Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

Summary of Significant Accounting Policies

Organization

OG&Egenerates, transmits, distributes and sells electric energy in Oklahoma and western Arkansas.  Its operationsare subject to regulation by the OCC, the APSC and the FERC. OG&E was incorporated in 1902 under the laws of the Oklahoma Territory. OG&E is the largest electric utility in Oklahoma and its franchised service territory includes Fort Smith, Arkansas and the surrounding communities.  OG&E sold its retail natural gas business in 1928 and is no longer engaged in the natural gas distribution business.OG&E is a wholly-owned subsidiary of OGE Energy, an energy and energy services provider offering physical delivery and related services for both electricity and natural gas primarily in the south central United States.

Basis of Presentation

The CondensedFinancial Statements included herein have been prepared by OG&E, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations; however, OG&E believes that the disclosures are adequate to prevent the information presented from being misleading.

In the opinion of management, all adjustments necessary to fairly present thefinancial position of OG&E atSeptember 30, 2016andDecember 31, 2015, the results of its operations for the three and nine months endedSeptember 30, 2016and2015 and its cash flows for thenine months endedSeptember 30, 2016 and 2015, have been included and are of a normal recurring nature except as otherwise disclosed.

Due to seasonal fluctuations and other factors, OG&E'soperating results for thethree and nine months endedSeptember 30, 2016are not necessarily indicative of the results that may be expected for the year endingDecember 31, 2016or for any future period.The CondensedFinancial Statements and Notes thereto should be read in conjunction with the auditedFinancial Statements and Notes thereto included in OG&E's 2015Form 10-K.

Schedule of Regulatory Assets and Liabilities [Text Block]

Accounting Records

The accounting records of OG&E are maintained in accordance with the Uniform System of Accounts prescribed by the FERC and adopted by the OCC and the APSC.  Additionally, OG&E, as a regulated utility, is subject to accounting principles for certain types of rate-regulated activities, which provide that certain incurred costs that would otherwise be charged to expense can be deferred as regulatory assets, based on the expected recovery from customers in future rates.  Likewise, certain actual or anticipated credits that would otherwise reduce expense can be deferred as regulatory liabilities, based on the expected flowback to customers in future rates.  Management's expected recovery of deferred costs and flowback of deferred credits generally results from specific decisions by regulators granting such ratemaking treatment.

OG&E records certain incurred costs and obligations as regulatory assets or liabilities if, based on regulatory orders or other available evidence, it is probable that the costs or obligations will be included in amounts allowable for recovery or refund in future rates.

The following table is a summary of OG&E's regulatory assets and liabilities at:

(In millions)	September 30, 2016		December 31, 2015
Regulatory Assets
Current
Oklahoma demand program rider under recovery (A)	$	48.9	$	36.6
SPP cost tracker rider under recovery (A)	2.4		4.5
Fuel clause under recoveries	0.5		—
Other (A)	7.6		5.4
Total Current Regulatory Assets	$	59.4	$	46.5
Non-Current
Benefit obligations regulatory asset	$	235.0	$	242.2
Income taxes recoverable from customers, net	60.0		56.7
Smart Grid	43.4		43.6
Deferred storm expenses	35.9		27.6
Unamortized loss on reacquired debt	13.7		14.8
Other	16.8		17.3
Total Non-Current Regulatory Assets	$	404.8	$	402.2
Regulatory Liabilities
Current
Fuel clause over recoveries	$	1.4	$	61.3
Other (B)	3.8		7.5
Total Current Regulatory Liabilities	$	5.2	$	68.8
Non-Current
Accrued removal obligations, net	$	260.1	$	254.9
Pension tracker	30.9		17.7
Other (C)	1.0		1.0
Total Non-Current Regulatory Liabilities	$	292.0	$	273.6

(A) Included in Other Current Assets on theCondensedBalance Sheets.

(B) Included in Other Current Liabilities on theCondensedBalance Sheets.

(C) Prior year amount of$1.0 millionreclassified from Deferred Other Liabilities to Non-Current Regulatory Liabilities.

Management continuously monitors the future recoverability of regulatory assets.When in management's judgment future recovery becomes impaired, the amount of the regulatory asset is adjusted, as appropriate.If OG&E were required to discontinue the application of accounting principles for certain types of rate-regulated activities for some or all of its operations, it could result in writing off the related regulatory assets, which could have significant financial effects.

Asset Retirement Obligation Disclosure [Text Block]

Asset Retirement Obligations

The following table summarizes changes to OG&E's asset retirement obligations during thenine months endedSeptember 30, 2016and2015.

	Nine Months Ended September 30,
(In millions)	2016			2015
Balance at January 1	$	63.3		$	58.6
Accretion expense	2.1			1.9
Liabilities settled	(0.2		)	(0.4		)
Revisions in estimated cash flows	—			1.6
Balance at September 30	$	65.2		$	61.7

Reclassifications [Text Block]

Reclassifications

Certain prior-year amounts have been reclassified to conform to the current year presentation.

TheDecember 31, 2015 Condensed Balance Sheethas been adjusted for the reclassification of$16.3 millionof debt issuance costs from Total Deferred Charges and Other Assets to Long-Term Debt to be consistent with the2016presentation due to the adoption of ASU 2015-03, "Simplifying the Presentation of Debt Issuance Costs," in2016.