Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

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.

December 31 (In millions)	2022		2021
REGULATORY ASSETS
Current:
Oklahoma fuel clause under recoveries	$	474.3	$	140.4
Arkansas fuel clause under recoveries		40.6		11.5
Oklahoma Energy Efficiency Rider under recoveries (A)		7.7		11.7
Other (A)		4.7		19.0
Total current regulatory assets	$	527.3	$	182.6
Non-current:
Oklahoma deferred storm expenses	$	206.3	$	172.8
Benefit obligations regulatory asset		119.7		109.2
Arkansas Winter Storm Uri costs		78.2		88.9
Pension tracker		57.2		42.9
Sooner Dry Scrubbers		18.1		18.9
Arkansas deferred pension expenses		12.3		12.1
Unamortized loss on reacquired debt		8.0		8.9
COVID-19 impacts		7.7		8.2
Frontier Plant deferred expenses		5.2		6.7
Oklahoma Winter Storm Uri costs		—		747.9
Other		11.6		14.3
Total non-current regulatory assets	$	524.3	$	1,230.8
REGULATORY LIABILITIES
Current:
SPP cost tracker over recovery (B)	$	3.0	$	—
Other (B)		2.5		2.5
Total current regulatory liabilities	$	5.5	$	2.5
Non-current:
Income taxes refundable to customers, net	$	894.7	$	930.7
Accrued removal obligations, net		250.5		296.8
Other		1.9		3.6
Total non-current regulatory liabilities	$	1,147.1	$	1,231.1

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

Included in Other Current Liabilities in the balance sheets.

Summary of Components of Benefit Obligation

The following table presents a summary of the components of the benefit obligations regulatory asset.

December 31 (In millions)	2022		2021
Pension Plan and Restoration of Retirement Income Plan:
Net loss	$	110.0	$	89.6
Postretirement Benefit Plans:
Net loss		9.7		23.2
Prior service cost		—		(3.6	)
Total	$	119.7	$	109.2

Schedule of Jointly Owned Utility Plants

The following tables present OG&E's ownership interest in the jointly-owned McClain Plant and the jointly-owned Redbud Plant, and, as disclosed below, only OG&E's ownership interest is reflected in the property, plant and equipment and accumulated depreciation balances in these tables. The owners of the remaining interests in the McClain Plant and the Redbud Plant are responsible for providing their own financing of capital expenditures. Also, only OG&E's proportionate interests of any direct expenses of the

McClain Plant and the Redbud Plant, such as fuel, maintenance expense and other operating expenses, are included in the applicable financial statement captions in the statements of income.

December 31, 2022 (In millions)	Percentage Ownership			Total Property, Plant and Equipment		Accumulated Depreciation		Net Property, Plant and Equipment
McClain Plant (A)		77	%	$	261.9	$	119.4	$	142.5
Redbud Plant (A)(B)		51	%	$	542.1	$	225.2	$	316.9

(A)Construction work in progress was $0.7 million and $1.5 million for the McClain and Redbud Plants, respectively.

(B)This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $78.2 million.

December 31, 2021 (In millions)	Percentage Ownership			Total Property, Plant and Equipment		Accumulated Depreciation		Net Property, Plant and Equipment
McClain Plant (A)		77	%	$	258.5	$	109.0	$	149.5
Redbud Plant (A)(B)		51	%	$	538.2	$	203.4	$	334.8

(A)Construction work in progress was $0.2 million and $0.2 million for the McClain and Redbud Plants, respectively.

(B)This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $72.8 million.

Summary of Property Plant and Equipment

The following tables present the Registrants' major classes of property, plant and equipment and related accumulated depreciation.

December 31, 2022 (In millions)	Total Property, Plant and Equipment		Accumulated Depreciation		Net Property, Plant and Equipment
OG&E:
Distribution assets	$	5,781.3	$	1,527.1	$	4,254.2
Electric generation assets (A)		5,188.1		1,982.7		3,205.4
Transmission assets (B)		3,180.5		667.9		2,512.6
Intangible plant		384.0		193.6		190.4
Other property and equipment		591.3		213.2		378.1
OG&E property, plant and equipment		15,125.2		4,584.5		10,540.7
Non-OG&E property, plant and equipment		6.1		—		6.1
Total OGE Energy property, plant and equipment	$	15,131.3	$	4,584.5	$	10,546.8

(A)This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $78.3 million.

(B)This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $1.0 million.

December 31, 2021 (In millions)	Total Property, Plant and Equipment		Accumulated Depreciation		Net Property, Plant and Equipment
OG&E:
Distribution assets	$	5,225.8	$	1,477.5	$	3,748.3
Electric generation assets (A)		5,037.9		1,839.0		3,198.9
Transmission assets (B)		3,038.2		627.0		2,411.2
Intangible plant		301.1		171.7		129.4
Other property and equipment		542.7		203.7		339.0
OG&E property, plant and equipment		14,145.7		4,318.9		9,826.8
Non-OG&E property, plant and equipment		6.1		—		6.1
Total OGE Energy property, plant and equipment	$	14,151.8	$	4,318.9	$	9,832.9

(A)This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $72.8 million.

(B)This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.9 million.

Schedule of Change in Asset Retirement Obligation

The following table presents changes to OG&E's asset retirement obligations during the years ended December 31, 2022 and 2021.

(In millions)	2022			2021
Balance at January 1	$	80.2		$	79.6
Accretion expense		0.6			0.6
Liabilities settled		(2.5	)		—
Balance at December 31	$	78.3		$	80.2

Summary of Accumulated Other Comprehensive Income (Loss) (Details)

The following table presents changes in the components of accumulated other comprehensive income (loss) attributable to OGE Energy during 2022 and 2021. All amounts below are presented net of tax.

	Pension Plan and Restoration of Retirement Income Plan						Postretirement Benefit Plans
(In millions)	Net Gain (Loss)			Prior Service Cost (Credit)			Net Gain (Loss)			Prior Service Cost (Credit)			Other Comprehensive Gain (Loss) from Unconsolidated Affiliates			Total
Balance at December 31, 2020	$	(33.9	)	$	(0.2	)	$	1.7		$	1.6		$	(1.3	)	$	(32.1	)
Other comprehensive income (loss) before reclassifications		1.4			(1.1	)		(0.7	)		—			1.3			0.9
Amounts reclassified from accumulated other comprehensive income (loss)		1.6			0.1			0.1			(1.4	)		—			0.4
Settlement cost		6.0			—			—			—			—			6.0
Net current period other comprehensive income (loss)		9.0			(1.0	)		(0.6	)		(1.4	)		1.3			7.3
Balance at December 31, 2021		(24.9	)		(1.2	)		1.1			0.2			—			(24.8	)
Other comprehensive income (loss) before reclassifications		(7.6	)		—			5.5			—			—			(2.1	)
Amounts reclassified from accumulated other comprehensive income (loss)		1.4			0.2			—			(0.2	)		—			1.4
Settlement cost		13.6			—			—			—			—			13.6
Net current period other comprehensive income (loss)		7.4			0.2			5.5			(0.2	)		—			12.9
Balance at December 31, 2022	$	(17.5	)	$	(1.0	)	$	6.6		$	—		$	—		$	(11.9	)

Reclassified Out of Accumulated Other Comprehensive Income (Loss)

The following table presents significant amounts reclassified out of accumulated other comprehensive income (loss) by the respective line items in net income during the years ended December 31, 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
	Year Ended December 31,
(In millions)	2022			2021
Amortization of Pension Plan and Restoration of Retirement Income Plan items:
Actuarial losses	$	(1.6	)	$	(2.5	)	(A)
Prior service cost		(0.3	)		(0.1	)	(A)
Settlement cost		(17.9	)		(8.7	)	(A)
		(19.8	)		(11.3	)	Income Before Taxes
		(4.6	)		(3.6	)	Income Tax Expense
	$	(15.2	)	$	(7.7	)	Net Income
Amortization of postretirement benefit plans items:
Prior service credit	$	0.3		$	1.8		(A)
Actuarial losses		—			(0.1	)	(A)
		0.3			1.7		Income Before Taxes
		0.1			0.4		Income Tax Expense
	$	0.2		$	1.3		Net Income
Total reclassifications for the period, net of tax	$	(15.0	)	$	(6.4	)	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).

Summarized Balance Sheet Financial Information for Equity Method Investment

The following tables present summarized unaudited financial information for 100 percent of Enable as of December 2, 2021 and for the period of January 1, 2021 through December 2, 2021 and the year ended December 31, 2020.

Balance Sheet	December 2, 2021
(In millions)
Current assets	$	594
Non-current assets	$	11,227
Current liabilities	$	1,254
Non-current liabilities	$	3,281

Summarized Income Statement Financial Information for Equity Method Investment

	Period of
Income Statement	January 1, 2021 through December 2, 2021		Year Ended December 31, 2020
(In millions)
Total revenues	$	3,466	$	2,463
Cost of natural gas and NGLs (excluding depreciation and amortization)	$	1,959	$	965
Operating income	$	634	$	465
Net income	$	461	$	52

Reconciliation of Equity in Earnings (Losses) of Unconsolidated Affiliates

The following table presents a reconciliation of OGE Energy's equity in earnings (losses) of unconsolidated affiliates for the period of January 1, 2021 through December 2, 2021 and the year ended December 31, 2020.

	Period of
(In millions)	January 1, 2021 through December 2, 2021			Year Ended December 31, 2020
Enable net income	$	461.0		$	52.0
Differences due to timing of OGE Energy and Enable accounting close		9.0			—
Enable net income used to calculate OGE Energy's equity in earnings	$	470.0		$	52.0
OGE Energy's percent ownership at period end		25.5	%		25.5	%
OGE Energy's portion of Enable net income	$	119.8		$	13.2
Amortization of basis difference and dilution recognition (A)		50.0			98.8
Impairment of OGE Energy's equity method investment in Enable (B)		—			(780.0	)
Equity in earnings (losses) of unconsolidated affiliates (C)	$	169.8		$	(668.0	)

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

(B)During the year ended December 31, 2020, OGE Energy recorded a $780.0 million impairment on its investment in Enable as, effective March 31, 2020, OGE estimated the fair value of its investment in Enable was below the book value and concluded the decline in value was not temporary.

(C)For the year ended December 31, 2020, Enable recorded a $225.0 million impairment on an equity method investment, which ran through OGE Energy's portion of Enable net income and was offset by basis differences that flow through the amortization of basis difference and dilution recognition line item above.

Schedule of Related Party Transactions

The following table presents summarized related party transactions between OG&E and Enable during the period of January 1, 2021 through December 2, 2021 and the year ended December 31, 2020.

	Period of
(In millions)	January 1, 2021 through December 2, 2021			Year Ended December 31, 2020
Operating revenues:
Electricity to power electric compression assets	$	13.3		$	15.1
Fuel, purchased power and direct transmission expense:
Natural gas transportation services	$	32.7		$	32.8
Natural gas purchases (sales)	$	(33.5	)	$	2.7