Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions	Sep. 30, 2022 USD ($)
State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	$ 500
Federal [Member]
Carryforwards [Line Items]
Tax credits, carryforward amount	655
IPL [Member] | State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	9
IPL [Member] | Federal [Member]
Carryforwards [Line Items]
Tax credits, carryforward amount	437
WPL [Member] | State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	2
WPL [Member] | Federal [Member]
Carryforwards [Line Items]
Tax credits, carryforward amount	$ 208