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Asset Retirement Obligations | 12 Months Ended
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Dec. 31, 2014
Schedule of Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations (AROs) | ASSET RETIREMENT OBLIGATIONS Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind projects, certain ash ponds, active ash landfills, certain coal yards and above ground storage tanks. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Balance, January 1 |  | $109.7 |  |  |  | $101.5 |  |  |  | $47.9 |  |  |  | $45.5 |  |  |  | $52.4 |  |  |  | $46.9 |
Revisions in estimated cash flows | — |  |  | 5.6 |  |  | — |  |  | 0.1 |  |  | — |  |  | 5.5 |
Liabilities settled | (3.4 | ) |  | (2.3 | ) |  | (1.4 | ) |  | (0.6 | ) |  | (2.0 | ) |  | (1.7 | )
Liabilities incurred | 3.7 |  |  | 1.2 |  |  | 3.5 |  |  | 1.2 |  |  | 0.2 |  |  | — |
Accretion expense | 4.0 |  |  | 3.7 |  |  | 1.8 |  |  | 1.7 |  |  | 1.8 |  |  | 1.7 |
Balance, December 31 |  | $114.0 |  |  |  | $109.7 |  |  |  | $51.8 |  |  |  | $47.9 |  |  |  | $52.4 |  |  |  | $52.4 |
In addition, certain AROs related to EGU assets have not been recognized. Due to an indeterminate remediation date, the fair values of the AROs for these assets cannot be currently estimated. A liability for these AROs will be recorded when fair value is determinable. Removal costs of these EGUs are being recovered in rates and are recorded in regulatory liabilities. In December 2014, the EPA issued the final CCR rule, which regulates CCR as a non-hazardous waste. IPL and WPL have current and former coal-fired EGUs with existing coal ash surface impoundments, as well as active CCR company-owned landfills that are impacted by this rule. Alliant Energy, IPL and WPL are currently evaluating the final rule to determine the full impact of the final CCR rule, including any additional AROs that may need to be recognized in 2015 as a result of this rule. Expenditures incurred by IPL and WPL to comply with the CCR rule are anticipated to be recovered in rates from their customers. Refer to Note 16(e) for further discussion of the final CCR rule.
IPL [Member] |
Schedule of Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations (AROs) | ASSET RETIREMENT OBLIGATIONS Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind projects, certain ash ponds, active ash landfills, certain coal yards and above ground storage tanks. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Balance, January 1 |  | $109.7 |  |  |  | $101.5 |  |  |  | $47.9 |  |  |  | $45.5 |  |  |  | $52.4 |  |  |  | $46.9 |
Revisions in estimated cash flows | — |  |  | 5.6 |  |  | — |  |  | 0.1 |  |  | — |  |  | 5.5 |
Liabilities settled | (3.4 | ) |  | (2.3 | ) |  | (1.4 | ) |  | (0.6 | ) |  | (2.0 | ) |  | (1.7 | )
Liabilities incurred | 3.7 |  |  | 1.2 |  |  | 3.5 |  |  | 1.2 |  |  | 0.2 |  |  | — |
Accretion expense | 4.0 |  |  | 3.7 |  |  | 1.8 |  |  | 1.7 |  |  | 1.8 |  |  | 1.7 |
Balance, December 31 |  | $114.0 |  |  |  | $109.7 |  |  |  | $51.8 |  |  |  | $47.9 |  |  |  | $52.4 |  |  |  | $52.4 |
In addition, certain AROs related to EGU assets have not been recognized. Due to an indeterminate remediation date, the fair values of the AROs for these assets cannot be currently estimated. A liability for these AROs will be recorded when fair value is determinable. Removal costs of these EGUs are being recovered in rates and are recorded in regulatory liabilities. In December 2014, the EPA issued the final CCR rule, which regulates CCR as a non-hazardous waste. IPL and WPL have current and former coal-fired EGUs with existing coal ash surface impoundments, as well as active CCR company-owned landfills that are impacted by this rule. Alliant Energy, IPL and WPL are currently evaluating the final rule to determine the full impact of the final CCR rule, including any additional AROs that may need to be recognized in 2015 as a result of this rule. Expenditures incurred by IPL and WPL to comply with the CCR rule are anticipated to be recovered in rates from their customers. Refer to Note 16(e) for further discussion of the final CCR rule.
WPL [Member] |
Schedule of Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations (AROs) | ASSET RETIREMENT OBLIGATIONS Recognized AROs relate to legal obligations for the removal, closure or dismantlement of several assets including, but not limited to, wind projects, certain ash ponds, active ash landfills, certain coal yards and above ground storage tanks. Recognized AROs also include legal obligations for the management and final disposition of asbestos and polychlorinated biphenyls. AROs are recorded in “Other liabilities” on the balance sheets. Refer to Note 2 for information regarding regulatory assets related to AROs. A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Balance, January 1 |  | $109.7 |  |  |  | $101.5 |  |  |  | $47.9 |  |  |  | $45.5 |  |  |  | $52.4 |  |  |  | $46.9 |
Revisions in estimated cash flows | — |  |  | 5.6 |  |  | — |  |  | 0.1 |  |  | — |  |  | 5.5 |
Liabilities settled | (3.4 | ) |  | (2.3 | ) |  | (1.4 | ) |  | (0.6 | ) |  | (2.0 | ) |  | (1.7 | )
Liabilities incurred | 3.7 |  |  | 1.2 |  |  | 3.5 |  |  | 1.2 |  |  | 0.2 |  |  | — |
Accretion expense | 4.0 |  |  | 3.7 |  |  | 1.8 |  |  | 1.7 |  |  | 1.8 |  |  | 1.7 |
Balance, December 31 |  | $114.0 |  |  |  | $109.7 |  |  |  | $51.8 |  |  |  | $47.9 |  |  |  | $52.4 |  |  |  | $52.4 |
In addition, certain AROs related to EGU assets have not been recognized. Due to an indeterminate remediation date, the fair values of the AROs for these assets cannot be currently estimated. A liability for these AROs will be recorded when fair value is determinable. Removal costs of these EGUs are being recovered in rates and are recorded in regulatory liabilities. In December 2014, the EPA issued the final CCR rule, which regulates CCR as a non-hazardous waste. IPL and WPL have current and former coal-fired EGUs with existing coal ash surface impoundments, as well as active CCR company-owned landfills that are impacted by this rule. Alliant Energy, IPL and WPL are currently evaluating the final rule to determine the full impact of the final CCR rule, including any additional AROs that may need to be recognized in 2015 as a result of this rule. Expenditures incurred by IPL and WPL to comply with the CCR rule are anticipated to be recovered in rates from their customers. Refer to Note 16(e) for further discussion of the final CCR rule.

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- Definition The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7569-110849 + Details
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