Revenues (Tables)

12 Months Ended

Dec. 31, 2018

Disaggregation of Revenue [Line Items]

Disaggregation of Revenues

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy						IPL						WPL
	2018		2017		2016		2018		2017		2016		2018		2017		2016
Electric Utility:
Retail - residential		$1,063.4		$1,006.2		$1,001.1		$590.6		$535.6		$536.7		$472.8		$470.6		$464.4
Retail - commercial	735.6		710.3		712.6		486.8		452.7		445.4		248.8		257.6		267.2
Retail - industrial	888.8		853.1		851.1		500.8		459.7		460.4		388.0		393.4		390.7
Wholesale	188.4		238.4		256.6		71.2		95.5		94.2		117.2		142.9		162.4
Bulk power and other	124.1		86.7		54.1		81.7		55.4		33.0		42.4		31.3		21.1
Total Electric Utility	3,000.3		2,894.7		2,875.5		1,731.1		1,598.9		1,569.7		1,269.2		1,295.8		1,305.8
Gas Utility:
Retail - residential	254.4		224.7		197.6		152.3		123.2		110.6		102.1		101.5		87.0
Retail - commercial	133.0		123.2		109.6		75.9		67.9		61.9		57.1		55.3		47.7
Retail - industrial	14.9		16.7		15.2		10.2		11.1		10.6		4.7		5.6		4.6
Transportation/other	44.3		36.3		33.0		27.8		23.8		20.9		16.5		12.5		12.1
Total Gas Utility	446.6		400.9		355.4		266.2		226.0		204.0		180.4		174.9		151.4
Other Utility:
Steam	35.2		34.6		33.9		35.2		34.6		33.9		—		—		—
Other utility	12.8		12.9		14.7		9.8		10.8		12.8		3.0		2.1		1.9
Total Other Utility	48.0		47.5		48.6		45.0		45.4		46.7		3.0		2.1		1.9
Non-Utility and Other:
Transportation and other	39.6		39.1		40.5		—		—		—		—		—		—
Total Non-Utility and Other	39.6		39.1		40.5		—		—		—		—		—		—
Total revenues		$3,534.5		$3,382.2		$3,320.0		$2,042.3		$1,870.3		$1,820.4		$1,452.6		$1,472.8		$1,459.1

IPL [Member]

Disaggregation of Revenue [Line Items]

Disaggregation of Revenues

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy						IPL						WPL
	2018		2017		2016		2018		2017		2016		2018		2017		2016
Electric Utility:
Retail - residential		$1,063.4		$1,006.2		$1,001.1		$590.6		$535.6		$536.7		$472.8		$470.6		$464.4
Retail - commercial	735.6		710.3		712.6		486.8		452.7		445.4		248.8		257.6		267.2
Retail - industrial	888.8		853.1		851.1		500.8		459.7		460.4		388.0		393.4		390.7
Wholesale	188.4		238.4		256.6		71.2		95.5		94.2		117.2		142.9		162.4
Bulk power and other	124.1		86.7		54.1		81.7		55.4		33.0		42.4		31.3		21.1
Total Electric Utility	3,000.3		2,894.7		2,875.5		1,731.1		1,598.9		1,569.7		1,269.2		1,295.8		1,305.8
Gas Utility:
Retail - residential	254.4		224.7		197.6		152.3		123.2		110.6		102.1		101.5		87.0
Retail - commercial	133.0		123.2		109.6		75.9		67.9		61.9		57.1		55.3		47.7
Retail - industrial	14.9		16.7		15.2		10.2		11.1		10.6		4.7		5.6		4.6
Transportation/other	44.3		36.3		33.0		27.8		23.8		20.9		16.5		12.5		12.1
Total Gas Utility	446.6		400.9		355.4		266.2		226.0		204.0		180.4		174.9		151.4
Other Utility:
Steam	35.2		34.6		33.9		35.2		34.6		33.9		—		—		—
Other utility	12.8		12.9		14.7		9.8		10.8		12.8		3.0		2.1		1.9
Total Other Utility	48.0		47.5		48.6		45.0		45.4		46.7		3.0		2.1		1.9
Non-Utility and Other:
Transportation and other	39.6		39.1		40.5		—		—		—		—		—		—
Total Non-Utility and Other	39.6		39.1		40.5		—		—		—		—		—		—
Total revenues		$3,534.5		$3,382.2		$3,320.0		$2,042.3		$1,870.3		$1,820.4		$1,452.6		$1,472.8		$1,459.1

WPL [Member]

Disaggregation of Revenue [Line Items]

Disaggregation of Revenues

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

	Alliant Energy						IPL						WPL
	2018		2017		2016		2018		2017		2016		2018		2017		2016
Electric Utility:
Retail - residential		$1,063.4		$1,006.2		$1,001.1		$590.6		$535.6		$536.7		$472.8		$470.6		$464.4
Retail - commercial	735.6		710.3		712.6		486.8		452.7		445.4		248.8		257.6		267.2
Retail - industrial	888.8		853.1		851.1		500.8		459.7		460.4		388.0		393.4		390.7
Wholesale	188.4		238.4		256.6		71.2		95.5		94.2		117.2		142.9		162.4
Bulk power and other	124.1		86.7		54.1		81.7		55.4		33.0		42.4		31.3		21.1
Total Electric Utility	3,000.3		2,894.7		2,875.5		1,731.1		1,598.9		1,569.7		1,269.2		1,295.8		1,305.8
Gas Utility:
Retail - residential	254.4		224.7		197.6		152.3		123.2		110.6		102.1		101.5		87.0
Retail - commercial	133.0		123.2		109.6		75.9		67.9		61.9		57.1		55.3		47.7
Retail - industrial	14.9		16.7		15.2		10.2		11.1		10.6		4.7		5.6		4.6
Transportation/other	44.3		36.3		33.0		27.8		23.8		20.9		16.5		12.5		12.1
Total Gas Utility	446.6		400.9		355.4		266.2		226.0		204.0		180.4		174.9		151.4
Other Utility:
Steam	35.2		34.6		33.9		35.2		34.6		33.9		—		—		—
Other utility	12.8		12.9		14.7		9.8		10.8		12.8		3.0		2.1		1.9
Total Other Utility	48.0		47.5		48.6		45.0		45.4		46.7		3.0		2.1		1.9
Non-Utility and Other:
Transportation and other	39.6		39.1		40.5		—		—		—		—		—		—
Total Non-Utility and Other	39.6		39.1		40.5		—		—		—		—		—		—
Total revenues		$3,534.5		$3,382.2		$3,320.0		$2,042.3		$1,870.3		$1,820.4		$1,452.6		$1,472.8		$1,459.1