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		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
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	418.1							418.1
Other comprehensive income, net of tax	$ 5.8	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
Net Income (Loss), Including portion attributable to noncontrolling interest, Number of Shares			0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	112.9	85.1	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	112.9	85.1	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	0.7		$ 0.0		$ 0.0	0.0		0.0		0.7
Dividends, Common Stock, Cash	(80.6)	45.0	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	(80.6)	45.0	0.0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Number of Shares			0	0	0
Stock-based compensation	2.3	0.6	$ 0.0	$ 0.0	$ 0.0	2.3	0.6	0.0	0.0	0.0
Balance	3,640.8	4,558.0	$ 2.0	$ 100.9	$ (0.1)	1,118.9	1,469.7	2,547.9	2,987.4	(27.9)
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	252.5	223.8	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	252.5	223.8	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	1.6	0.0	$ 0.0		$ 0.0	0.0		0.0		1.6
Dividends, Common Stock, Cash	(82.1)	220.0	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	(82.1)	220.0	0.0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Number of Shares			0	0	0
Stock-based compensation	2.1	0.6	$ 0.0	$ 0.0	$ 0.0	2.1	0.6	0.0	0.0	0.0
Balance	3,814.9	4,562.4	$ 2.0	$ 100.9	$ (0.1)	1,121.0	1,470.3	2,718.3	2,991.2	(26.3)
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		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
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	615.4							615.4
Other comprehensive income, net of tax	$ 10.4	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
Net Income (Loss), Including portion attributable to noncontrolling interest, Number of Shares			0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	73.1	100.7	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	73.1	100.7	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	0.9		$ 0.0		$ 0.0	0.0		0.0		0.9
Dividends, Common Stock, Cash	(82.1)		$ 0.0		$ 0.0	0.0		(82.1)		0.0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Number of Shares			100	0	0
Stock-based compensation	2.3	0.7	$ 0.0	$ 0.0	$ 0.0	2.3	0.7	0.0	0.0	0.0
Balance	4,256.9	4,744.0	$ 2.0	$ 100.9	$ (0.1)	1,127.5	1,472.3	3,143.6	3,170.8	(16.1)
Common Stock, Shares, Outstanding			200,200	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	262.8	253.1	$ 0.0	$ 0.0	$ 0.0	0.0	0.0	262.8	253.1	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	1.7	0.0	$ 0.0		$ 0.0	0.0		0.0		1.7
Dividends, Common Stock, Cash	(82.9)		$ 0.0		$ 0.0	0.0		(82.9)		0.0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Number of Shares			0	0	0
Stock-based compensation	2.2	0.8	$ 0.0	$ 0.0	$ 0.0	2.2	0.8	0.0	0.0	0.0
Balance	$ 4,440.7	$ 4,997.9	$ 2.0	$ 100.9	$ (0.1)	$ 1,129.7	$ 1,473.1	$ 3,323.5	$ 3,423.9	$ (14.4)
Common Stock, Shares, Outstanding			200,200	40,400
Treasury Stock, Common, Shares					0