Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions	Dec. 31, 2023 USD ($)
State [Member]
Tax carryforwards, net operating losses	$ 428
State [Member] | IPL [Member]
Tax carryforwards, net operating losses	6
State [Member] | WPL [Member]
Tax carryforwards, net operating losses	1
Federal [Member]
Tax carryforwards, tax credits	649
Federal [Member] | IPL [Member]
Tax carryforwards, tax credits	449
Federal [Member] | WPL [Member]
Tax carryforwards, tax credits	$ 191