Debt (Tables)

9 Months Ended

Sep. 30, 2021

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):

September 30, 2021	Alliant Energy	IPL	WPL
Amount outstanding	$316	$—	$3
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$684	$100	$397

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$422	$8	$—	$320	$139
Average amount outstanding (based on daily outstanding balances)	$560	$252	$—	$—	$221	$83
Weighted average interest rates	0.2%	0.2%	0.2%	N/A	0.1%	0.2%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$648	$463	$19	$8	$320	$212
Average amount outstanding (based on daily outstanding balances)	$479	$252	$—	$—	$196	$86
Weighted average interest rates	0.2%	1.1%	0.2%	0.5%	0.1%	1.2%

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):

September 30, 2021	Alliant Energy	IPL	WPL
Amount outstanding	$316	$—	$3
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$684	$100	$397

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$422	$8	$—	$320	$139
Average amount outstanding (based on daily outstanding balances)	$560	$252	$—	$—	$221	$83
Weighted average interest rates	0.2%	0.2%	0.2%	N/A	0.1%	0.2%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$648	$463	$19	$8	$320	$212
Average amount outstanding (based on daily outstanding balances)	$479	$252	$—	$—	$196	$86
Weighted average interest rates	0.2%	1.1%	0.2%	0.5%	0.1%	1.2%

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):

September 30, 2021	Alliant Energy	IPL	WPL
Amount outstanding	$316	$—	$3
Weighted average interest rates	0.2%	N/A	0.1%
Available credit facility capacity	$684	$100	$397

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2021	2020	2021	2020	2021	2020
Maximum amount outstanding (based on daily outstanding balances)	$648	$422	$8	$—	$320	$139
Average amount outstanding (based on daily outstanding balances)	$560	$252	$—	$—	$221	$83
Weighted average interest rates	0.2%	0.2%	0.2%	N/A	0.1%	0.2%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$648	$463	$19	$8	$320	$212
Average amount outstanding (based on daily outstanding balances)	$479	$252	$—	$—	$196	$86
Weighted average interest rates	0.2%	1.1%	0.2%	0.5%	0.1%	1.2%