Income Taxes (Schedule Of Effective Income Tax Rates) (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Tax Rate [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefits	3.00%	2.00%	2.00%
Production tax credits	(18.00%)	(17.00%)	(17.00%)
Amortization of excess deferred taxes	(2.00%)	(18.00%)	(13.00%)
Effect of rate-making on property-related differences	(1.00%)	(1.00%)	(3.00%)
Adjustment for prior period taxes	1.00%	1.00%	1.00%
Other items, net	(1.00%)	0.00%	(1.00%)
Overall income tax rate	3.00%	(12.00%)	(10.00%)
IPL [Member]
Effective Tax Rate [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefits	(2.00%)	(1.00%)	(1.00%)
Production tax credits	(34.00%)	(27.00%)	(28.00%)
Amortization of excess deferred taxes	(2.00%)	(4.00%)	(5.00%)
Effect of rate-making on property-related differences	(1.00%)	(2.00%)	(4.00%)
Adjustment for prior period taxes	1.00%	2.00%	1.00%
Other items, net	1.00%	0.00%	0.00%
Overall income tax rate	(16.00%)	(11.00%)	(16.00%)
WPL [Member]
Effective Tax Rate [Line Items]
Statutory federal income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefits	6.00%	6.00%	6.00%
Production tax credits	(5.00%)	(6.00%)	(7.00%)
Amortization of excess deferred taxes	(3.00%)	(43.00%)	(26.00%)
Effect of rate-making on property-related differences	(2.00%)	(1.00%)	(2.00%)
Adjustment for prior period taxes	0.00%	0.00%	0.00%
Other items, net	0.00%	(1.00%)	0.00%
Overall income tax rate	17.00%	(24.00%)	(8.00%)