0.1	)	$	(0.1	)	$	(0.2	)	$	(0.2	)	(A)
Prior service cost		—			—			(0.1	)		(0.1	)	(A)
		(0.1	)		(0.1	)		(0.3	)		(0.3	)	Income Before Taxes
		—			—			(0.1	)		(0.1	)	Income Tax Expense
	$	(0.1	)	$	(0.1	)	$	(0.2	)	$	(0.2	)	Net Income
Amortization of postretirement benefit plans items:
Actuarial gains	$	—		$	—		$	0.1		$	0.1		(A)
		—			—			0.1			0.1		Income Before Taxes
		—			—			0.1			—		Income Tax Expense
	$	—		$	—		$	—		$	0.1		Net Income
Total reclassifications for the period, net of tax	$	(0.1	)	$	(0.1	)	$	(0.2	)	$	(0.1	)	Net Income

(A)These accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit cost (see Note 10 for additional information).