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Asset Retirement Obligations | 3 Months Ended
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Mar. 31, 2015
Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations | ASSET RETIREMENT OBLIGATIONS A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Balance, January 1 |  | $114.0 |  |  |  | $109.7 |  |  |  | $51.8 |  |  |  | $47.9 |  |  |  | $52.4 |  |  |  | $52.4 |
Liabilities settled | (2.2 | ) |  | (0.5 | ) |  | (2.2 | ) |  | (0.3 | ) |  | — |  |  | (0.2 | )
Liabilities incurred | — |  |  | 16.5 |  |  | — |  |  | 16.3 |  |  | — |  |  | 0.2 |
Accretion expense | 1.0 |  |  | 1.0 |  |  | 0.4 |  |  | 0.5 |  |  | 0.4 |  |  | 0.4 |
Balance, March 31 |  | $112.8 |  |  |  | $126.7 |  |  |  | $50.0 |  |  |  | $64.4 |  |  |  | $52.8 |  |  |  | $52.8 |
CCR Rule - In April 2015, the EPA published the final CCR Rule, which regulates CCR as a non-hazardous waste and is effective October 2015. 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 expected to be impacted by this rule. Alliant Energy, IPL and WPL are currently evaluating the final CCR Rule to determine its full impact. Alliant Energy, IPL and WPL currently anticipate recognizing additional AROs in the second quarter of 2015 as a result of the final CCR Rule as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Estimated ARO increase not to exceed | $85 |  | $75 |  | $10
Expenditures incurred by IPL and WPL to comply with the CCR Rule are anticipated to be recovered in rates from their customers.
IPL [Member] |
Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations | ASSET RETIREMENT OBLIGATIONS A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Balance, January 1 |  | $114.0 |  |  |  | $109.7 |  |  |  | $51.8 |  |  |  | $47.9 |  |  |  | $52.4 |  |  |  | $52.4 |
Liabilities settled | (2.2 | ) |  | (0.5 | ) |  | (2.2 | ) |  | (0.3 | ) |  | — |  |  | (0.2 | )
Liabilities incurred | — |  |  | 16.5 |  |  | — |  |  | 16.3 |  |  | — |  |  | 0.2 |
Accretion expense | 1.0 |  |  | 1.0 |  |  | 0.4 |  |  | 0.5 |  |  | 0.4 |  |  | 0.4 |
Balance, March 31 |  | $112.8 |  |  |  | $126.7 |  |  |  | $50.0 |  |  |  | $64.4 |  |  |  | $52.8 |  |  |  | $52.8 |
CCR Rule - In April 2015, the EPA published the final CCR Rule, which regulates CCR as a non-hazardous waste and is effective October 2015. 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 expected to be impacted by this rule. Alliant Energy, IPL and WPL are currently evaluating the final CCR Rule to determine its full impact. Alliant Energy, IPL and WPL currently anticipate recognizing additional AROs in the second quarter of 2015 as a result of the final CCR Rule as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Estimated ARO increase not to exceed | $85 |  | $75 |  | $10
Expenditures incurred by IPL and WPL to comply with the CCR Rule are anticipated to be recovered in rates from their customers.
WPL [Member] |
Asset Retirement Obligations [Line Items] |
Asset Retirement Obligations | ASSET RETIREMENT OBLIGATIONS A reconciliation of the changes in AROs associated with long-lived assets is as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014 |  | 2015 |  | 2014
Balance, January 1 |  | $114.0 |  |  |  | $109.7 |  |  |  | $51.8 |  |  |  | $47.9 |  |  |  | $52.4 |  |  |  | $52.4 |
Liabilities settled | (2.2 | ) |  | (0.5 | ) |  | (2.2 | ) |  | (0.3 | ) |  | — |  |  | (0.2 | )
Liabilities incurred | — |  |  | 16.5 |  |  | — |  |  | 16.3 |  |  | — |  |  | 0.2 |
Accretion expense | 1.0 |  |  | 1.0 |  |  | 0.4 |  |  | 0.5 |  |  | 0.4 |  |  | 0.4 |
Balance, March 31 |  | $112.8 |  |  |  | $126.7 |  |  |  | $50.0 |  |  |  | $64.4 |  |  |  | $52.8 |  |  |  | $52.8 |
CCR Rule - In April 2015, the EPA published the final CCR Rule, which regulates CCR as a non-hazardous waste and is effective October 2015. 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 expected to be impacted by this rule. Alliant Energy, IPL and WPL are currently evaluating the final CCR Rule to determine its full impact. Alliant Energy, IPL and WPL currently anticipate recognizing additional AROs in the second quarter of 2015 as a result of the final CCR Rule as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
Estimated ARO increase not to exceed | $85 |  | $75 |  | $10
Expenditures incurred by IPL and WPL to comply with the CCR Rule are anticipated to be recovered in rates from their customers.

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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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