STATEMENTS OF CAPITALIZATION (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
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	$ 100.9us-gaap_CommonStockValue	$ 100.9us-gaap_CommonStockValue
Premium on common stock	918.3	915.4
Retained earnings	1,985.0	1,813.0
Total stockholder's equity	3,004.2us-gaap_StockholdersEquity	2,829.3us-gaap_StockholdersEquity
Total long-term debt	2,655.3us-gaap_LongTermDebt	2,300.2us-gaap_LongTermDebt
Total capitalization	5,659.5	5,129.5
OG&E [Member]
Stockholder's Equity [Abstract]
Unamortized discount	(10.3)	(5.5)
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 August 1, 2034 [Member] \| Senior Notes [Member]
Stockholder's Equity [Abstract]
Long term debt, gross	0	140.0
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	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	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	10.2	10.3
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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This element represents the total consolidated (as applicable) capitalization of the entity which is comprised of its long-term debt and equity instruments. The table may be detailed by subsidiary (legal entity) and include information by type of debt or equity detailed by instrument.

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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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Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Weighted average interest rate of debt outstanding.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cumulative amount of the reporting entity's undistributed earnings or deficit.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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