Redeemable Preferred Stock	9 Months Ended
Redeemable Preferred Stock	Sep. 30, 2013
Redeemable Preferred Stock	REDEEMABLE PREFERRED STOCK IPL - In March 2013, IPL issued 8,000,000 shares of 5.1% cumulative preferred stock and received proceeds of $200 million. The proceeds were used by IPL to redeem its 8.375% cumulative preferred stock, reduce commercial paper classified as long-term debt by $40 million and for other general corporate purposes. Alliant Energy and IPL incurred $5 million of issuance costs related to this transaction, which were recorded as a reduction of “Additional paid-in capital” on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets during the nine months ended September 30, 2013. On or after March 15, 2018, IPL may, at its option, redeem the 5.1% cumulative preferred stock for cash at a redemption price of $25 per share plus accrued and unpaid dividends up to the redemption date. The articles of incorporation of IPL contain a provision that grants the holders of its 5.1% cumulative preferred stock voting rights to elect two members of IPL’s Board of Directors if preferred dividends equal to six or more quarterly dividend requirements (whether or not consecutive) are in arrears. Such voting rights would not provide the holders of IPL’s preferred stock control of the decision on redemption of IPL’s preferred stock and could not force IPL to exercise its call option. Therefore, IPL’s 5.1% cumulative preferred stock is presented in total equity on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets in a manner consistent with noncontrolling interests. In March 2013, IPL redeemed all 6,000,000 outstanding shares of its 8.375% cumulative preferred stock for $150 million plus accrued and unpaid dividends to the redemption date. Alliant Energy and IPL recorded a $5 million charge during the nine months ended September 30, 2013 related to this transaction in “Preferred dividend requirements” in their Condensed Consolidated Statements of Income. WPL - In March 2013, WPL redeemed all 1,049,225 outstanding shares of its 4.40% through 6.50% cumulative preferred stock for $61 million plus accrued and unpaid dividends to the redemption date. Alliant Energy and WPL recorded a $1 million charge during the nine months ended September 30, 2013 related to this transaction in “Preferred dividend requirements” in their Condensed Consolidated Statements of Income. Refer to Note 10 for information on the fair value of cumulative preferred stock.
IPL [Member]
Redeemable Preferred Stock	REDEEMABLE PREFERRED STOCK IPL - In March 2013, IPL issued 8,000,000 shares of 5.1% cumulative preferred stock and received proceeds of $200 million. The proceeds were used by IPL to redeem its 8.375% cumulative preferred stock, reduce commercial paper classified as long-term debt by $40 million and for other general corporate purposes. Alliant Energy and IPL incurred $5 million of issuance costs related to this transaction, which were recorded as a reduction of “Additional paid-in capital” on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets during the nine months ended September 30, 2013. On or after March 15, 2018, IPL may, at its option, redeem the 5.1% cumulative preferred stock for cash at a redemption price of $25 per share plus accrued and unpaid dividends up to the redemption date. The articles of incorporation of IPL contain a provision that grants the holders of its 5.1% cumulative preferred stock voting rights to elect two members of IPL’s Board of Directors if preferred dividends equal to six or more quarterly dividend requirements (whether or not consecutive) are in arrears. Such voting rights would not provide the holders of IPL’s preferred stock control of the decision on redemption of IPL’s preferred stock and could not force IPL to exercise its call option. Therefore, IPL’s 5.1% cumulative preferred stock is presented in total equity on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets in a manner consistent with noncontrolling interests. In March 2013, IPL redeemed all 6,000,000 outstanding shares of its 8.375% cumulative preferred stock for $150 million plus accrued and unpaid dividends to the redemption date. Alliant Energy and IPL recorded a $5 million charge during the nine months ended September 30, 2013 related to this transaction in “Preferred dividend requirements” in their Condensed Consolidated Statements of Income. WPL - In March 2013, WPL redeemed all 1,049,225 outstanding shares of its 4.40% through 6.50% cumulative preferred stock for $61 million plus accrued and unpaid dividends to the redemption date. Alliant Energy and WPL recorded a $1 million charge during the nine months ended September 30, 2013 related to this transaction in “Preferred dividend requirements” in their Condensed Consolidated Statements of Income. Refer to Note 10 for information on the fair value of cumulative preferred stock.
WPL [Member]
Redeemable Preferred Stock	REDEEMABLE PREFERRED STOCK IPL - In March 2013, IPL issued 8,000,000 shares of 5.1% cumulative preferred stock and received proceeds of $200 million. The proceeds were used by IPL to redeem its 8.375% cumulative preferred stock, reduce commercial paper classified as long-term debt by $40 million and for other general corporate purposes. Alliant Energy and IPL incurred $5 million of issuance costs related to this transaction, which were recorded as a reduction of “Additional paid-in capital” on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets during the nine months ended September 30, 2013. On or after March 15, 2018, IPL may, at its option, redeem the 5.1% cumulative preferred stock for cash at a redemption price of $25 per share plus accrued and unpaid dividends up to the redemption date. The articles of incorporation of IPL contain a provision that grants the holders of its 5.1% cumulative preferred stock voting rights to elect two members of IPL’s Board of Directors if preferred dividends equal to six or more quarterly dividend requirements (whether or not consecutive) are in arrears. Such voting rights would not provide the holders of IPL’s preferred stock control of the decision on redemption of IPL’s preferred stock and could not force IPL to exercise its call option. Therefore, IPL’s 5.1% cumulative preferred stock is presented in total equity on Alliant Energy’s and IPL’s Condensed Consolidated Balance Sheets in a manner consistent with noncontrolling interests. In March 2013, IPL redeemed all 6,000,000 outstanding shares of its 8.375% cumulative preferred stock for $150 million plus accrued and unpaid dividends to the redemption date. Alliant Energy and IPL recorded a $5 million charge during the nine months ended September 30, 2013 related to this transaction in “Preferred dividend requirements” in their Condensed Consolidated Statements of Income. WPL - In March 2013, WPL redeemed all 1,049,225 outstanding shares of its 4.40% through 6.50% cumulative preferred stock for $61 million plus accrued and unpaid dividends to the redemption date. Alliant Energy and WPL recorded a $1 million charge during the nine months ended September 30, 2013 related to this transaction in “Preferred dividend requirements” in their Condensed Consolidated Statements of Income. Refer to Note 10 for information on the fair value of cumulative preferred stock.