Debt (Tables)

9 Months Ended

Sep. 30, 2023

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

September 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$451	$—	$120
Weighted average interest rates	5.5%	—%	5.4%
Available credit facility capacity	$549	$250	$180

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$474	$449	$7	$—	$125	$251
Average amount outstanding (based on daily outstanding balances)	$440	$353	$—	$—	$86	$110
Weighted average interest rates	5.5%	2.4%	5.5%	—%	5.4%	2.0%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$367	$377	$2	$—	$135	$160
Weighted average interest rates	5.1%	1.2%	5.3%	—%	4.9%	0.9%

IPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

September 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$451	$—	$120
Weighted average interest rates	5.5%	—%	5.4%
Available credit facility capacity	$549	$250	$180

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$474	$449	$7	$—	$125	$251
Average amount outstanding (based on daily outstanding balances)	$440	$353	$—	$—	$86	$110
Weighted average interest rates	5.5%	2.4%	5.5%	—%	5.4%	2.0%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$367	$377	$2	$—	$135	$160
Weighted average interest rates	5.1%	1.2%	5.3%	—%	4.9%	0.9%

WPL [Member]

Short-term Debt [Line Items]

Other Short-Term Borrowings

Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions):

September 30, 2023	Alliant Energy	IPL	WPL
Amount outstanding	$451	$—	$120
Weighted average interest rates	5.5%	—%	5.4%
Available credit facility capacity	$549	$250	$180

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2023	2022	2023	2022	2023	2022
Maximum amount outstanding (based on daily outstanding balances)	$474	$449	$7	$—	$125	$251
Average amount outstanding (based on daily outstanding balances)	$440	$353	$—	$—	$86	$110
Weighted average interest rates	5.5%	2.4%	5.5%	—%	5.4%	2.0%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$793	$577	$70	$—	$349	$252
Average amount outstanding (based on daily outstanding balances)	$367	$377	$2	$—	$135	$160
Weighted average interest rates	5.1%	1.2%	5.3%	—%	4.9%	0.9%