CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Millions	Total	OG&E [Member]	Common Stock	Common Stock OG&E [Member]	Treasury Stock [Member]	Premium on Common Stock	Premium on Common Stock OG&E [Member]	Retained Earnings	Retained Earnings OG&E [Member]	Accumulated Other Comprehensive Income (Loss)
Changes in Stockholders' Equity
Balance	$ 3,631.8	$ 3,975.6	$ 2.0	$ 100.9	$ (5.3)	$ 1,122.6	$ 938.6	$ 2,544.6	$ 2,936.1	$ (32.1)
Common Stock, Shares, Outstanding			200,100	40,400
Treasury Stock, Common, Shares					100
Net Income (Loss), Including portion attributable to noncontrolling interest, Number of Shares			0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	52.7	$ 11.2	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	52.7	11.2	0.0
Proceeds from Contributed Capital, Shares		0
Other Comprehensive Income (Loss), Net of Tax, Number of Shares			0		0
Dividends, Common Stock, Cash, Number of Shares			0		0
Other comprehensive income, net of tax	3.5	$ 0.0	$ 0.0		$ 0.0	0.0		0.0		3.5
Dividends, Common Stock, Cash	(81.7)		$ 0.0		$ 0.0	0.0		(81.7)		0.0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Number of Shares			0	0	(100)
Stock-based compensation	$ (0.8)	0.5	$ 0.0	$ 0.0	$ 5.2	(6.0)	0.5	0.0	0.0	0.0
Proceeds from Contributed Capital		530.0		0.0			530.0		0.0
Common Stock, Dividends, Per Share, Declared	$ 0.4025
Balance	$ 3,605.5	4,517.3	$ 2.0	$ 100.9	$ (0.1)	1,116.6	1,469.1	2,515.6	2,947.3	(28.6)
Common Stock, Shares, Outstanding			200,100	40,400
Treasury Stock, Common, Shares					0
Balance	4,056.3	4,602.8	$ 2.0	$ 100.9	$ (0.1)	1,123.8	1,470.8	2,955.4	3,031.1	(24.8)
Common Stock, Shares, Outstanding			200,100	40,400
Treasury Stock, Common, Shares					0
Net Income (Loss), Including portion attributable to noncontrolling interest, Number of Shares			0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	279.5	39.0	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	279.5	39.0	0.0
Other Comprehensive Income (Loss), Net of Tax, Number of Shares			0		0
Dividends, Common Stock, Cash, Number of Shares			0		0
Other comprehensive income, net of tax	7.8	0.0	$ 0.0		$ 0.0	0.0		0.0		7.8
Dividends, Common Stock, Cash	(82.3)		$ 0.0		$ 0.0	0.0		(82.3)		0.0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Number of Shares			0	0	0
Stock-based compensation	$ 1.4	0.8	$ 0.0	$ 0.0	$ 0.0	1.4	0.8	0.0	0.0	0.0
Common Stock, Dividends, Per Share, Declared	$ 0.4100
Balance	$ 4,262.7	$ 4,642.6	$ 2.0	$ 100.9	$ (0.1)	$ 1,125.2	$ 1,471.6	$ 3,152.6	$ 3,070.1	$ (17.0)
Common Stock, Shares, Outstanding			200,100	40,400
Treasury Stock, Common, Shares					0