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v3.19.3.a.u2

Summary Of Significant Accounting Policies (Narrative) (Details) | 12 Months Ended
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Dec. 31, 2019 customer MW
General: |
Electric capacity of wind farm (in megawatts) | 1,000
IPL [Member] |
General: |
Generation and distribution of steam, number of customers served (in customers) | customer | 2
Property, Plant and Equipment: |
AFUDC accrual recorded, percentage of estimated CWIP | 100.00%
WPL [Member] |
Property, Plant and Equipment: |
AFUDC accrual recorded, percentage of estimated CWIP | 50.00%
AFUDC rates, projects with approval | 100.00%
Alliant Energy Finance, LLC [Member] |
General: |
Ownership interest | 50.00%
Electric capacity of wind farm (in megawatts) | 225
Sheboygan Falls Energy Facility [Member] |
General: |
Fossil-fueled EGU capacity (in megawatts) | 347
Finance lease, lease term | 20 years

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