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Commitments And Contingencies (Narrative) (Details) $ in Millions | 9 Months Ended
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Sep. 30, 2015 USD ($) site
Commitments and Contingencies [Line Items] |
Minimum future commitments | $ 2,315
Performance guarantees outstanding | 123
Present value abandonment obligation | 27
Maximum indemnification limit | 17
IPL [Member] |
Commitments and Contingencies [Line Items] |
Minimum future commitments | $ 1,861
Number of sites monitoring and remediating (in sites) | site | 24
WPL [Member] |
Commitments and Contingencies [Line Items] |
Minimum future commitments | $ 454
Number of sites monitoring and remediating (in sites) | site | 5
Capital Purchase Obligation [Member] |
Commitments and Contingencies [Line Items] |
Minimum future commitments | $ 27
Capital Purchase Obligation [Member] | IPL [Member] |
Commitments and Contingencies [Line Items] |
Minimum future commitments | 8
Capital Purchase Obligation [Member] | WPL [Member] |
Commitments and Contingencies [Line Items] |
Minimum future commitments | 19
Performance guarantees outstanding, 2016 [Member] |
Commitments and Contingencies [Line Items] |
Performance guarantees outstanding | 48
Performance guarantees outstanding, 2017 [Member] |
Commitments and Contingencies [Line Items] |
Performance guarantees outstanding | 75
Civil Penalty [Member] | IPL [Member] |
Commitments and Contingencies [Line Items] |
Environmental mitigation projects to be completed, value | 1
Environmental Issue [Member] | IPL [Member] |
Commitments and Contingencies [Line Items] |
Environmental mitigation projects to be completed, value | 6
Environmental Issue [Member] | WPL [Member] |
Commitments and Contingencies [Line Items] |
Environmental mitigation projects to be completed, value | $ 7
Minimum [Member] |
Commitments and Contingencies [Line Items] |
Warranty period | 12 months
Maximum [Member] |
Commitments and Contingencies [Line Items] |
Warranty period | 60 months

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- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248 + Details
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- Definition Amount of damages awarded to the plaintiff in the legal matter. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349 + Details
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