Commitments And Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Long-term Purchase Commitment [Line Items]

Other Purchase Commitments

At December 31, 2018, the related minimum future commitments were as follows (in millions):

Alliant Energy	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power (a)		$159		$135		$149		$140		$155		$307		$1,045
Natural gas	254		151		119		94		67		196		881
Coal (b)	102		49		26		9		9		—		195
Other (c)	60		4		3		2		2		—		71
		$575		$339		$297		$245		$233		$503		$2,192

IPL	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power (a)		$144		$135		$149		$140		$155		$307		$1,030
Natural gas	124		55		42		33		26		83		363
Coal (b)	52		29		20		9		9		—		119
Other (c)	24		3		3		2		2		—		34
		$344		$222		$214		$184		$192		$390		$1,546

WPL	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power		$15		$—		$—		$—		$—		$—		$15
Natural gas	130		96		77		61		41		113		518
Coal (b)	50		20		6		—		—		—		76
Other (c)	23		—		—		—		—		—		23
		$218		$116		$83		$61		$41		$113		$632

(a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, subject to IUB approval. In December 2018, IPL received an order from the IUB, which was effective in January 2019, approving recovery of the buyout payment. As a result, Alliant Energy’s and IPL’s amounts in the above table do not include the September 2020 buyout payment, and the minimum future commitments reflect IPL’s purchase of capacity and the resulting energy from DAEC through December 2025, the original term of the PPA prior to the amendment. Amounts in the above table for 2021 and beyond relate to the DAEC PPA.

(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 December 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 December 31, 2018.

Schedule of Environmental Liabilities

At December 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 December 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$29		$8	-	$24
Current and non-current environmental liabilities	15				12

IPL [Member]

Long-term Purchase Commitment [Line Items]

Other Purchase Commitments

At December 31, 2018, the related minimum future commitments were as follows (in millions):

Alliant Energy	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power (a)		$159		$135		$149		$140		$155		$307		$1,045
Natural gas	254		151		119		94		67		196		881
Coal (b)	102		49		26		9		9		—		195
Other (c)	60		4		3		2		2		—		71
		$575		$339		$297		$245		$233		$503		$2,192

IPL	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power (a)		$144		$135		$149		$140		$155		$307		$1,030
Natural gas	124		55		42		33		26		83		363
Coal (b)	52		29		20		9		9		—		119
Other (c)	24		3		3		2		2		—		34
		$344		$222		$214		$184		$192		$390		$1,546

WPL	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power		$15		$—		$—		$—		$—		$—		$15
Natural gas	130		96		77		61		41		113		518
Coal (b)	50		20		6		—		—		—		76
Other (c)	23		—		—		—		—		—		23
		$218		$116		$83		$61		$41		$113		$632

(a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, subject to IUB approval. In December 2018, IPL received an order from the IUB, which was effective in January 2019, approving recovery of the buyout payment. As a result, Alliant Energy’s and IPL’s amounts in the above table do not include the September 2020 buyout payment, and the minimum future commitments reflect IPL’s purchase of capacity and the resulting energy from DAEC through December 2025, the original term of the PPA prior to the amendment. Amounts in the above table for 2021 and beyond relate to the DAEC PPA.

(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 December 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 December 31, 2018.

Schedule of Environmental Liabilities

At December 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 December 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$29		$8	-	$24
Current and non-current environmental liabilities	15				12

WPL [Member]

Long-term Purchase Commitment [Line Items]

Other Purchase Commitments

At December 31, 2018, the related minimum future commitments were as follows (in millions):

Alliant Energy	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power (a)		$159		$135		$149		$140		$155		$307		$1,045
Natural gas	254		151		119		94		67		196		881
Coal (b)	102		49		26		9		9		—		195
Other (c)	60		4		3		2		2		—		71
		$575		$339		$297		$245		$233		$503		$2,192

IPL	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power (a)		$144		$135		$149		$140		$155		$307		$1,030
Natural gas	124		55		42		33		26		83		363
Coal (b)	52		29		20		9		9		—		119
Other (c)	24		3		3		2		2		—		34
		$344		$222		$214		$184		$192		$390		$1,546

WPL	2019		2020		2021		2022		2023		Thereafter		Total
Purchased power		$15		$—		$—		$—		$—		$—		$15
Natural gas	130		96		77		61		41		113		518
Coal (b)	50		20		6		—		—		—		76
Other (c)	23		—		—		—		—		—		23
		$218		$116		$83		$61		$41		$113		$632

(a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, subject to IUB approval. In December 2018, IPL received an order from the IUB, which was effective in January 2019, approving recovery of the buyout payment. As a result, Alliant Energy’s and IPL’s amounts in the above table do not include the September 2020 buyout payment, and the minimum future commitments reflect IPL’s purchase of capacity and the resulting energy from DAEC through December 2025, the original term of the PPA prior to the amendment. Amounts in the above table for 2021 and beyond relate to the DAEC PPA.

(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 December 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 December 31, 2018.