Report of Business Segments (Tables)

9 Months Ended

Sep. 30, 2014

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

The following tables summarize the results of the Company's business segments during the three and nine months endedSeptember 30, 2014 and 2013.

Three Months Ended September 30, 2014	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	754.7	$	—		$	—		$	—		$	754.7
Cost of sales	305.3		—			—			—			305.3
Other operation and maintenance	111.0		0.3			(3.2		)	—			108.1
Depreciation and amortization	69.4		—			2.3			—			71.7
Taxes other than income	20.6		—			0.9			—			21.5
Operating income (loss)	248.4		(0.3		)	—			—			248.1
Equity in earnings of unconsolidated affiliates	—		44.7			—			—			44.7
Other income (expense)	2.9		—			(0.3		)	(0.1		)	2.5
Interest expense	35.3		—			2.0			(0.1		)	37.2
Income tax expense	58.7		16.2			(4.1		)	—			70.8
Net income (loss)	$	157.3	$	28.2		$	1.8		$	—		$	187.3
Investment in unconsolidated affiliates (at historical cost)	$	—	$	1,311.1		$	—		$	—		$	1,311.1
Total assets	$	8,003.1	$	1,427.2		$	204.1		$	(171.7	)	$	9,462.7

Three Months Ended September 30, 2013	Electric Utility		Natural Gas Midstream Operations		Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	723.2	$	—	$	—		$	—		$	723.2
Cost of sales	273.0		—		—			—			273.0
Other operation and maintenance	105.9		—		(3.7		)	—			102.2
Depreciation and amortization	62.5		—		2.9			—			65.4
Taxes other than income	20.8		—		0.9			—			21.7
Operating income (loss)	261.0		—		(0.1		)	—			260.9
Equity in earnings of unconsolidated affiliates	—		46.0		—			—			46.0
Other income (expense)	4.1		—		(1.4		)	—			2.7
Interest expense	31.6		—		2.1			—			33.7
Income tax expense	62.0		0.2		(1.6		)	0.1			60.7
Net income (loss)	$	171.5	$	45.8	$	(2.0	)	$	(0.1	)	$	215.2
Investment in unconsolidated affiliates (at historical cost)	$	—	$	1,295.8	$	—		$	—		$	1,295.8
Total assets	$	7,704.0	$	1,311.3	$	172.2		$	(43.3	)	$	9,144.2

Nine Months Ended September 30, 2014	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	1,926.9	$	—		$	—		$	—		$	1,926.9
Cost of sales	869.6		—			—			—			869.6
Other operation and maintenance	343.1		0.7			(11.9		)	—			331.9
Depreciation and amortization	198.7		—			8.5			—			207.2
Taxes other than income	63.1		—			3.4			—			66.5
Operating income (loss)	452.4		(0.7		)	—			—			451.7
Equity in earnings of unconsolidated affiliates	—		131.9			—			—			131.9
Other income (expense)	4.5		—			(0.8		)	(0.2		)	3.5
Interest expense	106.7		—			6.0			(0.2		)	112.5
Income tax expense	95.3		49.6			(7.7		)	—			137.2
Net income (loss)	$	254.9	$	81.6		$	0.9		$	—		$	337.4
Investment in unconsolidated affiliates (at historical cost)	$	—	$	1,311.1		$	—		$	—		$	1,311.1
Total assets	$	8,003.1	$	1,427.2		$	204.1		$	(171.7	)	$	9,462.7

Nine Months Ended September 30, 2013	Electric Utility		Natural Gas Midstream Operations		Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	1,753.3	$	630.4	$	—		$	(24.9	)	$	2,358.8
Cost of sales	733.6		489.0		—			(26.0		)	1,196.6
Other operation and maintenance	318.0		60.9		(6.7		)	—			372.2
Depreciation and amortization	185.8		36.8		9.1			—			231.7
Taxes other than income	63.9		10.5		3.7			—			78.1
Operating income (loss)	452.0		33.2		(6.1		)	1.1			480.2
Equity in earnings of unconsolidated affiliates	—		64.5		—			—			64.5
Other income (expense)	9.5		8.9		(4.0		)	(0.5		)	13.9
Interest expense	96.0		10.6		6.1			(0.5		)	112.2
Income tax expense	102.0		16.5		(8.9		)	0.6			110.2
Net income (loss)	263.5		79.5		(7.3		)	0.5			336.2
Less: Net income attributable to noncontrolling interest	—		6.6		—			(0.4		)	6.2
Net income attributable to OGE Energy	$	263.5	$	72.9	$	(7.3	)	$	0.9		$	330.0
Investment in unconsolidated affiliates (at historical cost)	$	—	$	1,295.8	$	—		$	—		$	1,295.8
Total assets	$	7,704.0	$	1,311.3	$	172.2		$	(43.3	)	$	9,144.2