Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-4

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- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482987/272-10-50-3

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- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

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- Definition

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.

+ References

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- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

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Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2024
Commitments and Contingencies [Line Items]
Minimum future commitments			$ 995
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			$ 448
MISO base return on equity, percentage			10.25%
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			$ 505
Federal Energy Regulatory Commission [Member]
Commitments and Contingencies [Line Items]
MISO base return on equity, percentage	10.02%	9.88%	9.98%
Indemnification Agreement [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum			$ 43
Whiting Petroleum Affiliate [Member]
Commitments and Contingencies [Line Items]
Partnership share, percent			6.00%
Obligations, maximum			$ 49
Capital Purchase Commitment [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			99
Capital Purchase Commitment [Member] \| IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			24
Capital Purchase Commitment [Member] \| WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments			72
Purchased Power [Member] \| Indemnification Agreement [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum			17
Renewable Tax Credits Transferred [Member] \| Indemnification Agreement [Member] \| IPL [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum			165
Renewable Tax Credits Transferred [Member] \| Indemnification Agreement [Member] \| WPL [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum			$ 105