Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2022

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
	2022	2021	2022	2021	2022	2021
Balance, January 1	$294	$251	$213	$177	$81	$74
Revisions in estimated cash flows	19	50	15	44	4	6
Liabilities settled	(48)	(17)	(39)	(13)	(9)	(4)
Liabilities incurred	6	3	—	—	6	3
Accretion expense	8	7	6	5	2	2
Balance, December 31	$279	$294	$195	$213	$84	$81

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
	2022	2021	2022	2021	2022	2021
Balance, January 1	$294	$251	$213	$177	$81	$74
Revisions in estimated cash flows	19	50	15	44	4	6
Liabilities settled	(48)	(17)	(39)	(13)	(9)	(4)
Liabilities incurred	6	3	—	—	6	3
Accretion expense	8	7	6	5	2	2
Balance, December 31	$279	$294	$195	$213	$84	$81

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
	2022	2021	2022	2021	2022	2021
Balance, January 1	$294	$251	$213	$177	$81	$74
Revisions in estimated cash flows	19	50	15	44	4	6
Liabilities settled	(48)	(17)	(39)	(13)	(9)	(4)
Liabilities incurred	6	3	—	—	6	3
Accretion expense	8	7	6	5	2	2
Balance, December 31	$279	$294	$195	$213	$84	$81