Benefit Plans (Assumptions Used To Measure Benefit Plans) (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	5.65%	5.36%	5.54%
Discount rate for net periodic cost	5.36%	5.54%	2.91%
Expected rate of return on plan assets	7.73%	7.80%	7.80%
Interest crediting rate for Alliant Energy Cash Balance Pension Plan	6.24%	10.75%	9.22%
Pension Plans, Defined Benefit [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	5.66%	5.35%	5.55%
Discount rate for net periodic cost	5.35%	5.55%	2.94%
Expected rate of return on plan assets	7.60%	7.80%	7.80%
Rate of compensation increase	3.75%	3.30%	3.30%
Pension Plans, Defined Benefit [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	5.66%	5.35%	5.54%
Discount rate for net periodic cost	5.35%	5.54%	2.94%
Expected rate of return on plan assets	7.80%	7.80%	7.80%
Rate of compensation increase	3.50%	3.30%	3.30%
Other Postretirement Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	5.62%	5.40%	5.53%
Discount rate for net periodic cost	5.40%	5.53%	2.81%
Expected rate of return on plan assets	6.22%	6.50%	6.40%
Other Postretirement Benefits Plans [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	5.61%	5.40%	5.53%
Discount rate for net periodic cost	5.40%	5.53%	2.80%
Expected rate of return on plan assets	6.60%	6.90%	6.50%
Other Postretirement Benefits Plans [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligations	5.61%	5.40%	5.53%
Discount rate for net periodic cost	5.40%	5.53%	2.79%
Expected rate of return on plan assets	5.61%	5.65%	5.49%
Minimum [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	3.50%	3.30%	3.30%
Maximum [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	4.50%	4.50%	4.50%