REVENUES

Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.

IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term.

IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings.

Revenues from Alliant Energy’s non-utility business customers are primarily from its Transportation business, which includes a short-line railway that provides freight service, hauling services on the Mississippi River, and other transfer and storage services.

As of December 31, 2018, revenue expected to be recognized in any future year related to remaining performance obligations is not material, as the majority of revenues are recognized as services are rendered or commodities are delivered, and are from contracts with durations of less than one year. Alliant Energy, IPL and WPL do not have any material contract assets or contract liabilities, or contract acquisition fulfillment costs.

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

Disaggregation of Revenue [Line Items]

Revenues

REVENUES

Revenues from Alliant Energy’s, IPL’s and WPL’s utility businesses are primarily from electric and gas sales provided to customers based on approved tariffs or specific contracts with customers. IPL’s and WPL’s primary performance obligations under such arrangements are to deliver electricity and gas, and their customers simultaneously receive and consume the electricity and gas. For such arrangements, revenues are recognized equivalent to the value of the electricity or gas supplied during each period, including amounts billed during each period and changes in amounts estimated to be billed at the end of each period. IPL and WPL apply the right to invoice method to measure progress towards completing performance obligations to transfer electricity and gas to their customers.

IPL provides retail electric and gas service to customers in Iowa, and WPL provides retail and wholesale electric and retail gas service to customers in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa, as well as steam from its Prairie Creek Generating Station to high-pressure steam customers in Iowa.

IPL’s and WPL’s retail electric and gas revenues include sales to residential, commercial and industrial customers. IPL’s and WPL’s retail electric and gas customer prices are based on IPL’s and WPL’s cost of service and are determined through general rate review proceedings and various tariff filings with the IUB and PSCW, respectively. Such tariff-based services provide electricity or gas to customers without a defined contractual term.

IPL and WPL have wholesale electric market-based rate authority from FERC allowing them to participate in wholesale energy markets (e.g. MISO) and transact directly with third parties. This authority from FERC allows sales of electricity referred to as bulk power sales based on current market values. FERC also allows IPL and WPL to enter into power supply agreements with municipalities and rural electric cooperatives with defined contractual terms, which include standard pricing mechanisms that are detailed in current tariffs accepted by FERC through wholesale rate review proceedings.

Revenues from Alliant Energy’s non-utility business customers are primarily from its Transportation business, which includes a short-line railway that provides freight service, hauling services on the Mississippi River, and other transfer and storage services.

As of December 31, 2018, revenue expected to be recognized in any future year related to remaining performance obligations is not material, as the majority of revenues are recognized as services are rendered or commodities are delivered, and are from contracts with durations of less than one year. Alliant Energy, IPL and WPL do not have any material contract assets or contract liabilities, or contract acquisition fulfillment costs.

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