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Business Segment Information (Schedule Of Operating Income Derived From Revenues And Expenses By Segment) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2016 | Sep. 30, 2015
Segment Reporting Information [Line Items] |  |  |  |
Revenues | $ 861.3 | $ 817.2 | $ 3,195.5 | $ 3,554.0
Consolidated Operating Income (Loss) | 113.7 | 109.7 | 633.3 | 580.4
Gas Distribution Operations |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 395.5 | 384.7 | 1,945.2 | 2,349.7
Consolidated Operating Income (Loss) | 4.3 | 20.0 | 392.7 | 394.9
Gas Distribution Operations | Unaffiliated |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 392.4 | 384.6 | 1,935.6 | 2,349.3
Gas Distribution Operations | Intersegment |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 3.1 | 0.1 | 9.6 | 0.4
Electric Operations |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 465.8 | 428.6 | 1,249.8 | 1,200.1
Consolidated Operating Income (Loss) | 112.8 | 98.5 | 251.5 | 214.2
Electric Operations | Unaffiliated |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 465.4 | 428.4 | 1,249.2 | 1,199.5
Electric Operations | Intersegment |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 0.4 | 0.2 | 0.6 | 0.6
Corporate and Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 104.0 | 98.3 | 308.8 | 293.3
Consolidated Operating Income (Loss) | (3.4) | (8.8) | (10.9) | (28.7)
Corporate and Other | Unaffiliated |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 3.5 | 4.2 | 10.7 | 5.2
Corporate and Other | Intersegment |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 100.5 | 94.1 | 298.1 | 288.1
Eliminations |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | $ (104.0) | $ (94.4) | $ (308.3) | $ (289.1)

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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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