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Commitments And Contingencies (Other Purchase Commitments) (Details) - USD ($) $ in Millions | 1 Months Ended |
--- | --- | ---
Sep. 30, 2020 | Dec. 31, 2019
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | $ 499
Minimum future commitments, 2021 |  |  | 223
Minimum future commitments, 2022 |  |  | 160
Minimum future commitments, 2023 |  |  | 128
Minimum future commitments, 2024 |  |  | 84
Minimum future commitments, Thereafter |  |  | 199
Minimum future commitments, Total |  |  | 1,293
Individual commitments incurred |  |  | 1
Purchased Power [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [1] |  | 111
Minimum future commitments, 2021 | [1] |  | 0
Minimum future commitments, 2022 | [1] |  | 0
Minimum future commitments, 2023 | [1] |  | 0
Minimum future commitments, 2024 | [1] |  | 0
Minimum future commitments, Thereafter | [1] |  | 0
Minimum future commitments, Total | [1] |  | 111
Natural Gas [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | 257
Minimum future commitments, 2021 |  |  | 183
Minimum future commitments, 2022 |  |  | 139
Minimum future commitments, 2023 |  |  | 109
Minimum future commitments, 2024 |  |  | 77
Minimum future commitments, Thereafter |  |  | 187
Minimum future commitments, Total |  |  | 952
Coal [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [2] |  | 75
Minimum future commitments, 2021 | [2] |  | 27
Minimum future commitments, 2022 | [2] |  | 10
Minimum future commitments, 2023 | [2] |  | 10
Minimum future commitments, 2024 | [2] |  | 0
Minimum future commitments, Thereafter | [2] |  | 0
Minimum future commitments, Total | [2] |  | 122
Other [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [3] |  | 56
Minimum future commitments, 2021 | [3] |  | 13
Minimum future commitments, 2022 | [3] |  | 11
Minimum future commitments, 2023 | [3] |  | 9
Minimum future commitments, 2024 | [3] |  | 7
Minimum future commitments, Thereafter | [3] |  | 12
Minimum future commitments, Total | [3] |  | 108
IPL [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | 315
Minimum future commitments, 2021 |  |  | 126
Minimum future commitments, 2022 |  |  | 91
Minimum future commitments, 2023 |  |  | 80
Minimum future commitments, 2024 |  |  | 56
Minimum future commitments, Thereafter |  |  | 99
Minimum future commitments, Total |  |  | 767
IPL [Member] | Purchased Power [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [1] |  | 110
Minimum future commitments, 2021 | [1] |  | 0
Minimum future commitments, 2022 | [1] |  | 0
Minimum future commitments, 2023 | [1] |  | 0
Minimum future commitments, 2024 | [1] |  | 0
Minimum future commitments, Thereafter | [1] |  | 0
Minimum future commitments, Total | [1] |  | 110
IPL [Member] | Natural Gas [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | 135
Minimum future commitments, 2021 |  |  | 101
Minimum future commitments, 2022 |  |  | 77
Minimum future commitments, 2023 |  |  | 67
Minimum future commitments, 2024 |  |  | 55
Minimum future commitments, Thereafter |  |  | 89
Minimum future commitments, Total |  |  | 524
IPL [Member] | Coal [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [2] |  | 46
Minimum future commitments, 2021 | [2] |  | 21
Minimum future commitments, 2022 | [2] |  | 10
Minimum future commitments, 2023 | [2] |  | 10
Minimum future commitments, 2024 | [2] |  | 0
Minimum future commitments, Thereafter | [2] |  | 0
Minimum future commitments, Total | [2] |  | 87
IPL [Member] | Other [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [3] |  | 24
Minimum future commitments, 2021 | [3] |  | 4
Minimum future commitments, 2022 | [3] |  | 4
Minimum future commitments, 2023 | [3] |  | 3
Minimum future commitments, 2024 | [3] |  | 1
Minimum future commitments, Thereafter | [3] |  | 10
Minimum future commitments, Total | [3] |  | 46
WPL [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | 176
Minimum future commitments, 2021 |  |  | 89
Minimum future commitments, 2022 |  |  | 63
Minimum future commitments, 2023 |  |  | 43
Minimum future commitments, 2024 |  |  | 23
Minimum future commitments, Thereafter |  |  | 99
Minimum future commitments, Total |  |  | 493
WPL [Member] | Purchased Power [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | 1
Minimum future commitments, 2021 |  |  | 0
Minimum future commitments, 2022 |  |  | 0
Minimum future commitments, 2023 |  |  | 0
Minimum future commitments, 2024 |  |  | 0
Minimum future commitments, Thereafter |  |  | 0
Minimum future commitments, Total |  |  | 1
WPL [Member] | Natural Gas [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 |  |  | 122
Minimum future commitments, 2021 |  |  | 82
Minimum future commitments, 2022 |  |  | 62
Minimum future commitments, 2023 |  |  | 42
Minimum future commitments, 2024 |  |  | 22
Minimum future commitments, Thereafter |  |  | 98
Minimum future commitments, Total |  |  | 428
WPL [Member] | Coal [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [2] |  | 29
Minimum future commitments, 2021 | [2] |  | 6
Minimum future commitments, 2022 | [2] |  | 0
Minimum future commitments, 2023 | [2] |  | 0
Minimum future commitments, 2024 | [2] |  | 0
Minimum future commitments, Thereafter | [2] |  | 0
Minimum future commitments, Total | [2] |  | 35
WPL [Member] | Other [Member] |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Minimum future commitments, 2020 | [3] |  | 24
Minimum future commitments, 2021 | [3] |  | 1
Minimum future commitments, 2022 | [3] |  | 1
Minimum future commitments, 2023 | [3] |  | 1
Minimum future commitments, 2024 | [3] |  | 1
Minimum future commitments, Thereafter | [3] |  | 1
Minimum future commitments, Total | [3] |  | $ 29
Forecast [Member] | DAEC PPA [Member] |  |  |
Long-term Purchase Commitment [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 December 31, 2019 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 December 31, 2019.

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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 Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement maturing after the fifth fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement maturing in the fifth fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement maturing in the fourth fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement maturing in the next fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement maturing in the second fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments. + References No definition available. + Details
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- Definition Minimum amount of purchase arrangement maturing in the third fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments. + References No definition available. + Details
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