Report of Business Segments (Tables)

12 Months Ended

Dec. 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 years ended December 31, 2016, 2015and2014.

2016	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	2,259.2	$	—		$	—		$	—		$	2,259.2
Cost of sales	880.1		—			—			—			880.1
Other operation and maintenance	469.8		7.7			(11.9		)	—			465.6
Depreciation and amortization	316.4		—			6.2			—			322.6
Taxes other than income	84.0		—			3.6			—			87.6
Operating income (loss)	508.9		(7.7		)	2.1			—			503.3
Equity in earnings of unconsolidated affiliates	—		101.8			—			—			101.8
Other income (expense)	27.7		0.1			(4.3		)	(0.2		)	23.3
Interest expense	138.1		—			4.2			(0.2		)	142.1
Income tax expense (benefit)	114.4		40.5			(6.8		)	—			148.1
Net income	$	284.1	$	53.7		$	0.4		$	—		$	338.2
Investment in unconsolidated affiliates	$	—	$	1,158.6		$	—		$	—		$	1,158.6
Total assets	$	8,669.4	$	1,521.6		$	89.0		$	(340.4	)	$	9,939.6
Capital expenditures	$	660.1	$	—		$	—		$	—		$	660.1

2015	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	2,196.9	$	—		$	—		$	—		$	2,196.9
Cost of sales	865.0		—			—			—			865.0
Other operation and maintenance	444.5		7.5			(0.4		)	—			451.6
Depreciation and amortization	299.9		—			8.0			—			307.9
Taxes other than income	87.1		—			4.1			—			91.2
Operating income (loss)	500.4		(7.5		)	(11.7		)	—			481.2
Equity in earnings of unconsolidated affiliates (A)	—		15.5			—			—			15.5
Other income (expense)	20.0		0.4			0.9			(0.3		)	21.0
Interest expense	146.7		—			2.6			(0.3		)	149.0
Income tax expense (benefit)	104.8		(1.0		)	(6.4		)	—			97.4
Net income	$	268.9	$	9.4		$	(7.0	)	$	—		$	271.3
Investment in unconsolidated affiliates	$	—	$	1,194.4		$	—		$	—		$	1,194.4
Total assets	$	8,525.5	$	1,439.5		$	174.6		$	(559.0	)	$	9,580.6
Capital expenditures	$	551.6	$	—		$	(3.8	)	$	—		$	547.8

(A) In 2015, The Company recorded a$108.4 millionpre-tax charge during the third quarter of 2015 for its share of the goodwill impairment, as adjusted for the basis difference. See Note 3 for further discussion of Enable's goodwill impairment.

2014	Electric Utility		Natural Gas Midstream Operations			Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	2,453.1	$	—		$	—		$	—		$	2,453.1
Cost of sales	1,106.6		—			—			—			1,106.6
Other operation and maintenance	453.2		1.2			(14.8		)	—			439.6
Depreciation and amortization	270.8		—			10.6			—			281.4
Taxes other than income	84.5		—			4.2			—			88.7
Operating income (loss)	538.0		(1.2		)	—			—			536.8
Equity in earnings of unconsolidated affiliates	—		172.6			—			—			172.6
Other income (expense)	7.1		—			0.7			(0.2		)	7.6
Interest expense	141.5		—			7.1			(0.2		)	148.4
Income tax expense (benefit)	111.6		69.1			(7.9		)	—			172.8
Net income	292.0		102.3			1.5			—			395.8
Investment in unconsolidated affiliates	$	—	$	1,318.2		$	—		$	—		$	1,318.2
Total assets	$	8,248.9	$	1,461.2		$	128.6		$	(328.8	)	$	9,509.9
Capital expenditures	$	565.4	$	—		$	10.8		$	(6.9	)	$	569.3