Common Equity

3 Months Ended

Mar. 31, 2013

Common Equity [Line Items]

Common Equity

COMMON EQUITY

Common Share Activity - A summary of Alliant Energy’s common stock activity during the three months ended March 31, 2013 was as follows:

Shares outstanding, January 1	110,987,400
Equity-based compensation plans (Note 5(b))	(45,028	)
Other (a)	(20,357	)
Shares outstanding, March 31	110,922,015

(a) Includes shares transferred from employees to Alliant Energy to satisfy tax withholding requirements in connection with the vesting of certain restricted stock under the equity-based compensation plans.

Dividend Restrictions - As of March 31, 2013, IPL’s amount of retained earnings that were free of dividend restrictions was $398 million. As of March 31, 2013, WPL’s amount of retained earnings that were free of dividend restrictions was $90 million for the remainder of 2013.

Restricted Net Assets of Subsidiaries - As of March 31, 2013, the amount of net assets of IPL and WPL that were not available to be transferred to their parent company, Alliant Energy, in the form of loans, advances or cash dividends without the consent of IPL’s and WPL’s regulatory authorities was $1.1 billion and $1.5 billion, respectively.

Capital Transactions with Subsidiaries - For the three months ended March 31, 2013, IPL received capital contributions of $30.0 million from its parent company. For the three months ended March 31, 2013, IPL and WPL paid common stock dividends of $31.6 million and $29.1 million, respectively, to their parent company.

IPL [Member]

Common Equity [Line Items]

Common Equity

COMMON EQUITY

Common Share Activity - A summary of Alliant Energy’s common stock activity during the three months ended March 31, 2013 was as follows:

Shares outstanding, January 1	110,987,400
Equity-based compensation plans (Note 5(b))	(45,028	)
Other (a)	(20,357	)
Shares outstanding, March 31	110,922,015

(a) Includes shares transferred from employees to Alliant Energy to satisfy tax withholding requirements in connection with the vesting of certain restricted stock under the equity-based compensation plans.

Dividend Restrictions - As of March 31, 2013, IPL’s amount of retained earnings that were free of dividend restrictions was $398 million. As of March 31, 2013, WPL’s amount of retained earnings that were free of dividend restrictions was $90 million for the remainder of 2013.

Restricted Net Assets of Subsidiaries - As of March 31, 2013, the amount of net assets of IPL and WPL that were not available to be transferred to their parent company, Alliant Energy, in the form of loans, advances or cash dividends without the consent of IPL’s and WPL’s regulatory authorities was $1.1 billion and $1.5 billion, respectively.

Capital Transactions with Subsidiaries - For the three months ended March 31, 2013, IPL received capital contributions of $30.0 million from its parent company. For the three months ended March 31, 2013, IPL and WPL paid common stock dividends of $31.6 million and $29.1 million, respectively, to their parent company.

WPL [Member]

Common Equity [Line Items]

Common Equity

COMMON EQUITY

Common Share Activity - A summary of Alliant Energy’s common stock activity during the three months ended March 31, 2013 was as follows:

Shares outstanding, January 1	110,987,400
Equity-based compensation plans (Note 5(b))	(45,028	)
Other (a)	(20,357	)
Shares outstanding, March 31	110,922,015

(a) Includes shares transferred from employees to Alliant Energy to satisfy tax withholding requirements in connection with the vesting of certain restricted stock under the equity-based compensation plans.

Dividend Restrictions - As of March 31, 2013, IPL’s amount of retained earnings that were free of dividend restrictions was $398 million. As of March 31, 2013, WPL’s amount of retained earnings that were free of dividend restrictions was $90 million for the remainder of 2013.

Restricted Net Assets of Subsidiaries - As of March 31, 2013, the amount of net assets of IPL and WPL that were not available to be transferred to their parent company, Alliant Energy, in the form of loans, advances or cash dividends without the consent of IPL’s and WPL’s regulatory authorities was $1.1 billion and $1.5 billion, respectively.

Capital Transactions with Subsidiaries - For the three months ended March 31, 2013, IPL received capital contributions of $30.0 million from its parent company. For the three months ended March 31, 2013, IPL and WPL paid common stock dividends of $31.6 million and $29.1 million, respectively, to their parent company.