Debt (Tables)

3 Months Ended

Mar. 31, 2019

Debt Disclosure [Line Items]

Other Short-Term Borrowings

Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):

March 31, 2019	Alliant Energy	IPL	WPL
Commercial paper outstanding	$514.7	$—	$138.4
Commercial paper weighted average interest rates	2.6%	N/A	2.5%
Available credit facility capacity (a)	$370.3	$135.0	$161.6

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2019	2018	2019	2018	2019	2018
Maximum amount outstanding (based on daily outstanding balances)	$600.6	$336.4	$50.4	$3.0	$195.1	$36.7
Average amount outstanding (based on daily outstanding balances)	$498.8	$310.1	$0.6	$—	$138.1	$11.5
Weighted average interest rates	2.7%	1.9%	2.8%	1.8%	2.5%	1.6%

(a) Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at March 31, 2019.

IPL [Member]

Debt Disclosure [Line Items]

Other Short-Term Borrowings

Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):

March 31, 2019	Alliant Energy	IPL	WPL
Commercial paper outstanding	$514.7	$—	$138.4
Commercial paper weighted average interest rates	2.6%	N/A	2.5%
Available credit facility capacity (a)	$370.3	$135.0	$161.6

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2019	2018	2019	2018	2019	2018
Maximum amount outstanding (based on daily outstanding balances)	$600.6	$336.4	$50.4	$3.0	$195.1	$36.7
Average amount outstanding (based on daily outstanding balances)	$498.8	$310.1	$0.6	$—	$138.1	$11.5
Weighted average interest rates	2.7%	1.9%	2.8%	1.8%	2.5%	1.6%

(a) Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at March 31, 2019.

WPL [Member]

Debt Disclosure [Line Items]

Other Short-Term Borrowings

Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):

March 31, 2019	Alliant Energy	IPL	WPL
Commercial paper outstanding	$514.7	$—	$138.4
Commercial paper weighted average interest rates	2.6%	N/A	2.5%
Available credit facility capacity (a)	$370.3	$135.0	$161.6

	Alliant Energy		IPL		WPL
Three Months Ended March 31	2019	2018	2019	2018	2019	2018
Maximum amount outstanding (based on daily outstanding balances)	$600.6	$336.4	$50.4	$3.0	$195.1	$36.7
Average amount outstanding (based on daily outstanding balances)	$498.8	$310.1	$0.6	$—	$138.1	$11.5
Weighted average interest rates	2.7%	1.9%	2.8%	1.8%	2.5%	1.6%

(a) Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at March 31, 2019.