Segments Of Business (Tables)

12 Months Ended

Dec. 31, 2014

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to Alliant Energy’s business segments, products and services and geographic information was as follows (in millions):

	Utility										Non-Regulated,		Alliant Energy
2014	Electric			Gas		Other		Total			Parent and Other		Consolidated
Operating revenues		$2,713.6			$517.5		$66.1		$3,297.2			$53.1		$3,350.3
Depreciation and amortization	347.0			29.9		1.8		378.7			9.4		388.1
Operating income	442.4			53.8		14.0		510.2			33.4		543.6
Interest expense								176.3			4.3		180.6
Equity income from unconsolidated investments, net	(42.8		)	—		—		(42.8		)	2.4		(40.4		)
Income taxes								33.9			10.4		44.3
Net income attributable to Alliant Energy common shareowners								364.5			18.6		383.1
Total assets	9,660.4			913.5		1,016.1		11,590.0			495.9		12,085.9
Investments in equity method subsidiaries	294.3			—		—		294.3			2.3		296.6
Construction and acquisition expenditures	774.8			63.2		0.9		838.9			63.9		902.8

	Utility										Non-Regulated,		Alliant Energy
2013	Electric			Gas		Other		Total			Parent and Other		Consolidated
Operating revenues		$2,689.0			$464.8		$71.3		$3,225.1			$51.7		$3,276.8
Depreciation and amortization	333.0			28.8		1.5		363.3			7.6		370.9
Operating income	444.5			57.3		6.3		508.1			25.8		533.9
Interest expense								166.3			6.5		172.8
Equity income from unconsolidated investments, net	(43.7		)	—		—		(43.7		)	—		(43.7		)
Income taxes								49.3			4.6		53.9
Net income attributable to Alliant Energy common shareowners								349.5			8.8		358.3
Total assets	9,018.6			859.3		732.5		10,610.4			502.0		11,112.4
Investments in equity method subsidiaries	279.1			—		—		279.1			2.3		281.4
Construction and acquisition expenditures	677.3			47.0		7.3		731.6			66.7		798.3

	Utility										Non-Regulated,			Alliant Energy
2012	Electric			Gas		Other		Total			Parent and Other			Consolidated
Operating revenues		$2,589.3			$396.3		$56.7		$3,042.3			$52.2			$3,094.5
Depreciation and amortization	299.3			29.1		1.4		329.8			2.6			332.4
Operating income	426.2			51.5		7.4		485.1			34.6			519.7
Interest expense								158.7			(2.0		)	156.7
Equity (income) loss from unconsolidated investments, net	(42.1		)	—		—		(42.1		)	0.8			(41.3		)
Income taxes								74.8			14.6			89.4
Net income attributable to Alliant Energy common shareowners								300.0			19.8			319.8
Total assets	8,438.8			814.8		966.0		10,219.6			565.9			10,785.5
Investments in equity method subsidiaries	264.3			—		—		264.3			2.3			266.6
Construction and acquisition expenditures	994.0			31.4		0.1		1,025.5			132.6			1,158.1

Schedule of Products and Services

Alliant Energy’s consolidated operating revenues by segment, which were substantially all related to services, were as follows:

	2014		2013		2012
Utility electric operations	81	%	82	%	84	%
Utility gas operations	15	%	14	%	13	%
Utility other	2	%	2	%	2	%
Other	2	%	2	%	1	%
	100	%	100	%	100	%

IPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to IPL’s business segments was as follows (in millions):

2014	Electric		Gas		Other		Total
Operating revenues		$1,493.3		$296.5		$58.3		$1,848.1
Depreciation and amortization	178.7		17.0		1.8		197.5
Operating income	166.8		25.7		16.7		209.2
Interest expense							89.9
Income tax benefit							(51.7		)
Earnings available for common stock							184.4
Total assets	5,398.3		544.1		519.4		6,461.8
Construction and acquisition expenditures	490.0		35.1		0.9		526.0

2013	Electric		Gas		Other		Total
Operating revenues		$1,491.8		$273.9		$53.1		$1,818.8
Depreciation and amortization	173.1		16.5		1.5		191.1
Operating income	173.1		29.8		9.1		212.0
Interest expense							81.3
Income tax benefit							(37.9		)
Earnings available for common stock							173.6
Total assets	4,905.3		518.8		381.9		5,806.0
Construction and acquisition expenditures	365.4		27.5		7.3		400.2

2012	Electric		Gas		Other		Total
Operating revenues		$1,371.1		$226.7		$52.5		$1,650.3
Depreciation and amortization	171.2		16.3		1.4		188.9
Operating income	166.2		24.2		9.9		200.3
Interest expense							78.5
Income tax benefit							(19.8		)
Earnings available for common stock							137.6
Total assets	4,500.9		479.5		476.6		5,457.0
Construction and acquisition expenditures	291.0		16.4		0.1		307.5

WPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to WPL’s business segments was as follows (in millions):

2014	Electric			Gas		Other			Total
Operating revenues		$1,220.3			$221.0		$7.8			$1,449.1
Depreciation and amortization	168.3			12.9		—			181.2
Operating income (loss)	275.6			28.1		(2.7		)	301.0
Interest expense									86.4
Equity income from unconsolidated investments	(42.8		)	—		—			(42.8		)
Income taxes									85.6
Earnings available for common stock									180.1
Total assets	4,262.1			369.4		496.7			5,128.2
Investments in equity method subsidiaries	294.3			—		—			294.3
Construction and acquisition expenditures	284.8			28.1		—			312.9

2013	Electric			Gas		Other			Total
Operating revenues		$1,197.2			$190.9		$18.2			$1,406.3
Depreciation and amortization	159.9			12.3		—			172.2
Operating income (loss)	271.4			27.5		(2.8		)	296.1
Interest expense									85.0
Equity income from unconsolidated investments	(43.7		)	—		—			(43.7		)
Income taxes									87.2
Earnings available for common stock									175.9
Total assets	4,113.3			340.5		350.6			4,804.4
Investments in equity method subsidiaries	279.1			—		—			279.1
Construction and acquisition expenditures	311.9			19.5		—			331.4

2012	Electric			Gas		Other			Total
Operating revenues		$1,218.2			$169.6		$4.2			$1,392.0
Depreciation and amortization	128.1			12.8		—			140.9
Operating income (loss)	260.0			27.3		(2.5		)	284.8
Interest expense									80.2
Equity income from unconsolidated investments	(42.1		)	—		—			(42.1		)
Income taxes									94.6
Earnings available for common stock									162.4
Total assets	3,937.9			335.3		489.4			4,762.6
Investments in equity method subsidiaries	264.3			—		—			264.3
Construction and acquisition expenditures	703.0			15.0		—			718.0