Report of Business Segments (Details) - USD ($) $ in Millions		11 Months Ended		12 Months Ended
		Dec. 02, 2021		Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating revenues				$ 3,653.7	$ 2,122.3		$ 2,231.6
Fuel, purchased power and direct transmission expense				2,127.6	644.6		786.9
Other operation and maintenance				463.1	462.8		491.8
Depreciation and amortization				416.0	391.3		355.0
Taxes other than income				102.8	101.4		93.6
Operating income (loss)				544.2	522.2		504.3
Equity in earnings of unconsolidated affiliates		$ 169.8	[1]	169.8	(668.0)	[1],[2]	113.9	[1]
Other income (expense)				(21.6)	3.2		(6.9)
Interest expense				158.3	158.5		147.9
Income tax expense (benefit)				141.2	(127.4)		29.8
NET INCOME (LOSS)				737.3	(173.7)		433.6
Investment in unconsolidated affiliates				0.0	374.3		1,132.9
Total assets				12,606.4	10,718.8		11,024.3
Capital expenditures				778.5	650.5		635.5
Equity Method Investment, Other than Temporary Impairment	[3]	$ 0.0			(780.0)		0.0
Gain (Loss) on Disposition of Assets				344.4	0.0		0.0
Electric Utility [Member]
Segment Reporting Information [Line Items]
Operating revenues				3,653.7	2,122.3		2,231.6
Fuel, purchased power and direct transmission expense				2,127.6	644.6		786.9
Other operation and maintenance				464.7	464.4		492.5
Depreciation and amortization				416.0	391.3		355.0
Taxes other than income				99.3	97.2		89.5
Operating income (loss)				546.1	524.8		507.7
Equity in earnings of unconsolidated affiliates				0.0	0.0	[2]	0.0
Other income (expense)				7.7	4.1		3.1
Interest expense				152.0	154.8		140.5
Income tax expense (benefit)				41.8	34.7		20.1
NET INCOME (LOSS)				360.0	339.4		350.2
Investment in unconsolidated affiliates					0.0		0.0
Total assets				11,688.0	10,489.0		10,076.6
Capital expenditures				778.5	650.5		635.5
Gain (Loss) on Disposition of Assets				0.0
Natural Gas Midstream Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues				0.0	0.0		0.0
Fuel, purchased power and direct transmission expense				0.0	0.0		0.0
Other operation and maintenance				1.6	1.7		2.8
Depreciation and amortization				0.0	0.0		0.0
Taxes other than income				0.2	0.4		0.4
Operating income (loss)				(1.8)	(2.1)		(3.2)
Equity in earnings of unconsolidated affiliates				169.8	(668.0)	[2]	113.9
Other income (expense)				(26.4)	(2.9)		(8.6)
Interest expense				0.0	0.0		0.0
Income tax expense (benefit)				101.0	(158.0)		20.7
NET INCOME (LOSS)				385.0	(515.0)		81.4
Investment in unconsolidated affiliates					374.3		1,132.9
Total assets				786.6	378.1		1,135.4
Capital expenditures				0.0	0.0		0.0
Gain (Loss) on Disposition of Assets				344.4
Other Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues				0.0	0.0		0.0
Fuel, purchased power and direct transmission expense				0.0	0.0		0.0
Other operation and maintenance				(3.2)	(3.3)		(3.5)
Depreciation and amortization				0.0	0.0		0.0
Taxes other than income				3.3	3.8		3.7
Operating income (loss)				(0.1)	(0.5)		(0.2)
Equity in earnings of unconsolidated affiliates				0.0	0.0	[2]	0.0
Other income (expense)				(2.0)	3.6		2.2
Interest expense				7.2	5.3		11.0
Income tax expense (benefit)				(1.6)	(4.1)		(11.0)
NET INCOME (LOSS)				(7.7)	1.9		2.0
Investment in unconsolidated affiliates					0.0		0.0
Total assets				350.3	116.4		107.0
Capital expenditures				0.0	0.0		0.0
Gain (Loss) on Disposition of Assets				0.0
Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues				0.0	0.0		0.0
Fuel, purchased power and direct transmission expense				0.0	0.0		0.0
Other operation and maintenance				0.0	0.0		0.0
Depreciation and amortization				0.0	0.0		0.0
Taxes other than income				0.0	0.0		0.0
Operating income (loss)				0.0	0.0		0.0
Equity in earnings of unconsolidated affiliates				0.0	0.0	[2]	0.0
Other income (expense)				(0.9)	(1.6)		(3.6)
Interest expense				(0.9)	(1.6)		(3.6)
Income tax expense (benefit)				0.0	0.0		0.0
NET INCOME (LOSS)				0.0	0.0		0.0
Investment in unconsolidated affiliates					0.0		0.0
Total assets				(218.5)	(264.7)		(294.7)
Capital expenditures				0.0	$ 0.0		$ 0.0
Gain (Loss) on Disposition of Assets				$ 0.0

[1] For the year ended December 31, 2020, Enable recorded a $225.0 million impairment on its SESH equity method investment. Enable estimated the fair value of this equity method investment was below the carrying value at September 30, 2020 and concluded the decline in value was other than temporary due to the expiration of a transportation contract and the current status of renewal negotiations. The impairment 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

[2] In March 2020, OGE Energy recorded a $780.0 million impairment on its investment in Enable, as further discussed in Notes 5 and 7.

[3] Effective March 31, 2020, OGE Energy estimated the fair value of its investment in Enable was below the book value and concluded the decline in value was not temporary due to the severity of the decline and recent rapid deterioration, as well as the near term future outlook, of the midstream oil and gas industry. Accordingly, OGE Energy recorded a $780.0 million impairment on its investment in Enable in 2020. Further information concerning the fair value method used to measure the impairment on OGE Energy's investment in Enable can be found in Note 7.