Leases (Tables)

12 Months Ended

Dec. 31, 2022

Leases [Line Items]

Schedule of Lease Details

Operating lease details are as follows (dollars in millions):

	December 31, 2022			December 31, 2021
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$16	$9	$6	$14	$9	$5
Other current liabilities	$3	$1	$1	$2	$1	$1
Other liabilities	13	8	5	12	8	4
Total operating lease liabilities	$16	$9	$6	$14	$9	$5
Weighted average remaining lease term	10 years	11 years	9 years	9 years	11 years	8 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance lease details are as follows (dollars in millions):

	December 31, 2022		December 31, 2021
	Alliant Energy	WPL	Alliant Energy	WPL
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$15	n/a	$21
Leased land for solar generation	$133	133	$11	11
	$133	$148	$11	$32
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$12	n/a	$10
Leased land for solar generation	$5	5	$1	1
	5	17	1	11
Other liabilities:
Sheboygan Falls Energy Facility	n/a	19	n/a	31
Leased land for solar generation	131	131	11	11
	131	150	11	42
Total finance lease liabilities	$136	$167	$12	$53
Weighted average remaining lease term	34 years	28 years	34 years	10 years
Weighted average discount rate	5%	5%	3%	9%

	Alliant Energy			WPL
	2022	2021	2020	2022	2021	2020
Depreciation and amortization expenses	$—	$—	$—	$6	$6	$6
Interest expense	3	—	—	7	5	6
Total finance lease expense	$3	$—	$—	$13	$11	$12

Schedule of Operating Lease Liability Maturities

As of December 31, 2022, expected maturities of lease liabilities were as follows (in millions):

	2023	2024	2025	2026	2027	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$3	$2	$2	$2	$2	$9	$20	$4	$16
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	2	7	1	6
Finance Leases:
Alliant Energy	5	6	6	6	6	262	291	155	136
WPL	20	21	12	6	6	262	327	160	167

Schedule of Finance Lease Liability Maturities

As of December 31, 2022, expected maturities of lease liabilities were as follows (in millions):

	2023	2024	2025	2026	2027	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$3	$2	$2	$2	$2	$9	$20	$4	$16
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	2	7	1	6
Finance Leases:
Alliant Energy	5	6	6	6	6	262	291	155	136
WPL	20	21	12	6	6	262	327	160	167

IPL [Member]

Leases [Line Items]

Schedule of Lease Details

Operating lease details are as follows (dollars in millions):

	December 31, 2022			December 31, 2021
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$16	$9	$6	$14	$9	$5
Other current liabilities	$3	$1	$1	$2	$1	$1
Other liabilities	13	8	5	12	8	4
Total operating lease liabilities	$16	$9	$6	$14	$9	$5
Weighted average remaining lease term	10 years	11 years	9 years	9 years	11 years	8 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Schedule of Operating Lease Liability Maturities

As of December 31, 2022, expected maturities of lease liabilities were as follows (in millions):

	2023	2024	2025	2026	2027	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$3	$2	$2	$2	$2	$9	$20	$4	$16
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	2	7	1	6
Finance Leases:
Alliant Energy	5	6	6	6	6	262	291	155	136
WPL	20	21	12	6	6	262	327	160	167

WPL [Member]

Leases [Line Items]

Schedule of Lease Details

Operating lease details are as follows (dollars in millions):

	December 31, 2022			December 31, 2021
	Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL
Property, plant and equipment, net	$16	$9	$6	$14	$9	$5
Other current liabilities	$3	$1	$1	$2	$1	$1
Other liabilities	13	8	5	12	8	4
Total operating lease liabilities	$16	$9	$6	$14	$9	$5
Weighted average remaining lease term	10 years	11 years	9 years	9 years	11 years	8 years
Weighted average discount rate	4%	4%	4%	4%	4%	4%

Finance lease details are as follows (dollars in millions):

	December 31, 2022		December 31, 2021
	Alliant Energy	WPL	Alliant Energy	WPL
Property, plant and equipment, net:
Sheboygan Falls Energy Facility	n/a	$15	n/a	$21
Leased land for solar generation	$133	133	$11	11
	$133	$148	$11	$32
Other current liabilities:
Sheboygan Falls Energy Facility	n/a	$12	n/a	$10
Leased land for solar generation	$5	5	$1	1
	5	17	1	11
Other liabilities:
Sheboygan Falls Energy Facility	n/a	19	n/a	31
Leased land for solar generation	131	131	11	11
	131	150	11	42
Total finance lease liabilities	$136	$167	$12	$53
Weighted average remaining lease term	34 years	28 years	34 years	10 years
Weighted average discount rate	5%	5%	3%	9%

	Alliant Energy			WPL
	2022	2021	2020	2022	2021	2020
Depreciation and amortization expenses	$—	$—	$—	$6	$6	$6
Interest expense	3	—	—	7	5	6
Total finance lease expense	$3	$—	$—	$13	$11	$12

Schedule of Operating Lease Liability Maturities

As of December 31, 2022, expected maturities of lease liabilities were as follows (in millions):

	2023	2024	2025	2026	2027	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$3	$2	$2	$2	$2	$9	$20	$4	$16
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	2	7	1	6
Finance Leases:
Alliant Energy	5	6	6	6	6	262	291	155	136
WPL	20	21	12	6	6	262	327	160	167

Schedule of Finance Lease Liability Maturities

As of December 31, 2022, expected maturities of lease liabilities were as follows (in millions):

	2023	2024	2025	2026	2027	Thereafter	Total	Less: amount representing interest	Present value of minimum lease payments
Operating Leases:
Alliant Energy	$3	$2	$2	$2	$2	$9	$20	$4	$16
IPL	1	1	1	1	1	6	11	2	9
WPL	1	1	1	1	1	2	7	1	6
Finance Leases:
Alliant Energy	5	6	6	6	6	262	291	155	136
WPL	20	21	12	6	6	262	327	160	167