Investments (Tables)

12 Months Ended

Dec. 31, 2023

Schedule of Equity Method Investments [Line Items]

Unconsolidated Equity Investments

Alliant Energy’s unconsolidated investments accounted for under the equity method of accounting are as follows (in millions):

	Ownership Interest at	Carrying Value at December 31,		Equity (Income) / Loss
	December 31, 2023	2023	2022	2023	2022	2021
ATC Holdings	16%, 20%	$386	$358	($49)	($41)	($43)
Non-utility wind farm in Oklahoma	50%	104	101	(7)	(5)	(4)
Corporate venture investments	Various	74	62	(2)	(3)	(13)
Other	Various	21	21	(3)	(2)	(2)
		$585	$542	($61)	($51)	($62)

Summary Financial Information

Summary aggregate financial information from the financial statements of these holdings is as follows (in millions):

	Alliant Energy
	2023	2022	2021
Revenues	$898	$813	$802
Operating income	384	350	357
Net income	370	675	358
As of December 31:
Current assets	221	227
Non-current assets	9,032	8,292
Current liabilities	528	620
Non-current liabilities	3,584	3,285
Noncontrolling interest	259	289