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Common Equity | 12 Months Ended
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Dec. 31, 2014
Schedule of Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
| 2014 |  | 2013 |  | 2012
Shares outstanding, January 1 | 110,943,669 |  |  | 110,987,400 |  |  | 111,018,821 |
Equity-based compensation plans (Note 12(b)) | 35,547 |  |  | (23,374 | ) |  | 20,195 |
Other | (43,536 | ) |  | (20,357 | ) |  | (51,616 | )
Shares outstanding, December 31 | 110,935,680 |  |  | 110,943,669 |  |  | 110,987,400 |
At December 31, 2014, Alliant Energy had a total of 7.8 million shares available for issuance in the aggregate, pursuant to its OIP, Shareowner Direct Plan and 401(k) Savings Plan. Shareowner Rights Agreement - Alliant Energy has established an amended and restated Shareowner Rights Agreement. The rights under this agreement will only become exercisable if a person or group has acquired, or announced an intention to acquire, 15% or more of Alliant Energy’s outstanding common stock. Each right will initially entitle registered shareowners to purchase from Alliant Energy one-half of one share of Alliant Energy’s common stock. The rights will be exercisable at an initial price of $110.00 per full share, subject to adjustment. If any shareowner acquires 15% or more of the outstanding common stock of Alliant Energy, each right (subject to limitations) will entitle its holder to purchase, at the right’s then current exercise price, a number of common shares of Alliant Energy or of the acquirer having a market value at the time of twice the right’s per full share exercise price. Alliant Energy’s Board of Directors is authorized to reduce the 15% ownership threshold to not less than 10%. The amended and restated Shareowner Rights Agreement expires in December 2018. Dividend Restrictions - Alliant Energy does not have any significant common stock dividend restrictions. IPL and WPL each have common stock dividend restrictions based on applicable regulatory limitations. IPL also has common stock dividend restrictions based on the terms of its outstanding preferred stock. As of December 31, 2014, IPL and WPL were in compliance with all such dividend restrictions. IPL is restricted from paying common stock dividends to its parent company, Alliant Energy, if for any past or current dividend period, dividends on its preferred stock have not been paid, or declared and set apart for payment. IPL has paid all dividends on its preferred stock through 2014. Under the Federal Power Act, IPL may not pay dividends to its parent company in excess of the current amount of its retained earnings. Another limitation on IPL’s distributions to its parent company requires IPL to obtain IUB approval for a reasonable utility capital structure if its actual 13-month average common equity ratio (calculated on a financial basis consistent with IPL’s rate cases) falls below 42% of total capitalization. As of December 31, 2014, IPL’s amount of retained earnings that were free of dividend restrictions was $538 million. Currently, WPL has a regulatory limitation on distributions to its parent company from an order issued by the PSCW in July 2014. The order prohibits WPL from paying annual common stock dividends to its parent company in excess of $127 million in 2015 and $135 million in 2016 if WPL’s actual 13-month average common equity ratio (calculated on a financial basis consistent with WPL’s rate cases) would fall below 51.79% for 2015 and 52.25% for 2016. As of December 31, 2014, WPL’s amount of retained earnings that were free of dividend restrictions was $127 million for 2015. Restricted Net Assets of Subsidiaries - IPL and WPL do not have regulatory authority to lend or advance any amounts to their parent company. As of December 31, 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 as follows (in billions):
| 2014 |  | 2013
IPL |  | $1.3 |  |  |  | $1.2 |
WPL | 1.6 |  |  | 1.5 |
Capital Transactions With Subsidiaries - IPL, WPL and Resources paid common stock dividends and repayments of capital to their parent company, Alliant Energy, as follows (in millions):
| IPL |  | WPL |  | Resources
| 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012
Common stock dividends |  | $140.0 |  |  |  | $128.1 |  |  |  | $122.9 |  |  |  | $118.7 |  |  |  | $116.3 |  |  |  | $112.0 |  |  |  | $— |  |  |  | $— |  |  |  | $— |
Repayments of capital | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 50.0 |  |  | 95.0 |  |  | — |
Total distributions from common equity |  | $140.0 |  |  |  | $128.1 |  |  |  | $122.9 |  |  |  | $118.7 |  |  |  | $116.3 |  |  |  | $112.0 |  |  |  | $50.0 |  |  |  | $95.0 |  |  |  | $— |
IPL, WPL and Corporate Services received capital contributions from their parent company, Alliant Energy, as follows (in millions):
| 2014 |  | 2013 |  | 2012
IPL |  | $90.0 |  |  |  | $120.0 |  |  |  | $110.0 |
WPL | — |  |  | — |  |  | 90.0 |
Corporate Services | — |  |  | — |  |  | 30.0 |
Comprehensive Income - In 2014, 2013 and 2012, Alliant Energy’s other comprehensive income (loss) was ($0.4) million, $0.6 million and $0, respectively; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. In 2014, 2013 and 2012, IPL and WPL had no other comprehensive income; therefore their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.
IPL [Member] |
Schedule of Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
| 2014 |  | 2013 |  | 2012
Shares outstanding, January 1 | 110,943,669 |  |  | 110,987,400 |  |  | 111,018,821 |
Equity-based compensation plans (Note 12(b)) | 35,547 |  |  | (23,374 | ) |  | 20,195 |
Other | (43,536 | ) |  | (20,357 | ) |  | (51,616 | )
Shares outstanding, December 31 | 110,935,680 |  |  | 110,943,669 |  |  | 110,987,400 |
At December 31, 2014, Alliant Energy had a total of 7.8 million shares available for issuance in the aggregate, pursuant to its OIP, Shareowner Direct Plan and 401(k) Savings Plan. Shareowner Rights Agreement - Alliant Energy has established an amended and restated Shareowner Rights Agreement. The rights under this agreement will only become exercisable if a person or group has acquired, or announced an intention to acquire, 15% or more of Alliant Energy’s outstanding common stock. Each right will initially entitle registered shareowners to purchase from Alliant Energy one-half of one share of Alliant Energy’s common stock. The rights will be exercisable at an initial price of $110.00 per full share, subject to adjustment. If any shareowner acquires 15% or more of the outstanding common stock of Alliant Energy, each right (subject to limitations) will entitle its holder to purchase, at the right’s then current exercise price, a number of common shares of Alliant Energy or of the acquirer having a market value at the time of twice the right’s per full share exercise price. Alliant Energy’s Board of Directors is authorized to reduce the 15% ownership threshold to not less than 10%. The amended and restated Shareowner Rights Agreement expires in December 2018. Dividend Restrictions - Alliant Energy does not have any significant common stock dividend restrictions. IPL and WPL each have common stock dividend restrictions based on applicable regulatory limitations. IPL also has common stock dividend restrictions based on the terms of its outstanding preferred stock. As of December 31, 2014, IPL and WPL were in compliance with all such dividend restrictions. IPL is restricted from paying common stock dividends to its parent company, Alliant Energy, if for any past or current dividend period, dividends on its preferred stock have not been paid, or declared and set apart for payment. IPL has paid all dividends on its preferred stock through 2014. Under the Federal Power Act, IPL may not pay dividends to its parent company in excess of the current amount of its retained earnings. Another limitation on IPL’s distributions to its parent company requires IPL to obtain IUB approval for a reasonable utility capital structure if its actual 13-month average common equity ratio (calculated on a financial basis consistent with IPL’s rate cases) falls below 42% of total capitalization. As of December 31, 2014, IPL’s amount of retained earnings that were free of dividend restrictions was $538 million. Currently, WPL has a regulatory limitation on distributions to its parent company from an order issued by the PSCW in July 2014. The order prohibits WPL from paying annual common stock dividends to its parent company in excess of $127 million in 2015 and $135 million in 2016 if WPL’s actual 13-month average common equity ratio (calculated on a financial basis consistent with WPL’s rate cases) would fall below 51.79% for 2015 and 52.25% for 2016. As of December 31, 2014, WPL’s amount of retained earnings that were free of dividend restrictions was $127 million for 2015. Restricted Net Assets of Subsidiaries - IPL and WPL do not have regulatory authority to lend or advance any amounts to their parent company. As of December 31, 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 as follows (in billions):
| 2014 |  | 2013
IPL |  | $1.3 |  |  |  | $1.2 |
WPL | 1.6 |  |  | 1.5 |
Capital Transactions With Subsidiaries - IPL, WPL and Resources paid common stock dividends and repayments of capital to their parent company, Alliant Energy, as follows (in millions):
| IPL |  | WPL |  | Resources
| 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012
Common stock dividends |  | $140.0 |  |  |  | $128.1 |  |  |  | $122.9 |  |  |  | $118.7 |  |  |  | $116.3 |  |  |  | $112.0 |  |  |  | $— |  |  |  | $— |  |  |  | $— |
Repayments of capital | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 50.0 |  |  | 95.0 |  |  | — |
Total distributions from common equity |  | $140.0 |  |  |  | $128.1 |  |  |  | $122.9 |  |  |  | $118.7 |  |  |  | $116.3 |  |  |  | $112.0 |  |  |  | $50.0 |  |  |  | $95.0 |  |  |  | $— |
IPL, WPL and Corporate Services received capital contributions from their parent company, Alliant Energy, as follows (in millions):
| 2014 |  | 2013 |  | 2012
IPL |  | $90.0 |  |  |  | $120.0 |  |  |  | $110.0 |
WPL | — |  |  | — |  |  | 90.0 |
Corporate Services | — |  |  | — |  |  | 30.0 |
Comprehensive Income - In 2014, 2013 and 2012, Alliant Energy’s other comprehensive income (loss) was ($0.4) million, $0.6 million and $0, respectively; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. In 2014, 2013 and 2012, IPL and WPL had no other comprehensive income; therefore their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.
WPL [Member] |
Schedule of Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
| 2014 |  | 2013 |  | 2012
Shares outstanding, January 1 | 110,943,669 |  |  | 110,987,400 |  |  | 111,018,821 |
Equity-based compensation plans (Note 12(b)) | 35,547 |  |  | (23,374 | ) |  | 20,195 |
Other | (43,536 | ) |  | (20,357 | ) |  | (51,616 | )
Shares outstanding, December 31 | 110,935,680 |  |  | 110,943,669 |  |  | 110,987,400 |
At December 31, 2014, Alliant Energy had a total of 7.8 million shares available for issuance in the aggregate, pursuant to its OIP, Shareowner Direct Plan and 401(k) Savings Plan. Shareowner Rights Agreement - Alliant Energy has established an amended and restated Shareowner Rights Agreement. The rights under this agreement will only become exercisable if a person or group has acquired, or announced an intention to acquire, 15% or more of Alliant Energy’s outstanding common stock. Each right will initially entitle registered shareowners to purchase from Alliant Energy one-half of one share of Alliant Energy’s common stock. The rights will be exercisable at an initial price of $110.00 per full share, subject to adjustment. If any shareowner acquires 15% or more of the outstanding common stock of Alliant Energy, each right (subject to limitations) will entitle its holder to purchase, at the right’s then current exercise price, a number of common shares of Alliant Energy or of the acquirer having a market value at the time of twice the right’s per full share exercise price. Alliant Energy’s Board of Directors is authorized to reduce the 15% ownership threshold to not less than 10%. The amended and restated Shareowner Rights Agreement expires in December 2018. Dividend Restrictions - Alliant Energy does not have any significant common stock dividend restrictions. IPL and WPL each have common stock dividend restrictions based on applicable regulatory limitations. IPL also has common stock dividend restrictions based on the terms of its outstanding preferred stock. As of December 31, 2014, IPL and WPL were in compliance with all such dividend restrictions. IPL is restricted from paying common stock dividends to its parent company, Alliant Energy, if for any past or current dividend period, dividends on its preferred stock have not been paid, or declared and set apart for payment. IPL has paid all dividends on its preferred stock through 2014. Under the Federal Power Act, IPL may not pay dividends to its parent company in excess of the current amount of its retained earnings. Another limitation on IPL’s distributions to its parent company requires IPL to obtain IUB approval for a reasonable utility capital structure if its actual 13-month average common equity ratio (calculated on a financial basis consistent with IPL’s rate cases) falls below 42% of total capitalization. As of December 31, 2014, IPL’s amount of retained earnings that were free of dividend restrictions was $538 million. Currently, WPL has a regulatory limitation on distributions to its parent company from an order issued by the PSCW in July 2014. The order prohibits WPL from paying annual common stock dividends to its parent company in excess of $127 million in 2015 and $135 million in 2016 if WPL’s actual 13-month average common equity ratio (calculated on a financial basis consistent with WPL’s rate cases) would fall below 51.79% for 2015 and 52.25% for 2016. As of December 31, 2014, WPL’s amount of retained earnings that were free of dividend restrictions was $127 million for 2015. Restricted Net Assets of Subsidiaries - IPL and WPL do not have regulatory authority to lend or advance any amounts to their parent company. As of December 31, 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 as follows (in billions):
| 2014 |  | 2013
IPL |  | $1.3 |  |  |  | $1.2 |
WPL | 1.6 |  |  | 1.5 |
Capital Transactions With Subsidiaries - IPL, WPL and Resources paid common stock dividends and repayments of capital to their parent company, Alliant Energy, as follows (in millions):
| IPL |  | WPL |  | Resources
| 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012 |  | 2014 |  | 2013 |  | 2012
Common stock dividends |  | $140.0 |  |  |  | $128.1 |  |  |  | $122.9 |  |  |  | $118.7 |  |  |  | $116.3 |  |  |  | $112.0 |  |  |  | $— |  |  |  | $— |  |  |  | $— |
Repayments of capital | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 50.0 |  |  | 95.0 |  |  | — |
Total distributions from common equity |  | $140.0 |  |  |  | $128.1 |  |  |  | $122.9 |  |  |  | $118.7 |  |  |  | $116.3 |  |  |  | $112.0 |  |  |  | $50.0 |  |  |  | $95.0 |  |  |  | $— |
IPL, WPL and Corporate Services received capital contributions from their parent company, Alliant Energy, as follows (in millions):
| 2014 |  | 2013 |  | 2012
IPL |  | $90.0 |  |  |  | $120.0 |  |  |  | $110.0 |
WPL | — |  |  | — |  |  | 90.0 |
Corporate Services | — |  |  | — |  |  | 30.0 |
Comprehensive Income - In 2014, 2013 and 2012, Alliant Energy’s other comprehensive income (loss) was ($0.4) million, $0.6 million and $0, respectively; therefore, its comprehensive income was substantially equal to its net income and its comprehensive income attributable to Alliant Energy common shareowners was substantially equal to its net income attributable to Alliant Energy common shareowners for such periods. In 2014, 2013 and 2012, IPL and WPL had no other comprehensive income; therefore their comprehensive income was equal to their net income and their comprehensive income available for common stock was equal to their earnings available for common stock for such periods.

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- Definition The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(d),(e)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB TOPIC 4.C) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29-31) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 4.E) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 4 -Section C Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 4 -Section E Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Article 4 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Preferred Stock -URI http://asc.fasb.org/extlink&oid=6521494 Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30, 31 -Article 5 Reference 11: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 12: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 13: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 14: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 15: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644 Reference 16: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644 Reference 17: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644 Reference 18: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph d -Article 4 Reference 19: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656 + Details
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