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Asset Retirement Obligations (Tables) | 12 Months Ended
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Dec. 31, 2023
Schedule of Asset Retirement Obligations [Line Items] |
Reconciliation Of Changes In Asset Retirement Obligations (AROs) | A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2023 |  | 2022 |  | 2023 |  | 2022 |  | 2023 |  | 2022
Balance, January 1 | $279 |  |  | $294 |  |  | $195 |  |  | $213 |  |  | $84 |  |  | $81 |
Revisions in estimated cash flows | (6) |  |  | 19 |  |  | (9) |  |  | 15 |  |  | 3 |  |  | 4 |
Liabilities settled | (51) |  |  | (48) |  |  | (44) |  |  | (39) |  |  | (7) |  |  | (9) |
Liabilities incurred | 16 |  |  | 6 |  |  | 1 |  |  | — |  |  | 15 |  |  | 6 |
Accretion expense | 8 |  |  | 8 |  |  | 5 |  |  | 6 |  |  | 3 |  |  | 2 |
Balance, December 31 | $246 |  |  | $279 |  |  | $148 |  |  | $195 |  |  | $98 |  |  | $84 |
IPL [Member] |
Schedule of Asset Retirement Obligations [Line Items] |
Reconciliation Of Changes In Asset Retirement Obligations (AROs) | A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2023 |  | 2022 |  | 2023 |  | 2022 |  | 2023 |  | 2022
Balance, January 1 | $279 |  |  | $294 |  |  | $195 |  |  | $213 |  |  | $84 |  |  | $81 |
Revisions in estimated cash flows | (6) |  |  | 19 |  |  | (9) |  |  | 15 |  |  | 3 |  |  | 4 |
Liabilities settled | (51) |  |  | (48) |  |  | (44) |  |  | (39) |  |  | (7) |  |  | (9) |
Liabilities incurred | 16 |  |  | 6 |  |  | 1 |  |  | — |  |  | 15 |  |  | 6 |
Accretion expense | 8 |  |  | 8 |  |  | 5 |  |  | 6 |  |  | 3 |  |  | 2 |
Balance, December 31 | $246 |  |  | $279 |  |  | $148 |  |  | $195 |  |  | $98 |  |  | $84 |
WPL [Member] |
Schedule of Asset Retirement Obligations [Line Items] |
Reconciliation Of Changes In Asset Retirement Obligations (AROs) | A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2023 |  | 2022 |  | 2023 |  | 2022 |  | 2023 |  | 2022
Balance, January 1 | $279 |  |  | $294 |  |  | $195 |  |  | $213 |  |  | $84 |  |  | $81 |
Revisions in estimated cash flows | (6) |  |  | 19 |  |  | (9) |  |  | 15 |  |  | 3 |  |  | 4 |
Liabilities settled | (51) |  |  | (48) |  |  | (44) |  |  | (39) |  |  | (7) |  |  | (9) |
Liabilities incurred | 16 |  |  | 6 |  |  | 1 |  |  | — |  |  | 15 |  |  | 6 |
Accretion expense | 8 |  |  | 8 |  |  | 5 |  |  | 6 |  |  | 3 |  |  | 2 |
Balance, December 31 | $246 |  |  | $279 |  |  | $148 |  |  | $195 |  |  | $98 |  |  | $84 |

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- Definition Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481850/410-20-50-1 + Details
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