Income tax

No definition available.

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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- Definition

Amount of operating expense for routine plant maintenance, repairs and operations of regulated operation.

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Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2024
Income Taxes [Line Items]
Asset valuation charge for IPL's Lansing Generating Station	$ 0	$ 0	$ 60	$ 0
Income tax expense (benefit)	(62)	5	(104)	3
Steam Plant
Income Taxes [Line Items]
Asset retirement obligation charge for IPL's steam assets			20
Tax-related [Member]
Income Taxes [Line Items]
Income tax expense (benefit)		8
Forecast [Member]
Income Taxes [Line Items]
State income tax rate, percent					7.10%
IPL [Member]
Income Taxes [Line Items]
Asset valuation charge for IPL's Lansing Generating Station	0	0	60	0
Asset retirement obligation charge for IPL's steam assets	96	84	281	264
Income tax expense (benefit)	(68)	(31)	(112)	(55)
IPL [Member] \| Steam Plant
Income Taxes [Line Items]
Asset retirement obligation charge for IPL's steam assets			20
WPL [Member]
Income Taxes [Line Items]
Asset retirement obligation charge for IPL's steam assets	72	64	200	197
Income tax expense (benefit)	$ 4	$ 21	$ 13	$ 47