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Commitments And Contingencies | 6 Months Ended
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Jun. 30, 2020
Commitments and Contingencies Disclosure | COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation. WPL’s projects include the expansion of wind and solar generation. At June 30, 2020, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $60 million, $8 million and $52 million, respectively. NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At June 30, 2020, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $39 |  |  |  | $38 |  |  |  | $1 |
Natural gas | 1,017 |  |  | 536 |  |  | 481 |
Coal (b) | 101 |  |  | 62 |  |  | 39 |
Other (c) | 113 |  |  | 54 |  |  | 28 |
|  | $1,270 |  |  |  | $690 |  |  |  | $549 |
(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 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.
(c) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2020.
NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships and currently known obligations include costs associated with the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC’s guarantees, which do not include a maximum limit, apply to the Whiting Petroleum affiliate’s obligations and to the other partners. Alliant Energy Resources, LLC may be required to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations. As of June 30, 2020, the currently known partnership obligations are the abandonment obligations. The Whiting Petroleum affiliate’s share of these abandonment obligations on an undiscounted basis is estimated at $63 million as of June 30, 2020 based on information made available to Alliant Energy by Whiting Petroleum, and this represents Alliant Energy’s best estimate of the contingent obligations for potential future payments. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020. As a result of Whiting Petroleum’s deterioration in credit worthiness since January 1, 2020 likely from significantly depressed oil and gas prices and general market conditions, Alliant Energy currently expects credit exposure related to the guarantees and has recognized a $20 million credit loss liability as of June 30, 2020 related to the contingent obligations, which is recorded in “Other liabilities” on Alliant Energy’s balance sheet. The incremental pre-tax change in the liability, $8 million, was recorded as a credit loss expense within Alliant Energy’s “Other operation and maintenance” expenses for the six months ended June 30, 2020. There was no incremental pre-tax change in the liability recorded for the three months ended June 30, 2020. Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $82 million as of June 30, 2020 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of June 30, 2020 and December 31, 2019. IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of June 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020. NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At June 30, 2020, 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 June 30, 2020, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $12 |  | - | $29 |  |  | $10 |  | - | $24
Current and non-current environmental liabilities | 16 |  | 13
IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act. NOTE 13(e) Collective Bargaining Agreements - At June 30, 2020, employees covered by collective bargaining agreements represented 53%, 60% and 82% of total employees of Alliant Energy, IPL and WPL, respectively. On August 31, 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expires, representing 18% and 44% of total employees of Alliant Energy and IPL, respectively. While the process to renew the agreement is underway and a tentative agreement has been reached, Alliant Energy and IPL are unable to predict the outcome. NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order. In the second quarter of 2020, IPL and WPL received $10 million and $3 million, respectively, in refunds related to the November 2019 FERC order. Additional refunds are currently expected to be issued; however, as a result of the May 2020 FERC order, timing is uncertain. IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.
IPL [Member] |
Commitments and Contingencies Disclosure | COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation. WPL’s projects include the expansion of wind and solar generation. At June 30, 2020, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $60 million, $8 million and $52 million, respectively. NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At June 30, 2020, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $39 |  |  |  | $38 |  |  |  | $1 |
Natural gas | 1,017 |  |  | 536 |  |  | 481 |
Coal (b) | 101 |  |  | 62 |  |  | 39 |
Other (c) | 113 |  |  | 54 |  |  | 28 |
|  | $1,270 |  |  |  | $690 |  |  |  | $549 |
(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 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.
(c) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2020.
NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships and currently known obligations include costs associated with the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC’s guarantees, which do not include a maximum limit, apply to the Whiting Petroleum affiliate’s obligations and to the other partners. Alliant Energy Resources, LLC may be required to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations. As of June 30, 2020, the currently known partnership obligations are the abandonment obligations. The Whiting Petroleum affiliate’s share of these abandonment obligations on an undiscounted basis is estimated at $63 million as of June 30, 2020 based on information made available to Alliant Energy by Whiting Petroleum, and this represents Alliant Energy’s best estimate of the contingent obligations for potential future payments. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020. As a result of Whiting Petroleum’s deterioration in credit worthiness since January 1, 2020 likely from significantly depressed oil and gas prices and general market conditions, Alliant Energy currently expects credit exposure related to the guarantees and has recognized a $20 million credit loss liability as of June 30, 2020 related to the contingent obligations, which is recorded in “Other liabilities” on Alliant Energy’s balance sheet. The incremental pre-tax change in the liability, $8 million, was recorded as a credit loss expense within Alliant Energy’s “Other operation and maintenance” expenses for the six months ended June 30, 2020. There was no incremental pre-tax change in the liability recorded for the three months ended June 30, 2020. Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $82 million as of June 30, 2020 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of June 30, 2020 and December 31, 2019. IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of June 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020. NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At June 30, 2020, 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 June 30, 2020, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $12 |  | - | $29 |  |  | $10 |  | - | $24
Current and non-current environmental liabilities | 16 |  | 13
IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act. NOTE 13(e) Collective Bargaining Agreements - At June 30, 2020, employees covered by collective bargaining agreements represented 53%, 60% and 82% of total employees of Alliant Energy, IPL and WPL, respectively. On August 31, 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expires, representing 18% and 44% of total employees of Alliant Energy and IPL, respectively. While the process to renew the agreement is underway and a tentative agreement has been reached, Alliant Energy and IPL are unable to predict the outcome. NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order. In the second quarter of 2020, IPL and WPL received $10 million and $3 million, respectively, in refunds related to the November 2019 FERC order. Additional refunds are currently expected to be issued; however, as a result of the May 2020 FERC order, timing is uncertain. IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.
WPL [Member] |
Commitments and Contingencies Disclosure | COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation. WPL’s projects include the expansion of wind and solar generation. At June 30, 2020, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $60 million, $8 million and $52 million, respectively. NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At June 30, 2020, the related minimum future commitments were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Purchased power (a) |  | $39 |  |  |  | $38 |  |  |  | $1 |
Natural gas | 1,017 |  |  | 536 |  |  | 481 |
Coal (b) | 101 |  |  | 62 |  |  | 39 |
Other (c) | 113 |  |  | 54 |  |  | 28 |
|  | $1,270 |  |  |  | $690 |  |  |  | $549 |
(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 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.
(c) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2020.
NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships and currently known obligations include costs associated with the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC’s guarantees, which do not include a maximum limit, apply to the Whiting Petroleum affiliate’s obligations and to the other partners. Alliant Energy Resources, LLC may be required to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations. As of June 30, 2020, the currently known partnership obligations are the abandonment obligations. The Whiting Petroleum affiliate’s share of these abandonment obligations on an undiscounted basis is estimated at $63 million as of June 30, 2020 based on information made available to Alliant Energy by Whiting Petroleum, and this represents Alliant Energy’s best estimate of the contingent obligations for potential future payments. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020. As a result of Whiting Petroleum’s deterioration in credit worthiness since January 1, 2020 likely from significantly depressed oil and gas prices and general market conditions, Alliant Energy currently expects credit exposure related to the guarantees and has recognized a $20 million credit loss liability as of June 30, 2020 related to the contingent obligations, which is recorded in “Other liabilities” on Alliant Energy’s balance sheet. The incremental pre-tax change in the liability, $8 million, was recorded as a credit loss expense within Alliant Energy’s “Other operation and maintenance” expenses for the six months ended June 30, 2020. There was no incremental pre-tax change in the liability recorded for the three months ended June 30, 2020. Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $82 million as of June 30, 2020 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of June 30, 2020 and December 31, 2019. IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of June 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020. NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At June 30, 2020, 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 June 30, 2020, such amounts for WPL were not material.
| Alliant Energy |  | IPL
Range of estimated future costs |  | $12 |  | - | $29 |  |  | $10 |  | - | $24
Current and non-current environmental liabilities | 16 |  | 13
IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act. NOTE 13(e) Collective Bargaining Agreements - At June 30, 2020, employees covered by collective bargaining agreements represented 53%, 60% and 82% of total employees of Alliant Energy, IPL and WPL, respectively. On August 31, 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expires, representing 18% and 44% of total employees of Alliant Energy and IPL, respectively. While the process to renew the agreement is underway and a tentative agreement has been reached, Alliant Energy and IPL are unable to predict the outcome. NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order. In the second quarter of 2020, IPL and WPL received $10 million and $3 million, respectively, in refunds related to the November 2019 FERC order. Additional refunds are currently expected to be issued; however, as a result of the May 2020 FERC order, timing is uncertain. IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.

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