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Jointly-Owned Electric Utility Plant (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2013
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Jointly Owned Electric Utility Plant [Line Items] |
Electric Plant | $ 870.6
Accumulated Provision for Depreciation | 466.4
Construction Work in Progress | 485.6
Cost Of Removal Obligations Included In Regulatory Liabilities | 45.9
IPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
Electric Plant | 521.9
Accumulated Provision for Depreciation | 255.4
Construction Work in Progress | 214.4
Cost Of Removal Obligations Included In Regulatory Liabilities | 33.5
WPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
Electric Plant | 348.7
Accumulated Provision for Depreciation | 211.0
Construction Work in Progress | 271.2
Cost Of Removal Obligations Included In Regulatory Liabilities | 12.4
Ottumwa Unit 1 [Member] | IPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
In-service Dates | 1981
Ownership Interest % | 48.00%
Electric Plant | 246.8
Accumulated Provision for Depreciation | 125.3
Construction Work in Progress | 154.6
Cost Of Removal Obligations Included In Regulatory Liabilities | 12.8
George Neal Unit 4 [Member] | IPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
In-service Dates | 1979
Ownership Interest % | 25.70%
Electric Plant | 180.4
Accumulated Provision for Depreciation | 70.1
Construction Work in Progress | 0.6
Cost Of Removal Obligations Included In Regulatory Liabilities | 11.8
George Neal Unit 3 [Member] | IPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
In-service Dates | 1975
Ownership Interest % | 28.00%
Electric Plant | 59.5
Accumulated Provision for Depreciation | 40.3
Construction Work in Progress | 59.1
Cost Of Removal Obligations Included In Regulatory Liabilities | 5.7
Louisa Unit 1 [Member] | IPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
In-service Dates | 1983
Ownership Interest % | 4.00%
Electric Plant | 35.2
Accumulated Provision for Depreciation | 19.7
Construction Work in Progress | 0.1
Cost Of Removal Obligations Included In Regulatory Liabilities | 3.2
Columbia Units 1-2 [Member] | WPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
In-service Dates | 1975-1978
Ownership Interest % | 46.20%
Electric Plant | 255.5
Accumulated Provision for Depreciation | 159.4
Construction Work in Progress | 270.5
Cost Of Removal Obligations Included In Regulatory Liabilities | 10.1
Edgewater Unit 4 [Member] | WPL [Member] |
Jointly Owned Electric Utility Plant [Line Items] |
In-service Dates | 1969
Ownership Interest % | 68.20%
Electric Plant | 93.2
Accumulated Provision for Depreciation | 51.6
Construction Work in Progress | 0.7
Cost Of Removal Obligations Included In Regulatory Liabilities | $ 2.3

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- Definition Jointly Owned Utility Plant In-Service Dates + References No definition available. + Details
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- Definition The period end amount owned by the reporting utility of a jointly owned utility plant in service. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 10 -Section C + Details
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- Definition The period end amount of construction work in progress at a jointly owned electricity generation plant. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 10 -Section C + Details
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- Definition The period end amount of accumulated depreciation in a jointly owned electricity generation plant. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 10 -Section C + Details
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- Definition The proportionate share of interest (percent) in a jointly owned utility plant. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 10 -Section C + Details
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