XML 22 R35.htm IDEA: XBRL DOCUMENT
v3.19.3

Commitments And Contingencies (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2019
Commitments and Contingencies [Line Items] |
Other Purchase Commitments | At September 30, 2019, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $145 |  |  |  | $144 |  |  |  | $1 |
Natural gas | 892 |  |  | 460 |  |  | 432 |
Coal (b) | 117 |  |  | 76 |  |  | 41 |
Other (c) | 76 |  |  | 43 |  |  | 24 |
|  | $1,230 |  |  |  | $723 |  |  |  | $498 |
(a) | 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.
(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, 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 September 30, 2019.
MGP Site Estimated Future Costs And Recorded Liabilities | At September 30, 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 September 30, 2019, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $14 |  | - | $31 |  |  | $12 |  | - | $25
Current and non-current environmental liabilities | 19 |  | 16
IPL [Member] |
Commitments and Contingencies [Line Items] |
Other Purchase Commitments | At September 30, 2019, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $145 |  |  |  | $144 |  |  |  | $1 |
Natural gas | 892 |  |  | 460 |  |  | 432 |
Coal (b) | 117 |  |  | 76 |  |  | 41 |
Other (c) | 76 |  |  | 43 |  |  | 24 |
|  | $1,230 |  |  |  | $723 |  |  |  | $498 |
(a) | 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.
(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, 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 September 30, 2019.
MGP Site Estimated Future Costs And Recorded Liabilities | At September 30, 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 September 30, 2019, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $14 |  | - | $31 |  |  | $12 |  | - | $25
Current and non-current environmental liabilities | 19 |  | 16
WPL [Member] |
Commitments and Contingencies [Line Items] |
Other Purchase Commitments | At September 30, 2019, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $145 |  |  |  | $144 |  |  |  | $1 |
Natural gas | 892 |  |  | 460 |  |  | 432 |
Coal (b) | 117 |  |  | 76 |  |  | 41 |
Other (c) | 76 |  |  | 43 |  |  | 24 |
|  | $1,230 |  |  |  | $723 |  |  |  | $498 |
(a) | 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.
(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, 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 September 30, 2019.

X
- 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://fasb.org/us-gaap/role/ref/legacyRef -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
Name: | us-gaap_EnvironmentalExitCostsByCostTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_LongTermPurchaseCommitmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of key provisions of an arrangement under which the entity has agreed to purchase goods or services over a period of time greater than one year or the normal operating cycle, if longer, including the item for which expenditures will be made, minimum quantities, milestones, time period and committed amount. + References No definition available. + Details
Name: | us-gaap_LongTermPurchaseCommitmentTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=lnt_IplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=lnt_WplMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |