Debt (Tables)

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Line Items]

Other Short-Term Borrowings

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

September 30, 2017	Alliant Energy	IPL	WPL
Commercial paper outstanding	$390.3	$4.0	$224.6
Commercial paper weighted average interest rates	1.2%	1.4%	1.1%
Available credit facility capacity (a)	$569.7	$256.0	$175.4

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2017	2016	2017	2016	2017	2016
Maximum amount outstanding (based on daily outstanding balances)	$424.4	$248.0	$20.0	$3.1	$271.2	$55.4
Average amount outstanding (based on daily outstanding balances)	$386.2	$220.1	$0.4	$0.1	$217.0	$36.4
Weighted average interest rates	1.3%	0.6%	1.4%	0.6%	1.1%	0.4%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$424.4	$248.0	$20.0	$3.1	$271.2	$62.9
Average amount outstanding (based on daily outstanding balances)	$323.9	$210.7	$0.5	$—	$144.2	$33.2
Weighted average interest rates	1.1%	0.6%	1.2%	0.6%	1.0%	0.4%

(a) Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at September 30, 2017.

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):

September 30, 2017	Alliant Energy	IPL	WPL
Commercial paper outstanding	$390.3	$4.0	$224.6
Commercial paper weighted average interest rates	1.2%	1.4%	1.1%
Available credit facility capacity (a)	$569.7	$256.0	$175.4

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2017	2016	2017	2016	2017	2016
Maximum amount outstanding (based on daily outstanding balances)	$424.4	$248.0	$20.0	$3.1	$271.2	$55.4
Average amount outstanding (based on daily outstanding balances)	$386.2	$220.1	$0.4	$0.1	$217.0	$36.4
Weighted average interest rates	1.3%	0.6%	1.4%	0.6%	1.1%	0.4%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$424.4	$248.0	$20.0	$3.1	$271.2	$62.9
Average amount outstanding (based on daily outstanding balances)	$323.9	$210.7	$0.5	$—	$144.2	$33.2
Weighted average interest rates	1.1%	0.6%	1.2%	0.6%	1.0%	0.4%

(a) Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at September 30, 2017.

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):

September 30, 2017	Alliant Energy	IPL	WPL
Commercial paper outstanding	$390.3	$4.0	$224.6
Commercial paper weighted average interest rates	1.2%	1.4%	1.1%
Available credit facility capacity (a)	$569.7	$256.0	$175.4

	Alliant Energy		IPL		WPL
Three Months Ended September 30	2017	2016	2017	2016	2017	2016
Maximum amount outstanding (based on daily outstanding balances)	$424.4	$248.0	$20.0	$3.1	$271.2	$55.4
Average amount outstanding (based on daily outstanding balances)	$386.2	$220.1	$0.4	$0.1	$217.0	$36.4
Weighted average interest rates	1.3%	0.6%	1.4%	0.6%	1.1%	0.4%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)	$424.4	$248.0	$20.0	$3.1	$271.2	$62.9
Average amount outstanding (based on daily outstanding balances)	$323.9	$210.7	$0.5	$—	$144.2	$33.2
Weighted average interest rates	1.1%	0.6%	1.2%	0.6%	1.0%	0.4%

(a) Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at September 30, 2017.