XML 92 R72.htm IDEA: XBRL DOCUMENT
v3.24.2.u1

Commitments And Contingencies (MPG Site Estimated Future Costs And Recorded Liabilities) (Details) - Natural Gas Processing Plant [Member] $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2024 USD ($)
Commitments and Contingencies [Line Items] |
Current and non-current environmental liabilities | $ 13
IPL [Member] |
Commitments and Contingencies [Line Items] |
Current and non-current environmental liabilities | 8
WPL [Member] |
Commitments and Contingencies [Line Items] |
Current and non-current environmental liabilities | 5
Minimum [Member] |
Commitments and Contingencies [Line Items] |
Range of estimated future costs | 8
Minimum [Member] | IPL [Member] |
Commitments and Contingencies [Line Items] |
Range of estimated future costs | 6
Minimum [Member] | WPL [Member] |
Commitments and Contingencies [Line Items] |
Range of estimated future costs | 2
Maximum [Member] |
Commitments and Contingencies [Line Items] |
Range of estimated future costs | 29
Maximum [Member] | IPL [Member] |
Commitments and Contingencies [Line Items] |
Range of estimated future costs | 18
Maximum [Member] | WPL [Member] |
Commitments and Contingencies [Line Items] |
Range of estimated future costs | $ 11

X
- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. + References Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 410 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (d)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481931/410-30-50-10 Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 410 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (d)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481931/410-30-50-10 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 410 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 16 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481899/410-30-55-16 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480102/450-20-S99-1 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481931/410-30-50-7 + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total anticipated costs associated with remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal, or abandonment of a particular property resulting from unanticipated contamination of the assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480102/450-20-S99-1 + Details
Name: | us-gaap_EnvironmentalExitCostsAnticipatedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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 No definition available. + Details
Name: | us-gaap_LongTermPurchaseCommitmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_NaturalGasProcessingPlantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lnt_IplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lnt_WplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |