Business Segment Information (Tables)

6 Months Ended

Jun. 30, 2014

Segment Reporting [Abstract]

Schedule Of Operating Income Derived From Revenues And Expenses By Segment

	Three Months Ended June 30,						Six Months Ended June 30,
(in millions)	2014			2013			2014			2013
Revenues
Gas Distribution Operations
Unaffiliated	$	616.5		$	572.4		$	2,181.9		$	1,717.3
Intersegment	0.1			—			0.3			0.2
Total	616.6			572.4			2,182.2			1,717.5
Columbia Pipeline Group Operations
Unaffiliated	311.3			242.3			614.5			500.7
Intersegment	32.2			31.5			74.6			74.5
Total	343.5			273.8			689.1			575.2
Electric Operations
Unaffiliated	405.3			384.9			855.5			762.3
Intersegment	0.1			0.2			0.3			0.4
Total	405.4			385.1			855.8			762.7
Corporate and Other
Unaffiliated	2.0			1.9			3.7			3.4
Intersegment	128.9			110.0			255.7			231.7
Total	130.9			111.9			259.4			235.1
Eliminations	(161.3		)	(141.7		)	(330.9		)	(306.8		)
Consolidated Gross Revenues	$	1,335.1		$	1,201.5		$	3,655.6		$	2,983.7
Operating Income (Loss)
Gas Distribution Operations	$	59.8		$	50.0		$	361.6		$	284.1
Columbia Pipeline Group Operations	103.7			88.8			262.6			222.3
Electric Operations	62.9			59.5			141.8			124.7
Corporate and Other	(6.8		)	(4.3		)	(12.7		)	(8.2		)
Consolidated Operating Income	$	219.6		$	194.0		$	753.3		$	622.9