Commitments And Contingencies (Tables)

3 Months Ended

Mar. 31, 2025

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At March 31, 2025, the related minimum future commitments, excluding amounts for purchased power commitments that do not have minimum thresholds but will require payment when electricity is generated by the provider, were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$872	$500	$372
Coal	112	62	50
Other (a)	130	59	33
	$1,114	$621	$455

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2025.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2025, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$8	-	$30	$6	-	$19	$2	-	$11
Current and non-current environmental liabilities	$13			$8			$5

IPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At March 31, 2025, the related minimum future commitments, excluding amounts for purchased power commitments that do not have minimum thresholds but will require payment when electricity is generated by the provider, were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$872	$500	$372
Coal	112	62	50
Other (a)	130	59	33
	$1,114	$621	$455

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2025.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2025, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$8	-	$30	$6	-	$19	$2	-	$11
Current and non-current environmental liabilities	$13			$8			$5

WPL [Member]

Commitments and Contingencies [Line Items]

Other Purchase Commitments

At March 31, 2025, the related minimum future commitments, excluding amounts for purchased power commitments that do not have minimum thresholds but will require payment when electricity is generated by the provider, were as follows (in millions):

	Alliant Energy	IPL	WPL
Natural gas	$872	$500	$372
Coal	112	62	50
Other (a)	130	59	33
	$1,114	$621	$455

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2025.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2025, 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):

	Alliant Energy			IPL			WPL
Range of estimated future costs	$8	-	$30	$6	-	$19	$2	-	$11
Current and non-current environmental liabilities	$13			$8			$5