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Commitments And Contingencies (Tables) | 3 Months Ended
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Mar. 31, 2019
Commitments and Contingencies [Line Items] |
Other Purchase Obligations | At March 31, 2019, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $221 |  |  |  | $219 |  |  |  | $2 |
Natural gas | 879 |  |  | 388 |  |  | 491 |
Coal (b) | 163 |  |  | 96 |  |  | 67 |
Other (c) | 88 |  |  | 49 |  |  | 26 |
|  | $1,351 |  |  |  | $752 |  |  |  | $586 |
(a) | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. As a result of amendments to shorten the term of the DAEC PPA, which were approved by the IUB and effective in January 2019, 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.
(b) | Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2019 regarding expected future usage, which is subject to change.
(c) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2019.
MGP Site Estimated Future Costs And Recorded Liabilities | At March 31, 2019, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2019, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $15 |  | - | $31 |  |  | $12 |  | - | $26
Current and non-current environmental liabilities | 19 |  | 16
IPL [Member] |
Commitments and Contingencies [Line Items] |
Other Purchase Obligations | At March 31, 2019, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $221 |  |  |  | $219 |  |  |  | $2 |
Natural gas | 879 |  |  | 388 |  |  | 491 |
Coal (b) | 163 |  |  | 96 |  |  | 67 |
Other (c) | 88 |  |  | 49 |  |  | 26 |
|  | $1,351 |  |  |  | $752 |  |  |  | $586 |
(a) | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. As a result of amendments to shorten the term of the DAEC PPA, which were approved by the IUB and effective in January 2019, 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.
(b) | Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2019 regarding expected future usage, which is subject to change.
(c) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2019.
MGP Site Estimated Future Costs And Recorded Liabilities | At March 31, 2019, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2019, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $15 |  | - | $31 |  |  | $12 |  | - | $26
Current and non-current environmental liabilities | 19 |  | 16
WPL [Member] |
Commitments and Contingencies [Line Items] |
Other Purchase Obligations | At March 31, 2019, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $221 |  |  |  | $219 |  |  |  | $2 |
Natural gas | 879 |  |  | 388 |  |  | 491 |
Coal (b) | 163 |  |  | 96 |  |  | 67 |
Other (c) | 88 |  |  | 49 |  |  | 26 |
|  | $1,351 |  |  |  | $752 |  |  |  | $586 |
(a) | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. As a result of amendments to shorten the term of the DAEC PPA, which were approved by the IUB and effective in January 2019, 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.
(b) | Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2019 regarding expected future usage, which is subject to change.
(c) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2019.

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- Definition Tabular disclosure of material liabilities for remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal or abandonment of a property as a result of unanticipated contamination of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q4) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
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