Debt (Tables)

3 Months Ended

Mar. 31, 2020

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

March 31, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$270.5	$—	$182.0
Weighted average interest rates	1.6%	N/A	1.7%
Available credit facility capacity	$729.5	$250.0	$118.0

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2020	2019	2020	2019	2020	2019
Maximum amount outstanding (based on daily outstanding balances)	$462.5	$600.6	$0.8	$50.4	$212.0	$195.1
Average amount outstanding (based on daily outstanding balances)	$382.3	$498.8	$—	$0.6	$167.0	$138.1
Weighted average interest rates	1.8%	2.7%	1.8%	2.8%	1.8%	2.5%

IPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

March 31, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$270.5	$—	$182.0
Weighted average interest rates	1.6%	N/A	1.7%
Available credit facility capacity	$729.5	$250.0	$118.0

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2020	2019	2020	2019	2020	2019
Maximum amount outstanding (based on daily outstanding balances)	$462.5	$600.6	$0.8	$50.4	$212.0	$195.1
Average amount outstanding (based on daily outstanding balances)	$382.3	$498.8	$—	$0.6	$167.0	$138.1
Weighted average interest rates	1.8%	2.7%	1.8%	2.8%	1.8%	2.5%

WPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

March 31, 2020	Alliant Energy	IPL	WPL
Amount outstanding	$270.5	$—	$182.0
Weighted average interest rates	1.6%	N/A	1.7%
Available credit facility capacity	$729.5	$250.0	$118.0

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2020	2019	2020	2019	2020	2019
Maximum amount outstanding (based on daily outstanding balances)	$462.5	$600.6	$0.8	$50.4	$212.0	$195.1
Average amount outstanding (based on daily outstanding balances)	$382.3	$498.8	$—	$0.6	$167.0	$138.1
Weighted average interest rates	1.8%	2.7%	1.8%	2.8%	1.8%	2.5%