Debt

3 Months Ended

Mar. 31, 2021

Debt [Line Items]

Debt

DEBT

Short-term Debt - 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, 2021	Alliant Energy	IPL	WPL
Amount outstanding	$336	$—	$148
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$664	$250	$152

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$578	$463	$—	$1	$275	$212
Average amount outstanding (based on daily outstanding balances)	$424	$382	$—	$—	$189	$167
Weighted average interest rates	0.2%	1.8%	—%	1.8%	0.2%	1.8%

IPL [Member]

Debt [Line Items]

Debt

DEBT

Short-term Debt - 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, 2021	Alliant Energy	IPL	WPL
Amount outstanding	$336	$—	$148
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$664	$250	$152

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$578	$463	$—	$1	$275	$212
Average amount outstanding (based on daily outstanding balances)	$424	$382	$—	$—	$189	$167
Weighted average interest rates	0.2%	1.8%	—%	1.8%	0.2%	1.8%

WPL [Member]

Debt [Line Items]

Debt

DEBT

Short-term Debt - 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, 2021	Alliant Energy	IPL	WPL
Amount outstanding	$336	$—	$148
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$664	$250	$152

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$578	$463	$—	$1	$275	$212
Average amount outstanding (based on daily outstanding balances)	$424	$382	$—	$—	$189	$167
Weighted average interest rates	0.2%	1.8%	—%	1.8%	0.2%	1.8%