Debt

9 Months Ended

Sep. 30, 2013

Debt Instrument [Line Items]

Debt

DEBT

(a) Short-term Debt - Information regarding commercial paper classified as short-term debt and back-stopped by Alliant Energy’s, IPL’s and WPL’s credit facilities was as follows (dollars in millions):

	Alliant Energy	Parent
September 30, 2013	(Consolidated)	Company	IPL	WPL
Commercial paper:
Amount outstanding	$237.3	$93.9	$—	$143.4
Weighted average remaining maturity	1 day	2 days	N/A	1 day
Weighted average interest rates	0.2%	0.2%	N/A	0.1%
Available credit facility capacity (a)	$697.7	$206.1	$235.0	$256.6

	Alliant Energy						IPL						WPL
Three Months Ended September 30	2013			2012			2013			2012			2013			2012
Maximum amount outstanding (based on daily outstanding balances)		$284.1			$185.3			$—			$19.5			$165.4			$35.6
Average amount outstanding (based on daily outstanding balances)		$228.8			$133.0			$—			$1.3			$140.9			$11.9
Weighted average interest rates	0.2		%	0.4		%	N/A			0.4		%	0.2		%	0.3		%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$284.1			$185.3			$26.3			$35.4			$165.4			$35.6
Average amount outstanding (based on daily outstanding balances)		$197.2			$100.2			$1.7			$7.2			$113.4			$13.3
Weighted average interest rates	0.2		%	0.4		%	0.4		%	0.4		%	0.2		%	0.3		%

(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, 2013. Refer to Note 8(b) for further discussion of $65 million of commercial paper outstanding at September 30, 2013 classified as long-term debt on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets.

(b) Long-term Debt - As of September 30, 2013, $65 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets due to the existence of long-term credit facilities that back-stop this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of September 30, 2013, this commercial paper balance had a remaining maturity of 2 days and a 0.25% interest rate.

In October 2013, IPL issued $250 million of 4.7% senior debentures due 2043. The proceeds from the issuance were used by IPL to reduce cash proceeds received from its sales of accounts receivables program, reduce commercial paper classified as long-term debt and for general working capital purposes.

IPL [Member]

Debt Instrument [Line Items]

Debt

DEBT

(a) Short-term Debt - Information regarding commercial paper classified as short-term debt and back-stopped by Alliant Energy’s, IPL’s and WPL’s credit facilities was as follows (dollars in millions):

	Alliant Energy	Parent
September 30, 2013	(Consolidated)	Company	IPL	WPL
Commercial paper:
Amount outstanding	$237.3	$93.9	$—	$143.4
Weighted average remaining maturity	1 day	2 days	N/A	1 day
Weighted average interest rates	0.2%	0.2%	N/A	0.1%
Available credit facility capacity (a)	$697.7	$206.1	$235.0	$256.6

	Alliant Energy						IPL						WPL
Three Months Ended September 30	2013			2012			2013			2012			2013			2012
Maximum amount outstanding (based on daily outstanding balances)		$284.1			$185.3			$—			$19.5			$165.4			$35.6
Average amount outstanding (based on daily outstanding balances)		$228.8			$133.0			$—			$1.3			$140.9			$11.9
Weighted average interest rates	0.2		%	0.4		%	N/A			0.4		%	0.2		%	0.3		%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$284.1			$185.3			$26.3			$35.4			$165.4			$35.6
Average amount outstanding (based on daily outstanding balances)		$197.2			$100.2			$1.7			$7.2			$113.4			$13.3
Weighted average interest rates	0.2		%	0.4		%	0.4		%	0.4		%	0.2		%	0.3		%

(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, 2013. Refer to Note 8(b) for further discussion of $65 million of commercial paper outstanding at September 30, 2013 classified as long-term debt on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets.

(b) Long-term Debt - As of September 30, 2013, $65 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets due to the existence of long-term credit facilities that back-stop this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of September 30, 2013, this commercial paper balance had a remaining maturity of 2 days and a 0.25% interest rate.

In October 2013, IPL issued $250 million of 4.7% senior debentures due 2043. The proceeds from the issuance were used by IPL to reduce cash proceeds received from its sales of accounts receivables program, reduce commercial paper classified as long-term debt and for general working capital purposes.

WPL [Member]

Debt Instrument [Line Items]

Debt

DEBT

(a) Short-term Debt - Information regarding commercial paper classified as short-term debt and back-stopped by Alliant Energy’s, IPL’s and WPL’s credit facilities was as follows (dollars in millions):

	Alliant Energy	Parent
September 30, 2013	(Consolidated)	Company	IPL	WPL
Commercial paper:
Amount outstanding	$237.3	$93.9	$—	$143.4
Weighted average remaining maturity	1 day	2 days	N/A	1 day
Weighted average interest rates	0.2%	0.2%	N/A	0.1%
Available credit facility capacity (a)	$697.7	$206.1	$235.0	$256.6

	Alliant Energy						IPL						WPL
Three Months Ended September 30	2013			2012			2013			2012			2013			2012
Maximum amount outstanding (based on daily outstanding balances)		$284.1			$185.3			$—			$19.5			$165.4			$35.6
Average amount outstanding (based on daily outstanding balances)		$228.8			$133.0			$—			$1.3			$140.9			$11.9
Weighted average interest rates	0.2		%	0.4		%	N/A			0.4		%	0.2		%	0.3		%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances)		$284.1			$185.3			$26.3			$35.4			$165.4			$35.6
Average amount outstanding (based on daily outstanding balances)		$197.2			$100.2			$1.7			$7.2			$113.4			$13.3
Weighted average interest rates	0.2		%	0.4		%	0.4		%	0.4		%	0.2		%	0.3		%

(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, 2013. Refer to Note 8(b) for further discussion of $65 million of commercial paper outstanding at September 30, 2013 classified as long-term debt on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets.