SEGMENTS OF BUSINESS (Tables)

9 Months Ended

Sep. 30, 2013

Segment Reporting [Abstract]

Schedule of segment revenues and net income (loss) attributed to common shareholders

The tables below present information related to our reportable segments:

	Regulated Operations											Nonutility and Nonregulated Operations
(Millions)	Natural Gas Utility			Electric Utility			Electric Transmission Investment		Total Regulated Operations			Integrys Energy Services			Holding Company and Other			Reconciling Eliminations			Integrys Energy Group Consolidated
Three Months Ended
September 30, 2013
External revenues	$	253.0		$	353.9		$	—	$	606.9		$	512.7		$	10.1		$	—		$	1,129.7
Intersegment revenues	4.2			0.1			—		4.3			0.3			0.3			(4.9		)	—
Depreciation and amortization expense	35.6			25.7			—		61.3			2.9			5.5			(0.1		)	69.6
Earnings from equity method investments	—			—			22.3		22.3			0.5			0.3			—			23.1
Miscellaneous income	0.4			2.8			—		3.2			6.2			5.7			(3.0		)	12.1
Interest expense	12.7			8.8			—		21.5			0.5			14.1			(3.0		)	33.1
Provision (benefit) for income taxes	(19.5		)	25.1			8.6		14.2			6.6			(2.8		)	—			18.0
Net income (loss) from continuing operations	(19.5		)	40.9			13.7		35.1			12.3			(8.0		)	—			39.4
Discontinued operations	—			—			—		—			(0.6		)	—			—			(0.6		)
Preferred stock dividends of subsidiary	(0.1		)	(0.6		)	—		(0.7		)	—			—			—			(0.7		)
Net income (loss) attributed to common shareholders	(19.6		)	40.3			13.7		34.4			11.7			(8.0		)	—			38.1

	Regulated Operations											Nonutility and Nonregulated Operations
(Millions)	Natural Gas Utility			Electric Utility			Electric Transmission Investment		Total Regulated Operations			Integrys Energy Services			Holding Company and Other			Reconciling Eliminations			Integrys Energy Group Consolidated
Three Months Ended
September 30, 2012
External revenues	$	215.5		$	366.8		$	—	$	582.3		$	335.5		$	9.9		$	—		$	927.7
Intersegment revenues	4.5			—			—		4.5			0.1			0.3			(4.9		)	—
Depreciation and amortization expense	33.2			22.3			—		55.5			2.7			4.8			(0.1		)	62.9
Earnings from equity method investments	—			—			21.7		21.7			0.5			—			—			22.2
Miscellaneous income	0.1			0.9			—		1.0			0.3			5.7			(3.9		)	3.1
Interest expense	11.7			8.9			—		20.6			0.5			12.7			(3.9		)	29.9
Provision (benefit) for income taxes	(11.5		)	19.5			8.3		16.3			16.1			(2.8		)	—			29.6
Net income (loss) from continuing operations	(13.9		)	47.8			13.4		47.3			32.2			(5.2		)	—			74.3
Discontinued operations	—			—			—		—			(8.0		)	—			—			(8.0		)
Preferred stock dividends of subsidiary	(0.1		)	(0.6		)	—		(0.7		)	—			—			—			(0.7		)
Noncontrolling interest in subsidiaries	—			—			—		—			—			0.1			—			0.1
Net income (loss) attributed to common shareholders	(14.0		)	47.2			13.4		46.6			24.2			(5.1		)	—			65.7

	Regulated Operations											Nonutility and Nonregulated Operations
(Millions)	Natural Gas Utility			Electric Utility			Electric Transmission Investment		Total Regulated Operations			Integrys Energy Services			Holding Company and Other			Reconciling Eliminations			Integrys Energy Group Consolidated
Nine Months Ended
September 30, 2013
External revenues	$	1,412.4		$	1,012.7		$	—	$	2,425.1		$	1,470.7		$	28.1		$	—		$	3,923.9
Intersegment revenues	8.6			0.1			—		8.7			0.9			1.0			(10.6		)	—
Depreciation and amortization expense	100.1			73.0			—		173.1			8.4			14.9			(0.4		)	196.0
Earnings from equity method investments	—			—			66.0		66.0			1.2			1.0			—			68.2
Miscellaneous income	0.8			6.6			—		7.4			8.0			18.0			(10.1		)	23.3
Interest expense	37.3			26.4			—		63.7			1.5			35.9			(10.1		)	91.0
Provision (benefit) for income taxes	43.1			56.9			25.3		125.3			11.7			(12.7		)	—			124.3
Net income (loss) from continuing operations	72.0			94.5			40.7		207.2			22.5			(12.0		)	—			217.7
Discontinued operations	—			—			—		—			(1.2		)	5.9			—			4.7
Preferred stock dividends of subsidiary	(0.4		)	(1.9		)	—		(2.3		)	—			—			—			(2.3		)
Noncontrolling interest in subsidiaries	—			—			—		—			—			0.1			—			0.1
Net income (loss) attributed to common shareholders	71.6			92.6			40.7		204.9			21.3			(6.0		)	—			220.2

	Regulated Operations											Nonutility and Nonregulated Operations
(Millions)	Natural Gas Utility			Electric Utility			Electric Transmission Investment		Total Regulated Operations			Integrys Energy Services			Holding Company and Other			Reconciling Eliminations			Integrys Energy Group Consolidated
Nine Months Ended
September 30, 2012
External revenues	$	1,131.3		$	985.6		$	—	$	2,116.9		$	873.7		$	24.6		$	—		$	3,015.2
Intersegment revenues	8.1			—			—		8.1			0.6			1.5			(10.2		)	—
Depreciation and amortization expense	98.3			66.4			—		164.7			7.4			15.9			(0.4		)	187.6
Earnings from equity method investments	—			—			63.8		63.8			1.2			0.5			—			65.5
Miscellaneous income	0.6			1.5			—		2.1			0.8			16.4			(12.1		)	7.2
Interest expense	35.1			27.1			—		62.2			1.5			38.4			(12.1		)	90.0
Provision (benefit) for income taxes	32.6			42.4			24.0		99.0			23.6			(16.0		)	—			106.6
Net income (loss) from continuing operations	53.8			94.3			39.8		187.9			46.0			(9.1		)	—			224.8
Discontinued operations	—			—			—		—			(11.0		)	1.8			—			(9.2		)
Preferred stock dividends of subsidiary	(0.4		)	(1.9		)	—		(2.3		)	—			—			—			(2.3		)
Noncontrolling interest in subsidiaries	—			—			—		—			—			0.1			—			0.1
Net income (loss) attributed to common shareholders	53.4			92.4			39.8		185.6			35.0			(7.2		)	—			213.4