Leases (Tables)

12 Months Ended

Dec. 31, 2019

Leases [Line Items]

Schedule of Lease Details

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

	December 31, 2019
	Alliant Energy			IPL			WPL
Property, plant and equipment, net		$16			$10			$6
Other current liabilities		$2			$1			$1
Other liabilities	14			9			5
Total operating lease liabilities		$16			$10			$6
Weighted average remaining lease term	11 years			12 years			10 years
Weighted average discount rate	4		%	4		%	4		%
	2019
	Alliant Energy			IPL			WPL
Operating lease cost		$2			$1			$1

Schedule of Operating Lease Liability Maturities

As of December 31, 2019, expected maturities of lease liabilities were as follows (in millions):

	2020		2021		2022		2023		2024		Thereafter		Total		Less: amount representing interest		Present value of minimum lease payments
Operating Leases:
Alliant Energy		$2		$2		$2		$2		$2		$10		$20		$4		$16
IPL	1		1		1		1		1		7		12		2		10
WPL	1		1		1		1		1		3		8		2		6
WPL’s Finance Lease:
Sheboygan Falls Energy Facility	15		15		15		15		15		5		80		20		60

Schedule of Future Minimum Payments for Operating Leases

As of December 31, 2018, future minimum operating (excluding contingent rentals) and capital lease payments were as follows (in millions):

	2019		2020		2021		2022		2023		Thereafter		Total		Less: amount representing interest		Present value of minimum capital lease payments
Operating Leases:
Alliant Energy		$5		$5		$3		$3		$2		$12		$30
IPL	3		2		2		2		2		12		23
WPL	2		3		1		—		—		—		6
WPL’s Capital Lease:
Sheboygan Falls Energy Facility		$15		$15		$15		$15		$15		$19		$94		$26		$68

IPL [Member]

Leases [Line Items]

Schedule of Lease Details

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

	December 31, 2019
	Alliant Energy			IPL			WPL
Property, plant and equipment, net		$16			$10			$6
Other current liabilities		$2			$1			$1
Other liabilities	14			9			5
Total operating lease liabilities		$16			$10			$6
Weighted average remaining lease term	11 years			12 years			10 years
Weighted average discount rate	4		%	4		%	4		%
	2019
	Alliant Energy			IPL			WPL
Operating lease cost		$2			$1			$1

Schedule of Operating Lease Liability Maturities

As of December 31, 2019, expected maturities of lease liabilities were as follows (in millions):

	2020		2021		2022		2023		2024		Thereafter		Total		Less: amount representing interest		Present value of minimum lease payments
Operating Leases:
Alliant Energy		$2		$2		$2		$2		$2		$10		$20		$4		$16
IPL	1		1		1		1		1		7		12		2		10
WPL	1		1		1		1		1		3		8		2		6
WPL’s Finance Lease:
Sheboygan Falls Energy Facility	15		15		15		15		15		5		80		20		60

Schedule of Future Minimum Payments for Operating Leases

As of December 31, 2018, future minimum operating (excluding contingent rentals) and capital lease payments were as follows (in millions):

	2019		2020		2021		2022		2023		Thereafter		Total		Less: amount representing interest		Present value of minimum capital lease payments
Operating Leases:
Alliant Energy		$5		$5		$3		$3		$2		$12		$30
IPL	3		2		2		2		2		12		23
WPL	2		3		1		—		—		—		6
WPL’s Capital Lease:
Sheboygan Falls Energy Facility		$15		$15		$15		$15		$15		$19		$94		$26		$68

WPL [Member]

Leases [Line Items]

Schedule of Lease Details

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

	December 31, 2019
	Alliant Energy			IPL			WPL
Property, plant and equipment, net		$16			$10			$6
Other current liabilities		$2			$1			$1
Other liabilities	14			9			5
Total operating lease liabilities		$16			$10			$6
Weighted average remaining lease term	11 years			12 years			10 years
Weighted average discount rate	4		%	4		%	4		%
	2019
	Alliant Energy			IPL			WPL
Operating lease cost		$2			$1			$1

WPL’s finance lease details are as follows (dollars in millions):

	December 31, 2019
Property, plant and equipment, net		$32
Other current liabilities		$9
Finance lease obligations - Sheboygan Falls Energy Facility	51
Total finance lease liabilities		$60
Remaining lease term	5 years
Discount rate	11		%
	2019
Depreciation expense		$6
Interest expense	7
Total finance lease expense		$13

Schedule of Operating Lease Liability Maturities

As of December 31, 2019, expected maturities of lease liabilities were as follows (in millions):

	2020		2021		2022		2023		2024		Thereafter		Total		Less: amount representing interest		Present value of minimum lease payments
Operating Leases:
Alliant Energy		$2		$2		$2		$2		$2		$10		$20		$4		$16
IPL	1		1		1		1		1		7		12		2		10
WPL	1		1		1		1		1		3		8		2		6
WPL’s Finance Lease:
Sheboygan Falls Energy Facility	15		15		15		15		15		5		80		20		60

Schedule of Finance Lease Liability Maturities

As of December 31, 2019, expected maturities of lease liabilities were as follows (in millions):

	2020		2021		2022		2023		2024		Thereafter		Total		Less: amount representing interest		Present value of minimum lease payments
Operating Leases:
Alliant Energy		$2		$2		$2		$2		$2		$10		$20		$4		$16
IPL	1		1		1		1		1		7		12		2		10
WPL	1		1		1		1		1		3		8		2		6
WPL’s Finance Lease:
Sheboygan Falls Energy Facility	15		15		15		15		15		5		80		20		60

Schedule of Future Minimum Payments for Operating Leases

As of December 31, 2018, future minimum operating (excluding contingent rentals) and capital lease payments were as follows (in millions):

	2019		2020		2021		2022		2023		Thereafter		Total		Less: amount representing interest		Present value of minimum capital lease payments
Operating Leases:
Alliant Energy		$5		$5		$3		$3		$2		$12		$30
IPL	3		2		2		2		2		12		23
WPL	2		3		1		—		—		—		6
WPL’s Capital Lease:
Sheboygan Falls Energy Facility		$15		$15		$15		$15		$15		$19		$94		$26		$68

Schedule of Future Minimum Payments for Capital Leases

As of December 31, 2018, future minimum operating (excluding contingent rentals) and capital lease payments were as follows (in millions):

	2019		2020		2021		2022		2023		Thereafter		Total		Less: amount representing interest		Present value of minimum capital lease payments
Operating Leases:
Alliant Energy		$5		$5		$3		$3		$2		$12		$30
IPL	3		2		2		2		2		12		23
WPL	2		3		1		—		—		—		6
WPL’s Capital Lease:
Sheboygan Falls Energy Facility		$15		$15		$15		$15		$15		$19		$94		$26		$68