Report of Business Segments (Tables)

3 Months Ended

Mar. 31, 2016

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 three months endedMarch 31, 2016and2015.

Three Months Ended March 31, 2016	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	433.1	$	—		$	—		$	—		$	433.1
Cost of sales	177.9		—			—			—			177.9
Other operation and maintenance	116.3		0.2			(2.6		)	—			113.9
Depreciation and amortization	76.7		—			1.8			—			78.5
Taxes other than income	23.6		—			1.3			—			24.9
Operating income (loss)	38.6		(0.2		)	(0.5		)	—			37.9
Equity in earnings of unconsolidated affiliates	—		28.3			—			—			28.3
Other income (expense)	5.3		—			0.3			(0.1		)	5.5
Interest expense	35.5		—			0.9			(0.1		)	36.3
Income tax expense (benefit)	2.3		10.1			(2.2		)	—			10.2
Net income	$	6.1	$	18.0		$	1.1		$	—		$	25.2
Investment in unconsolidated affiliates	$	—	$	1,187.4		$	—		$	—		$	1,187.4
Total assets	$	8,288.5	$	1,467.9		$	98.7		$	(331.8	)	$	9,523.3

Three Months Ended March 31, 2015	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	480.1	$	—		$	—		$	—		$	480.1
Cost of sales	211.6		—			—			—			211.6
Other operation and maintenance	114.3		0.8			(3.4		)	—			111.7
Depreciation and amortization	73.8		—			2.1			—			75.9
Taxes other than income	23.1		—			1.4			—			24.5
Operating income (loss)	57.3		(0.8		)	(0.1		)	—			56.4
Equity in earnings of unconsolidated affiliates	—		31.7			—			—			31.7
Other income (expense)	2.9		—			2.5			—			5.4
Interest expense	36.8		—			0.6			—			37.4
Income tax expense (benefit)	6.3		8.1			(1.5		)	—			12.9
Net income	$	17.1	$	22.8		$	3.3		$	—		$	43.2
Investment in unconsolidated affiliates	$	—	$	1,315.7		$	—		$	—		$	1,315.7
Total assets	$	8,217.7	$	1,476.7		$	122.3		$	(332.4	)	$	9,484.3