Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments	$ 148	$ 10
Money market fund investments interest rate, percentage	5.00%
IPL [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments	$ 30	10
Money market fund investments interest rate, percentage	5.00%
WPL [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments	$ 83	$ 0
Money market fund investments interest rate, percentage	5.00%