CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues from contracts with customers	[1]	$ 564.5	$ 492.0	$ 2,185.5	$ 912.4
Other revenues		12.9	11.5	22.5	22.4
Operating revenues		577.4	503.5	2,208.0	934.8
FUEL, PURCHASED POWER AND DIRECT TRANSMISSION EXPENSE		200.0	137.4	1,546.8	272.4
OPERATING EXPENSES
Other operation and maintenance		119.2	117.5	228.5	237.5
Depreciation and amortization		102.9	97.3	201.6	191.7
Taxes other than income		25.8	25.9	53.0	51.5
Operating expenses		247.9	240.7	483.1	480.7
OPERATING INCOME		129.5	125.4	178.1	181.7
OTHER INCOME (EXPENSE)
Equity in earnings (losses) of unconsolidated affiliates		33.5	26.9	86.7	(719.6)	[2]
Allowance for equity funds used during construction		1.6	1.3	2.9	2.6
Other net periodic benefit expense		(1.3)	(1.0)	(2.7)	(1.5)
Other income		6.3	14.1	9.3	21.5
Other expense		(6.7)	(12.4)	(8.7)	(18.5)
Net other income (expense)		33.4	28.9	87.5	(715.5)
INTEREST EXPENSE
Interest on long-term debt		37.8	38.8	76.2	75.4
Allowance for borrowed funds used during construction		(0.7)	(0.5)	(1.5)	(1.0)
Interest on short-term debt and other interest charges		2.8	2.5	4.6	4.7
Interest expense		39.9	40.8	79.3	79.1
INCOME (LOSS) BEFORE TAXES		123.0	113.5	186.3	(612.9)
INCOME TAX EXPENSE (BENEFIT)		10.1	27.6	20.7	(207.0)
NET INCOME (LOSS)		$ 112.9	$ 85.9	$ 165.6	$ (405.9)
BASIC AVERAGE COMMON SHARES OUTSTANDING		200.2	200.2	200.1	200.2
DILUTED AVERAGE COMMON SHARES OUTSTANDING		200.4	200.5	200.2	200.2
BASIC EARNINGS (LOSS) PER AVERAGE COMMON SHARE		$ 0.56	$ 0.43	$ 0.83	$ (2.03)
DILUTED EARNINGS (LOSS) PER AVERAGE COMMON SHARE		$ 0.56	$ 0.43	$ 0.83	$ (2.03)
Other Comprehensive Income (Loss), Net of Tax		$ 0.7	$ 0.9	$ 4.2	$ 0.0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		113.6	86.8	169.8	(405.9)
OG&E [Member]
Revenues from contracts with customers		564.5	492.0	2,185.5	912.4
Other revenues		12.9	11.5	22.5	22.4
Operating revenues		577.4	503.5	2,208.0	934.8
FUEL, PURCHASED POWER AND DIRECT TRANSMISSION EXPENSE		200.0	137.4	1,546.8	272.4
OPERATING EXPENSES
Other operation and maintenance		118.3	117.7	228.6	238.7
Depreciation and amortization		102.9	97.3	201.6	191.7
Taxes other than income		25.0	25.0	50.7	48.9
Operating expenses		246.2	240.0	480.9	479.3
OPERATING INCOME		131.2	126.1	180.3	183.1
OTHER INCOME (EXPENSE)
Allowance for equity funds used during construction		1.6	1.3	2.9	2.6
Other net periodic benefit expense		(1.2)	(1.0)	(2.1)	(1.5)
Other income		1.1	1.1	2.8	2.6
Other expense		(0.3)	(0.9)	(0.7)	(1.4)
Net other income (expense)		1.2	0.5	2.9	2.3
INTEREST EXPENSE
Interest on long-term debt		37.4	38.8	75.8	75.4
Allowance for borrowed funds used during construction		(0.7)	(0.5)	(1.5)	(1.0)
Interest on short-term debt and other interest charges		1.2	1.0	2.0	1.8
Interest expense		37.9	39.3	76.3	76.2
INCOME (LOSS) BEFORE TAXES		94.5	87.3	106.9	109.2
INCOME TAX EXPENSE (BENEFIT)		9.4	8.4	10.6	10.4
NET INCOME (LOSS)		85.1	78.9	96.3	98.8
Other Comprehensive Income (Loss), Net of Tax		0.0	0.0	0.0	0.0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 85.1	$ 78.9	$ 96.3	$ 98.8

[1] In February 2021, Winter Storm Uri resulted in record winter peak demand for electricity and extremely high natural gas and purchased power prices in OG&E's service territory. Operating revenues significantly increased due to increased fuel, purchased power and direct transmission expenses, which are recoverable from customers, as a result of Winter Storm Uri. For further discussion, see Note 15 and "Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operation."

[2] In 2020, OGE Energy recorded a $780.0 million impairment on its investment in Enable, as further discussed in Note 4