Debt (Credit Facilities) (Details) $ in Millions	Sep. 30, 2021 USD ($)
Debt [Line Items]
Amount outstanding	$ 316
Weighted average interest rates	0.20%
Available credit facility capacity	$ 684
IPL [Member]
Debt [Line Items]
Amount outstanding	0
Available credit facility capacity	100
WPL [Member]
Debt [Line Items]
Amount outstanding	$ 3
Weighted average interest rates	0.10%
Available credit facility capacity	$ 397

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.

No definition available.

+ Details

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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-Name Accounting Standards Codification
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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

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- Definition

Weighted average interest rate of short-term debt outstanding calculated at point in time.

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- Details

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