Report of Business Segments (Tables)

12 Months Ended

Dec. 31, 2013

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 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