STATEMENTS OF CAPITALIZATION - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Stockholder's Equity [Abstract]
Common stock, par value $2.50 per share; authorized 100.0 shares; and outstanding 40.4 and 40.4 shares, respectively	$ 100.9	$ 100.9
Premium on common stock	920.9	918.3
Retained earnings	2,133.9	1,985.0
Total stockholder's equity	3,155.7	3,004.2
Total long-term debt	2,655.6	2,655.3
Less long-term debt due within one year	(110.0)	0.0
Total long-term debt (excluding debt due within one year)	2,545.6	2,655.3
Total Capitalization (including long-term debt due within one year)	5,811.3	5,659.5
OG&E [Member]
Stockholder's Equity [Abstract]
Unamortized discount	(9.8)	(10.3)
OG&E [Member] \| Series Due January 15, 2016 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 110.0	110.0
Debt, Weighted Average Interest Rate	5.15%
OG&E [Member] \| Series Due July 15, 2017 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 125.0	125.0
Debt, Weighted Average Interest Rate	6.50%
OG&E [Member] \| Series Due September 1, 2018 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	6.35%
OG&E [Member] \| Series Due January 15, 2019 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	8.25%
OG&E [Member] \| Series Due July 15, 2027 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 125.0	125.0
Debt, Weighted Average Interest Rate	6.65%
OG&E [Member] \| Series Due April 15, 2028 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 100.0	100.0
Debt, Weighted Average Interest Rate	6.50%
OG&E [Member] \| Series Due January 15, 2036 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 110.0	110.0
Debt, Weighted Average Interest Rate	5.75%
OG&E [Member] \| Series Due February 1, 2038 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 200.0	200.0
Debt, Weighted Average Interest Rate	6.45%
OG&E [Member] \| Series Due June 1, 2040 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	5.85%
OG&E [Member] \| Senior Notes due May 15, 2041 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	5.25%
OG&E [Member] \| Series due May 1, 2043 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	3.90%
OG&E [Member] \| Series due March 15, 2044 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	4.55%
OG&E [Member] \| Series due December 15, 2044 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 250.0	250.0
Debt, Weighted Average Interest Rate	4.00%
OG&E [Member] \| Due August 31, 2062 [Member] \| Long-term Debt [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 10.0	10.2
Debt, Weighted Average Interest Rate	3.70%
Debentures Subject to Mandatory Redemption [Member]
Stockholder's Equity [Abstract]
Total long-term debt	$ 135.4
Debentures Subject to Mandatory Redemption [Member] \| OG&E [Member] \| Garfield Industrial Authority Bond, Due January 1, 2025 [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	47.0	47.0
Debentures Subject to Mandatory Redemption [Member] \| OG&E [Member] \| Muskogee Industrial Authority Bond, Due January 1, 2025 [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	32.4	32.4
Debentures Subject to Mandatory Redemption [Member] \| OG&E [Member] \| Muskogee Industrial Authority Bond, Due June 1, 2027 [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	$ 56.0	$ 56.0

Value received from shareholders in common stock-related transactions that are in excess of par value or stated value and amounts received from other stock-related transactions. Includes only common stock transactions (excludes preferred stock transactions). May be called contributed capital, capital in excess of par, capital surplus, or paid-in capital.

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Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

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