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Income Taxes | 3 Months Ended
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Mar. 31, 2024
Income Taxes [Line Items] |
Income Taxes | INCOME TAXES Income Tax Rates - Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.
| Alliant Energy |  | IPL |  | WPL
| 2024 |  | 2023 |  |  |  |  |  | 2024 |  | 2023 |  |  |  |  |  | 2024 |  | 2023 |  |  |  |
Overall income tax rate | (7%) |  | (1%) |  |  |  |  |  | (19%) |  | (18%) |  |  |  |  |  | 6% |  | 12% |  |  |  |
Deferred Tax Assets and Liabilities - Carryforwards - At March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
State net operating losses | 2025-2044 |  | $403 |  | $6 |  | $1
Federal tax credits | 2032-2044 |  | 685 |  | 462 |  | 214
IPL [Member] |
Income Taxes [Line Items] |
Income Taxes | INCOME TAXES Income Tax Rates - Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.
| Alliant Energy |  | IPL |  | WPL
| 2024 |  | 2023 |  |  |  |  |  | 2024 |  | 2023 |  |  |  |  |  | 2024 |  | 2023 |  |  |  |
Overall income tax rate | (7%) |  | (1%) |  |  |  |  |  | (19%) |  | (18%) |  |  |  |  |  | 6% |  | 12% |  |  |  |
Deferred Tax Assets and Liabilities - Carryforwards - At March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
State net operating losses | 2025-2044 |  | $403 |  | $6 |  | $1
Federal tax credits | 2032-2044 |  | 685 |  | 462 |  | 214
WPL [Member] |
Income Taxes [Line Items] |
Income Taxes | INCOME TAXES Income Tax Rates - Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences.
| Alliant Energy |  | IPL |  | WPL
| 2024 |  | 2023 |  |  |  |  |  | 2024 |  | 2023 |  |  |  |  |  | 2024 |  | 2023 |  |  |  |
Overall income tax rate | (7%) |  | (1%) |  |  |  |  |  | (19%) |  | (18%) |  |  |  |  |  | 6% |  | 12% |  |  |  |
Deferred Tax Assets and Liabilities - Carryforwards - At March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
State net operating losses | 2025-2044 |  | $403 |  | $6 |  | $1
Federal tax credits | 2032-2044 |  | 685 |  | 462 |  | 214

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- Definition The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480990/946-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org//740/tableOfContent Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-14 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 21 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-21 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 270 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482526/740-270-50-1 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 17 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-17 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I.5.Q1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 11.C) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482603/740-30-50-2 + Details
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