Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Regulatory Assets and Liabilities [Table Text Block]

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

	September 30,		December 31,
(In millions)	2022		2021
REGULATORY ASSETS
Current:
Oklahoma fuel clause under recoveries	$	467.0	$	140.4
Arkansas fuel clause under recoveries	40.2		11.5
SPP cost tracker under recovery (A)	0.2		9.3
Oklahoma Energy Efficiency Rider under recoveries (A)	—		11.7
Other (A)	6.7		9.7
Total current regulatory assets	$	514.1	$	182.6
Non-current:
Oklahoma Winter Storm Uri costs	$	—	$	747.9
Oklahoma deferred storm expenses	203.3		172.8
Benefit obligations regulatory asset	99.1		109.2
Arkansas Winter Storm Uri costs	80.6		88.9
Pension tracker	47.6		42.9
Sooner Dry Scrubbers	18.3		18.9
Arkansas deferred pension expenses	11.8		12.1
Unamortized loss on reacquired debt	8.3		8.9
COVID-19 impacts	8.0		8.2
Frontier Plant deferred expenses	5.6		6.7
Smart Grid	0.3		3.9
Other	11.0		10.4
Total non-current regulatory assets	$	493.9	$	1,230.8
REGULATORY LIABILITIES
Current:
Oklahoma investment tax credit rider under credit (B)	$	5.3	$	—
Oklahoma Energy Efficiency Rider over recoveries (B)	5.2		—
Other (B)	1.5		2.5
Total current regulatory liabilities	$	12.0	$	2.5
Non-current:
Income taxes refundable to customers, net	$	904.2	$	930.7
Accrued removal obligations, net	272.5		296.8
Other	2.0		3.6
Total non-current regulatory liabilities	$	1,178.7	$	1,231.1

(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) [Table Text Block]

The following tables present changes in the components of accumulated other comprehensive income (loss) attributable to OGE Energy during the nine months ended September 30, 2022 and 2021. 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, 2021	$	(26.1)	$	1.3	$	(24.8)
Other comprehensive income (loss) before reclassifications	—		—		—
Amounts reclassified from accumulated other comprehensive income	1.0		(0.1)		0.9
Settlement cost	9.5		—		9.5
Balance at September 30, 2022	$	(15.6)	$	1.2	$	(14.4)

(In millions)	Pension Plan and Restoration of Retirement Income Plan		Postretirement Benefit Plans		Other Comprehensive Gain (Loss) from Unconsolidated Affiliates		Total
Balance at December 31, 2020	$	(34.1)	$	3.3	$	(1.3)	$	(32.1)
Other comprehensive income before reclassifications	—		—		0.6		0.6
Amounts reclassified from accumulated other comprehensive income (loss)	1.3		(0.9)		—		0.4
Settlement cost	4.8		—		—		4.8
Balance at September 30, 2021	$	(28.0)	$	2.4	$	(0.7)	$	(26.3)

Schedule of Amounts Reclassified out of Accumulated Other Comprehensive Income [Table Text Block]

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 nine months ended September 30, 2022 and 2021.

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				Nine Months Ended
	September 30,				September 30,
(In millions)	2022		2021		2022		2021
Amortization of Pension Plan and Restoration of Retirement Income Plan items:
Actuarial losses	$	(0.4)	$	(0.6)	$	(1.2)	$	(1.8)	(A)
Prior service cost	(0.1)		(0.1)		(0.2)		(0.1)		(A)
Settlement cost	(1.9)		(1.4)		(12.4)		(6.7)		(A)
	(2.4)		(2.1)		(13.8)		(8.6)		Income Before Taxes
	(0.6)		(0.5)		(3.3)		(2.5)		Income Tax Expense
	$	(1.8)	$	(1.6)	$	(10.5)	$	(6.1)	Net Income
Amortization of postretirement benefit plans items:
Prior service credit	$	0.2	$	0.4	$	0.2	$	1.3	(A)
Actuarial losses	—		—		—		(0.1)		(A)
	0.2		0.4		0.2		1.2		Income Before Taxes
	0.1		0.1		0.1		0.3		Income Tax Expense
	$	0.1	$	0.3	$	0.1	$	0.9	Net Income
Total reclassifications for the period, net of tax	$	(1.7)	$	(1.3)	$	(10.4)	$	(5.2)	Net Income

(A)These accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit cost (see Note 11 for additional information).

Reconciliation of Equity in Earnings of Unconsolidated Affiliates [Table Text Block]

The following table presents a reconciliation of OGE Energy's equity in earnings of unconsolidated affiliates for the three and nine months ended September 30, 2021.

(In millions)	Three Months Ended			Nine Months Ended
Enable net income	$	107.0		$	341.0
OGE Energy's percent ownership at period end	25.5		%	25.5		%
OGE Energy's portion of Enable net income	$	27.5		$	87.0
Amortization of basis difference and dilution recognition (A)	13.7			40.9
Equity in earnings of unconsolidated affiliates	$	41.2		$	127.9

(A)Includes loss on dilution, net of proportional basis difference recognition.