Report of Business Segments

12 Months Ended

Dec. 31, 2013

Segment Reporting [Abstract]

Report of Business Segments

Report of Business Segments

Prior to May 1, 2013, the Company's business was divided into three segments as follows: (i) electric utility, which is engaged in the generation, transmission, distribution and sale of electric energy, (ii) natural gas transportation and storage and (iii) natural gas gathering and processing. On March 14, 2013, OGE Energy entered into a Master Formation Agreement with the ArcLight group and CenterPoint Energy, Inc., pursuant to which OGE Energy, the ArcLight Group and CenterPoint Energy, Inc., agreed to form Enable Midstream Partners to own and operate the midstream businesses of OGE Energy and CenterPoint that will initially be structured as a private limited partnership. The transaction closed on May 1, 2013. As a result, effective May 1, 2013, OGE Energydeconsolidated its interest in Enogex Holdings LLC andbegan accounting for its interest in Enable using the equity method of accounting. The Company's business is now divided into two segments for financial reporting purposes as follows: (i) electric utility and (ii) natural gas midstream operations. The former natural gas transportation and storage segment and natural gas gathering and processing segment have been combined into the natural gas midstream operations segment and have been restated for all prior periods presented. Equity in earnings of unconsolidated affiliates in the natural gas midstream operations segment includes OGE Energy's equity interest in Enable from May 1, 2013 through December 31, 2013. Operating income for the natural gas midstream operations segment represents results of operations for Enogex Holdings LLC through April 30, 2013. Investment in unconsolidated affiliates in the natural gas midstream operations segment represents OGE Energy's investment in Enable at December 31, 2013.  Other Operations primarily includes the operations of the holding company.  Intersegment revenues are recorded at prices comparable to those of unaffiliated customers and are affected by regulatory considerations. In reviewing its segment operating results, the Company focuses on operating income and equity in earnings of unconsolidated affiliates as its measure of segment profit and loss, and, therefore, has presented this information below. The following tables summarize the results of the Company's business segments for the years ended December 31, 2013, 2012and2011.

2013	Electric Utility		Natural Gas Midstream Operations		Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	2,262.2	$	630.4	$	—		$	(24.9	)	$	2,867.7
Cost of sales	965.9		489.0		—			(26.0		)	1,428.9
Other operation and maintenance	438.8		60.9		(10.5		)	—			489.2
Depreciation and amortization	248.4		36.8		12.1			—			297.3
Taxes other than income	83.8		10.5		4.5			—			98.8
Operating income (loss)	$	525.3	$	33.2	$	(6.1	)	$	1.1		$	553.5
Equity in earnings of unconsolidated affiliates	$	—	$	101.9	$	—		$	—		$	101.9
Investment in unconsolidated affiliates (at historical cost)	$	—	$	1,298.8	$	—		$	—		$	1,298.8
Total assets	$	7,694.9	$	1,348.6	$	216.2		$	(125.0	)	$	9,134.7
Capital expenditures	$	797.6	$	181.5	$	11.5		$	—		$	990.6

2012	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	2,141.2	$	1,608.6		$	—		$	(78.6	)	$	3,671.2
Cost of sales	879.1		1,120.1			—			(80.5		)	1,918.7
Other operation and maintenance	446.3		172.9			(17.7		)	—			601.5
Depreciation and amortization	248.7		108.8			13.5			—			371.0
Impairment of assets	—		0.4			—			—			0.4
Gain on insurance proceeds	—		(7.5		)	—			—			(7.5		)
Taxes other than income	77.7		28.3			4.2			—			110.2
Operating income (loss)	$	489.4	$	185.6		$	—		$	1.9		$	676.9
Total assets	$	7,222.4	$	2,681.3		$	242.6		$	(224.1	)	$	9,922.2
Capital expenditures	$	704.4	$	506.5		$	18.3		$	—		$	1,229.2

2011	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	2,211.5	$	1,787.1		$	—		$	(82.7	)	$	3,915.9
Cost of sales	1,013.5		1,346.6			—			(82.2		)	2,277.9
Other operation and maintenance	436.0		162.5			(17.3		)	—			581.2
Depreciation and amortization	216.1		77.6			13.4			—			307.1
Impairment of assets	—		6.3			—			—			6.3
Gain on insurance proceeds	—		(3.0		)	—			—			(3.0		)
Taxes other than income	73.6		22.0			4.1			—			99.7
Operating income (loss)	$	472.3	$	175.1		$	(0.2	)	$	(0.5	)	$	646.7
Total assets	$	6,620.9	$	2,289.0		$	155.0		$	(158.9	)	$	8,906.0
Capital expenditures	$	844.5	$	612.5		$	13.8		$	—		$	1,470.8