Commitments And Contingencies (Tables)

3 Months Ended

Mar. 31, 2018

Commitments and Contingencies [Line Items]

Other Purchase Obligations

At March 31, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a)		$1,175		$1,127		$48
Natural gas	892		362		530
Coal (b)	165		88		77
Other (c)	46		26		6
		$2,278		$1,603		$661

(a) Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2018, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$30		$9	-	$25
Current and non-current environmental liabilities	16				13

IPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Obligations

At March 31, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a)		$1,175		$1,127		$48
Natural gas	892		362		530
Coal (b)	165		88		77
Other (c)	46		26		6
		$2,278		$1,603		$661

(a) Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2018, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$30		$9	-	$25
Current and non-current environmental liabilities	16				13

WPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Obligations

At March 31, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a)		$1,175		$1,127		$48
Natural gas	892		362		530
Coal (b)	165		88		77
Other (c)	46		26		6
		$2,278		$1,603		$661

(a) Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.