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Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | $ 717.2 | $ 750.3 | $ 1,614.6 | $ 1,703.1
Operating income (loss) | 109.0 | 103.3 | 261.9 | 257.5
Income from continuing operations, net of tax | 68.9 | 62.1 | 165.5 | 170.1
Loss from discontinued operations, net of tax | (1.3) | (0.3) | (1.3) | (0.3)
Net income (loss) attributable to common shareowners | 67.6 | 61.8 | 164.2 | 169.8
IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 382.2 | 411.9 | 871.2 | 940.8
Operating income (loss) | 33.8 | 34.0 | 99.3 | 91.5
Net income (loss) attributable to common shareowners | 16.7 | 18.4 | 64.5 | 61.8
WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 324.7 | 324.5 | 721.8 | 734.9
Operating income (loss) | 68.3 | 60.0 | 149.1 | 147.7
Net income (loss) attributable to common shareowners | 39.0 | 34.6 | 83.6 | 89.4
Electric [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 640.4 | 643.9 | 1,311.7 | 1,319.7
Operating income (loss) | 100.9 | 89.1 | 205.6 | 183.4
Electric [Member] | IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 339.4 | 354.6 | 702.0 | 728.8
Operating income (loss) | 33.9 | 29.0 | 74.2 | 55.5
Electric [Member] | WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 301.0 | 289.3 | 609.7 | 590.9
Operating income (loss) | 67.0 | 60.1 | 131.4 | 127.9
Gas [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 51.7 | 76.9 | 250.1 | 317.6
Operating income (loss) | (2.0) | 2.7 | 34.3 | 45.7
Gas [Member] | IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 29.8 | 43.7 | 141.0 | 179.4
Operating income (loss) | (2.4) | 1.6 | 18.2 | 24.9
Gas [Member] | WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 21.9 | 33.2 | 109.1 | 138.2
Operating income (loss) | 0.4 | 1.1 | 16.1 | 20.8
Other Utilities [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 14.8 | 15.6 | 31.2 | 38.4
Operating income (loss) | 3.2 | 2.2 | 8.5 | 10.1
Other Utilities [Member] | IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 13.0 | 13.6 | 28.2 | 32.6
Operating income (loss) | 2.3 | 3.4 | 6.9 | 11.1
Other Utilities [Member] | WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 1.8 | 2.0 | 3.0 | 5.8
Operating income (loss) | 0.9 | (1.2) | 1.6 | (1.0)
Utilities Business [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 706.9 | 736.4 | 1,593.0 | 1,675.7
Operating income (loss) | 102.1 | 94.0 | 248.4 | 239.2
Income from continuing operations, net of tax | 55.7 | 53.0 | 148.1 | 151.2
Loss from discontinued operations, net of tax | 0.0 | 0.0 | 0.0 | 0.0
Net income (loss) attributable to common shareowners | 55.7 | 53.0 | 148.1 | 151.2
Non-Regulated [Member] | Other Segments [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Operating revenues | 10.3 | 13.9 | 21.6 | 27.4
Operating income (loss) | 6.9 | 9.3 | 13.5 | 18.3
Income from continuing operations, net of tax | 13.2 | 9.1 | 17.4 | 18.9
Loss from discontinued operations, net of tax | (1.3) | (0.3) | (1.3) | (0.3)
Net income (loss) attributable to common shareowners | $ 11.9 | $ 8.8 | $ 16.1 | $ 18.6

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