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Income Taxes (Schedule Of Effective Income Tax Rates) (Details) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014
Effective Tax Rate [Line Items] |  |  |  |
Statutory federal income tax rate | 35.00% | 35.00% | 35.00% | 35.00%
IPL's tax benefit riders | (10.60%) | (11.90%) | (10.20%) | (11.90%)
Effect of rate-making on property-related differences | (8.40%) | (4.80%) | (7.00%) | (5.10%)
Production tax credits | (6.50%) | (6.10%) | (6.40%) | (6.50%)
Other items, net | 4.10% | 4.80% | 4.30% | 4.70%
Overall income tax rate | 13.60% | 17.00% | 15.70% | 16.20%
IPL [Member] |  |  |  |
Effective Tax Rate [Line Items] |  |  |  |
Statutory federal income tax rate | 35.00% | 35.00% | 35.00% | 35.00%
IPL's tax benefit riders | (25.30%) | (36.60%) | (25.20%) | (32.80%)
Effect of rate-making on property-related differences | (22.30%) | (14.40%) | (16.60%) | (13.00%)
Production tax credits | (7.20%) | (8.00%) | (7.20%) | (8.20%)
Other items, net | 4.10% | 4.60% | 4.20% | 4.60%
Overall income tax rate | (15.70%) | (19.40%) | (9.80%) | (14.40%)
WPL [Member] |  |  |  |
Effective Tax Rate [Line Items] |  |  |  |
Statutory federal income tax rate | 35.00% | 35.00% | 35.00% | 35.00%
Effect of rate-making on property-related differences | (0.70%) | (0.20%) | (0.60%) | (0.70%)
Production tax credits | (6.70%) | (5.80%) | (6.40%) | (6.20%)
Other items, net | 4.60% | 5.00% | 4.70% | 4.90%
Overall income tax rate | 32.20% | 34.00% | 32.70% | 33.00%

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- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 2 -Article 4 + Details
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