Report of Business Segments (Tables)

6 Months Ended

Jun. 30, 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 during the three and six months endedJune 30, 2016 and 2015.

Three Months Ended June 30, 2016	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	551.4	$	—		$	—		$	—		$	551.4
Cost of sales	197.7		—			—			—			197.7
Other operation and maintenance	124.8		7.8			(5.0		)	—			127.6
Depreciation and amortization	78.4		—			1.7			—			80.1
Taxes other than income	19.1		—			1.0			—			20.1
Operating income (loss)	131.4		(7.8		)	2.3			—			125.9
Equity in earnings of unconsolidated affiliates	—		16.7			—			—			16.7
Other income (expense)	7.0		—			(1.4		)	(0.1		)	5.5
Interest expense	35.0		—			1.1			(0.1		)	36.0
Income tax expense (benefit)	31.1		9.3			0.2			—			40.6
Net income (loss)	$	72.3	$	(0.4	)	$	(0.4	)	$	—		$	71.5
Investment in unconsolidated affiliates	$	—	$	1,168.8		$	—		$	—		$	1,168.8
Total assets	$	8,380.2	$	1,481.8		$	94.9		$	(297.7	)	$	9,659.2

Three Months Ended June 30, 2015	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	549.9	$	—		$	—		$	—		$	549.9
Cost of sales	210.9		—			—			—			210.9
Other operation and maintenance	115.6		0.2			(2.6		)	—			113.2
Depreciation and amortization	74.3		—			1.9			—			76.2
Taxes other than income	21.6		—			0.8			—			22.4
Operating income (loss)	127.5		(0.2		)	(0.1		)	—			127.2
Equity in earnings of unconsolidated affiliates	—		28.2			—			—			28.2
Other income (expense)	4.4		—			0.8			(0.1		)	5.1
Interest expense	37.3		—			0.8			(0.1		)	38.0
Income tax expense (benefit)	25.6		10.0			(0.6		)	—			35.0
Net income (loss)	$	69.0	$	18.0		$	0.5		$	—		$	87.5
Investment in unconsolidated affiliates	$	—	$	1,309.2		$	—		$	—		$	1,309.2
Total assets	$	8,315.7	$	1,486.6		$	121.8		$	(348.0	)	$	9,576.1

Six Months Ended June 30, 2016	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	984.5	$	—		$	—		$	—		$	984.5
Cost of sales	375.6		—			—			—			375.6
Other operation and maintenance	241.1		8.0			(7.6		)	—			241.5
Depreciation and amortization	155.1		—			3.5			—			158.6
Taxes other than income	42.7		—			2.3			—			45.0
Operating income (loss)	170.0		(8.0		)	1.8			—			163.8
Equity in earnings of unconsolidated affiliates	—		45.0			—			—			45.0
Other income (expense)	12.3		—			(1.1		)	(0.2		)	11.0
Interest expense	70.5		—			2.0			(0.2		)	72.3
Income tax expense (benefit)	33.4		19.4			(2.0		)	—			50.8
Net income (loss)	$	78.4	$	17.6		$	0.7		$	—		$	96.7
Investment in unconsolidated affiliates	$	—	$	1,168.8		$	—		$	—		$	1,168.8
Total assets	$	8,380.2	$	1,481.8		$	94.9		$	(297.7	)	$	9,659.2

Six Months Ended June 30, 2015	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	1,030.0	$	—		$	—		$	—		$	1,030.0
Cost of sales	422.5		—			—			—			422.5
Other operation and maintenance	229.9		1.0			(6.0		)	—			224.9
Depreciation and amortization	148.1		—			4.0			—			152.1
Taxes other than income	44.7		—			2.2			—			46.9
Operating income (loss)	184.8		(1.0		)	(0.2		)	—			183.6
Equity in earnings of unconsolidated affiliates	—		59.9			—			—			59.9
Other income (expense)	7.3		—			3.3			(0.1		)	10.5
Interest expense	74.1		—			1.4			(0.1		)	75.4
Income tax expense (benefit)	31.9		18.1			(2.1		)	—			47.9
Net income (loss)	$	86.1	$	40.8		$	3.8		$	—		$	130.7
Investment in unconsolidated affiliates	$	—	$	1,309.2		$	—		$	—		$	1,309.2
Total assets	$	8,315.7	$	1,486.6		$	121.8		$	(348.0	)	$	9,576.1