Segments Of Business (Tables)

12 Months Ended

Dec. 31, 2016

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to Alliant Energy’s business segments, which represent the services provided to its customers, was as follows (in millions):

	Utility											Non-Regulated,			Alliant Energy
2016	Electric			Gas		Other			Total			Parent and Other			Consolidated
Operating revenues		$2,875.5			$355.4		$48.6			$3,279.5			$40.5			$3,320.0
Depreciation and amortization	367.0			34.2		2.1			403.3			8.3			411.6
Operating income (loss)	571.9			30.7		(4.8		)	597.8			(60.8		)	537.0
Interest expense									194.6			1.6			196.2
Equity (income) loss from unconsolidated investments, net	(39.8		)	—		—			(39.8		)	0.2			(39.6		)
Income tax expense (benefit)									87.4			(28.0		)	59.4
Net income (loss) attributable to Alliant Energy common shareowners									406.0			(34.5		)	371.5
Total assets	11,040.5			1,091.1		781.0			12,912.6			461.2			13,373.8
Investments in equity method subsidiaries	325.3			—		—			325.3			0.7			326.0
Construction and acquisition expenditures	1,005.5			137.1		0.1			1,142.7			54.1			1,196.8

	Utility										Non-Regulated,			Alliant Energy
2015	Electric			Gas		Other		Total			Parent and Other			Consolidated
Operating revenues		$2,770.5			$381.2		$57.9		$3,209.6			$44.0			$3,253.6
Depreciation and amortization	358.6			31.1		1.8		391.5			9.8			401.3
Operating income	514.1			34.6		1.9		550.6			26.4			577.0
Interest expense								189.2			(2.1		)	187.1
Equity (income) loss from unconsolidated investments, net	(35.1		)	—		—		(35.1		)	1.3			(33.8		)
Income taxes								60.2			10.2			70.4
Net income attributable to Alliant Energy common shareowners								362.3			15.9			378.2
Total assets	10,211.3			939.3		828.9		11,979.5			515.7			12,495.2
Investments in equity method subsidiaries	302.0			—		—		302.0			0.9			302.9
Construction and acquisition expenditures	855.8			106.4		1.4		963.6			70.7			1,034.3

	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 (loss) from unconsolidated investments, net	(42.8		)	—		—		(42.8		)	2.4		(40.4		)
Income taxes								36.4			7.9		44.3
Net income attributable to Alliant Energy common shareowners								362.0			21.1		383.1
Total assets	9,660.4			913.5		993.9		11,567.8			495.7		12,063.5
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

IPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to IPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2016	Electric		Gas		Other		Total
Operating revenues		$1,569.7		$204.0		$46.7		$1,820.4
Depreciation and amortization	189.4		19.3		2.1		210.8
Operating income	252.0		15.5		3.3		270.8
Interest expense							103.2
Income tax benefit							(5.9		)
Earnings available for common stock							215.6
Total assets	6,278.2		653.3		373.2		7,304.7
Construction and acquisition expenditures	598.1		91.5		0.1		689.7

2015	Electric		Gas		Other		Total
Operating revenues		$1,503.8		$217.3		$53.4		$1,774.5
Depreciation and amortization	187.9		17.5		1.8		207.2
Operating income	218.8		17.7		5.4		241.9
Interest expense							96.8
Income tax benefit							(22.7		)
Earnings available for common stock							186.0
Total assets	5,754.1		548.2		406.8		6,709.1
Construction and acquisition expenditures	561.2		56.7		1.4		619.3

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							(48.9		)
Earnings available for common stock							181.6
Total assets	5,398.3		544.1		507.8		6,450.2
Construction and acquisition expenditures	490.0		35.1		0.9		526.0

WPL [Member]

Segment Reporting Information [Line Items]

Schedule of Segments of Business

Certain financial information relating to WPL’s business segments, which represent the services provided to its customers, was as follows (in millions):

2016	Electric			Gas		Other			Total
Operating revenues		$1,305.8			$151.4		$1.9			$1,459.1
Depreciation and amortization	177.6			14.9		—			192.5
Operating income (loss)	319.9			15.2		(8.1		)	327.0
Interest expense									91.4
Equity income from unconsolidated investments	(39.8		)	—		—			(39.8		)
Income taxes									93.3
Earnings available for common stock									190.4
Total assets	4,444.7			437.8		407.8			5,290.3
Investments in equity method subsidiaries	7.7			—		—			7.7
Construction and acquisition expenditures	407.4			45.6		—			453.0

2015	Electric			Gas		Other			Total
Operating revenues		$1,266.7			$163.9		$4.5			$1,435.1
Depreciation and amortization	170.7			13.6		—			184.3
Operating income (loss)	295.3			16.9		(3.5		)	308.7
Interest expense									92.4
Equity income from unconsolidated investments	(35.1		)	—		—			(35.1		)
Income taxes									82.9
Earnings available for common stock									176.3
Total assets	4,457.2			391.1		422.1			5,270.4
Investments in equity method subsidiaries	302.0			—		—			302.0
Construction and acquisition expenditures	294.6			49.7		—			344.3

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									85.3
Earnings available for common stock									180.4
Total assets	4,262.1			369.4		486.1			5,117.6
Investments in equity method subsidiaries	294.3			—		—			294.3
Construction and acquisition expenditures	284.8			28.1		—			312.9