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Common Equity | 9 Months Ended
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Sep. 30, 2019
Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2019 | 236,063,279 |
Equity forward agreements | 3,790,300 |
Shareowner Direct Plan | 390,630 |
Equity-based compensation plans | 101,478 |
Other | (2,738 | )
Shares outstanding, September 30, 2019 | 240,342,949 |
Equity Forward Agreements - In December 2018, Alliant Energy entered into forward sale agreements with various counterparties in connection with a public offering of 8,358,973 shares of Alliant Energy common stock. The initial forward sale price of $44.33 per share is subject to daily adjustment based on a floating interest rate factor, and will decrease by other fixed amounts specified in the forward sale agreements. In 2019, Alliant Energy settled $167 million under the forward sale agreements by delivering 3,790,300 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $43.99 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes. As of September 30, 2019, 671,237 incremental shares were included in the calculation of diluted EPS related to the remaining securities under the forward sale agreements. Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):
Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $2.4 |  |  |  | $2,108.4 |  |  |  | $2,597.8 |  |  |  | $1.0 |  |  |  | ($10.0 | ) |  |  | $200.0 |  |  |  | $4,899.6 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 226.0 |  |  |  |  |  |  |  |  | 226.0 |
Common stock dividends ($0.355 per share) |  |  |  |  | (84.7 | ) |  |  |  |  |  |  |  | (84.7 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 124.8 |  |  |  |  |  |  |  |  |  |  | 124.8 |
Equity-based compensation plans and other |  |  | 3.7 |  |  |  |  |  |  | (0.2 | ) |  |  |  | 3.5 |
Ending balance, September 30 |  | $2.4 |  |  |  | $2,236.9 |  |  |  | $2,739.1 |  |  |  | $1.0 |  |  |  | ($10.2 | ) |  |  | $200.0 |  |  |  | $5,169.2 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $2.3 |  |  |  | $1,947.2 |  |  |  | $2,412.5 |  |  |  | $0.1 |  |  |  | ($11.4 | ) |  |  | $200.0 |  |  |  | $4,550.7 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 205.5 |  |  |  |  |  |  |  |  | 205.5 |
Common stock dividends ($0.335 per share) |  |  |  |  | (78.5 | ) |  |  |  |  |  |  |  | (78.5 | )
At-the-market offering program and Shareowner Direct Plan issuances | 0.1 |  |  | 91.1 |  |  |  |  |  |  |  |  |  |  | 91.2 |
Equity-based compensation plans and other |  |  | (0.1 | ) |  |  |  |  |  | 1.9 |  |  |  |  | 1.8 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (0.3 | ) |  |  |  |  |  | (0.3 | )
Ending balance, September 30 |  | $2.4 |  |  |  | $2,038.2 |  |  |  | $2,539.5 |  |  |  | ($0.2 | ) |  |  | ($9.5 | ) |  |  | $200.0 |  |  |  | $4,770.4 |
Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $2.4 |  |  |  | $2,045.5 |  |  |  | $2,545.9 |  |  |  | $1.7 |  |  |  | ($9.8 | ) |  |  | $200.0 |  |  |  | $4,785.7 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 445.7 |  |  |  |  |  |  |  |  | 445.7 |
Common stock dividends ($1.065 per share) |  |  |  |  | (252.5 | ) |  |  |  |  |  |  |  | (252.5 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 185.4 |  |  |  |  |  |  |  |  |  |  | 185.4 |
Equity-based compensation plans and other |  |  | 6.0 |  |  |  |  |  |  | (0.4 | ) |  |  |  | 5.6 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (0.7 | ) |  |  |  |  |  | (0.7 | )
Ending balance, September 30 |  | $2.4 |  |  |  | $2,236.9 |  |  |  | $2,739.1 |  |  |  | $1.0 |  |  |  | ($10.2 | ) |  |  | $200.0 |  |  |  | $5,169.2 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $2.3 |  |  |  | $1,845.5 |  |  |  | $2,346.0 |  |  |  | ($0.5 | ) |  |  | ($11.1 | ) |  |  | $200.0 |  |  |  | $4,382.2 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 426.8 |  |  |  |  |  |  |  |  | 426.8 |
Common stock dividends ($1.005 per share) |  |  |  |  | (233.3 | ) |  |  |  |  |  |  |  | (233.3 | )
At-the-market offering program and Shareowner Direct Plan issuances | 0.1 |  |  | 191.2 |  |  |  |  |  |  |  |  |  |  | 191.3 |
Equity-based compensation plans and other |  |  | 1.5 |  |  |  |  |  |  | 1.6 |  |  |  |  | 3.1 |
Other comprehensive income, net of tax |  |  |  |  |  |  | 0.3 |  |  |  |  |  |  | 0.3 |
Ending balance, September 30 |  | $2.4 |  |  |  | $2,038.2 |  |  |  | $2,539.5 |  |  |  | ($0.2 | ) |  |  | ($9.5 | ) |  |  | $200.0 |  |  |  | $4,770.4 |
IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $788.9 |  |  |  | $200.0 |  |  |  | $3,345.1 |
Earnings available for common stock |  |  |  |  | 141.1 |  |  |  |  | 141.1 |
Common stock dividends |  |  |  |  | (42.1 | ) |  |  |  | (42.1 | )
Ending balance, September 30 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $887.9 |  |  |  | $200.0 |  |  |  | $3,444.1 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $33.4 |  |  |  | $1,927.8 |  |  |  | $692.9 |  |  |  | $200.0 |  |  |  | $2,854.1 |
Earnings available for common stock |  |  |  |  | 126.5 |  |  |  |  | 126.5 |
Common stock dividends |  |  |  |  | (41.9 | ) |  |  |  | (41.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,027.8 |  |  |  | $777.5 |  |  |  | $200.0 |  |  |  | $3,038.7 |
IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $33.4 |  |  |  | $2,222.8 |  |  |  | $774.5 |  |  |  | $200.0 |  |  |  | $3,230.7 |
Earnings available for common stock |  |  |  |  | 239.4 |  |  |  |  | 239.4 |
Common stock dividends |  |  |  |  | (126.0 | ) |  |  |  | (126.0 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $887.9 |  |  |  | $200.0 |  |  |  | $3,444.1 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $33.4 |  |  |  | $1,797.8 |  |  |  | $678.5 |  |  |  | $200.0 |  |  |  | $2,709.7 |
Earnings available for common stock |  |  |  |  | 224.9 |  |  |  |  | 224.9 |
Common stock dividends |  |  |  |  | (125.9 | ) |  |  |  | (125.9 | )
Capital contributions from parent |  |  | 230.0 |  |  |  |  |  |  | 230.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,027.8 |  |  |  | $777.5 |  |  |  | $200.0 |  |  |  | $3,038.7 |
WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, July 1 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $810.0 |  |  |  | $2,185.2 |
Earnings available for common stock |  |  |  |  | 75.5 |  |  | 75.5 |
Common stock dividends |  |  |  |  | (35.9 | ) |  | (35.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,409.0 |  |  |  | $849.6 |  |  |  | $2,324.8 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |
Beginning balance, July 1 |  | $66.2 |  |  |  | $1,259.0 |  |  |  | $730.0 |  |  |  | $2,055.2 |
Earnings available for common stock |  |  |  |  | 76.3 |  |  | 76.3 |
Common stock dividends |  |  |  |  | (34.9 | ) |  | (34.9 | )
Capital contributions from parent |  |  | 50.0 |  |  |  |  | 50.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $771.4 |  |  |  | $2,146.6 |
WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, January 1 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $774.3 |  |  |  | $2,149.5 |
Earnings available for common stock |  |  |  |  | 183.2 |  |  | 183.2 |
Common stock dividends |  |  |  |  | (107.9 | ) |  | (107.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,409.0 |  |  |  | $849.6 |  |  |  | $2,324.8 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |
Beginning balance, January 1 |  | $66.2 |  |  |  | $1,109.0 |  |  |  | $706.3 |  |  |  | $1,881.5 |
Earnings available for common stock |  |  |  |  | 170.1 |  |  | 170.1 |
Common stock dividends |  |  |  |  | (105.0 | ) |  | (105.0 | )
Capital contributions from parent |  |  | 200.0 |  |  |  |  | 200.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $771.4 |  |  |  | $2,146.6 |
Comprehensive Income - For the three and nine months ended September 30, 2019 and 2018, Alliant Energy’s other comprehensive income was not material; 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. For the three and nine months ended September 30, 2019 and 2018, 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] |
Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2019 | 236,063,279 |
Equity forward agreements | 3,790,300 |
Shareowner Direct Plan | 390,630 |
Equity-based compensation plans | 101,478 |
Other | (2,738 | )
Shares outstanding, September 30, 2019 | 240,342,949 |
Equity Forward Agreements - In December 2018, Alliant Energy entered into forward sale agreements with various counterparties in connection with a public offering of 8,358,973 shares of Alliant Energy common stock. The initial forward sale price of $44.33 per share is subject to daily adjustment based on a floating interest rate factor, and will decrease by other fixed amounts specified in the forward sale agreements. In 2019, Alliant Energy settled $167 million under the forward sale agreements by delivering 3,790,300 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $43.99 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes. As of September 30, 2019, 671,237 incremental shares were included in the calculation of diluted EPS related to the remaining securities under the forward sale agreements. Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):
Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $2.4 |  |  |  | $2,108.4 |  |  |  | $2,597.8 |  |  |  | $1.0 |  |  |  | ($10.0 | ) |  |  | $200.0 |  |  |  | $4,899.6 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 226.0 |  |  |  |  |  |  |  |  | 226.0 |
Common stock dividends ($0.355 per share) |  |  |  |  | (84.7 | ) |  |  |  |  |  |  |  | (84.7 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 124.8 |  |  |  |  |  |  |  |  |  |  | 124.8 |
Equity-based compensation plans and other |  |  | 3.7 |  |  |  |  |  |  | (0.2 | ) |  |  |  | 3.5 |
Ending balance, September 30 |  | $2.4 |  |  |  | $2,236.9 |  |  |  | $2,739.1 |  |  |  | $1.0 |  |  |  | ($10.2 | ) |  |  | $200.0 |  |  |  | $5,169.2 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $2.3 |  |  |  | $1,947.2 |  |  |  | $2,412.5 |  |  |  | $0.1 |  |  |  | ($11.4 | ) |  |  | $200.0 |  |  |  | $4,550.7 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 205.5 |  |  |  |  |  |  |  |  | 205.5 |
Common stock dividends ($0.335 per share) |  |  |  |  | (78.5 | ) |  |  |  |  |  |  |  | (78.5 | )
At-the-market offering program and Shareowner Direct Plan issuances | 0.1 |  |  | 91.1 |  |  |  |  |  |  |  |  |  |  | 91.2 |
Equity-based compensation plans and other |  |  | (0.1 | ) |  |  |  |  |  | 1.9 |  |  |  |  | 1.8 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (0.3 | ) |  |  |  |  |  | (0.3 | )
Ending balance, September 30 |  | $2.4 |  |  |  | $2,038.2 |  |  |  | $2,539.5 |  |  |  | ($0.2 | ) |  |  | ($9.5 | ) |  |  | $200.0 |  |  |  | $4,770.4 |
Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $2.4 |  |  |  | $2,045.5 |  |  |  | $2,545.9 |  |  |  | $1.7 |  |  |  | ($9.8 | ) |  |  | $200.0 |  |  |  | $4,785.7 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 445.7 |  |  |  |  |  |  |  |  | 445.7 |
Common stock dividends ($1.065 per share) |  |  |  |  | (252.5 | ) |  |  |  |  |  |  |  | (252.5 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 185.4 |  |  |  |  |  |  |  |  |  |  | 185.4 |
Equity-based compensation plans and other |  |  | 6.0 |  |  |  |  |  |  | (0.4 | ) |  |  |  | 5.6 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (0.7 | ) |  |  |  |  |  | (0.7 | )
Ending balance, September 30 |  | $2.4 |  |  |  | $2,236.9 |  |  |  | $2,739.1 |  |  |  | $1.0 |  |  |  | ($10.2 | ) |  |  | $200.0 |  |  |  | $5,169.2 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $2.3 |  |  |  | $1,845.5 |  |  |  | $2,346.0 |  |  |  | ($0.5 | ) |  |  | ($11.1 | ) |  |  | $200.0 |  |  |  | $4,382.2 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 426.8 |  |  |  |  |  |  |  |  | 426.8 |
Common stock dividends ($1.005 per share) |  |  |  |  | (233.3 | ) |  |  |  |  |  |  |  | (233.3 | )
At-the-market offering program and Shareowner Direct Plan issuances | 0.1 |  |  | 191.2 |  |  |  |  |  |  |  |  |  |  | 191.3 |
Equity-based compensation plans and other |  |  | 1.5 |  |  |  |  |  |  | 1.6 |  |  |  |  | 3.1 |
Other comprehensive income, net of tax |  |  |  |  |  |  | 0.3 |  |  |  |  |  |  | 0.3 |
Ending balance, September 30 |  | $2.4 |  |  |  | $2,038.2 |  |  |  | $2,539.5 |  |  |  | ($0.2 | ) |  |  | ($9.5 | ) |  |  | $200.0 |  |  |  | $4,770.4 |
IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $788.9 |  |  |  | $200.0 |  |  |  | $3,345.1 |
Earnings available for common stock |  |  |  |  | 141.1 |  |  |  |  | 141.1 |
Common stock dividends |  |  |  |  | (42.1 | ) |  |  |  | (42.1 | )
Ending balance, September 30 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $887.9 |  |  |  | $200.0 |  |  |  | $3,444.1 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $33.4 |  |  |  | $1,927.8 |  |  |  | $692.9 |  |  |  | $200.0 |  |  |  | $2,854.1 |
Earnings available for common stock |  |  |  |  | 126.5 |  |  |  |  | 126.5 |
Common stock dividends |  |  |  |  | (41.9 | ) |  |  |  | (41.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,027.8 |  |  |  | $777.5 |  |  |  | $200.0 |  |  |  | $3,038.7 |
IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $33.4 |  |  |  | $2,222.8 |  |  |  | $774.5 |  |  |  | $200.0 |  |  |  | $3,230.7 |
Earnings available for common stock |  |  |  |  | 239.4 |  |  |  |  | 239.4 |
Common stock dividends |  |  |  |  | (126.0 | ) |  |  |  | (126.0 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $887.9 |  |  |  | $200.0 |  |  |  | $3,444.1 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $33.4 |  |  |  | $1,797.8 |  |  |  | $678.5 |  |  |  | $200.0 |  |  |  | $2,709.7 |
Earnings available for common stock |  |  |  |  | 224.9 |  |  |  |  | 224.9 |
Common stock dividends |  |  |  |  | (125.9 | ) |  |  |  | (125.9 | )
Capital contributions from parent |  |  | 230.0 |  |  |  |  |  |  | 230.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,027.8 |  |  |  | $777.5 |  |  |  | $200.0 |  |  |  | $3,038.7 |
WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, July 1 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $810.0 |  |  |  | $2,185.2 |
Earnings available for common stock |  |  |  |  | 75.5 |  |  | 75.5 |
Common stock dividends |  |  |  |  | (35.9 | ) |  | (35.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,409.0 |  |  |  | $849.6 |  |  |  | $2,324.8 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |
Beginning balance, July 1 |  | $66.2 |  |  |  | $1,259.0 |  |  |  | $730.0 |  |  |  | $2,055.2 |
Earnings available for common stock |  |  |  |  | 76.3 |  |  | 76.3 |
Common stock dividends |  |  |  |  | (34.9 | ) |  | (34.9 | )
Capital contributions from parent |  |  | 50.0 |  |  |  |  | 50.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $771.4 |  |  |  | $2,146.6 |
WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, January 1 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $774.3 |  |  |  | $2,149.5 |
Earnings available for common stock |  |  |  |  | 183.2 |  |  | 183.2 |
Common stock dividends |  |  |  |  | (107.9 | ) |  | (107.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,409.0 |  |  |  | $849.6 |  |  |  | $2,324.8 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |
Beginning balance, January 1 |  | $66.2 |  |  |  | $1,109.0 |  |  |  | $706.3 |  |  |  | $1,881.5 |
Earnings available for common stock |  |  |  |  | 170.1 |  |  | 170.1 |
Common stock dividends |  |  |  |  | (105.0 | ) |  | (105.0 | )
Capital contributions from parent |  |  | 200.0 |  |  |  |  | 200.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $771.4 |  |  |  | $2,146.6 |
Comprehensive Income - For the three and nine months ended September 30, 2019 and 2018, Alliant Energy’s other comprehensive income was not material; 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. For the three and nine months ended September 30, 2019 and 2018, 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] |
Common Equity [Line Items] |
Common Equity | COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2019 | 236,063,279 |
Equity forward agreements | 3,790,300 |
Shareowner Direct Plan | 390,630 |
Equity-based compensation plans | 101,478 |
Other | (2,738 | )
Shares outstanding, September 30, 2019 | 240,342,949 |
Equity Forward Agreements - In December 2018, Alliant Energy entered into forward sale agreements with various counterparties in connection with a public offering of 8,358,973 shares of Alliant Energy common stock. The initial forward sale price of $44.33 per share is subject to daily adjustment based on a floating interest rate factor, and will decrease by other fixed amounts specified in the forward sale agreements. In 2019, Alliant Energy settled $167 million under the forward sale agreements by delivering 3,790,300 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $43.99 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes. As of September 30, 2019, 671,237 incremental shares were included in the calculation of diluted EPS related to the remaining securities under the forward sale agreements. Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):
Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $2.4 |  |  |  | $2,108.4 |  |  |  | $2,597.8 |  |  |  | $1.0 |  |  |  | ($10.0 | ) |  |  | $200.0 |  |  |  | $4,899.6 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 226.0 |  |  |  |  |  |  |  |  | 226.0 |
Common stock dividends ($0.355 per share) |  |  |  |  | (84.7 | ) |  |  |  |  |  |  |  | (84.7 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 124.8 |  |  |  |  |  |  |  |  |  |  | 124.8 |
Equity-based compensation plans and other |  |  | 3.7 |  |  |  |  |  |  | (0.2 | ) |  |  |  | 3.5 |
Ending balance, September 30 |  | $2.4 |  |  |  | $2,236.9 |  |  |  | $2,739.1 |  |  |  | $1.0 |  |  |  | ($10.2 | ) |  |  | $200.0 |  |  |  | $5,169.2 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $2.3 |  |  |  | $1,947.2 |  |  |  | $2,412.5 |  |  |  | $0.1 |  |  |  | ($11.4 | ) |  |  | $200.0 |  |  |  | $4,550.7 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 205.5 |  |  |  |  |  |  |  |  | 205.5 |
Common stock dividends ($0.335 per share) |  |  |  |  | (78.5 | ) |  |  |  |  |  |  |  | (78.5 | )
At-the-market offering program and Shareowner Direct Plan issuances | 0.1 |  |  | 91.1 |  |  |  |  |  |  |  |  |  |  | 91.2 |
Equity-based compensation plans and other |  |  | (0.1 | ) |  |  |  |  |  | 1.9 |  |  |  |  | 1.8 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (0.3 | ) |  |  |  |  |  | (0.3 | )
Ending balance, September 30 |  | $2.4 |  |  |  | $2,038.2 |  |  |  | $2,539.5 |  |  |  | ($0.2 | ) |  |  | ($9.5 | ) |  |  | $200.0 |  |  |  | $4,770.4 |
Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $2.4 |  |  |  | $2,045.5 |  |  |  | $2,545.9 |  |  |  | $1.7 |  |  |  | ($9.8 | ) |  |  | $200.0 |  |  |  | $4,785.7 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 445.7 |  |  |  |  |  |  |  |  | 445.7 |
Common stock dividends ($1.065 per share) |  |  |  |  | (252.5 | ) |  |  |  |  |  |  |  | (252.5 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 185.4 |  |  |  |  |  |  |  |  |  |  | 185.4 |
Equity-based compensation plans and other |  |  | 6.0 |  |  |  |  |  |  | (0.4 | ) |  |  |  | 5.6 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (0.7 | ) |  |  |  |  |  | (0.7 | )
Ending balance, September 30 |  | $2.4 |  |  |  | $2,236.9 |  |  |  | $2,739.1 |  |  |  | $1.0 |  |  |  | ($10.2 | ) |  |  | $200.0 |  |  |  | $5,169.2 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $2.3 |  |  |  | $1,845.5 |  |  |  | $2,346.0 |  |  |  | ($0.5 | ) |  |  | ($11.1 | ) |  |  | $200.0 |  |  |  | $4,382.2 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 426.8 |  |  |  |  |  |  |  |  | 426.8 |
Common stock dividends ($1.005 per share) |  |  |  |  | (233.3 | ) |  |  |  |  |  |  |  | (233.3 | )
At-the-market offering program and Shareowner Direct Plan issuances | 0.1 |  |  | 191.2 |  |  |  |  |  |  |  |  |  |  | 191.3 |
Equity-based compensation plans and other |  |  | 1.5 |  |  |  |  |  |  | 1.6 |  |  |  |  | 3.1 |
Other comprehensive income, net of tax |  |  |  |  |  |  | 0.3 |  |  |  |  |  |  | 0.3 |
Ending balance, September 30 |  | $2.4 |  |  |  | $2,038.2 |  |  |  | $2,539.5 |  |  |  | ($0.2 | ) |  |  | ($9.5 | ) |  |  | $200.0 |  |  |  | $4,770.4 |
IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $788.9 |  |  |  | $200.0 |  |  |  | $3,345.1 |
Earnings available for common stock |  |  |  |  | 141.1 |  |  |  |  | 141.1 |
Common stock dividends |  |  |  |  | (42.1 | ) |  |  |  | (42.1 | )
Ending balance, September 30 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $887.9 |  |  |  | $200.0 |  |  |  | $3,444.1 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |
Beginning balance, July 1 |  | $33.4 |  |  |  | $1,927.8 |  |  |  | $692.9 |  |  |  | $200.0 |  |  |  | $2,854.1 |
Earnings available for common stock |  |  |  |  | 126.5 |  |  |  |  | 126.5 |
Common stock dividends |  |  |  |  | (41.9 | ) |  |  |  | (41.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,027.8 |  |  |  | $777.5 |  |  |  | $200.0 |  |  |  | $3,038.7 |
IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $33.4 |  |  |  | $2,222.8 |  |  |  | $774.5 |  |  |  | $200.0 |  |  |  | $3,230.7 |
Earnings available for common stock |  |  |  |  | 239.4 |  |  |  |  | 239.4 |
Common stock dividends |  |  |  |  | (126.0 | ) |  |  |  | (126.0 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,322.8 |  |  |  | $887.9 |  |  |  | $200.0 |  |  |  | $3,444.1 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |  |  |
Beginning balance, January 1 |  | $33.4 |  |  |  | $1,797.8 |  |  |  | $678.5 |  |  |  | $200.0 |  |  |  | $2,709.7 |
Earnings available for common stock |  |  |  |  | 224.9 |  |  |  |  | 224.9 |
Common stock dividends |  |  |  |  | (125.9 | ) |  |  |  | (125.9 | )
Capital contributions from parent |  |  | 230.0 |  |  |  |  |  |  | 230.0 |
Ending balance, September 30 |  | $33.4 |  |  |  | $2,027.8 |  |  |  | $777.5 |  |  |  | $200.0 |  |  |  | $3,038.7 |
WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Three Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, July 1 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $810.0 |  |  |  | $2,185.2 |
Earnings available for common stock |  |  |  |  | 75.5 |  |  | 75.5 |
Common stock dividends |  |  |  |  | (35.9 | ) |  | (35.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,409.0 |  |  |  | $849.6 |  |  |  | $2,324.8 |
Three Months Ended September 30, 2018 |  |  |  |  |  |  |
Beginning balance, July 1 |  | $66.2 |  |  |  | $1,259.0 |  |  |  | $730.0 |  |  |  | $2,055.2 |
Earnings available for common stock |  |  |  |  | 76.3 |  |  | 76.3 |
Common stock dividends |  |  |  |  | (34.9 | ) |  | (34.9 | )
Capital contributions from parent |  |  | 50.0 |  |  |  |  | 50.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $771.4 |  |  |  | $2,146.6 |
WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, January 1 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $774.3 |  |  |  | $2,149.5 |
Earnings available for common stock |  |  |  |  | 183.2 |  |  | 183.2 |
Common stock dividends |  |  |  |  | (107.9 | ) |  | (107.9 | )
Capital contributions from parent |  |  | 100.0 |  |  |  |  | 100.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,409.0 |  |  |  | $849.6 |  |  |  | $2,324.8 |
Nine Months Ended September 30, 2018 |  |  |  |  |  |  |
Beginning balance, January 1 |  | $66.2 |  |  |  | $1,109.0 |  |  |  | $706.3 |  |  |  | $1,881.5 |
Earnings available for common stock |  |  |  |  | 170.1 |  |  | 170.1 |
Common stock dividends |  |  |  |  | (105.0 | ) |  | (105.0 | )
Capital contributions from parent |  |  | 200.0 |  |  |  |  | 200.0 |
Ending balance, September 30 |  | $66.2 |  |  |  | $1,309.0 |  |  |  | $771.4 |  |  |  | $2,146.6 |
Comprehensive Income - For the three and nine months ended September 30, 2019 and 2018, Alliant Energy’s other comprehensive income was not material; 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. For the three and nine months ended September 30, 2019 and 2018, 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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