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Common Equity (Tables) | 3 Months Ended
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Mar. 31, 2024
Schedule of Capitalization, Equity [Line Items] |
Common Share Activity | A summary of Alliant Energy’s common stock activity was as follows:
Shares outstanding, January 1, 2024 | 256,096,848 |
Shareowner Direct Plan | 127,917 |
Equity-based compensation plans | 154,267 |
Shares outstanding, March 31, 2024 | 256,379,032 |
Changes in Shareowners' Equity | A summary of changes in shareowners’ equity was as follows (in millions):
Alliant Energy |  |  |  |  |  |  | Accumulated |  | Shares in |  |  |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  |  |  | Common
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $3 |  | $3,030 |  | $3,756 |  | $1 |  | ($13) |  |  |  | $6,777
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 158 |  |  |  |  |  |  |  | 158
Common stock dividends ($0.48 per share) |  |  |  |  | (123) |  |  |  |  |  |  |  | (123)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | (3) |  |  |  |  |  | 1 |  |  |  | (2)
Other comprehensive income, net of tax |  |  |  |  |  |  | 1 |  |  |  |  |  | 1
Ending balance, March 31, 2024 | $3 |  | $3,033 |  | $3,791 |  | $2 |  | ($12) |  |  |  | $6,817
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $3 |  | $2,777 |  | $3,509 |  | $— |  | ($13) |  |  |  | $6,276
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 163 |  |  |  |  |  |  |  | 163
Common stock dividends ($0.4525 per share) |  |  |  |  | (113) |  |  |  |  |  |  |  | (113)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | (3) |  |  |  |  |  |  |  |  |  | (3)
Other comprehensive loss, net of tax |  |  |  |  |  |  | (1) |  |  |  |  |  | (1)
Ending balance, March 31, 2023 | $3 |  | $2,780 |  | $3,559 |  | ($1) |  | ($13) |  |  |  | $6,328
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $33 |  | $2,887 |  | $1,054 |  |  |  | $3,974
Net income |  |  |  |  | 63 |  |  |  | 63
Common stock dividends |  |  |  |  | (50) |  |  |  | (50)
Capital contributions from parent |  |  | 50 |  |  |  |  |  | 50
Ending balance, March 31, 2024 | $33 |  | $2,937 |  | $1,067 |  |  |  | $4,037
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $33 |  | $2,807 |  | $968 |  |  |  | $3,808
Net income |  |  |  |  | 72 |  |  |  | 72
Common stock dividends |  |  |  |  | (70) |  |  |  | (70)
Ending balance, March 31, 2023 | $33 |  | $2,807 |  | $970 |  |  |  | $3,810
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $66 |  | $2,478 |  | $1,353 |  |  |  | $3,897
Net income |  |  |  |  | 92 |  |  |  | 92
Common stock dividends |  |  |  |  | (49) |  |  |  | (49)
Capital contributions from parent |  |  | 55 |  |  |  |  |  | 55
Ending balance, March 31, 2024 | $66 |  | $2,533 |  | $1,396 |  |  |  | $3,995
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $66 |  | $2,233 |  | $1,192 |  |  |  | $3,491
Net income |  |  |  |  | 88 |  |  |  | 88
Common stock dividends |  |  |  |  | (46) |  |  |  | (46)
Capital contributions from parent |  |  | 180 |  |  |  |  |  | 180
Ending balance, March 31, 2023 | $66 |  | $2,413 |  | $1,234 |  |  |  | $3,713
IPL [Member] |
Schedule of Capitalization, Equity [Line Items] |
Changes in Shareowners' Equity | A summary of changes in shareowners’ equity was as follows (in millions):
Alliant Energy |  |  |  |  |  |  | Accumulated |  | Shares in |  |  |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  |  |  | Common
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $3 |  | $3,030 |  | $3,756 |  | $1 |  | ($13) |  |  |  | $6,777
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 158 |  |  |  |  |  |  |  | 158
Common stock dividends ($0.48 per share) |  |  |  |  | (123) |  |  |  |  |  |  |  | (123)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | (3) |  |  |  |  |  | 1 |  |  |  | (2)
Other comprehensive income, net of tax |  |  |  |  |  |  | 1 |  |  |  |  |  | 1
Ending balance, March 31, 2024 | $3 |  | $3,033 |  | $3,791 |  | $2 |  | ($12) |  |  |  | $6,817
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $3 |  | $2,777 |  | $3,509 |  | $— |  | ($13) |  |  |  | $6,276
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 163 |  |  |  |  |  |  |  | 163
Common stock dividends ($0.4525 per share) |  |  |  |  | (113) |  |  |  |  |  |  |  | (113)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | (3) |  |  |  |  |  |  |  |  |  | (3)
Other comprehensive loss, net of tax |  |  |  |  |  |  | (1) |  |  |  |  |  | (1)
Ending balance, March 31, 2023 | $3 |  | $2,780 |  | $3,559 |  | ($1) |  | ($13) |  |  |  | $6,328
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $33 |  | $2,887 |  | $1,054 |  |  |  | $3,974
Net income |  |  |  |  | 63 |  |  |  | 63
Common stock dividends |  |  |  |  | (50) |  |  |  | (50)
Capital contributions from parent |  |  | 50 |  |  |  |  |  | 50
Ending balance, March 31, 2024 | $33 |  | $2,937 |  | $1,067 |  |  |  | $4,037
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $33 |  | $2,807 |  | $968 |  |  |  | $3,808
Net income |  |  |  |  | 72 |  |  |  | 72
Common stock dividends |  |  |  |  | (70) |  |  |  | (70)
Ending balance, March 31, 2023 | $33 |  | $2,807 |  | $970 |  |  |  | $3,810
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $66 |  | $2,478 |  | $1,353 |  |  |  | $3,897
Net income |  |  |  |  | 92 |  |  |  | 92
Common stock dividends |  |  |  |  | (49) |  |  |  | (49)
Capital contributions from parent |  |  | 55 |  |  |  |  |  | 55
Ending balance, March 31, 2024 | $66 |  | $2,533 |  | $1,396 |  |  |  | $3,995
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $66 |  | $2,233 |  | $1,192 |  |  |  | $3,491
Net income |  |  |  |  | 88 |  |  |  | 88
Common stock dividends |  |  |  |  | (46) |  |  |  | (46)
Capital contributions from parent |  |  | 180 |  |  |  |  |  | 180
Ending balance, March 31, 2023 | $66 |  | $2,413 |  | $1,234 |  |  |  | $3,713
WPL [Member] |
Schedule of Capitalization, Equity [Line Items] |
Changes in Shareowners' Equity | A summary of changes in shareowners’ equity was as follows (in millions):
Alliant Energy |  |  |  |  |  |  | Accumulated |  | Shares in |  |  |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  |  |  | Common
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $3 |  | $3,030 |  | $3,756 |  | $1 |  | ($13) |  |  |  | $6,777
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 158 |  |  |  |  |  |  |  | 158
Common stock dividends ($0.48 per share) |  |  |  |  | (123) |  |  |  |  |  |  |  | (123)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | (3) |  |  |  |  |  | 1 |  |  |  | (2)
Other comprehensive income, net of tax |  |  |  |  |  |  | 1 |  |  |  |  |  | 1
Ending balance, March 31, 2024 | $3 |  | $3,033 |  | $3,791 |  | $2 |  | ($12) |  |  |  | $6,817
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $3 |  | $2,777 |  | $3,509 |  | $— |  | ($13) |  |  |  | $6,276
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 163 |  |  |  |  |  |  |  | 163
Common stock dividends ($0.4525 per share) |  |  |  |  | (113) |  |  |  |  |  |  |  | (113)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | (3) |  |  |  |  |  |  |  |  |  | (3)
Other comprehensive loss, net of tax |  |  |  |  |  |  | (1) |  |  |  |  |  | (1)
Ending balance, March 31, 2023 | $3 |  | $2,780 |  | $3,559 |  | ($1) |  | ($13) |  |  |  | $6,328
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $33 |  | $2,887 |  | $1,054 |  |  |  | $3,974
Net income |  |  |  |  | 63 |  |  |  | 63
Common stock dividends |  |  |  |  | (50) |  |  |  | (50)
Capital contributions from parent |  |  | 50 |  |  |  |  |  | 50
Ending balance, March 31, 2024 | $33 |  | $2,937 |  | $1,067 |  |  |  | $4,037
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $33 |  | $2,807 |  | $968 |  |  |  | $3,808
Net income |  |  |  |  | 72 |  |  |  | 72
Common stock dividends |  |  |  |  | (70) |  |  |  | (70)
Ending balance, March 31, 2023 | $33 |  | $2,807 |  | $970 |  |  |  | $3,810
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended March 31, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $66 |  | $2,478 |  | $1,353 |  |  |  | $3,897
Net income |  |  |  |  | 92 |  |  |  | 92
Common stock dividends |  |  |  |  | (49) |  |  |  | (49)
Capital contributions from parent |  |  | 55 |  |  |  |  |  | 55
Ending balance, March 31, 2024 | $66 |  | $2,533 |  | $1,396 |  |  |  | $3,995
Three Months Ended March 31, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $66 |  | $2,233 |  | $1,192 |  |  |  | $3,491
Net income |  |  |  |  | 88 |  |  |  | 88
Common stock dividends |  |  |  |  | (46) |  |  |  | (46)
Capital contributions from parent |  |  | 180 |  |  |  |  |  | 180
Ending balance, March 31, 2023 | $66 |  | $2,413 |  | $1,234 |  |  |  | $3,713

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- Definition Tabular disclosure of changes in the separate accounts comprising stockholders' equity (in addition to retained earnings) and of the changes in the number of shares of equity securities during at least the most recent annual fiscal period and any subsequent interim period presented is required to make the financial statements sufficiently informative if both financial position and results of operations are presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481112/505-10-50-2 + Details
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