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Income Taxes (Schedule Of Components Of Income Tax) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Current tax expense (benefit): |  |  |
Federal | $ 4.4 | $ (29.3) | $ 58.6
State | (3.6) | 11.6 | 15.7
Deferred tax expense (benefit): |  |  |
Federal | 123.9 | 157.8 | 99.0
State | 15.6 | 23.9 | (16.8)
Production tax credits | (31.0) | (24.8) | (27.1)
Investment tax credits | (1.6) | (1.7) | (1.8)
Provision recorded as a change in uncertain tax positions, current | 0 | 8.0 | 16.3
Provision recorded as a change in uncertain tax positions, deferred | (0.4) | (7.6) | (38.3)
Provision recorded as a change in accrued interest | (0.5) | (0.2) | (0.5)
Income tax expense (benefit) | 53.9 | 89.4 | 69.2
IPL's tax benefit riders [Member] |  |  |
Current tax expense (benefit): |  |  |
IPL's tax benefit riders | (52.9) | (48.3) | (35.9)
IPL [Member] |  |  |
Current tax expense (benefit): |  |  |
Federal | 11.7 | (7.7) | 54.5
State | (0.1) | 9.1 | 20.0
Deferred tax expense (benefit): |  |  |
Federal | 20.0 | 37.4 | (11.6)
State | (0.8) | 3.2 | (16.4)
Production tax credits | (14.4) | (12.5) | (12.3)
Investment tax credits | (0.6) | (0.6) | (0.6)
Provision recorded as a change in uncertain tax positions, current | 0 | 8.1 | 16.6
Provision recorded as a change in uncertain tax positions, deferred | 0 | (8.2) | (17.6)
Provision recorded as a change in accrued interest | (0.8) | (0.3) | (0.3)
Income tax expense (benefit) | (37.9) | (19.8) | (3.6)
IPL [Member] | IPL's tax benefit riders [Member] |  |  |
Current tax expense (benefit): |  |  |
IPL's tax benefit riders | (52.9) | (48.3) | (35.9)
WPL [Member] |  |  |
Current tax expense (benefit): |  |  |
Federal | (5.7) | 7.2 | (4.3)
State | 6.0 | (0.9) | (7.1)
Deferred tax expense (benefit): |  |  |
Federal | 92.7 | 81.1 | 111.3
State | 11.8 | 20.3 | 19.0
Production tax credits | (16.6) | (12.3) | (14.8)
Investment tax credits | (1.0) | (1.1) | (1.2)
Provision recorded as a change in uncertain tax positions, current | 0 | (0.1) | (0.3)
Provision recorded as a change in uncertain tax positions, deferred | (0.4) | 0.6 | (20.7)
Provision recorded as a change in accrued interest | 0.4 | (0.2) | 0
Income tax expense (benefit) | $ 87.2 | $ 94.6 | $ 81.9

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- Definition Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I.7) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Current Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6509736 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319 Reference 4: 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)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 6 -Section I -Paragraph Question 1-7 + Details
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