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Commitments And Contingencies (Other Purchase Commitments) (Details) - USD ($) $ in Millions | 1 Months Ended | 6 Months Ended
--- | --- | ---
Sep. 30, 2020 | Jun. 30, 2020
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments |  |  | $ 1,270
Individual commitments incurred |  |  | 1
IPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments |  |  | 690
Individual commitments incurred |  |  | 1
WPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments |  |  | 549
Individual commitments incurred |  |  | 1
Purchased Power [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [1] |  | 39
Purchased Power [Member] | IPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [1] |  | 38
Purchased Power [Member] | WPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [1] |  | 1
Natural gas [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments |  |  | 1,017
Natural gas [Member] | IPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments |  |  | 536
Natural gas [Member] | WPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments |  |  | 481
Coal [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [2] |  | 101
Coal [Member] | IPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [2] |  | 62
Coal [Member] | WPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [2] |  | 39
Other [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [3] |  | 113
Other [Member] | IPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [3] |  | 54
Other [Member] | WPL [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Minimum future commitments | [3] |  | $ 28
Forecast [Member] | DAEC PPA [Member] |  |  |
Commitments and Contingencies [Line Items] |  |  |
Buyout payment |  | $ 110 |
[1] | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. As a result of an amendment to shorten the term of the DAEC PPA, Alliant Energy’s and IPL’s amounts include minimum future commitments related to IPL’s purchase of capacity and the resulting energy from DAEC through September 2020, and do not include the September 2020 buyout payment of $110 million.
[2] | Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of June 30, 2020 regarding expected future usage, which is subject to change.
[3] | Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2020.

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- Definition Individual commitments incurred in excess of $1 million + References No definition available. + Details
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- Definition Long-term Contract for Purchase of Electric Power, Buyout Payment + References No definition available. + Details
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- Definition The minimum amount the entity agreed to spend under the long-term purchase commitment. + References No definition available. + Details
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- Details
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- Details
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