XML 83 R63.htm IDEA: XBRL DOCUMENT

Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Derivative Instruments [Line Items]
Non-current interest rate derivative assets	$ 160		$ 160		$ 177
Accumulated other comprehensive income, interest rate swap	3		3		$ 1
Interest expense, interest rate swap	108	$ 96	215	$ 190
Alliant Energy Finance LLC [Member] \| Interest Rate Swap [Member] \| Term Loan Credit Agreement [Member]
Derivative Instruments [Line Items]
Non-current interest rate derivative assets	3		3
Accumulated other comprehensive income, interest rate swap	3		3
Interest expense, interest rate swap	$ 1	$ 1	$ 2	$ 1

Amount, after tax, of accumulated increase (decrease) in equity from transaction and other event and circumstance from nonowner source.

Amount of the cost of borrowed funds accounted for as interest expense.