XML 48 R28.htm IDEA: XBRL DOCUMENT
v3.24.3

Common Equity (Tables) | 9 Months Ended
--- | ---
Sep. 30, 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 | 348,087 |
Equity-based compensation plans | 154,267 |
Shares outstanding, September 30, 2024 | 256,599,202 |
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 September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $3 |  | $3,042 |  | $3,755 |  | $3 |  | ($12) |  |  |  | $6,791
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 295 |  |  |  |  |  |  |  | 295
Common stock dividends ($0.48 per share) |  |  |  |  | (123) |  |  |  |  |  |  |  | (123)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  | (1) |  |  |  | 3
Other comprehensive loss, net of tax |  |  |  |  |  |  | (4) |  |  |  |  |  | (4)
Ending balance, September 30, 2024 | $3 |  | $3,052 |  | $3,927 |  | ($1) |  | ($13) |  |  |  | $6,968
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $3 |  | $2,854 |  | $3,606 |  | $3 |  | ($14) |  |  |  | $6,452
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 259 |  |  |  |  |  |  |  | 259
Common stock dividends ($0.4525 per share) |  |  |  |  | (115) |  |  |  |  |  |  |  | (115)
At-the-market offering program and Shareowner Direct Plan issuances |  |  | 125 |  |  |  |  |  |  |  |  |  | 125
Equity-based compensation plans and other |  |  | 3 |  |  |  |  |  | 1 |  |  |  | 4
Other comprehensive income, net of tax |  |  |  |  |  |  | 1 |  |  |  |  |  | 1
Ending balance, September 30, 2023 | $3 |  | $2,982 |  | $3,750 |  | $4 |  | ($13) |  |  |  | $6,726
Alliant Energy |  |  |  |  |  |  | Accumulated |  | Shares in |  |  |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  |  |  | Common
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $3 |  | $3,030 |  | $3,756 |  | $1 |  | ($13) |  |  |  | $6,777
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 540 |  |  |  |  |  |  |  | 540
Common stock dividends ($1.44 per share) |  |  |  |  | (369) |  |  |  |  |  |  |  | (369)
Shareowner Direct Plan issuances |  |  | 18 |  |  |  |  |  |  |  |  |  | 18
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  |  |  |  | 4
Other comprehensive loss, net of tax |  |  |  |  |  |  | (2) |  |  |  |  |  | (2)
Ending balance, September 30, 2024 | $3 |  | $3,052 |  | $3,927 |  | ($1) |  | ($13) |  |  |  | $6,968
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $3 |  | $2,777 |  | $3,509 |  | $— |  | ($13) |  |  |  | $6,276
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 582 |  |  |  |  |  |  |  | 582
Common stock dividends ($1.3575 per share) |  |  |  |  | (341) |  |  |  |  |  |  |  | (341)
At-the-market offering program and Shareowner Direct Plan issuances |  |  | 201 |  |  |  |  |  |  |  |  |  | 201
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  |  |  |  | 4
Other comprehensive income, net of tax |  |  |  |  |  |  | 4 |  |  |  |  |  | 4
Ending balance, September 30, 2023 | $3 |  | $2,982 |  | $3,750 |  | $4 |  | ($13) |  |  |  | $6,726
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $33 |  | $3,012 |  | $1,035 |  |  |  | $4,080
Net income |  |  |  |  | 190 |  |  |  | 190
Common stock dividends |  |  |  |  | (50) |  |  |  | (50)
Capital contributions from parent |  |  | 200 |  |  |  |  |  | 200
Ending balance, September 30, 2024 | $33 |  | $3,212 |  | $1,175 |  |  |  | $4,420
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $33 |  | $2,847 |  | $989 |  |  |  | $3,869
Net income |  |  |  |  | 170 |  |  |  | 170
Common stock dividends |  |  |  |  | (70) |  |  |  | (70)
Capital contributions from parent |  |  | 20 |  |  |  |  |  | 20
Ending balance, September 30, 2023 | $33 |  | $2,867 |  | $1,089 |  |  |  | $3,989
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $33 |  | $2,887 |  | $1,054 |  |  |  | $3,974
Net income |  |  |  |  | 272 |  |  |  | 272
Common stock dividends |  |  |  |  | (151) |  |  |  | (151)
Capital contributions from parent |  |  | 325 |  |  |  |  |  | 325
Ending balance, September 30, 2024 | $33 |  | $3,212 |  | $1,175 |  |  |  | $4,420
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $33 |  | $2,807 |  | $968 |  |  |  | $3,808
Net income |  |  |  |  | 331 |  |  |  | 331
Common stock dividends |  |  |  |  | (210) |  |  |  | (210)
Capital contributions from parent |  |  | 60 |  |  |  |  |  | 60
Ending balance, September 30, 2023 | $33 |  | $2,867 |  | $1,089 |  |  |  | $3,989
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $66 |  | $2,533 |  | $1,411 |  |  |  | $4,010
Net income |  |  |  |  | 114 |  |  |  | 114
Common stock dividends |  |  |  |  | (49) |  |  |  | (49)
Ending balance, September 30, 2024 | $66 |  | $2,533 |  | $1,476 |  |  |  | $4,075
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $66 |  | $2,413 |  | $1,260 |  |  |  | $3,739
Net income |  |  |  |  | 107 |  |  |  | 107
Common stock dividends |  |  |  |  | (46) |  |  |  | (46)
Capital contributions from parent |  |  | 65 |  |  |  |  |  | 65
Ending balance, September 30, 2023 | $66 |  | $2,478 |  | $1,321 |  |  |  | $3,865
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $66 |  | $2,478 |  | $1,353 |  |  |  | $3,897
Net income |  |  |  |  | 270 |  |  |  | 270
Common stock dividends |  |  |  |  | (147) |  |  |  | (147)
Capital contributions from parent |  |  | 55 |  |  |  |  |  | 55
Ending balance, September 30, 2024 | $66 |  | $2,533 |  | $1,476 |  |  |  | $4,075
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $66 |  | $2,233 |  | $1,192 |  |  |  | $3,491
Net income |  |  |  |  | 267 |  |  |  | 267
Common stock dividends |  |  |  |  | (138) |  |  |  | (138)
Capital contributions from parent |  |  | 245 |  |  |  |  |  | 245
Ending balance, September 30, 2023 | $66 |  | $2,478 |  | $1,321 |  |  |  | $3,865
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 September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $3 |  | $3,042 |  | $3,755 |  | $3 |  | ($12) |  |  |  | $6,791
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 295 |  |  |  |  |  |  |  | 295
Common stock dividends ($0.48 per share) |  |  |  |  | (123) |  |  |  |  |  |  |  | (123)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  | (1) |  |  |  | 3
Other comprehensive loss, net of tax |  |  |  |  |  |  | (4) |  |  |  |  |  | (4)
Ending balance, September 30, 2024 | $3 |  | $3,052 |  | $3,927 |  | ($1) |  | ($13) |  |  |  | $6,968
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $3 |  | $2,854 |  | $3,606 |  | $3 |  | ($14) |  |  |  | $6,452
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 259 |  |  |  |  |  |  |  | 259
Common stock dividends ($0.4525 per share) |  |  |  |  | (115) |  |  |  |  |  |  |  | (115)
At-the-market offering program and Shareowner Direct Plan issuances |  |  | 125 |  |  |  |  |  |  |  |  |  | 125
Equity-based compensation plans and other |  |  | 3 |  |  |  |  |  | 1 |  |  |  | 4
Other comprehensive income, net of tax |  |  |  |  |  |  | 1 |  |  |  |  |  | 1
Ending balance, September 30, 2023 | $3 |  | $2,982 |  | $3,750 |  | $4 |  | ($13) |  |  |  | $6,726
Alliant Energy |  |  |  |  |  |  | Accumulated |  | Shares in |  |  |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  |  |  | Common
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $3 |  | $3,030 |  | $3,756 |  | $1 |  | ($13) |  |  |  | $6,777
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 540 |  |  |  |  |  |  |  | 540
Common stock dividends ($1.44 per share) |  |  |  |  | (369) |  |  |  |  |  |  |  | (369)
Shareowner Direct Plan issuances |  |  | 18 |  |  |  |  |  |  |  |  |  | 18
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  |  |  |  | 4
Other comprehensive loss, net of tax |  |  |  |  |  |  | (2) |  |  |  |  |  | (2)
Ending balance, September 30, 2024 | $3 |  | $3,052 |  | $3,927 |  | ($1) |  | ($13) |  |  |  | $6,968
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $3 |  | $2,777 |  | $3,509 |  | $— |  | ($13) |  |  |  | $6,276
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 582 |  |  |  |  |  |  |  | 582
Common stock dividends ($1.3575 per share) |  |  |  |  | (341) |  |  |  |  |  |  |  | (341)
At-the-market offering program and Shareowner Direct Plan issuances |  |  | 201 |  |  |  |  |  |  |  |  |  | 201
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  |  |  |  | 4
Other comprehensive income, net of tax |  |  |  |  |  |  | 4 |  |  |  |  |  | 4
Ending balance, September 30, 2023 | $3 |  | $2,982 |  | $3,750 |  | $4 |  | ($13) |  |  |  | $6,726
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $33 |  | $3,012 |  | $1,035 |  |  |  | $4,080
Net income |  |  |  |  | 190 |  |  |  | 190
Common stock dividends |  |  |  |  | (50) |  |  |  | (50)
Capital contributions from parent |  |  | 200 |  |  |  |  |  | 200
Ending balance, September 30, 2024 | $33 |  | $3,212 |  | $1,175 |  |  |  | $4,420
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $33 |  | $2,847 |  | $989 |  |  |  | $3,869
Net income |  |  |  |  | 170 |  |  |  | 170
Common stock dividends |  |  |  |  | (70) |  |  |  | (70)
Capital contributions from parent |  |  | 20 |  |  |  |  |  | 20
Ending balance, September 30, 2023 | $33 |  | $2,867 |  | $1,089 |  |  |  | $3,989
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $33 |  | $2,887 |  | $1,054 |  |  |  | $3,974
Net income |  |  |  |  | 272 |  |  |  | 272
Common stock dividends |  |  |  |  | (151) |  |  |  | (151)
Capital contributions from parent |  |  | 325 |  |  |  |  |  | 325
Ending balance, September 30, 2024 | $33 |  | $3,212 |  | $1,175 |  |  |  | $4,420
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $33 |  | $2,807 |  | $968 |  |  |  | $3,808
Net income |  |  |  |  | 331 |  |  |  | 331
Common stock dividends |  |  |  |  | (210) |  |  |  | (210)
Capital contributions from parent |  |  | 60 |  |  |  |  |  | 60
Ending balance, September 30, 2023 | $33 |  | $2,867 |  | $1,089 |  |  |  | $3,989
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $66 |  | $2,533 |  | $1,411 |  |  |  | $4,010
Net income |  |  |  |  | 114 |  |  |  | 114
Common stock dividends |  |  |  |  | (49) |  |  |  | (49)
Ending balance, September 30, 2024 | $66 |  | $2,533 |  | $1,476 |  |  |  | $4,075
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $66 |  | $2,413 |  | $1,260 |  |  |  | $3,739
Net income |  |  |  |  | 107 |  |  |  | 107
Common stock dividends |  |  |  |  | (46) |  |  |  | (46)
Capital contributions from parent |  |  | 65 |  |  |  |  |  | 65
Ending balance, September 30, 2023 | $66 |  | $2,478 |  | $1,321 |  |  |  | $3,865
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $66 |  | $2,478 |  | $1,353 |  |  |  | $3,897
Net income |  |  |  |  | 270 |  |  |  | 270
Common stock dividends |  |  |  |  | (147) |  |  |  | (147)
Capital contributions from parent |  |  | 55 |  |  |  |  |  | 55
Ending balance, September 30, 2024 | $66 |  | $2,533 |  | $1,476 |  |  |  | $4,075
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $66 |  | $2,233 |  | $1,192 |  |  |  | $3,491
Net income |  |  |  |  | 267 |  |  |  | 267
Common stock dividends |  |  |  |  | (138) |  |  |  | (138)
Capital contributions from parent |  |  | 245 |  |  |  |  |  | 245
Ending balance, September 30, 2023 | $66 |  | $2,478 |  | $1,321 |  |  |  | $3,865
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 September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $3 |  | $3,042 |  | $3,755 |  | $3 |  | ($12) |  |  |  | $6,791
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 295 |  |  |  |  |  |  |  | 295
Common stock dividends ($0.48 per share) |  |  |  |  | (123) |  |  |  |  |  |  |  | (123)
Shareowner Direct Plan issuances |  |  | 6 |  |  |  |  |  |  |  |  |  | 6
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  | (1) |  |  |  | 3
Other comprehensive loss, net of tax |  |  |  |  |  |  | (4) |  |  |  |  |  | (4)
Ending balance, September 30, 2024 | $3 |  | $3,052 |  | $3,927 |  | ($1) |  | ($13) |  |  |  | $6,968
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $3 |  | $2,854 |  | $3,606 |  | $3 |  | ($14) |  |  |  | $6,452
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 259 |  |  |  |  |  |  |  | 259
Common stock dividends ($0.4525 per share) |  |  |  |  | (115) |  |  |  |  |  |  |  | (115)
At-the-market offering program and Shareowner Direct Plan issuances |  |  | 125 |  |  |  |  |  |  |  |  |  | 125
Equity-based compensation plans and other |  |  | 3 |  |  |  |  |  | 1 |  |  |  | 4
Other comprehensive income, net of tax |  |  |  |  |  |  | 1 |  |  |  |  |  | 1
Ending balance, September 30, 2023 | $3 |  | $2,982 |  | $3,750 |  | $4 |  | ($13) |  |  |  | $6,726
Alliant Energy |  |  |  |  |  |  | Accumulated |  | Shares in |  |  |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  |  |  | Common
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $3 |  | $3,030 |  | $3,756 |  | $1 |  | ($13) |  |  |  | $6,777
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 540 |  |  |  |  |  |  |  | 540
Common stock dividends ($1.44 per share) |  |  |  |  | (369) |  |  |  |  |  |  |  | (369)
Shareowner Direct Plan issuances |  |  | 18 |  |  |  |  |  |  |  |  |  | 18
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  |  |  |  | 4
Other comprehensive loss, net of tax |  |  |  |  |  |  | (2) |  |  |  |  |  | (2)
Ending balance, September 30, 2024 | $3 |  | $3,052 |  | $3,927 |  | ($1) |  | ($13) |  |  |  | $6,968
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $3 |  | $2,777 |  | $3,509 |  | $— |  | ($13) |  |  |  | $6,276
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 582 |  |  |  |  |  |  |  | 582
Common stock dividends ($1.3575 per share) |  |  |  |  | (341) |  |  |  |  |  |  |  | (341)
At-the-market offering program and Shareowner Direct Plan issuances |  |  | 201 |  |  |  |  |  |  |  |  |  | 201
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  |  |  |  | 4
Other comprehensive income, net of tax |  |  |  |  |  |  | 4 |  |  |  |  |  | 4
Ending balance, September 30, 2023 | $3 |  | $2,982 |  | $3,750 |  | $4 |  | ($13) |  |  |  | $6,726
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $33 |  | $3,012 |  | $1,035 |  |  |  | $4,080
Net income |  |  |  |  | 190 |  |  |  | 190
Common stock dividends |  |  |  |  | (50) |  |  |  | (50)
Capital contributions from parent |  |  | 200 |  |  |  |  |  | 200
Ending balance, September 30, 2024 | $33 |  | $3,212 |  | $1,175 |  |  |  | $4,420
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $33 |  | $2,847 |  | $989 |  |  |  | $3,869
Net income |  |  |  |  | 170 |  |  |  | 170
Common stock dividends |  |  |  |  | (70) |  |  |  | (70)
Capital contributions from parent |  |  | 20 |  |  |  |  |  | 20
Ending balance, September 30, 2023 | $33 |  | $2,867 |  | $1,089 |  |  |  | $3,989
IPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $33 |  | $2,887 |  | $1,054 |  |  |  | $3,974
Net income |  |  |  |  | 272 |  |  |  | 272
Common stock dividends |  |  |  |  | (151) |  |  |  | (151)
Capital contributions from parent |  |  | 325 |  |  |  |  |  | 325
Ending balance, September 30, 2024 | $33 |  | $3,212 |  | $1,175 |  |  |  | $4,420
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $33 |  | $2,807 |  | $968 |  |  |  | $3,808
Net income |  |  |  |  | 331 |  |  |  | 331
Common stock dividends |  |  |  |  | (210) |  |  |  | (210)
Capital contributions from parent |  |  | 60 |  |  |  |  |  | 60
Ending balance, September 30, 2023 | $33 |  | $2,867 |  | $1,089 |  |  |  | $3,989
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2024 | $66 |  | $2,533 |  | $1,411 |  |  |  | $4,010
Net income |  |  |  |  | 114 |  |  |  | 114
Common stock dividends |  |  |  |  | (49) |  |  |  | (49)
Ending balance, September 30, 2024 | $66 |  | $2,533 |  | $1,476 |  |  |  | $4,075
Three Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2023 | $66 |  | $2,413 |  | $1,260 |  |  |  | $3,739
Net income |  |  |  |  | 107 |  |  |  | 107
Common stock dividends |  |  |  |  | (46) |  |  |  | (46)
Capital contributions from parent |  |  | 65 |  |  |  |  |  | 65
Ending balance, September 30, 2023 | $66 |  | $2,478 |  | $1,321 |  |  |  | $3,865
WPL |  |  | Additional |  |  |  |  |  | Total
| Common |  | Paid-In |  | Retained |  |  |  | Common
| Stock |  | Capital |  | Earnings |  |  |  | Equity
Nine Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2023 | $66 |  | $2,478 |  | $1,353 |  |  |  | $3,897
Net income |  |  |  |  | 270 |  |  |  | 270
Common stock dividends |  |  |  |  | (147) |  |  |  | (147)
Capital contributions from parent |  |  | 55 |  |  |  |  |  | 55
Ending balance, September 30, 2024 | $66 |  | $2,533 |  | $1,476 |  |  |  | $4,075
Nine Months Ended September 30, 2023 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2022 | $66 |  | $2,233 |  | $1,192 |  |  |  | $3,491
Net income |  |  |  |  | 267 |  |  |  | 267
Common stock dividends |  |  |  |  | (138) |  |  |  | (138)
Capital contributions from parent |  |  | 245 |  |  |  |  |  | 245
Ending balance, September 30, 2023 | $66 |  | $2,478 |  | $1,321 |  |  |  | $3,865

X
- Definition Tabular disclosure of an entity's capital units or capital shares, including the value of capital units or capital shares, units authorized, units outstanding and other information necessary to a fair presentation. + References No definition available. + Details
Name: | us-gaap_ScheduleOfCapitalUnitsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfCapitalizationEquityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_ScheduleOfStockholdersEquityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=lnt_IplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lnt_WplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |