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Asset Retirement Obligations | 12 Months Ended
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Dec. 31, 2023
Schedule of Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations (AROs) | ASSET RETIREMENT OBLIGATIONS Recognized AROs relate to legal obligations for the removal, closure, dismantlement and management of several assets including, but not limited to, wind farms, active ash landfills, ash ponds, solar generation, above ground storage tanks and batteries. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to 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] |
Asset Retirement Obligations (AROs) | ASSET RETIREMENT OBLIGATIONS Recognized AROs relate to legal obligations for the removal, closure, dismantlement and management of several assets including, but not limited to, wind farms, active ash landfills, ash ponds, solar generation, above ground storage tanks and batteries. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to 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] |
Asset Retirement Obligations (AROs) | ASSET RETIREMENT OBLIGATIONS Recognized AROs relate to legal obligations for the removal, closure, dismantlement and management of several assets including, but not limited to, wind farms, active ash landfills, ash ponds, solar generation, above ground storage tanks and batteries. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other current liabilities” and “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to 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 The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481850/410-20-50-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org//410-20/tableOfContent Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 20 -Topic 410 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481850/410-20-50-2 + Details
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