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Commitments And Contingencies (Tables) | 9 Months Ended
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Sep. 30, 2018
Commitments and Contingencies [Line Items] |
Other Purchase Obligations | At September 30, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $1,089 |  |  |  | $1,063 |  |  |  | $26 |
Natural gas | 921 |  |  | 394 |  |  | 527 |
Coal (b) | 169 |  |  | 84 |  |  | 85 |
Other (c) | 43 |  |  | 24 |  |  | 5 |
|  | $2,222 |  |  |  | $1,565 |  |  |  | $643 |
(a) | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. 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 December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment.
(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 September 30, 2018 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 September 30, 2018.
MGP Site Estimated Future Costs And Recorded Liabilities | At September 30, 2018, 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 September 30, 2018, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $11 |  | - | $29 |  |  | $9 |  | - | $25
Current and non-current environmental liabilities | 16 |  | 13
IPL [Member] |
Commitments and Contingencies [Line Items] |
Other Purchase Obligations | At September 30, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $1,089 |  |  |  | $1,063 |  |  |  | $26 |
Natural gas | 921 |  |  | 394 |  |  | 527 |
Coal (b) | 169 |  |  | 84 |  |  | 85 |
Other (c) | 43 |  |  | 24 |  |  | 5 |
|  | $2,222 |  |  |  | $1,565 |  |  |  | $643 |
(a) | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. 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 December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment.
(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 September 30, 2018 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 September 30, 2018.
MGP Site Estimated Future Costs And Recorded Liabilities | At September 30, 2018, 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 September 30, 2018, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $11 |  | - | $29 |  |  | $9 |  | - | $25
Current and non-current environmental liabilities | 16 |  | 13
WPL [Member] |
Commitments and Contingencies [Line Items] |
Other Purchase Obligations | At September 30, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $1,089 |  |  |  | $1,063 |  |  |  | $26 |
Natural gas | 921 |  |  | 394 |  |  | 527 |
Coal (b) | 169 |  |  | 84 |  |  | 85 |
Other (c) | 43 |  |  | 24 |  |  | 5 |
|  | $2,222 |  |  |  | $1,565 |  |  |  | $643 |
(a) | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. 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 December 2025. In July 2018, IPL entered into an amendment to shorten the term of the DAEC PPA by five years in exchange for a $110 million buyout payment by IPL in September 2020, which is not included in Alliant Energy’s and IPL’s amounts. The amendment to the DAEC PPA is contingent upon IUB approval of IPL’s July 2018 application regarding recovery of the buyout payment.
(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 September 30, 2018 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 September 30, 2018.

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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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