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Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2021

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation Of Changes In Asset Retirement Obligations (AROs)

A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

			Alliant Energy												IPL												WPL
			2021						2020						2021						2020						2021						2020
Balance, January 1			$251						$196						$177						$134						$74						$62
Revisions in estimated cash flows			50						13						44						9						6						4
Liabilities settled			(17)						(13)						(13)						(9)						(4)						(4)
Liabilities incurred			3						48						—						38						3						10
Accretion expense			7						7						5						5						2						2
Balance, December 31			$294						$251						$213						$177						$81						$74

IPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation Of Changes In Asset Retirement Obligations (AROs)

A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

			Alliant Energy												IPL												WPL
			2021						2020						2021						2020						2021						2020
Balance, January 1			$251						$196						$177						$134						$74						$62
Revisions in estimated cash flows			50						13						44						9						6						4
Liabilities settled			(17)						(13)						(13)						(9)						(4)						(4)
Liabilities incurred			3						48						—						38						3						10
Accretion expense			7						7						5						5						2						2
Balance, December 31			$294						$251						$213						$177						$81						$74

WPL [Member]

Schedule of Asset Retirement Obligations [Line Items]

Reconciliation Of Changes In Asset Retirement Obligations (AROs)

A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):

			Alliant Energy												IPL												WPL
			2021						2020						2021						2020						2021						2020
Balance, January 1			$251						$196						$177						$134						$74						$62
Revisions in estimated cash flows			50						13						44						9						6						4
Liabilities settled			(17)						(13)						(13)						(9)						(4)						(4)
Liabilities incurred			3						48						—						38						3						10
Accretion expense			7						7						5						5						2						2
Balance, December 31			$294						$251						$213						$177						$81						$74

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[Line Items] for Schedule of Asset Retirement Obligations [Table]

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Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859

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