Segments Of Business

3 Months Ended

Mar. 31, 2018

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reporting related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. As of December 31, 2017, ATC Holdings are no longer included in Alliant Energy’s utility electric operations reportable segment or WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this change were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three months ended March 31, 2017.

Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations.

									ATC Holdings,
	Utility								Non-Utility,		Alliant Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Three Months Ended March 31, 2018
Revenues		$708.7		$185.6		$13.2		$907.5		$8.8		$916.3
Operating income	126.7		31.5		1.4		159.6		6.1		165.7
Net income attributable to Alliant Energy common shareowners							100.7		20.2		120.9
Three Months Ended March 31, 2017
Revenues		$677.6		$154.3		$11.7		$843.6		$10.3		$853.9
Operating income	110.9		28.6		0.4		139.9		7.3		147.2
Amounts attributable to Alliant Energy common shareowners:
Income from continuing operations, net of tax							82.7		16.3		99.0
Income from discontinued operations, net of tax							—		1.4		1.4
Net income							82.7		17.7		100.4

IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations.

	Electric		Gas		Other		Total
	(in millions)
Three Months Ended March 31, 2018
Revenues		$405.7		$108.1		$12.0		$525.8
Operating income	57.5		16.9		1.2		75.6
Earnings available for common stock							46.7
Three Months Ended March 31, 2017
Revenues		$356.2		$83.1		$11.2		$450.5
Operating income	35.3		14.6		1.4		51.3
Earnings available for common stock							37.2

WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations.

	Electric		Gas		Other			Total
	(in millions)
Three Months Ended March 31, 2018
Revenues		$303.0		$77.5		$1.2			$381.7
Operating income	69.2		14.6		0.2			84.0
Earnings available for common stock								54.0
Three Months Ended March 31, 2017
Revenues		$321.4		$71.2		$0.5			$393.1
Operating income (loss)	75.6		14.0		(1.0		)	88.6
Earnings available for common stock								45.5

IPL [Member]

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reporting related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. As of December 31, 2017, ATC Holdings are no longer included in Alliant Energy’s utility electric operations reportable segment or WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this change were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three months ended March 31, 2017.

Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations.

									ATC Holdings,
	Utility								Non-Utility,		Alliant Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Three Months Ended March 31, 2018
Revenues		$708.7		$185.6		$13.2		$907.5		$8.8		$916.3
Operating income	126.7		31.5		1.4		159.6		6.1		165.7
Net income attributable to Alliant Energy common shareowners							100.7		20.2		120.9
Three Months Ended March 31, 2017
Revenues		$677.6		$154.3		$11.7		$843.6		$10.3		$853.9
Operating income	110.9		28.6		0.4		139.9		7.3		147.2
Amounts attributable to Alliant Energy common shareowners:
Income from continuing operations, net of tax							82.7		16.3		99.0
Income from discontinued operations, net of tax							—		1.4		1.4
Net income							82.7		17.7		100.4

IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations.

	Electric		Gas		Other		Total
	(in millions)
Three Months Ended March 31, 2018
Revenues		$405.7		$108.1		$12.0		$525.8
Operating income	57.5		16.9		1.2		75.6
Earnings available for common stock							46.7
Three Months Ended March 31, 2017
Revenues		$356.2		$83.1		$11.2		$450.5
Operating income	35.3		14.6		1.4		51.3
Earnings available for common stock							37.2

WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations.

	Electric		Gas		Other			Total
	(in millions)
Three Months Ended March 31, 2018
Revenues		$303.0		$77.5		$1.2			$381.7
Operating income	69.2		14.6		0.2			84.0
Earnings available for common stock								54.0
Three Months Ended March 31, 2017
Revenues		$321.4		$71.2		$0.5			$393.1
Operating income (loss)	75.6		14.0		(1.0		)	88.6
Earnings available for common stock								45.5

WPL [Member]

Segment Reporting Information [Line Items]

Segments Of Business

SEGMENTS OF BUSINESS

In the fourth quarter of 2017, Alliant Energy and WPL modified the segment reporting related to ATC Holdings, consistent with information used by their chief operating decision maker to evaluate performance and allocate resources. As of December 31, 2017, ATC Holdings are no longer included in Alliant Energy’s utility electric operations reportable segment or WPL’s electric operations reportable segment. As a result, all prior period amounts impacted by this change were reclassified to conform to the new presentation. Alliant Energy’s related amounts were reclassified from “Electric Utility” to “ATC Holdings, Non-Utility, Parent and Other” in the table below. There was no resulting change to WPL’s segment reporting for the three months ended March 31, 2017.

Alliant Energy - Certain financial information relating to Alliant Energy’s business segments is as follows. Intersegment revenues were not material to Alliant Energy’s operations.

									ATC Holdings,
	Utility								Non-Utility,		Alliant Energy
	Electric		Gas		Other		Total		Parent and Other		Consolidated
	(in millions)
Three Months Ended March 31, 2018
Revenues		$708.7		$185.6		$13.2		$907.5		$8.8		$916.3
Operating income	126.7		31.5		1.4		159.6		6.1		165.7
Net income attributable to Alliant Energy common shareowners							100.7		20.2		120.9
Three Months Ended March 31, 2017
Revenues		$677.6		$154.3		$11.7		$843.6		$10.3		$853.9
Operating income	110.9		28.6		0.4		139.9		7.3		147.2
Amounts attributable to Alliant Energy common shareowners:
Income from continuing operations, net of tax							82.7		16.3		99.0
Income from discontinued operations, net of tax							—		1.4		1.4
Net income							82.7		17.7		100.4

IPL - Certain financial information relating to IPL’s business segments is as follows. Intersegment revenues were not material to IPL’s operations.

	Electric		Gas		Other		Total
	(in millions)
Three Months Ended March 31, 2018
Revenues		$405.7		$108.1		$12.0		$525.8
Operating income	57.5		16.9		1.2		75.6
Earnings available for common stock							46.7
Three Months Ended March 31, 2017
Revenues		$356.2		$83.1		$11.2		$450.5
Operating income	35.3		14.6		1.4		51.3
Earnings available for common stock							37.2

WPL - Certain financial information relating to WPL’s business segments is as follows. Intersegment revenues were not material to WPL’s operations.

	Electric		Gas		Other			Total
	(in millions)
Three Months Ended March 31, 2018
Revenues		$303.0		$77.5		$1.2			$381.7
Operating income	69.2		14.6		0.2			84.0
Earnings available for common stock								54.0
Three Months Ended March 31, 2017
Revenues		$321.4		$71.2		$0.5			$393.1
Operating income (loss)	75.6		14.0		(1.0		)	88.6
Earnings available for common stock								45.5