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Income Taxes (Schedule Of Effective Income Tax Rates) (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
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 | (10.10%) | (11.90%) | (9.10%) | (8.20%)
IPL's tax benefit riders | (8.30%) | (13.10%) | (8.10%) | (10.20%)
Production tax credits | (6.20%) | (9.00%) | (6.00%) | (7.20%)
Other items, net | 2.80% | 4.40% | 3.10% | 3.50%
Overall income tax rate | 13.20% | 5.40% | 14.90% | 12.90%
IPL [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 | (22.60%) | (16.50%) | (20.60%) | (14.80%)
IPL's tax benefit riders | (20.90%) | (20.10%) | (20.10%) | (19.60%)
Production tax credits | (7.00%) | (6.00%) | (6.80%) | (6.10%)
Other items, net | 2.30% | 5.40% | 2.70% | 4.20%
Overall income tax rate | (13.20%) | (2.20%) | (9.80%) | (1.30%)
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 | (1.90%) | (0.70%) | (1.80%) | (0.80%)
Production tax credits | (7.00%) | (5.70%) | (7.00%) | (6.10%)
Other items, net | 5.50% | 4.00% | 4.90% | 4.40%
Overall income tax rate | 31.60% | 32.60% | 31.10% | 32.50%

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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=65882285&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=65882285&loc=d3e32687-109319 + Details
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